L-1

LAKE (Colonial)

57-6-1 Colonial Applies to Model Cl Air­ (3) All plastic locks must be replaced within craft Serial Numbers 2 Through 10 Inclu­ the next 10 hours of operation with metal locks sive, and Serial Number 13. fabricated of 0.025 2024-T3 aluminum alloy Compliance required by May 1,1957. material or equivalent. To prevent unwanted extension of the land­ (Colonial Service Bulletin No. 15 covers this ing gear, a more positive lock must be installed same subject.) for the landing gear selector valve lever in 59-15-2 Colonial Applies to All Models C-l accordance with Colonial Service Bulletin No. and C-2 Aircraft. 1 dated January 25, 1957. Compliance required as indicated. 57-13-1 Colonial Applies to All Model C-l An incident has recently been experienced Aircraft. where the rivets fastening the aluminum throt­ Compliance required within next 10 hours tle control handle to the steel bell crank have of operation or July 15, 1957, whichever occurs loosened and sheared. Accordingly these two first unless already accomplished, and every 100 rivets should be inspected immediately and re­ hours' operation thereafter. placed with the following hardware if any Inspect with 10-power glass the engine pylon looseness is apparent: Two each AN 23-8 clevis side strut attaching fittings (P/N 3208-10) bolt, AN 960D10L washer, and AN 364-1032 for cracks in the weld areas. (Inspection may self-locking thin nut. In any case the rivets be readily accomplished after removal of the should be replaced with the foregoing parts fairing cuff, P/N 5400-33.) Fittings with not later than the next periodic inspection or cracks originating across the edge may be sal­ December 1, 1959, whichever comes first. vaged for use if the crack can be removed by In order to accomplish this modification it grinding to a maximum depth of y16 inch meas­ is necessary to remove the throttle from its sup­ ured in from the edge. Fittings with cracks porting bracket to change the rivets to bolts. located in areas other than the edge or in excess In addition the slot in the bracket should be of the salvage limits must be replaced. widened to allow y8-inch minimum clearance (Colonial Service Bulletin No. 4 revision 1 between the end of the bolt and the edge of the dated May 22, 1957, covers this same subject.) bracket. 59-12-5 Colonial Applies to Models C-l and (Colonial Service Bulletin No. 14 revision A C-2 Aircraft Serial Numbers 1 Through 132. covers the same subject.) Compliance required as indicated. 59-17-4 Colonial Applies to All Models C-l Due to a recent incident where the plastic and C-2 Aircraft. lock for the control surface hinge pin cracked, Compliance required within the next 10 thus making it possible for the hinge pin to hours but not later than October 15, 1959, and work out, the following inspection and replace­ at each 100 hours thereafter. ment of all plastic locks is required. Prior to Due to failures in service, remove, inspect, next flight inspect the control surface hinge pin and replace, if damaged, the two AN 4 bolts locks. attaching the wing rear spar to the hull on (1) If made of metal, no further action nec­ each side at hull Station 138. The bolts are essary. located adjacent to the inboard flap hinge and (2) If made of plastic material inspect for are accessible through the wheel wells. Re­ cracks. Parts found cracked must be replaced move only one bolt per side at a time and re­ with locks fabricated of 0.025 2021-T3 alumi­ place before removing the other bolt. The num alloy material or equivalent before fur­ torque applied to these bolts shall not exceed ther operation. 70 inch-pounds. L-2 LAKE (COLONIAL)

60-22-1 Lake (Colonial) Amdt. 213 Part (a) Replace AN 7-35 engine-to-engine 507 Federal Register October 29, 1960. Ap­ mount bolts with MS 20007-48 or NAS 464- plies to Colonial C-2 Serial Numbers 115, 7L-51 strength bolts or equivalent (4 places). 121, 126 and Subsequent. Lake Serial (b) Replace Lord Mounts P/N J-7402-1 Numbers 244 and 245. with Lord Mounts P/N J-7402-5 or -6, or Compliance required within 100 hours' time equivalent (4 places). in service after effective date of this amend­ ment. (Lake Service Bulletin Number 2 covers Due to several failures of the engine mount this same subject.) bolts, the following shall be accomplished: This directive effective November 29, 1960. L-3

LOCKHEED

46-13-1 Lockheed (Was Service Note 2 of (b) Rework the hopper assembly to pro­ AD-723-2.) Applies to All Model 18 Air­ vide better support at the sump by installing a craft. new support assembly (P/N 174321). At each When replacing the landing gear actuating engine change, remove plate and elbow on cylinder flexible hose, P/N 55252-3, the length bottom of sump housing (P/N 114690) and of ferrules should be compared. If longer fer­ inspect hopper with a light and mirror. (Lock­ rules are found on the new hoses, an elbow heed Service Bulletin No. 18-99 dated Septem­ should be inserted between the hose and the ber 29, 1943, covers this same subject.) cylinder aft port, to prevent possible damage 2. If the hopper type oil tank is to be re­ to the hose by the landing gear scissors. (Lock­ moved, the following action must be taken heed Service Letter No. 18-28, dated June 15, (applies only to Serial Numbers 2294 and up, 1945, revised December 10, 1945, covers this except Serial Numbers 2359, 2403, 2464, and same subject.) 2465): Remove the hopper type oil tank and pro­ 46-13-2 Lockheed (Was Mandatory Note peller feathering lines and replace with a 18 of AD-723-2). Applies Only to Model conventional type tank (P/N 73662), fitted 18 Airplanes Used in Scheduled Air Carrier with a standpipe to provide a reservoir of oil Operation. for propeller feathering, and install a sepa­ Compliance required not later than April rate feathering line from the oil tank to the 30, 1946. feathering pump. (Lockheed Service Bulletin In order to comply with CAR Special Reg­ No. 18-100 dated March 3, 1944, covers this ulation 333, the present fuel system plumbing same subject.) equipment shall be replaced with a dual fuel 3. On airplanes which have conventional oil system in accordance with Lockheed Service tanks other than P/N 73662, the standpipe Bulletin No. 18/SB-113, dated August 17, at the outlet in each tank must be revised in 1945, or any other dual fuel system approved one of the following manners, whichever is by the Administrator. applicable. (Applies to all Series 18 airplanes, 46-13-3 Lockheed (Was Mandatory Note except Models 18-07 and 18-40, with Serial 6 of AD-723-2.) Applies to Model 18 Air­ Numbers 2293 and below, 2359, 2403, 2464, and craft. 2465.) Compliance required before next 10 hours (a) If the tanks are equipped with the of operation. 31 standard 3 ^2-inch long standpipes (P/N The oil tanks should be examined to deter­ 164101), the standpipe in each tank should mine whether or not they are of the hopper 1 be removed and a new 4 %6-inch standpipe type, and appropriate action in one of the (P/N 16401, change D) installed. following manners must be taken: (b) If the tanks are equipped with oil 1. If a hopper type oil tank is installed and stick gage foam guards, the existing stand- is to be retained in accordance with Note 14 pipe in each tank should be cut off near the (b) of Aircraft Specification A-723-4 (for bottom of the tank, the foam guard cut off use with oil dilution), the following action approximately 5.38 inches from the bottom must be taken (applies only to Serial Numbers 2294 and up): surface of the oil tank outlet connection boss, and a new standpipe assembly (P/N 173806) (a) Install a propeller feathering reserve installed. oil tank (P/N 174399) forward of the firewall. (Lockheed Service Bulletin No. 18/SB-115 (Lockheed Service Bulletin No. 18-105 dated dated April 18, 1945, covers this same subject.) October 19, 1943, covers this same subject.) IJOCKHEED

47-10-2 Lockheed (Was Mandatory Note 47-10-6 Lockheed (Was Mandatory Note 1 of AD-763-3). Applies Only to Model 49 7 of AD-763-3.) Applies to All Model 49 Serial Numbers 2021 to 2054. Inclusive. Serials Incorporating Parker 4-1042-11-2 Compliance required prior to March 1, 1947. Plug Valves in the Fuel System. Compliance required prior to March 15, Install an AN 3161-P15 (or equivalent) 1947. non-trip-free circuit breaker in the elevator Rework all fuel tank shutoff and fuel cross tab control circuit. The breaker is to be lo­ transfer valves by installing new type shaft cated in the pilots" control stand, with access sealing rings, valve caps, packing caps, cap through a plate immediately forward of the gaskets and cap attachment screws. This re­ control quadrant. Minor wiring changes to work also applies to valves previously re­ connect the circuit breaker are also necessary. worked, as identified by the use of counter­ (LAC Service Bulletin 049 SB-4 covers this sunk head screws with star lock washers or same subject.) fillister head screws. 47-10-3 Lockheed (Was Mandatory Note (LAC Service Instruction 049/SI-74, re­ 2 of AD-763-3.) Applies Only to Model 49 vised September 9, 1946, or subsequent, covers Serial Numbers 2021 to 2079, Inclusive. this same subject.) Compliance required prior to March 1, 1947. 47-10-7 Lockheed (Was Mandatory Note 8 (Note: AD 47-10-2 must be complied with of AD-763-3.) Applies Only to Model 49 prior to or in conjunction with this Note.) Serial Numbers 2021 to 2088, Inclusive. Install non-trip-free circuit breakers in the Compliance required prior to April 1, 1947. rudder and elevator auxiliary boost motor cir­ Replace the existing restrictor valve P/N cuits, in place of switches and relays, and re­ 66404) in each main landing gear down line vise the wiring of the circuits as necessary. with a winterized type restrictor valve (LAC (LAC Service Bulletin 049 SB-22 covers this P/N 667489.) same subject.) (LAC Service Instruction 049/SL-75, covers this same subject.) 47-10-4 Lockheed (Was Mandatory Note 4 of AD-763-3.) Applies Only to" Model 47-10-8 Lockheed (Was Mandatory Note 9 49 Serial Numbers 2021. 2022. 2026, 2027, of AD-763-3.) Applies Only to Model 49 2028, 2034, and 2035. Serial Numbers 1975 to 1978, Inclusive; Compliance required prior to March 15, 1980; and 2021 to 2059, Inclusive. 1947. Compliance required prior to August 9,1946. Rework the elevator booster shifter horn Add 12 grounding jumpers between the en­ assembly by reducing the width of the teeth gine autosyn transmitters and their support on 278488 gear. 0.120 inch should be removed brackets. (LAC Service Bulletin 049 SB-20 from each end of all the teeth. covers this same subject.) (LAC Service Bulletin 049/SB-19 covers 47-10-5 Lockheed (Was Mandatory Note this same subject.) 6 of AD-763-3.) Applies Only to Model 49 47-10-9 Lockheed (Was Mandatory Note Serial Numbers 2021 to 2088, Inclusive. 11 of AD-763-3.) Applies to All Model 49 Compliance required prior to March 15, Serials Up to and Including 2088. 1947. Compliance required after each engine Inspect landing gear selector valve (Bendix change. P/N 403875-0-1) installed in forward cargo When found necessary as a result of engine compartment. Those valves bearing Serial replacement in a quick-change powerplant Numbers 1 through 120 and identified by let­ unit, add seal plates to the engine oil lines ter UR" following the serial number have been where they pass through the engine fire seals, reworked to incorporate a new type poppet. and add cover plates to the alternate oil line All unreworked valves should be replaced with cutouts in the fire seals. reworked valves. (LAC Service Instruction (LAC Service Instruction 49/51-39 and 049/SI-34 covers this same subject.) LAC Service Bulletin 49/SB-63 cover this LOCKHEED L-5 same subject for Models 49-51 and 49-46, re­ 47-10-15 Lockheed (Was Mandatory Note spectively.) 17 of AD-763-3.) Applies to All Model 49 Serials Up to and Including 2075. 47-10-10 Lockheed (Was Mandatory Note Compliance required prior to recertification. 12 of AD-763-3.) Applies to All Model 49 Prior to recertification of all aircraft whose Serials Up to and Including 2088. certificates were revoked by direction of the Compliance required immediately. Administrator on July 11, 1946, the following Remove all soundproofing pads adjacent to Service Documents must be complied with. and surrounding the voltage regulators. LOCKHEED SEBVICE BULIETINS : (LAC Service Bulletin 49/SB-171 covers *49/SB-50, revised August 24, 1946—Revision of this same subject.) Cabin Air Recirculating Fan. 49/SB-S8, dated July 22, 1946—Sealing of Main 47-10-11 Lockheed (Was Mandatory Note Landing Gear Doors. 13 of AD-763-3.) Applies to All Model 49 49/SB-86, dated July 18, 1946—Rerouting of Ther­ Serials Up to and Including 2088. mocouple Wires. *49/SB-91, revised September 10, 1946—Replace­ Compliance required not later than 200 hours ments of Electrical Power Feed—Through Studs. of operation after March 1,1947. *49/SB-93, revised August 11, 1946—Rework of Replace all Fenwal] Type S-2223 fire detec­ Exhaust System Ball Joints and Collector Segment. tor units on fire seals and firewalls and in na­ 49/SB-95, dated July 22, 1946—Insulation of Gen­ erator Circuit Breakers. celles and cabin heater compartments with (a) 49/SB-97, revised October 28, 1946—Sealing, Type 17343-3-150 fire detector units (100 units Draining, and Ventilation of Nacelles. for each Model 49-51 aircraft, 116 units for 49/SB-98, dated July 26, 1946—Removal of Engine each Model 49^6 aircraft.) Filtered Air Components and Plumbing. (LAC Service Bulletin 49/SB-65 covers this *49/SB-100, revised August 27, 1946—Replacement same subject.) of Fuel Pressure Warning Units. 49/SB-101, revised August 6, 1947—Modification 47-10-13 Lockheed (Was Mandatory Note of Hydraulic Pump Case Drain Lines. 15 AD-763-3.) Applies to All Model 49 49/SB-102, dated July 23, 1946—Relocation of En­ gine Fuel Pump Lines. Serials Up to and Including 2075. 49/SB-104, revised July 23, 1946—Replacement of Compliance required prior to July 1, 1947. Windshield Wiper Motor Circuit Fuse. (a) On all firewalls, replace aluminum alloy 49/SB-106, dated July 22, 1946—Replacement of bulkhead fittings for fuel, oil, and hydraulic Windshield Heater Wire. lines with nickel steel fittings or others of 49/SB-109, revised August 22, 1946—Provision for Vacuum Pump Cooling. equivalent fire resistance. 49/SB-113, revised August 6, 1946—Replacement (LAC Service Bulletin 49/SB-108 covers of Aluminum Electrical Wires and Terminals. this same subject.) 49/SB-114, revised July 31, 1946—Protection of (b) In nacelle zones 1 and 2 replace all tub­ Electrical Receptacle. 49/SB-115, dated July 23, 1946—Insulation of Gal­ ing having cut-length hose connections with ley Circuit Breaker. flexible coupled hose assemblies. 49/SB-116, revised August 2, 1946—Installation of (LAC Service Bulletin 49/SB-103 covers Generator Field Circuit Breaker (Switch Type). this same subject.) *49/SB-117, revised September 5, 1946—Insulation of Right Angle Electrical Terminals and Electrical 47-10-14 Lockheed (Was Mandatory Note Wiring. 16 of AD-763-3.) Applies to All Model 49 49/SB-118, revised August 10, 1946—Support of Serials Up to and Including 2088. Electrical Wiring in Main Gear Wheel Well. 49/SB-119, revised July 27, 1946—Sealing of Main Compliance required prior to April 15, 1947. Landing Gear Door Hinge. Install a single flexible hose assembly be­ 49/SB-119A, revised August 13, 1946—Sealing of tween each fuel pump and flowmeter in place Main Landing Gear Doors. of the combination of short hose assembly •Service Documents identified by an asterisk and by (a) and tube with hose couplings. have been revised subsquent to issuance Of AD-763 (Special) dated Aug. 21, 1946, aa indicated by the later revision date effective in each Instance. Aircraft previously recertiflcated (LAC Service Bulletin 49/SB-143 covers in accordance with AD-763 (Special) should be checked for compliance with these later revisions within next 200 hours this same subject.) of operations. L-6 LOCKHEED

*49/SB-121, revised September 16, 1946—Installa­ No. 58, revised August 15, 1946—Combating Belly tion of Fire Resistant Hoses and Double Hose Clamps Cargo Compartment and Fuselage Fires. ia Nacelle Zones 2 and 3. No. 60, dated August 10, 1946 (Canceled). 49/SB-122, dated July 25, 1946— Installation of TWA Engineering Order No. 2762—Rework of Aux­ Stainless Steel CO, Lines. iliary Hydraulic Supply Tank and Discharge Line. *49/SB-123, revised August 27, 1946—Replacement of Alcohol Tank, Supply Lines and Vent Line (4- 47-10-16 Lockheed (Was Mandatory Note pump system). 18 of AD-763-3.) Applies to All Model 49-46 49/SB-125, dated June 23, 1946— Removal of Cargo Serials Up to and Including 2075 and to All Compartment Insulation. Model 49-51 Airplanes. (This supersedes 49/SB-126, dated July 23, 1946—Protection of Elec­ Supplement Number 1 to AD-763 (Special) trical Junctions and Disconnects at Fire Wall. 49/SB-127, revised Jnly 31, 1946—Sealing of Cabin Dated August 26,1946.) Heater Panel. Compliance required prior to June 1, 1947. 49/SB-131, revised August 10, 1946—Rerouting of All Model 49-51 aircraft shall be converted Drain Line for Deicer Distributor Oil Separator. 49/SB-132, revised August 12, 1946—Attachment to Model 49-46 aircraft. Prior to recertifica- of Electrical Wire Bundles in Forward Passenger tion of Model 49^16 aircraft converted from Compartment Model 49-51 aircraft, the following Service 49/SR-133, revised July 31, 1946—Installation of Bulletins in addition to those listed in Note Brass Liners and Double Hose Clamps in Line Be­ 47-10-15 must be complied with: tween Sump Tank and Propeller Feathering Pump. (a) 49/SB-134, revised October 28. 1946—Installa­ "49/SB-l, revised June 7, 1946—Installation of tion of Protective Shield for Engine Tonjuemeter Two-Speed Supercharger Controls. Plumbing. *49/SB-14, revised July 27, 1946—Installation of Bendix Direct Fuel Injection System. 49/SB-135, revised August 11, 1946—Addition of 49/SB-24, dated June 5, 1946—Rework of Engine Fuselage Drain Provisions. Cowl Diaphragm Structure. 49/SB-136, dated July 31, 1946—Protection of 49/SR-124, revised July 27, 1946—Rewiring of En­ Cabin Heater Flexible Fuel Line. gine Fire Detector System. 49/SE-137, dated Jnly 27, 1646—Addition of Double Hose Clamps on Inboard Fuel Tank Interconnection Wright Aeronautical Corp, Bulletin C18-23, dated Line. October 4, 1946—Fuel Injection Tube Installation. •49/SB-138, revised September 25, 1946— Provi­ **49/SB-230, dated November 3, 1946—Engine Oil Cooler Temperature Control Regulators—Recalibra- sions for Increase of C02 Capacity. •49/SB-155, revised August 28, 1946—Installation tion of. of Copper Wires in Lieu of Aluminum Wires. *'49/36-231, dated November 2, 1946—Engine Oil "49/SB-161, dated August 29. 1946—Replacement Pump Pressure and Engine Oil Pressure Gauge Range of Alcohol Tank, Supply Lines, and Vent Line (2- Markings—Adjustment of, pump system). 47-10-17 Lockheed (Was Mandatory Note LOCKHEED SERVICE INSTBTJCTIOSS '• 19 of AD 763-3.) Applies to All Model 49 •49/SI-22, revised October 10, 1946—Installation Serials Up to and Including 2075. of Engine Plumbing and Electrical Wiring Heat Pro­ Compliance required prior to resumption tective System. *49/SI^l, revised August 16, 1946— Nacelle Fire of cabin supercharger operation. Extinguishing System Revisions. Prior to resumption of cabin supercharger 49/SI-105, revised August 7, 1946—Replacement of operation, the following Lockheed Service Bul­ Hydraulic Secondary Return Line. letins must be complied with: LOCKHEED SEEVICE INFORMATION LETTERS : 49/SB-107, revised November 22, 1946—Replace­ •No. 42, revised September 10. 1946 (Canceled). ment of Cabin Supercharger Drive Shafts. No. 56, dated August 10, 1946—Periodic Inspection 49/SB-141, revised August 7, 1946—Replacement of Vacuum Pump Pressure Hose. of Cabin Supercharger. No. 57, revised August 15, 1946—Fuselage Fire 49/SB-156, revised September 17, 1946—Installa­ Control and Smoke Elimination Procedures. tion of Supercharger Oil Temperature Indicator. •Set-vice Bulletin 49/SB-14 has been revised subsequent to issuance of AD-763 (Special), Supplement No. 1, dated Aug. 26, 1946. Model 49-46 aircraft certificated in accord­ ance with that AD Supplement should be checked for compli­ ance with this later revision within next 200 honrs ol operation. ••Service Bulletin 49/SB-l was not listed in AD-763 (Special), Supplement No. 1, dated Aug. 26, 1946, but most ••Service Bulletin 49/SB-l 61 was not called for Hi AD-763 be complied with to permit use of new performance values (Special), bat has subsequently been found necessary, inas- shown in the Operation Manual for Model 49-46 aircraft, nmeh as Bulletin 4D/SB-123 does not adequately describe Lockheed Report No. 5S17. All Model 4S-46 aircraft cer­ Changes to 2-pufflp anti-icing systems. Aircraft ineorpor- tificated in accordance with that Supplement to AD-763 atlng 2rpomp anti-icing systems shonld be checked for con­ (Special) should be checked for compliance with Bulletins formity with Bulletin 49/SB-161 prior to certification. 49/SB-l, 230 and 231 within next 200 hours of operation. LOCKHEED L-7

The revision dates given for these three Bul­ 47-10-20 Lockheed (Was Mandatory Note letins are later than those listed in the Supple­ 22 of AD-763-3.) Applies to All Model 49 ment to AD-763 (Special) dated September Serials. Up to and Including 2075. 25, 1946. Aircraft on which the cabin super­ Compliance required prior to June 1, 1947. charging equipment was rendered operative in Replace all existing alcohol tanks with new accordance with that Supplement should be type heavier tanks, LAC P/N 296424. Replace checked for compliance with these later re­ existing tank cradles with new cradles LAC visions dates within the next 150 hours of P/N 296465. operation. (LAC Sendee Bulletin 49/SB-110, revised October 2,1946, or subsequent, covers this same 47-10-18 Lockheed (Was Mandatory Note subject.) 20 of AD-763-3.) Applies to All Model 49^16 Aircraft. 47-10-21 Lockheed (Was Mandatory Note Compliance required not later than 100 23 of AD-763-3.) Applies to Model 49 hours of operation after March 1,1947, or dur­ Serials Up to and Including 2088. ing conversion of Model 49-51 aircraft to Compliance required prior to July 1, 1947. Model 49-46 aircraft, whichever occurs first. Install steel torque links, LAC P/N 293882, The hose connections in the fuel line between on each main landing gear. air metering chamber and fuel injection pump (LAC Service Instruction 49/SI-100A cov­ shall be changed to incorporate fire resistant ers this same subject.) hose and double hose clamps, using Wright 47-10-22 Lockheed (Was Mandatory Note Aeronautical Corporation P/N 856864 and 24 of AD-763-3.) Applies to Model 49 855403. Serials 1975, 1976, 1977, and 2021 Through 47-10-19 Lockheed (Was Mandatory Note 2065. 21 of AD-763-3.) Applies to All Model 49 Compliance required prior to March 1, 1947. Serials Up to and Including 2088, Except as Install steel retainer washer (American La Noted. France P/N 2CD-3054C) in place of existing Compliance required not later than 100 hours aluminum alloy retainer washer on fire ex­ of operation after June 10, 1947. tinguisher selector valve. (a) In each cabin heater installation, re­ (LAC Service Bulletin 49/SB-27 covers this locate and waterproof the fuel solenoid valve same subject.) and replace and reroute the fuel pump bypass 47-10-23 Lockheed (Was Mandatory Note line. (LAC Service Bulletin 49/SB-73 covers 25 of AD-763-3.) Applies to Model 49 this same subject.) Serials 1975, 1976, and 2021 Through 2059. (b) In zone 2 of each nacelle, install heat Compliance required immediately. protective shield between propeller feathering Install AC364-524 steel nuts in place of any line and cowl diaphragm. Applies to all AC364-B524 brass nuts which may be installed serials up to and including 2082. on bolts through bathtub fittings at wing Sta­ (LAC Service Bulletin 49/SB-150 covers tion 80 (5 nuts per fitting, 170 nuts per air­ plane should be checked. this same subject.) (LAC Service Bulletin 49/SB-42 covers this (o) In each outboard nacelle main junc­ same subject.) tion box, replace existing mounting nuts (Tin- nerman) and PK screws with AN 366 nuts 47-10-24 Lockheed (Was Mandatory Note and NAS 221 screws. 27 of AD-763-3.) Applies to All Model (LAC Service Bulletin 49/SB-152 covers 49 Serials Up to and Including 2088. this same subject.) Compliance required prior to June 1, 1947. (d) Drill one V4-inch drain hole on lower Install thermal relief valve and bypass line center line of spinner fairing lower panel as­ in fuel crossfeed line adjacent to No. 4 cross sembly for each engine. transfer valve. (LAC Service Instruction 49/SI-95 covers (LAC Service Bulletin 49/SB-48 covers this this same subject.) same subject.) 47-10-25 Lockheed (Was Mandatory Note (LAC Service Bulletin 49/SB-214 covers 28 of AD-763-3.) Applies to All Model 49 this same subject.) Serials Incorporating Eclipse Type 1193, 47-10-30 Lockheed (Was Mandatory Note Model 1, Style A Generators on Which the 33 of AD-763-3.) Applies to Model 49 Serial Numbers Are Not Followed by the Serials 2047 Up to and Including 2075 and Letter "M". to Serials Prior to 2047 Which Have Had Compliance required prior to March 1,1947. 68092 Surge Box Flapper Valves Replaced Replace the 12 mounting head-to-yoke bolts by 285750 Valves in Accordance With Lock­ in each generator with new Vi-inch bolts (P/N heed SI-15, Dated June 18, 1946. 63937 referred to in Eclipse-Pioneer Bulletin Compliance required prior to April 1, 1947. No. 70). Replace fuel tank surge box flapper valves, (LAC Service Bulletin 49/SB-64 covers this LAC P/N 285750, with new type valve, LAC same subject.) P/N 285750-600. 47-10-26 Lockheed (Was Mandatory Note (LAC Service Instructions 49/SI-15, revised 29 of AD-763-3.) Applies to All Model 49 August 10, 1946, and 49/SI-15A, revised Au­ Serials Up to and Including 2075. gust 3, 1946, or subsequent, cover this same Compliance required prior to June 1, 1947. subject.) Reroute flap and fan motor drain lines to re­ 47-10-31 Lockheed (Was Service Note 1 of turn direct to main hydraulic system instead of AD-763-3.) Applies to All Model 49 Serials through aspirator, and install check valves at Up to and Including 2088. points where drain lines connect to the main At periods not to exceed 100 hours the webs system. of all landing gear torque arms should be ex­ (LAC Service Bulletin 49/SB-169 covers amined closely at the knee bolt ends for the this same subject.) presence of cracks. When a nose gear arm is 47-10-27 Lockheed (Was Mandatory Note found to be cracked, it should be replaced with a new part. When either main gear arm is 30 of AD-763-3.) Applies to All Model 49 found to be cracked, the 283557 or 292132 alu­ Serials Up to and Including 2078. minum alloy torque link assemblies on both Compliance required prior to July 1, 1947. main gears should be replaced with 293882 Install new type fuel tank vent outlets and steel torque link assemblies. When Note 47- add extension to fuel dump chutes. 10-21 is complied with, this periodic inspection (LAC Service Bulletin 49/SB-201 covers procedure for the main gear may be discon­ this same subject.) tinued. 47-10-28 Lockheed (Was Mandatory Note 47-10-32 Lockheed (Was Service Note 2 of 31 of AD-763-3.) Applies to All Model 49 AD-763-3.) Applies Only to Model 49 Serials L'p to and Including 2088. Serial Numbers 2021 to 2067, Inclusive. Compliance required prior to July 1, 1947. At each periodic inspection, examine the Enlarge holes in elevator cable seals in aft upper wing surface forward of the aileron pressure bulkhead to 0.19 ± 0.031-inch diam­ beam and just outboard of Station 458 joint eter. for the presence of buckles. If serious buckles (LAC Service Bulletin 49/SB-208 covers are found the skin in that area should be re­ this same subject,) placed and gussets added. After the entire af­ 47-10-29 Lockheed (Was Mandatory Note fected area (approximately 5 inches x 36 inches) has been reworked in this manner, no 32 of AD-763-3.) Applies to All Model 49 further periodic inspections will be required. Serials Prior to 2080 on Which Metal Ai­ lerons Are Installed. (LAC Service Instruction 49/SI-26 covers Compliance required prior to April 1, 1947. this same subject.) Between aileron Stations 69.5 and 99.7, in­ 47-10-33 Lockheed (Was Service Note 4 of stall drain holes in the lower aileron surface AD-763-3.) Applies to Model 49. outboard of each rib and forward of each Difficulties have been experienced with cylin­ stringer (17 holes total). der heads turning or unscrewing slightly on LOCKHEED L-9 certain Wright 739C18BA1 and 2 engines. called for in LAC Service Bulletin 49/SB-93 This condition has occurred on older type and AD 47-10-15, above, may continue to be cylinders having barrels designated as "light used, provided a rigid inspection for condition type" barrels. Later type cylinders have is made in accordance with LAC Service In­ "heavy type" barrels on which this turning formation Letter No. 42, except that the lowest tendency has been eliminated. Heavy type periodic inspection interval listed on each op­ cylinder barrels have a circumferential groove erator's approved aircraft maintenance speci­ on the mounting flange to distinguish them fication may be used instead of the 30-hour from the light type barrels. period referred to in the Lockheed Letter. Following procedure shall be established (b) The revised exhaust system ball joints for inspection and replacement as necessary of described in part (a) of this Note may be re­ light barrel cylinders: installed after completion of the 250-hour pe­ (a) Prior to certification or next 60 hours riod referred to in LAC Service Information of operation: Letter No. 42, provided that each ball joint (1) Mark detonation pickup bosses on light is disassembled as far as practicable at the barrel cylinders with yellow paint for ready end of these 250-hour periods and unsatis­ identification. factory parts are replaced. This 250-hour dis­ (2) Scribe front of these light barrel cylin­ assembly period may be increased upon appli­ ders by marking heavy flange near bottom cation by an operator and approval by the of cylinder head and continuing scribe line FAA, provided the service record of the com­ down seven barrel fins. Dark paint may be ponents used by the operator justified the in­ used as background for scribe lines. Wright crease requested. Aeronautical have provided a scribing tool (c) When the revised exhaust system ball which may be used for this purpose. The joints, described in part (a) of this AD, are scribe line should be on front of cylinders replaced by new type Solar ball joint parts, where it can be easily seen with engines in­ as listed in LAC Service Bulletin 49/SB-94, stalled in airplanes. the overhaul period for exhaust system ball (h) After each succeeding 35 to 60 hours joints may be established as the same as the of operation: engine overhaul period approved for the op­ (1) Inspect scribe lines for signs of cylin­ erator involved. Intermediate inspections simi­ der head turning. lar to those described in LAC Service Infor­

(2) Cylinder heads which have turned ^2 mation Letter No. 42 shall be conducted on inch or more since prior inspection should have the new type ball joint assemblies at intervals valve clearances checked and reset to normal as specified in the operator's approved aircraft cold clearances if necessary, provided total maintenance specification. head turning does not exceed y inch. s 47-10-36 Lockheed (Was Service Note 7 of (3) Cylinders on which heads have turned AD-763-3.) Applies to All Model 49 Serial more than Vs"inch total shall be replaced im­ Numbers Up to and Including 2088. mediately with heavy barrel cylinders. Between the edges of the inboard and out­ (c) At first engine overhaul, light barrel board nacelle attach angles, the rivets used cylinders Nos. 1, 11, 13, 15, and 17 shall be to attach the leading edge lower skin to the replaced with heavy barrel cylinders. Re­ front beam should be inspected for looseness placed cylinders may be used in other locations at periods not to exceed 200 hours of opera­ provided total amount of turning has not ex­ tion. When loose rivets are found the follow­ ceeded Vs inch. ing corrective action should be taken: 47_10-34 Lockheed (Was Service Note 5 of Add stiffener to lower surface of leading AD-763-3.) Applies to All Model 49 Serials edge skin between Stations 287 and 299, in­

mc Up to and Including 2088. stall %2' h rivets in place of existing y$ - (a) Revised exhaust system ball joint as­ inch rivets used to attach lower leading edge semblies (Solar P/N CV-611 and CV-615-1 skin to front bam between Station 287 and through CV-615-18, reworked in accordance outboard nacelle, and install six 10-32 screws with Solar E.O. Nos. 16696 and 16697), as in place of six rivets in this same rivet line L-10 LOCKHEED

(two each at Stations 263, 287, and 312). found, parts of heavier gage should be in­ After this rework has been accomplished, no stalled and the aileron rebalanced. The pe­ further periodic inspections will be required. riodic inspection may be discontinued when (LAC Service Instruction 49 SI-121 covers this modification has been made. this wing leading edge reinforcement and rivet (LAC Service Bulletin 49/SB-52 covers replacement.) this same subject.)

47-10-37 Lockheed (Was Service Note 8 of 47-43-10 Lockheed (Was Mandatory Note AD-763-3.) Applies to All Model 49 Serials 21 of AD-723-3.) Applies to All Model 18 Up to and Including 2071. Serial Numbers. At periods not to exceed 500 hours, check Compliance required prior to February 1, the tightness of the inboard pair of bolts in 1948. the outboard fulcrum and the outboard pair Inspect all Alfite Model 2CD1722 operating of bolts in the inboard fulcrum of each main heads for the C02 bottles (fire extinguishing landing gear, using a torque wrench. A con­ system) and nitrogen bottles (emergency land­ tinuous record should be kept to show whether ing gear extension system) to determine these bolts become more loose with time; whether these heads have been stamped with therefore, these bolts should not be tightened the letter "L" adjacent to the swivelnut. If during the periodic inspections. When any the head is not marked in this manner, dis­ of these 8 bolts loosen to a torque wrench read­ assemble the head and examine the cable sheave ing of approximately 900 inch-pounds, all ful­ for part number. All 2CD2248 sheaves should crum bolts (16 per airplane) should be re­ be reworked by rounding the inner shoulder moved, the fitting holes countersunk 0.064 x of the ramp at its lower end throughout a dis­ 45° to accommodate the bolt head fillets, the tance of 1V4 inches, to eliminate possible jam­ bolts replaced and tightened to a torque wrench ming of the mechanism. When reworked reading of 2,300-2,500 inch-pounds- The 500- sheaves are installed, the operating heads hour inspection may then be discontinued. should be identified by the letter "R" stamped (Lockheed Service Bulletin 49-SB-51, re­ adjacent to the swivelnut. vised March 3, 1947, covers this same subject.) (Lockheed Service Bulletin 18/SB-140 cov­ 47-10-38 Lockheed (Was Service Note 9 of ers this same subject.) AD-763-3.) Applies to All Model 49 Se­ 47-43-11 Lockheed (Was Mandatory Note rials Up to and Including 2059. 22 of AD-723-3.) Applies to All Model 18 At periods not to exceed 500 hours, inspect Serial Numbers. the shank end of each main landing gear drag link crosshead assembly for signs of cracks Compliance required prior to next periodic in the fillet region. If cracks are found, in­ inspection. stall new type crosshead assembly, LAC P/N Remove bolts connecting the elevator push- 288982, and, if necessary, replace the 283418 pull rod to the elevator horn and bellcrank drag links with 288983 drag links. The pe­ and ascertain that the shank diameter falls riodic inspection procedure may be discon­ within the limits of 0.248 to 0.250. Bolts out­ tinued when the new type crosshead assem­ side these limits should be replaced with NAS bly is installed. 54-12 bolts. In view of the similarity of the (LAC Service Instruction 49/SI-27 covers Lockheed bolts with the standard AN bolt, this same subject.) it is suggested that they be replaced with close tolerance bolts, NAS 54-12 and the push-pull 47-10-39 Lockheed (Was Service Note 10 of rod. P/N 72149 placarded "Use NAS 54-12 AD-763-3.) Applies to All Model 49 Serials bolt". Up to and Including 2046 on Which All Metal Ailerons Are Not Installed. 47-49-1 Lockheed (Was Mandatory Note 34 At periods not to exceed 250 hours, inspect of AD-763-3.) Applies to All Model 49 the aileron inboard of the trim tab for evi­ Serials Up to and Including 2088. dence of cracks hi the trailing edge and in Compliance required prior to December 31, the aft portions of the ribs. When cracks are 1947. LOCKHEED L-ll

Relocate the rudder trim tab cockpit con­ 47-49-5 Lockheed (Was Mandatory Note trol unit to comply with provisions of CAR 38 of AD-763-3.) Applies to All Model 49 4b.322 regarding plane and sense of motion Serials Up to and Including 2088. of control. Compliance required prior to February 15, (LAC Service Instruction 49/SI-18 covers 1948, this same subject.) Replace quick-disconnect fasteners used to attach aileron control cable housing on radio 47-49-2 Lockheed (Was Mandatory Note 35 operator's floor (LAC P/N 28717-8) with of AD-763-3.) Applies to All Model 49 screws and AN 366F8-32 nut plates. Serials Up to and Including 2088. (LAC Service Bulletin 49/SB-300 covers this Compliance required prior to February 15, same subject.) 1948. Inspect nose landing gear emergency exten­ 47-49-6 Lockheed (Was Mandatory Note sion line in nose wheel well (LAC P/N 272239- 39 of AD-763-3.) Applies to Model 49 164) to ascertain whether adequate clearance Serials 2076 to 2088, Inclusive. exists with respect to the nose gear actuating Compliance required not later than next No. cylinder. If adequate clearance does not exist, 3 inspection (or not later than next 150 hours replace this line with a new part, LAC 285106- for non-air-carrier operations). 311 or equivalent. The rear oil pressure gage operational plac­ (LAC Service Bulletin No. 49/SB-164 cov­ ard on the flight engineer's panel, LAC P/N ers this same subject.) 296770, must be removed or replaced with new placard, LAC P/N 296995 or equivalent. 47-49-3 Lockheed (Was Mandatory Note (LAC Service Bulletin 49/SB-245 covers this 36 of AD-763-3.) Applies to All Model 49 same subject.) Serials Up to and Including 2080, Except 2033, 2058 and 2071 Through 2075. 47-49-7 Lockheed (Was Mandatory Note Compliance required at next engine change 40 or AD-763-3.) Applies to All Model 49 period. Serials. Up to and Including 2088, Unless Inspect all attachments of rudders to torque Equipped With MLG Drag Strut Dampers. tube flanges for evidence of stripped threads Compliance required prior to February 1, or elongated holes. (This does not require re­ 1948. moval of rudders.) When such evidences are (a) Replace the NAS58A65 bolt used to found, redrill holes to next larger size and/or connect the two halves of each MLG upper install new nuts as required. drag link assembly, LAC P/N 283418 and (LAC Service Bulletin 49/SB-256 covers 288983, with a %-inch diameter high strength this same subject.) bolt, LAC P/N 297902. (LAC Service Bulletin 49/SB-368 covers in­ 47-49-4 Lockheed (Was Mandatory Note 37 stallation of MLG shock strut dampers.) of AD-763-3.) Applies to Model 49 Serials 2068 to 2088, Inclusive. (h) Reduce MLG shock strut inflation pressures to provide a static extension of 2 Compliance required within next 50 hours inches at maximum landing weight. of operation unless the 13^6-inch headless drive pin has been installed. 47-49-8 Lockheed (Was Service Note 8 of Inspect attachments of rudder pedal lever AD-763-3.) Applies to All Model 49 Se­ arms to the clip assembly in the 284587 rud­ rials Up to and Including 2046. der pedal slot cover guide assemblies to deter­ At periods not to exceed 250 hours, inspect mine whether it is possible for the flat head pin the aileron leading edge ribs at Stations 571 to cause jamming of the system. If any possi­ and 577, the adjacent leading edge skin and the bility of jamming exists, the flat head pin counterbalance supports for signs of cracks. should be replaced with a headless drive pin When cracks are found, install heavier sup­

1%6 inches long. ports, new rib elements, new leading edge (LAC Service Bulletin 49/SB-260 covers skin, and rib reinforcements, as required. this same subject.) When both ribs have been reinforced and heav- L-12 LOCKHEED ier supports installed, this periodic inspection placed at least before the next departure from may be discontinued. a terminal base. (LAC Service Bulletin 49/SB-162 covers (LAC Service Information Letter No. 101 this same subject.) covers the necessary inspection procedure.) (e) If new type laminated astrodome as­ 47-49-9 Lockheed (Was Service Note 9 of sembly and ring, LAC Parts 298679 and 298735, AD-763-3.) Applies to All Model 49 Se­ respectively, are installed with necessary seals rials Up to and Including 2088 and to Models and attachments, the requirements of parts (a), 649 and 749 Serials 2501 Through 2513, In­ (6), and (c), may be disregarded. The pre- clusive. flight inspection called for in (d) should be At each engine change period, inspect the continued. wing attaching pins at Station 80 to determine (LAC Service Bulletin 49/SB-324, revised whether any of these pins are working upward April 30, 1947, covers installation of the new through the fittings. If any pin has worked type astrodome and mounting ring.) up until only the lower chamfered portion pro­ trudes, replace the Station 80 cover strip with 47-49-11 Lockheed (Was Service Note 11 a new 0.064 24ST alclad strip. When this of AD-763-3.) Applies to Models 49, 649, strip has been replaced the periodic inspection and 749 Serials as Noted. of that joint may be discontinued. At periods not to exceed 50 hours of opera­ (LAC Service Bulletin 49/SB-151 covers tion, inspect the following fuel system elements this same subject.) to determine that they are tight and will not permit leakage or other hazardous conditions: 47-49-10 Lockheed (Was Service Xote 10 of (a) Fuel dump valve shaft gland nuts AD-763-3.) Applies to All Model 49 Air­ (Serials up to and including 2075). planes Which Are Equipped With Astro­ (b) Valves on drain lines from outboard domes During Pressurized Cabin Operations, portion of inboard fuel tanks, fuel system Unless Permanently Sealed Off. crossfeed lines, and cabin heater fuel lines (a) Prior to next flight, provide an in­ (Serials 2047 to 2088, inclusive, and 2501 to ternal cover plate for the astrodome opening 2503, inclusive).

fabricated of %6-inch 24ST aluminum alloy If safety wiring of these items is provided, or equivalent, with provisions for installing the required inspections may be discontinued. this plate in the astrodome opening in the (Lockheed Service Bulletin 49/SB-215 cov­ event of loss of the astrodome. ers part (a), and Lockheed Service Instruction (LAC Service Bulletin 49/SB-331 covers 49/SI-10A covers part (&).) this same subject.) 47-49-12 Lockheed (Was Service Note 12 of (b) Prior to the next flight, provide a AD-763-3.) Applies to All Models 49, 649, navigator's safety harness with suitable attach­ and 749 Serials Which Incorporate Short ments to the floor structure beneath the astro­ Type Metal Aft Doors for the Main Landing dome. Gear. (LAC Service Bulletin 49/SB-264 covers At periods not to exceed 250 hours inspect this same subject.) the metal aft doors of the main landing gear (c) Prior to next flight, install a placard for signs of cracks in the vicinity of the for­ adjacent to the astrodome opening, reading ward hinge attachments. When cracks are as follows: "Wear safety harness whenever found, satisfactory reinforcements and dou­ using astrodome. Check security of harness blet's should be installed. attachment to floor after each installation". When doublers have been installed (doublers (d) Prior to each flight, closely inspect only are necessary if the doors are not already each astrodome for cracks, crazing or other cracked) the periodic inspections may be dis­ defects, with particular attention given to area continued. around radius adjacent to the flange. When (LAC Service Bulletin 49/SB-274 covers any defects are found, the dome should be re­ this same subject.) LOCKHEED L-13

48-12-3 Lockheed Applies to All 649 and tacles for Used Towels, Paper, and Waste; 749 Series Aircraft As Specified by Civil Air 49/SB-181, Rework of Baggage Compartment Regulations Amendments 41-3, 42-2 and Lining; 49/SB-183B, Installation of Smoke

61-2. Detectors; 49/SB-184, Installation of C02 Pro­ To be accomplished not later than the dates visions in Cargo Compartment; 49/SB-188, specified in the above amendments as revised Enclosure of Cabin Heater Fuel Control Sys­ by special Civil Air Regulations Serial Nos. tem Components; 49/SB-191, Replacement of 385, 390, 390A, 390B and any subsequent regu­ Firewall and Fire Seal Fittings and Cable lations affecting these compliance dates. Seals; Installation of C02 Fire Extinguisher All air carrier aircraft must be modified in Check Valves; 49/SB-153, Sealing of Access all necessary respects to comply with the air­ Doors in Stub Wing Fillet; 49/SB-216, Relo­ craft fire prevention requirements outlined in cation of Fenwal Fire Detectors; 49/SI-44, CAR Amendments 41-3,42-2, and 61-2. Com­ Installation of Metal Main Landing Gear Aft pliance with those requirements may be com­ Doors. pleted as follows: 48-18-3 Lockheed Applies to Model 49-46 1. Revise the smoke detection system in Aircraft. accordance with LAC Service Bulletin 49/SB- Compliance required every 300 hours of 401. Other rework shown to be equivalent to operation. that covered by this Service Bulletin will also 1. Cabin supercharger drive shafts should be be acceptable. (Applies to Serial Nos. 2512 inspected at periods not to exceed 300 hours of through 2515, 2519 through 2543, 2545 through operation in accordance with instructions and 2550, 2552 through 2555, 2560, and 2561 only.) procedures specified in LAC Service Bulletin 2. Inspect all cabin interior fabrics and fin­ 49/SB-107, revised November 22, 1946. Con­ ishes to determine that any substitutes or re­ current with the foregoing inspection, the rear placements for the materials originally in­ drive shaft universal joint, clutch end bearing, stalled comply with the applicable sections of carbon oil seal and overriding clutch, should be CAR 4b. Safety Regulation Release 259 out­ completely overhauled. All defective parts lines acceptable procedures for complying with are to be replaced and clutch end bearing these particular requirements. 111GE is to be replaced regardless of condi­ 48-12-4 Lockheed Applies to All 49 and 149 tion. The sheet-metal retainer (LAC P/N Aircraft As Specified by Civil Air Regula­ 257643) is to be replaced as soon as practicable tions Amendments 41-3, 42-2, and 61-2. with bronze retainer (LAC P/N 299449). To be accomplished not later than the dates 2. The replacement of clutch end bearing specified in the above amendments as revised 111GE will not be necessary if the super­ by special Civil Air Regulations Serial Nos. charger is reworked to provide a double bear­ 385, 390, 390A, 390B and any subsequent regu­ ing support for the rear universal joint, and lations affecting these compliance dates. overrunning clutch assembly. This rework will also require replacing the present carbon All air carrier aircraft must be modified in faced oil seal with a slinger type and modify all necessary respects to comply with the fire the supercharger housing to suit. The pre- prevention requirements outlined in CAR flight inspections for oil seal damage can be Amendments 41-3, 42-2, and 61-2. Compli­ dispensed with when slinger type seals have ance with the requirements may be completed been installed. by accomplishing the modifications outlined in the following listed Lockheed Service Bul­ (LAC Service Bulletin 49/SB-393 covers letins. Other rework shown to be equivalent this same subject.) to that covered by the Service Bulletins will 48-18-4 Lockheed Applies to Model 49-46 also be acceptable. Aircraft Serial Numbers 1975 Through 1980 49/SB-175, Installation of Cabin Door Lou­ and 2021 Through 2088. ver Covers and Door Stops; 49/SB-179, In­ Compliance with the following was required spection and Replacement of Crew Seat Uphol­ prior to September 19, 1947, by direct notifica­ stery Covers; 49/SB-180, Rework of Recep­ tion of operators. L-14 LOCKHEED

Add thermocouple to cabin supercharger line at 1,875 r.p.m. Red band 1,900 to 2,000 bevel gear housing, and direct reading indica­ r.pjn. Green band 2,000 to 2,100 r.p.m. with tor in cockpit to record temperatures of the green radial line at 2,050 r.pjn. Red band rear supercharger universal coupling support 2,100 to 2,375 r.p.m. with green radial line at bearing. 2,400 r.pjn. Yellow band 2,400 to 2,800 r.p-m. (LAC Service Bulletin 49/SB-390 covers with red radial line at 2,800 r.pjn." this same subject.) 48-27-1 Lockheed Applies to All Model 49 48-19-2 Lockheed Applies to Models 49-46, Aircraft Modified to Permit Operation at 149-46, 649-79 and 749-79 Aircraft. 93,000 Pounds Takeoff and 83,000 Pounds Compliance required at nest Xo. 1 inspection, Landing Weights, and Model 49 Aircraft, and thereafter at periods not to exceed 550 Redesignated as Model 149, and Modified to hours of operation. Permit 100,000 Pounds Takeoff and 83,000 Inspect the two fittings,P/ X 256019, "Lever- Pounds Landing Weights. Cockpit Torque Tube", in the elevator control Compliance required not later than nest system for the presence of cracks or other signs wing change or aircraft overhaul, and in no of failure at the rivet attachment points, par­ event later than February 1,1949. ticularly at the base of the arm. Remove and In order to comply with the requirements of replace any defective parts. The periodic in­ Civil Air Regulations, fuel dump stand pipes spection may be discontinued if the two levers must be installed. are replaced with new parts, LAC No. 302349, (LAC Service Bulletin 49/SB-403 and LAC or are reinforced with additional fittings, LAC Service Instruction 49/SI-12 dated September No. 302337, or their equivalents. 25,1946, cover this same subject.) (LAC Service Bulletin 49/SB-456 covers the Pending the accomplishment of the above lever substitution or reinforcement.) change, operations are permissible at the in­ 48-26-1 Lockheed Applies to 649 and 749 creased weights'. Series Aircraft Equipped With Curtiss 48-27-3 Lockheed Applies to 649 and 749 C632S-A14/850-4C2-0 Propellers, Series Airplanes Equipped With Curtiss Compliance required by July 7, 1948, and C632S-A/850-4C2-0 Propellers. August 1,1948. Compliance required by August 1, 1948, and To avoid failures under certain operating February 1,1949. conditions, the following engine speed restric­ To increase the ability of the propeller hubs tions must be observed and two placards cover­ to withstand excessive stresses under certain ing these restrictions must be installed in the operating conditions the hubs must be returned cockpit. (Temporary placards mnst be in­ to Curtiss-Wright Corp., Propeller Division, stalled not later than July 8, 1948, and perma­ for shotpeening of the threaded portion of the nent placards to be supplied by Lockheed in­ hub barrels. Effective August 1, 1948, hubs stalled not later than August 1, 1948.) One not peened before accumulating 2,500 hours of placard must be in full view of the pilots and operating time are to be permanently removed one in full view of the flight engineer. Plac­ from Constellation operation. Hubs not peened ards should read as follows: before accumulating 2,000 hours of operating "In flight avoid continuous operation below time are to be temporarily withdrawn from 1,625 r.pjn. and between 1,725 and 1,850 r.pjn., operation until shotpeened. Peening must be 1,900 and 2,000 r.p.m., and between 2,100 and accomplished on all hubs by February 1, 1949, 2,375 r.pjn. On ground avoid continuous op­ regardless of accumulated operating time. eration between 1,200 and 1,450 r.p.m." For visual reference, all tachometers in the air­ 48-33-1 Lockheed Applies to All 49-46, plane must be marked as follows not later than 149-46, 649-79 and 749-79 Models, Through August 1, 1948: "Red Band 1,200 to 1,625 Serial Number 2588. r.pjn. Green band 1,625 to 1,725 r.pjn. with Compliance with new placard restrictions green radial line at 1,675 r.pjn. Red required immediately. Placards to be installed band 1,725 to 1,850 r.pon. with green radial not later than December 1,1948. LOCKHEED L-15

Remove existing fuel placards and install lent to that covered by the Service Bulletins three new placards covering fuel system opera­ will also be acceptable. tional procedure. Lockheed Service Bulletins' A. The placard to be removed from the Title 49-46 airplane is located on the Flight Engi­ Item CAB 4 JVo. Revision to Waste Paper Container. neer's lower instrument panel and reads: 1. .3824 18/SB-122 Installation of No Smok­ "CATJTTON : Do Not Land With More Than ing Placard. 18/SB-123 Installation of Fire Detec­ 900 Gallons of Fuel in Each Outer Tank". tion and Extinguishing B. The placard to be removed from the 649 2. .38250 18/SB-124 System. .38251 18/SB-125 Installation of Hydraulic airplane is located on the Flight Engineer's Reservoir Oil Tank uppermost panel and reads: Guard. 18/SB-126 Installation of Windshield "Fuel Load Restrictions Model 749. Take­ Alcohol Tank Guard. off: Do not Takeoff with Less Than the Fol­ 18/SB-127 Sealing of Baggage Com­ partment. lowing Fuel Loads": 3. .43 18/SB-135 Material Substitution— The placards to be added read as follows: Propeller Feathering Reserve Oil Tank 1. "This Airplane Must be Fueled, and Fuel Support. Used, in Accordance With the Charts in the 4. .4700 18/SB-130 Firewall Revision. Approved Operating Manual." (LAC, Part 5 49 .4900 18/SB-128 Replacement of Power M302166). Plant Lines and Fittings. 2. "At All Times, Fuel in Tanks 2 and 3 .4901 18/SB-129 Installation of Emergency Oil Shut-Off Valves. Must Not Exceed Fuel in Tanks 1 and 4, Re­ .4902 18/SB-131 Revision to Cabin Heater spectively." (LAC, Part M302163.) Ducts. .4902 18/SB-133 Replacement of Firewall 3. "Fuel Transfer from one Tank to Another and Power Plant Lines is not Permitted. When Operating the Fuel & Fittings. Installation of Dual Fuel System on Crossfeed, the Tanks not Being 18/SB-136 System Fire Resistant Used Must be Turned Off." (LAC, Part Plumbing Provisions for Selective Shut-Off—Pro­ M302109.) peller. On Models 49-46, 149, 649, and 749 install Anti-Icing System (Air­ 18/SB-141 planes having Standard placard 1 on Pilot's instrument panel and Systems) Provisions for placards 1, 2, and 3, on Flight Engineer's up­ Selective Shut-Off—Pro­ peller. permost instrument panel. Placard 3 has Anti-Icing System (Air­ been installed on airplane Serial Number 2577 18/SB-14IA planes with Tank & Pump in L.H. Nacelle). and subsequent, prior to delivery. (LAC Service Bulletin 49/SB^39, dated In addition to the above, inspect cabin inte­ March 23, 1948 covers this same subject.) rior fabrics and finishes to determine that these materials or any substitutes or replace­ 48-42-2 Lockheed Applies to All Model 18 ments for the materials originally installed Aircraft Operated in Scheduled and Non- comply with the applicable sections of CAR scheduled Air Carrier Passenger Service. 4b. Safety Regulation Release 259 outlines To be accomplished not later than the date acceptable procedures for complying with these established in accordance with the provisions particular requirements. of special Civil Regulation Serial Number SR-329, or any subsequent regulation affect­ 49-5-1 Lockheed Applies to All 749 Air­ ing this compliance date. craft Equipped With Curtiss 850-4C2-0 All Lockheed Model 18 aircraft mentioned Propeller Blades. above must be modified to comply with the fire Compliance required by March 25, 1949. prevention requirements as outlined in CAR Magnetically inspect the shank section, as Amendments 41-3, 42-2, and 61-2, Compli­ far outboard as the 18-inch station, of all ance with these requirements may be accom­ 850-4C2-0 blades delivered before November 1, plished by completing the modifications out­ 1948, having less than 700 hours service and lined in the following listed Lockheed Service which have not been magnafluxed since deliv­ Bulletins. Other rework shown to be equiva­ ery, using a coil not greater than 27 inches in L-16 LOCKHEED diameter and providing at least 8.000 ampere 49-49-1 Lockheed Applies to All Model 49 turns, inspection of blades with lowest service Series Aircraft Equipped With Eclipse- time should be accomplished first wherever Pioneer Model PB-10 Automatic Pilots. possible. Compliance required prior to reconnection in Curtiss Service Bulletin No. 47 covers this aircraft. same subject.) Prior to reconnection in the aircraft of the Eelipse-Pioneer Model PB-10 automatic pilot, 49-41-1 Lockheed Applies to All Models it is necessary to modify the installation to in­ 649. 749 and 749A Aircraft Equipped With clude provisions designed to safeguard the air­ Curtiss Model C632S-A Propellers and craft in the event of malfunctioning of the Wright Model 749C18BD4 Engines. autopilot. This modification has been deter­ Compliance required on items 1, 2 and 3 by mined to consist of the following interdepend­ October 11,1949. ent changes: In order to reduce the possibility of subject­ Modify the master direction indicator and ing propellers to excessive stresses and to detect wiring at the autopilot controller plug and hub cracks which may have been caused by such amplifier to change the direction signal from stresses, the following steps are to be taken: the rudder channel to the aileron channel; in­ 1. Change present 2,100-2.375 r.pju. restric­ stall resistors in series with the variable phase tion to 2,050-2,375. Placard airplane or mark of aileron, rudder and elevator servo motors to tachometer with green radial line for single reduce servo forces; install aileron servo dis­ point operation at 2,025 r.pjn. Other restric­ connect interlock switch and change wiring to tions listed in AD 48-26-1 still apply. this switch from the existing rudder servo dis­ 2. Limit gross weight to 102,000 pounds connect interlock switch. maximum. An acceptable method of accomplishing this 3. On hubs having more than 1.500 hours modification is described in LAC Service Bul­ total service time, visually inspect for cracks letin No. 49/SB-576. the rear outboard portions of the hub barrels. This supersedes AD 49-36-1. Inspection is to be continued at intervals as 49-52-1 Lockheed Applies to All Models 49, close to 10 hours as practical but not exceeding 149, 649, and 749 Aircraft. 20 hours maximum. It is strongly recom­ mended that whenever the necessary equipment Compliance required as indicated. is available, magnetic inspections be made at Numerous instances of malfunctioning of the the same intervals in accordance with Curtiss elevator booster system have been reported, Instruction entitled "Field Magnetic Inspec­ causing longitudinal hunting of the airplane tion of C6832S-A Hubs." Remove from serv­ and, in one instance, injury to some passengers when operation of the elevator boost shifter ice any hub showing a crack. To facilitate mechanism was accomplished. Also, in other these inspections, the propeller power unit is instances, it has sometimes been impossible to covered or sealed to prevent the entrance of actuate the shifter mechanism, probably as a water in the unit. As an alternate to the re­ result of frozen moisture accumulating on the moval of the spinner, these inspections may be mechanism. To minimize further difficulties conducted through three 5-inch diameter holes of these natures, the following must be accom­ located in the side of the spinner in accordance plished: with instructions issued by Curtiss. A. Booster Unit Rework and Lubrication. 4. All C632S-A hubs (P X 116366) with At or prior to next engine overhaul period, over 2,000 hours total time shall be retired rework all aileron, rudder and elevator booster from service as soon as possible and not later control valves, as follows: than November 30, 1949. 1. Drill six ^-inch water drain holes in the 5. Items 1 and 2 also apply when the valve cap; C-632S-B hub (P/N 129914) is used to replace 2. Line ream the bushing, P/N 266146-3, to theC632S-A hub (P/N 116366). 0.6270-inch/0.6285-inch diameter; LOCKHEED L-17

3. Replace AN 913-1 plug with AN 286-2 mation is contained in Lockheed Service Bul­ lubricator; letin 49/SB-502. Two E. O. 4681A describes 4. Pack cap assembly with AN G-25 grease, an approved method of complying with item B. or equivalent; The replacement link assemblies called for in 5. Reidentify valve and cap assemblies by LAC Service Bulletin 49/SB-502 utilize new adding a -2 to each part number. latch hooks, P/N 303689. Installation of Relubricate booster control valves with AN these new link assemblies does not preclude G-25 grease or equivalent at each engine over­ the necessity of removing the hook ends of the haul period. This lubrication interval may be latches, as specified in item B.) increased as substantiated by service experi­ This supersedes AD 49-22-1. ence. 52-8-1 Lockheed Applies to Certificated B. Rework of Elevator Shifter Latches. Army and Navy Versions of the Model At or prior to the next No. 3 inspection, all 18 Aircraft Designated C57, C57B, R50-1, elevator shifter latches, LAC P/N 278416, R50-2, R50-3, R50-5, R50-6, C60, C60A and shall be reworked to remove the end which C59. hooks around the anchor pin, LAC P/N 278484. (The overcenter spring on the shifter Compliance required at next annual inspec­ walking beam eliminates the necessity for the tion, but in no event later than June 1,1953. locking action of these hooks.) The shifter Inspect all Lockheed Model 18 Series air­ control system shall then be checked as follows : craft which have been converted from a mili­ With the shifter walking beam in "boost on" tary version to civil status, for compliance position, the control system should be rigged with Lockheed Drawing No. 50829, change A, so that (1) when the cockpit control is in full to provide seal at the inboard end of the inte­ down position, the reworked latch is in firm gral fuel tanks (inside fuselage) to prevent contact with the anchor pin but acts as a stop gasoline fumes from accumulating in the pas­ device only; (2) when the cockpit control re­ senger compartment in case of fuel tank leak­ lease button is depressed, the control spring- age. Inspection of the area can be accom­ back is approximately 0.25 inch. plished by removal of the overhead panels C. Rework of Elevator Booster Power adjacent to the fuselage skin in the No. 3 and Levers. As soon as practicable but not later No. 4 baggage compartments or by removing than next engine change, the feel lever bolt floor panels in the cabin. holes in the elevator walking beam assembly Diaphragms and vents must be installed in shall be chamfered in accordance with LAC accordance with Lockheed Drawing No. 50829 SD 67471. (or equivalent). D. Flight Manual Revisions. To be accom­ (Drawing No. 50829, change A, covering the plished not later than July 15, 1949. Depend­ required installation may be obtained from ent upon the airplane model involved, ascer­ Lockheed Aircraft Corp., Burbank, Calif.) tain that the Model 49 and Model 149 Flight 52-12-3 Lockheed Applies to Models 49-46, Manuals incorporate approved revision dated March 4, 1949, or that revised Model 649/749 149^6, 649-79, 649A-79, 749-79, 749A-79, Flight Manual dated February 5,1949, is being C-121A, and VC-121B Aircraft. utilized. (The 49/149 revision and Section Compliance required as indicated. III, paragraph 2 of the revised 649/749 Man­ Inspect the following by August 1,1952: ual outline the shifting techniques to be fol­ 1. Bulkhead ring at Station 527.6 for cracks lowed when shifting is desired.) in channel bend radius P/N 28398^-2 and -3 (Lockheed Service Bulletin 49/SB-578 dated for Models 49 and 149, and P/N 285772-2 and October 25, 1949, covers item A and Lockheed -3 for all other models, as well as bracket P/N Service Information Letter No. 425, dated Feb­ 252886 for all models. ruary 28, 1949, covers item D above. Item C 2. Inspect for and replace any missing or is covered by Lockheed telegram to all opera­ broken screws through the outer flangeo f the tors dated January 18, 1949, and similar infor­ bulkhead 527 visible under fillet. L-18 LOCKHEED

If no cracks are found on first inspection, August 1, 1952, and shall be completed no reinspect at 2,000-hour intervals until total later than November 1,1953. airplane time reaches 8,000 hours. After 8,000 I. In order to prevent inadventent actuation hours, reinspect at approximately 600-hour in­ of the propeller reversing solenoid valves, pro­ tervals. If cracks are found, operation may tect the reversing solenoid circuits from all continue prior to repair provided cracks are other electrical circuits and protect the revers­ marked and reinspected at approximately 200- ing solenoid circuits from each other. This is hour intervals and, farther, provided: (1) to be accomplished in accordance with attach­ Total length of all cracks on one side of air­ ment A and the following instructions which plane does not exceed sum of 2V4 inches not pertain to specific features to be considered in counting cracks, if any, in bracket 252886: (2) isolation of the circuits. Airplanes which Cracks in bracket 252886 left or right do not have other features not specifically referred to exceed sum of 2 inches. If cracks exceed either in this list shall be treated in an equivalent 2% inches in the channel or 2 inches in bracket, manner: repair by either the interim fix method or final A. The multiple pin connector assembly at fix. The interim fix may be accomplished by the reverse coordinating relay panel must com­ bolting steel blocks tightly to each side of bulk­ ply with item 2 of attachment A. head ring webs in the vicinity of the cracks, B. Protect the following exposed terminals with additional bolts through the steel flange as specified in item 3 of attachment A: of the ring and tapped into the steel blocks. (1) Exposed terminal on "A" relay in (Lockheed Service Bulletin Xo. 49/SB-714 reverse coordinating relay panel; covers this repair.) (2) Exposed terminals at throttle reversing The final fix consists primarily of replacing switches (not required if item IIA(l) is in­ the aluminum alloy bracket, P/N 252886, with stalled). a heat-treated alloy steel bracket of approxi­ C. Modify Hamilton Standard relay box, mately the same dimensions except for gage, where used, to shield the reversing solenoid and adding 0.078 inch heat-treated alloy steel circuit relay contacts, etc., from all other cir­ doublers to the cracked channels, all parts se­ cuits which are energized at any time except curely bolted together. when reversing is desired. Reversing relay (Lockheed Service Bulletin Xo. 49/SB-715 boxes which have separate pin connectors for describes this reinforcement.) the reversing solenoid wire and the remaining If the interim fix as described by Lockheed circuits shall be so installed that it will not be Service Bulletin Xo. 49/SB-714, or equivalent, possible inadvertently to interchange any con­ has been complied with, the inspection period nectors on any two relay boxes. may be increased to approximately 400-hour D. Reversing solenoid circuit wiring: Mod­ intervals until the final fix is applied. If the ify in accordance with item 4 of attachment A. final fix, as described in Service Bulletin No. II. Other circuit modifications: 49/SB-715, or equivalent, is complied with, no A. All airplanes shall be modified in one of further inspections are necessary. the following ways: The term "approximately" is used in connec­ (1) Install an additional switch in the re­ tion with the inspection periods to provide flex­ versing solenoid circuit which will prevent the ibility so that these periods may be integrated application of power to the circuit until the with operators' regular inspection periods, switch has been closed by operation of the land­ nearest to the periods specified herein. ing gear actuated throttle reversing lock sys­ 52-13-2 Lockheed Applies to All Constel­ tem, or lation (49 Series) Airplanes With Hamilton (2) Comply with Hamilton Standard Serv­ Standard Reversing Propellers. ice Bulletin XTo. 221. Items I, II and III are to be accomplished III. Pedestal design (same compliance date by means of a progressive modification pro­ as item I) : gram to be submitted to and approved by the A. Reversing throttle switch and lock bar FAA. This program shall begin no later than assembly: Modify the assembly by adding a LOCKHEED L-19

stop pin and plate for the lock bar and cutting ATTACHMENT A clearance notches on No. 1 and No. 4 switch Criteria for isolation of reversing circuits triggers. at terminal points and connections: IV. Maintenance practices: 1. Terminal Strips. The following methods of isolation can be used: A. At each nearest scheduled service to 350 (a) Elimination of connections at termi­ hours: nal strips by using continuous wiring, (1) Inspect the points specified in item IB (b) Providing separate, covered termi­ and any other critical points in the systems nal strip for reversing lead connections, where two or more solenoid wires run together. (c) Isolating the solenoid lead stud, ter­ These inspections may be discontinued if the minals and associated hardware from all other modifications made to the system are of the nearby studs or terminals by enclosing these type described in item 1(a) or 1 (b) of attach­ components in an insulating cover which is ment A. so designed or secured to the wiring that the (2) Perform an electrical check of the re­ wire will stay in place in case of breakage at verse safety switches in the pedestal assembly the terminal or so that the broken wire and to assure that the switch is open when the terminal will remain insulated by the cover throttles are moved forward out of the reverse from contact with other circuits if the wire position, unless it is shown that failure of any comes off its terminal. The nature of the of the reverse safety switches to open will be cover design or provisions for its attachment clearly apparent to the flight crew by reason of must be such that its installation will not be improper operation of the propeller control overlooked during maintenance, system. Because of the many technical consid­ (d) Removing or grounding studs adja­ erations involved, analyses showing that the cent to solenoid valve lead stud and securing objective of this revision has been accomplished all adjacent wiring and the reversing solenoid should be referred to the FAA for engineering lead to prevent contact of broken leads with evaluation and approval. reversing solenoid terminal or contact of (3) If item IIA(l) is installed, perform broken reversing solenoid lead with other ter­ an electrical check of the switch to assure that minals. If the adjacent studs are grounded, it opens when the throttle lock bar is in the rather than removed, the studs must be identi­ locked position. fied distinctively so that they will not inadvert­ B. At any time that an electrical fault oc­ ently be used for the attachment of wires serv­ curs in a circuit which is carried in the same ing other circuits. bundles or the same conduit as the reversing 2. Multiple Pin Connector Assemblies. The solenoid circuit, representative terminal points following methods of isolation can be used: in the faulty circuit are to be inspected to de­ (a) Elimination of pin connectors by us­ termine whether any damage may have oc­ ing continuous wiring, curred within the bundles or conduit. If there (b) Providing separate pin connectors for is evidence of possible damage, all the wiring each reversing solenoid circuit, involved is to be removed and inspected. Dam­ (c) Deactivating all pins adjacent to the aged wiring is to be replaced as necessary. one carrying the reversing solenoid circuit. V. Operating instructions: Comply with These pins are to be retained in the connector item 5 of attachment A. but identified distinctively so that they will not be used inadvertently. When distinctively VI. (Note: Propeller governor design identified, these pins may also be used for cir­ changes which are under development and cuits which cannot supply sufficient energy to whose purpose is to provide a high pressure actuate the reversing solenoid or circuits which hydraulic circuit bypass to safeguard against are energized only when reversing is desired. inadvertent reversing and to provide ability At the points where wires are attached to the to feather even when the reversing solenoid connector pins, all exposed metal parts are to is energized, are still under consideration and be protected with insulating covers so secured may be the subject of a future Directive.) that contact between circuits cannot occur in L-20 IJOCKHEED case of failure at the connection or in case for­ wing Station 326, left and right, with par­ eign material is left in the connector assembly. ticular reference to spar cap joggle areas using 3. Exposed Terminals on Relays and dye penetrant inspection method or equivalent. Switches. Protect these terminals in either 1. If crack is found in the forward flange one of the following ways: and does not extend into the vertical leg, stop (a) As specified in item 1 (c) for terminal drill the crack unless it terminates in a rivet strips, or hole and make permanent repair or install the (b) If the terminal is a type which can­ serviceable repair in accordance with LAC not be protected as specified above, cover all Drawing 325800. When serviceable repair is exposed metal components with insulating ma­ used, a visual inspection must be conducted at terial and secure all wires so that no wire can periodic intervals not to exceed 50 hours with touch another terminal if the wire breaks or dye penetrant inspection or equivalent method falls off its own terminal. Install insulating to be used at periods not to exceed every 200 barriers as necessary to prevent inadvertent hours until incorporation of the reinforcement contact between broken or loose wires and per LAC Drawing 325667, change A or equiva­ other terminals. lent. 4. Reversing Solenoid Circuit Wiring. Mod­ 2. If crack in the front spar flange extends ify in one of the following ways: into the vertical leg, remove tank sealant as (a) Physically isolate the wiring from necessary for skin and web inspection using all other circuits. dye penetrant inspection method or equivalent. (6) If the wiring is run in bundles with Reinforcement per LAC Drawing 325667, other wires, a shielded wire is to be used. The change A or equivalent is necessary before re­ shielding shall be grounded at both ends and suming commercial operation and normal in­ a protective cover shall also be provided over spection procedures. the shielding. The shielding shall be carried 3. If no cracks are found, reinspect using dye as close as possible to the terminal points. penetrant inspection method or equivalent on 5. Operating Instructions, Xot later than all aircraft with 10,000 hours or more total August 1, 1952, all operating instructions re­ flight time, at intervals not to exceed 200 hours, garding unfeathering procedures shall specify and on all other aircraft at each major air­ that the following practices are to be observed frame inspection period until such time as re­ and shall indicate that the reason is to guard inforcement per LAC Drawing 325667, change against inadvertent reversing during the un­ A or equivalent is accomplished. feathering operation: 54-1-2 See Hamilton Standard Propellers. (a) If unfeathering is being accomplished at night the wing illumination lights or land­ 54-22-1 Lockheed Applies to Models 49, ing lights are to be used to permit observation 649, 749, and 1049 Airplanes as Noted in of propeller operation. Referenced Service Bulletins. (b) The propeller is to be watched during Compliance required by April 1, 1955. unfeathering and the button is to be released A recent engine fire resulted in a premature when rotation starts. (This should normally failure of a flexible hose in the feathering line be in 1 or 2 seconds.) and in penetration of fire from zone 1 into (c) The tachometer is not to be used as a zone 2. guide for determining when unfeathering is to 1. To increase the fire resistance integrity of be terminated. the propeller feathering line between the pump and the governor, replace the existing flexible 53-5-1 See Curtiss Propellers. hose assemblies meeting current fire resistance 53-15-2 Lockheed Applies to All Models requirements. The following Lockheed Serv­ 049, 149, 649 and 749 Series Aircraft. ice Bulletins cover this subject: No. 49/SB-786 Compliance required as indicated. for Model 049 through 749 airplanes and No. At the first arrival at the main base, unless 1049/SB-2195 for Model 1049 airplanes. The already accomplished, inspect for cracks in the following hose assemblies may also be consid­ forward flange of the lower front spar cap at ered acceptable for this application: LOCKHEED L-21

(a) Aeroquip 680-1OS hose assemblies ing to occur and may result in flight hazards with Aeroquip 304 protective sleeves over end due to inability to actuate the landing gear. fittings. Bendix Pacific Division issued their Service •(b) Resistoflex—SSFR-3800-10 hose as­ Bulletin No. 71 dated December 26, 1952, for semblies. rework and inspection of these assemblies. 2. To increase the fireproof integrity of the Lockheed has written to all operators, August zone 1 fire seal diaphragm against burn- 20, 1954, specifying additional rework. through into zone 2 in the event of a power It is necessary, in order to increase service section fire install steel plates over the lower life of these cylinders, to either replace them engine cowling longerons adjacent to the dia­ with cylinders of the new Bendix design phragm. The following Lockheed Service Bul­ (which incorporate a %6-inch radius in the letins cover this subject: No. 49/SB-760 for barrel) or to accomplish the following: Model 649/749 airplanes and No. 1049/SB- 1. Rework cylinder assemblies 405308-0-1, 2115 for Model 1049 airplanes. -0-2, -0-3, -0-4, -0-5 and -1, to provide a %2- 54-24-2 Lockheed Applies to 1049C, Se­ inch relief radius at the juncture of the barrel rial Numbers 4520 Through 4548; Model bore relief area and bottom of the barrel, and

1049E, Serial Numbers 4549 Through 4556, to spot-peen this %2-inch radius area. 4558 Through 4560, and 4563 Through 2. Magnetically inspect the barrel internally 4565; Model 1049D, Serial Numbers 4163 and externally prior to and following the re­ Through 4166. work per item 1. If the barrel is cracked, it Compliance required as indicated. must be scrapped. 1. Perform a visual inspection of the outer (Bendix Service Bulletin No. 71 and Lock­ wing main beam web between Stations 551 and heed Letter FS/93931 to operators dated Au­ 637, left and right, for cracks as soon as prac­ gust 20, 1954, covers this same subject.) tical, and reinspect at intervals of approxi­ mately 125 hours until this area is reinforced 55-5-2 See Hamilton Standard Propellers. as outlined in paragraph 2. If cracks are found repair and reinforce as per paragraph 2 55-15-3 Douglas and Lockheed Applies to immediately. Inspection for fuel stains alone All Douglas DC-3 and C^7 Series Aircraft, as an indication of a crack is not sufficient due DC—4 and C-54 Series Aircraft; and All to the presence of sealant on the inside of the Lockheed 18 Series Aircraft Equipped With tank surface. Hamilton Standard Propellers Used in Air 2. Reinforce the main beam web between Carrier Passenger Operations. wing Stations 551 and 637, left and right as Compliance required by first scheduled en­ soon as possible, convenient with aircraft check gine change after November 1, 1955, but not periods, but not later than 1,000 hours after later than November 1,1956. receipt of parts from the manufacturer or To increase fire resistance integrity of the March 1, 1955, whichever occurs first. This propeller feathering system against damage may be accomplished by the addition of ex­ by a powerplant fire, all flexible hose com­ truded aluminum alloy (75ST6) stiffeners ponents of propeller feathering lines forward (LS347-3), one between each of the original of the firewall must be replaced with lines stiffeners in this area. and fittings which will meet the current fire (Lockheed Service Bulletin No. 1049/SB- resistance requirements. However, if the 2559 describes this reinforcement.) feathering line in zone 1 includes a section of steel tubing, flexible hose assemblies located 54-24-3 Lockheed Applies to All Models forward of the cylinders and connecting to the 49, 149, 649, 749, and 1049 Aircraft. governor are not affected by this directive. Compliance required no later than the next regularly scheduled landing gear overhaul for The following flexible hose assemblies are all subject type aircraft. acceptable for use in this application: Failures of Bendix No. 405308 main landing (a) Resistoflex SSFR-3800-10 hose assem­ gear actuating cylinder assembly are continu­ blies. L-22 LOCKHEED

(&) Aeroquip 680-10S hose assemblies Proper torque value for the AN 23-19 bolts with Aeroquip 304 protective sleeves over end is 10 to 20 inch-pounds. Nut torque must be fittings (Aeroquip assembly P X 304000). checked with a torque wrench and all over- {c) Aeroquip 309009 hose assemblies. torqued bolts replaced. If necessary, the next {d) Aeroquip 309009-8S hose assemblies size longer bolt (P/N AN 23-20) may be used (where feathering system requires this size). to facilitate installation within proper torque tolerances. Washers may be used as required, 55-15-6 Lockheed Applies to 049-149 Air­ but not to exceed two under the head or two craft, Serial Numbers 1963 Through 1980, under the nut, to prevent the nut from bottom­ 2021 Through 2088; 649-749 Aircraft, Serial ing on the shank. Numbers 2503 Through 2590. 2610, 2611, 2614 Through 2618: 1049C Aircraft. Serial 55-23-2 Lockheed Applies to Models 1049C, Numbers 4501 Through 454S: 1049E Air­ D, E, and G, Serial Numbers 4163 Through craft, Serial Numbers 4549 Through 4555, 4166, 4520 Through 4581, 4583 Through 4558, 4559. and 4563 Through 4565: 1049D 4605, 4608 Through 4615, and 4620. Aircraft, Serial Numbers 4163 Through Compliance required as indicated. 4166. 1. Inspect the outer wing main beam web Compliance required by April 1. 1956, for between wing Stations 510 and 668 left and Model 1019 aircraft and October 1, 1956, for right for cracks as soon as practical and repeat Models 049 149 and 649 749 aircraft. at 125-hour intervals until reinforcement in accordance with paragraph 2 is accom­ To improve the fire-resistance integrity of plished. If cracks are found repair imme­ the above aircraft, revisions to the system sup­ diately in accordance with Lockheed Repair plying cooling air to the accessory section of Manual, Report 8882, and continue 125-hour the powerplant installation are considered nec­ inspections until reinforcement per paragraph essary. 2 is accomplished. Inspection for fuel stains For 049-149 aircraft and 649-749 aircraft, alone as an indication of a crack is not sufficient the revision consists of installing a shutoff because of the presence of fuel sealant on the valve in a fireproof duct. forward side of the web. For the 1049C and E aircraft, the revision 2. To be accomplished as soon as possible, consist of replacing a section of aluminum duct but not later than next scheduled progres­ between the oil cooler scoop, and the existing sive overhaul time, and in no case later than shutoff valve, with a fireproof duct. This sec­ December 1, 1956, whichever occurs first: Re­ tion is in zone 1, and provides a possible zone inforce the main beam web, left and right, 1 to zone 2 firepath. between wing Stations 510 and 668. This shall Lockheed Service Bulletins 49 718, for 049/ be accomplished by the addition of three 149 aircraft: 1049/2384, for 1049 aircraft: and extruded 75S-T6 stiffeners, (LS2186 or 49 39lA, for 649-749 aircraft, cover these sub­ LS6097) or equivalent between each of the jects. original stiffeners. The LS347-3 stiffeners added previously in accordance with AD 55-17-1 Lockheed Applies to All Models 49, 54-24—2 on some of these aircraft may be re­ 149, 649, 749, and 1049 Airplanes. tained. In these cases, one new (LS2186 or Compliance required by December 1, 1955, LS6097 or equivalent) stiffener must be added unless already accomplished. between each of these and the original stiff­ A recent failure of wing flap torque tube eners in this area. assembly, P/N 326605-3. on a Model 1049C is (Lockheed Service Bulletin No. 1049/SB- attributed to a defective bolt. P X AX 23-19. 2753 also covers this subject.) Initial overtorque of the bolt is suspected as the cause of failure of the bolt. It is therefore 55-23-3 Lockheed Applies to Models 49, necessary that all Constellation and Super 149, 649, 749 and 1049 Aircraft, Serial Num­ Constellation airplanes be inspected to ascer­ bers 1963 Through 1980, 2021 Through 2088, tain proper installation of bolts, including bolt 2503 Through 2590, 2610, 2611, and 2614 torque, on all wing Sap torque tubes. Through 2677, 4001 Through 4024, 4163 LOCKHEED L-23

Through 4166, 4501 Through 4581. 4583 2. To be accomplished as soon as possible Through 4594, 4602 Through 4604, and 4613 but not to exceed next overhaul period after Through 4615. parts become available. The rudder and ele­ Compliance required as indicated. vator servo must be reinforced by installation 1. As soon as possible, but not later than of a secondary servo support bracket to pro­ next 250 hours conduct magnetic particle or vide additional support and vibration dampen­ magnaglow inspections on main landing gear ing. downlock spring cylinder assembly rod end (Bendix Eclipse-Pioneer Service Bulletin P/N 295168 for cracks in the threaded portion. No. 858 and Lockheed Service Bulletins Nos. If cracks are found replace the part immedi­ 49-864 and 1049-2830 also cover this subject.) ately. Repeat inspection, magnetic particle 56-25-1 Lockheed Applies to All Models 49, or 20-power magnifying glass at 300-hour in­ 149, 649, 649A, 749, 749A Aircraft; Model tervals until replacement in accordance with 1049 Serial Numbers 4001 Through 4024; paragraph 2 is accomplished. Model 1049C Serial Numbers 4501 Through 2v Replace downlock spring cylinder as­ 4520 and 4523 Through 4538. sembly P/N 270104 with new assembly P/N Compliance required at first block overhaul 475211 as soon as practical but not later than following receipt of parts or by March 1, 1958, the next progressive or base overhaul period whichever occurs first. approximately 2,500 hours. Concurrently with In view of the continuing series of incidents this replacement, line ream the lugs on the wherein flaps extend on one side of the aircraft downlock strut assembly to (0.3770 inch-0.3780 out of symmetry with the other side, a means inch) diameter and replace the spacer P/N shall be installed which will automatically 268225-2 with bushing P/N LS3859-4r-1094 shut off the hydraulic power to the flap actu­ and replace bolt AN 23-21 with AN 23-22 ating motors whenever an asymmetrical con­ attaching the lower end of the spring cylinder dition exists. One method of accomplishing assembly to the downlock strut. this means is described in Lockheed Service (Lockheed Service Bulletins 49/860 and Bulletin No. 49/SB-794 for the 49/749 Series 1049/2709 also cover this subject.) and No. 1049/SB-2270 for the 1049 Series.

56-8-1 See Curtiss Propellers. 56-26-1 Lockheed Applies to Super Con­ stellation 1049 Series Aircraft, LAC Serial 56-16-2 Lockheed Applies to All Models Numbers 4501 Through 4565, 4572 Through 49, 149, 649, 749 and 1049 Series Aircraft 4647 and 4163 Through 4166. Equipped With Bendix Eclipse-Pioneer Compliance required as soon as possible but Type PB-10 Series Automatic Pilot Instal­ not later than the next block overhaul or major lations. inspection period after parts become available. Compliance required as indicated. The relays housed within the generator Numerous instances of fatigue failures have feeder protection main relay box have been been reported in the side webs of the Bendix found capable of overheating at high generator Eclipse-Pioneer Type DQ-15 Series servo dis­ output. This could become excessive when one connect mounting brackets in the primary or more generators become inoperative. This flight control system. Since complete failure box contains the main DC bus, which is the could result in disabling the flight control tie-point of all primary electric power for the system, the following must be accomplished as airplane. To minimize the probability of com­ indicated: plete electrical outage in this vital area, greater 1. The rudder and elevator servo disconnect heat transfer capability shall be provided mounting bracket installations in the primary either by installing a blower and replacing the flight control system must be inspected by dye existing interconnecting bus bars with new bus penetrant or equivalent method, at 125-hour bars having increased cooling areas, or by an intervals until item 2 is accomplished. De­ equivalent means approved by the Chief, Engi­ fective servo mounting brackets must be dis­ neering and Manufacturing Branch, FAA carded. Western Region. L-24 LOCKHEED

(Lockheed 1049 Service Bulletin No. 2838, Removal of the perforated cover does not affect dated August 20,1956, contains FAA-approved the filtering characteristics of the filter ele­ rework information for compliance with this ment. Filter elements without the paper cov­ AD.) ering are identified as Purolator P/N 30868-3. This airworthiness directive does not apply 57-23-1 Lockheed Applies to All Model 18 to aircraft equipped with two 11 KYA alter­ Aircraft Equipped With Vacuum Systems. nators. Compliance required at next engine overhaul Revised July 25,1962. but not later than July 15,1958. 57-3-2 Lockheed and Douglas Applies to To guard against the possibility of exces­ Lockheed Models 49, 149, 649, 749 and 1049 sive air temperature and associated fire haz­ Series Airplanes and Douglas DC-7 Series ards in the vacuum system discharge line, one Airplanes With Wright Engines. of the following modifications must be accom­ Compliance required not later than Decem­ plished : ber 1, 1957. 1. Install a fusible plug in the side of the Under certain cold weather operating con­ vacuum pump discharge port at right angles ditions it is possible for the fuel inlet strainer to the axis of the discharge port boss. Some and other parts in the engine master control pumps incorporate a plugged hole in the dis­ to become clogged with ice as a result of charge port which may be enlarged to a %-inch entrained water in the fuel freezing on the pipe tapped hole to accommodate the fusible screen. This has caused a loss of power on plug. This plug should employ an AN 840-8D all engines simultaneously. fitting with a binary eutectic mixture of 67.8 To relieve strainer icing, a screen having percent tin and 32.2 percent cadmium, which a bypass valve Bendix P/N 366204 should be has a melting point of 351° F. A drawing de­ installed in replacement of the screen not hav­ scribing the design of such a plug is shown ing a bypass valve. Bendix Service Bulletin in Douglas Figure 2. The %-inch plug fitting No. 797 covers this subject. It should be noted is intended for pumps such as the Model 3P- that the incorporation of the screen with by­ 211 and 3P-485. For smaller pumps such as pass will not positively prevent power loss the 3P-207, and AN 840-6D fitting, incorporat­ from fuel ice: therefore, work is continuing to develop a means to protect other portions of ing the same modification as shown below, the master control downstream of the inlet should be used. Brass fittings of the same de­ strainer. If necessary, a supplement to this sign as the above dural fittings are acceptable. note will be published when additional in­ Incorporation of an overboard drain line formation becomes available. clamped to the fusible plug is recommended but is not mandatory. On installations which 57-3-3 Lockheed and Douglas Applies to do not use an overboard discharge line the pos­ Lockheed Models 49, 149, 649, 749 and 1049 sibility exists that the plug may damage other Series and Douglas DC-7 Series Airplanes. nacelle components if it can hit them upon be­ Compliance required by April 1, 1957, for ing blown out of the adapter at high velocity. Lockheed aircraft and by May 1, 1957, for Therefore, if no overboard discharge line is DC-7 aircraft. provided, the installation must be made in such Under certain cold weather operating con­ a manner that the plug will not be directed to­ ditions the perforated paper covering around ward any vulnerable components when it issues the Purolator micronic filter elements are sub­ from the adapter, or ject to accumulation of ice as a result of en­ 2. Employ an oil separator equivalent in trained water crystals in the fuel freezing on principle to the Genisco No. 40081 incorpor­ this covering. This interferes with proper fuel ating a pressure relief valve which can be filtering by causing the fuel to pass through disassembled for cleaning. the bypass valve in the filter unit. To make the micronic filter less susceptible 58-1-5 Lockheed Applies to All Models 49- to clogging by ice, the perforated paper cover­ 46, 149, 649, 649A, 749, 749A, and 1049-54 ing around the filter element is to be removed. Aircraft. LOCKHEED L-25

Compliance required as indicated. LAC approved equivalent. In addition to the As a result of cracks discovered in Lock­ X-ray inspections at 3,200 hours, aircraft with heed 749A wing skin and stringers, the follow­ over 20,000 hours must be visually inspected at ing inspections shall be accomplished on the 200-hour (maximum) intervals as follows: various model aircraft as indicated, and if any Inspect the bottom side of lower wing skin, cracks are discovered, they must be repaired for leaks resulting from cracks, from front prior to further operation. Any FAA/LAC beam to rear beam between W.S. 125 and W.S. approved repair may be used. 145 and between W.S. 191 and W.S. 215. This necessitates opening the kidney plate inspec­ Inspect and reinspect for cracks in the lower tion holes in the nacelle to wing fillets on the wing skin and stringers, left and right, from inboard and outboard sides and/or removal wing Station 125 through Station 215 between of the tail cone assembly of nacelles No. 2 and the front and rear beams. Inspections to be No. 3. This area should be given special at­ conducted at the following specified times and tention. If leaks are discovered and cracks sus­ intervals using X-ray and visual, or visual pected, tanks must be opened and stripped of means. The X-ray inspection method is recom­ sealant to visually inspect upper side of skin. mended if equipment is available, since cracks Inspect the upper side of lower wing skin for under the stringers would be detected. cracks in the dry area from front beam to rear I. For Models 649, 649A, 749, 749A and beam between W.S. 145 and W.S. 191. See 1049-54: Lockheed Sketches No. 101057 and No. 101058 A. The first inspection should be per­ for location of cracks which have been pre­ formed before 20,500 hours have been ac­ viously discovered \ or cumulated on the aircraft. For aircraft on (3) When X-ray equipment is not which inspections of STA 191 through 206 available, a visual inspection must be made have already been made in accordance with at 800-hour (maximum) intervals after open­ AD 56-3-1, initial inspections of additional ing the fuel tanks and removing the sealant indicated areas need not be earlier than and from the designated areas. It should be noted may be correlated with reinspections required that cracks under stringers cannot be detected by Bl, B2, and B3. by the visual inspection method. B. Reinspections must be accomplished in C. The reinspections required as per para­ accordance with one of the following pro­ graph Bl, B2, or B3, may be discontinued when grams : permanent reinforcement per Lockheed Draw­ (1) X-ray at 2,500 hours (maximum) ing No. 550236 has been accomplished, except intervals without opening the fuel tanks fol­ that: lowing the recommendations and technique In the area from W.S. 125 to W.S. 191 where outlined on Lockheed Sketch No. 101057 or the size and kind of material remains un­ a FAA/LAC approved equivalent. In addi­ changed (i.e., the old material is merely re­ tion to the X-ray inspection at this time, the placed with new) the reinspection program bottom side of the wing skin must be visually noted above must be reinstated not later than inspected from front to rear beam beneath the 20,000 hours after rework. nacelle to wing fillets on the inboard and out­ D. Lockheed Drawing Nos. 11755, 490668, board sides of No. 2 and No. 3 nacelles. This 492806, and 493312, describe approved perma­ necessitates opening the kidney plate inspection nent repairs for individually affected areas in holes in these fillets and/or removal of the tail which cracks have been previously discovered. cone assembly. See Lockheed Sketch No. Reinspections in the area between W.S. 191 and 101057 for location of cracks which have pre­ W.S. 215 may be discontinued if permanent re­ viously been discovered; or pair is made per Lockheed Drawing No. 11755. (2) X-ray at 3,200 hours (maximum) The reinspection program must be reinstated intervals by opening the fuel tanks and fol­ not later than 20,000 hours after rework is ac­ lowing the technique outlined on Lockheed complished in the individually affected areas Sketches No. 101057 and No. 101058, or FAA/ per drawing numbers 490668,492806, or 493312. L-26 LOCKHEED

n. For Models 49-46 and 149: system installed, particularly when the fire A. The first inspection should be per extinguishing agent containers are installed in formed before 25,500 hours have been accum­ the fuselage, one of the following must be ac­ ulated on the aircraft. For aircraft on •which complished. inspections of STA 191 through 206 have al­ 1. The Bromochloromethane (CB) fire ex­ ready been made in accordance with AD 56- tinguisher agent must be replaced with a 3-1, initial inspections of additional indicated quantity of Freon 13B1 (Bromo-tri or CF3Br), areas need not be earlier than and may be equal to 0.8 times the installed weight of Bro­ correlated with reinspection required by Bl, mochloromethane (CB) and a suitable breath­ B2, and B3. ing oxygen supply must be provided for the B. Same as paragraph LB. crew as specified in CAR 4b.651. 1. Same as paragraph LB. (1). 2. The Bromochloromethane (CB) fire ex­ 2. Same as paragraph I.B.(2) (except tinguisher agent must be replaced with a quan­ substituted 25,000 hours for 20.000 hours). tity of carbon dioxide (COs) equal to 1.25 3. Same as paragraph I.B.f 3). times the installed quantity of Bromochloro­ C. The reinspections required as per para­ methane (CB) and a suitable breathing oxygen graph Bl, B2, or B3 may be discontinued, supply must be provided for the crew as speci­ when permanent reinforcement per Lockheed fied in CAR 4b.651. Drawing No. 550236 has been accomplished, 3. The installed Bromocholormethane (CB) except that: system must be shown to comply with the re­ In the area from W.S 125 to W.S. 191 where quirements of CAR 4b.371(b) and 4b.484 the size and kind of material remains un­ (b)(2). changed (i.e., the old material is merely re­ NOTE : This may be accomplished by enclos­ placed with new) the reinspection program ing the containers with a similar or equivalent noted above must be reinstated not later than system to that shown on AiResearch Drawings 25,000 hours after rework. C-4900-77B sheets 1 to 3 inclusive. D. Lockheed Dwg. Nos. 11755, 490191, 58-11-2 Lockheed Applies to All Model 18 490668, 492806, and 493312 describe approved Aircraft. permanent repairs for individually affected Compliance required as indicated. areas in which cracks have been previously A number of reports has been received rela­ discovered. Reinspections in the area between tive to cracks in the welds of the drag strut W.S. 191 and W.S. 215 may be discontinued yoke (P/N XY450-2L-1) on the main landing if permanent repair is made per Lockheed gear. These cracks, as they progress, result Drawing No. 11755 or 490191. The reinspec­ in continuing reduction in the strength of the tion program must be reinstated not later than landing gear and hence render the landing gear 25,000 hours after rework is accomplished in unairworthy. It is, therefore, necessary to in­ the individually affected areas per drawing spect the main landing gear for cracks in Nos. 490668, 492806, or 493312. the area indicated as follows: This supersedes AD 56-3-1. 1. Not later than July 1, 1958, and at each 58-8-3 Douglas and Lockheed Applies to 500 hours of operation thereafter inspect the All Douglas DC-3, Lockheed 18, and PV-1 main landing gear by means of dye penetrant, Aircraft Having Bromochloromethane (CB) magnetic particle or equivalent. Fire Extinguisher Systems. (NOTE: Not 2. At each 100 hours of operation conduct Applicable to Systems Which Provide Leak- a visual inspection using an 8-power magni­ proof Enclosures for the Fire Extinguishing fying glass or equivalent. Agent Containers.) In the event cracks are found, the oleo strut Compliance required by October 1, 1958. must be replaced. Due to the toxicity hazard for crew and If the oleo strut is replaced by a new part passengers existing in these airplanes having the above inspections need not be resumed Bromochloromethane (CB) fire extinguishing until after 3,000 hours of service. LOCKHEED L-27 I For the purpose of compliance with this bolt to reduce the grip exposure to a minimum airworthiness directive, X-ray inspection is not of 0.003-inch. considered an equivalent of dye penetrant or (Lockheed Service Bulletin No. 18/SB-150 magnetic particle inspection. covers this same subject.) This supersedes AD 58-7-2. 58-13-3 Lockheed Applies to All Model 58-11-3 Lockheed Applies to All Models 18 1649A Aircraft. Series and PV-1 Aircraft. Compliance required as indicated. Compliance required as soon as possible, Model 1649A aircraft have been found to but not later than December 1, 1958. have possible hazardous wing bending oscil­ Numerous reports have been received of lation, dynamically induced by aileron oscilla­ cracks occurring at the base of the rudder cable tion, under certain combinations of boost pack­ attachment tangs, on rudder control quadrant, age tolerances and autopilot modulating piston Lockheed P/N 53026. There is evidence that follow-up failure. In order to correct this con­ excessive clearance may exist between the tangs dition, the following must be accomplished: and the rudder cable attach fittings which per­ Modify the aileron control valve by install­ mits a bending load to be applied at the base of ing a new modulating piston stop to meet the tangs, when the AN 5 attach bolts are limits of aileron deflection rates of 7.5° per tightened. second minimum and 11° per second maxi­ P/N 53026 should be inspected by means of mum. The valve is then to be reidentified as a dye penetrant or equivalent inspection means 668152-11 and to be painted yellow to denote in the areas noted above. If cracks are found, noninterchangeability with elevator and rud­ the parts must be replaced. der valves. Details of the necessary modifica­ Furthermore, the means of attaching the tions are given in Lockheed communication rudder cables to the quadrant must be modi­ FS/225805-W, dated June 13, 1958. fied to preclude over-loading the attach tangs This modification is to be accomplished as and subsequent occurrence of cracks due to the soon as maintenance schedules will permit but tightening of the attach bolts. not later than January 1, 1959. Until the Two acceptable means of accomplishing the modification is accomplished, the airplane must modification are noted below: be flown in autopilot operation at speeds not the tangs, when the AN 5 attach bolts are tight to exceed 215 KIAS. 1. Replace both the AN 5 bolts with AN 4- This supersedes AD 58-1H. 12A bolts, AN 365 nuts and AN 960-516 wash­ ers, under the head and nut in conjunction with 58-20-3 Lockheed Applies to Models 049,

5 a /l6 x 0.032-inch wall cadmium plated steel 149, 649, 649A, 749, and 749A Aircraft; spacer 1-inch long as a sleeve. The length Serial Numbers 1963 Through 1980; 2021 of the sleeve may protrude past the thickness of Through 2088; 2501 Through 2631; 2633

the washers a maximum of y16-inch or a mini­ Through 2638 and 2640. mum of 0.003 inch so that when tightened, the Compliance required as indicated. nut will bottom against the spacer and not on A recent in-flight failure of an aft pressure the washers. bulkhead has been determined to have resulted NOTE: TO compensate for machining toler­ from severe corrosion in the area of the ances and casting variation, additional washers lavatories. or various length sleeves may be used to obtain The following must be accomplished on all the proper sleeve exposure. aircraft which have accumulated 6,000 or more 2. Replace the AN 5 bolts with AN 25-20 flight hours. Items 1. and 2. are not applica­ clevis bolts, AN 516 washers, AN 320-5 nuts ble to any of the aircraft which have been and AN 380-2-3 cotter pins. inspected in accordance with 2. and repaired

NOTE: If more than i46-inch of bolt grip is as necessary per 3., within the past 4,000 exposed after installing the nut and washer, due hours. All affected aircraft will be limited to to machining tolerances and casting variation, 2 p.s.i. cabin pressure differential until 1. and place additional washers under the head of the 2. have been accomplished. L-28 LOCKHEED

1. Unless already accomplished per Lock­ 58-21-1 Lockheed Applies to All Models heed wire FS/228233W or FS/228562W, 049, 149, 649, 649A, 749, 749A, 1049-54, within nest 50 flight hours thoroughly exam­ 1049C, 1049D, 1049E, 1049G, and 1049H and ine the aft side of the pressure bulkhead (Sta­ 1649 Aircraft. tion 1037) and adjacent shell structure be­ Compliance required as indicated. tween stringers 24 and 48. Clean and apply This is a supplement to AD 58-20-3, in that concentrated pressure with a device, which it applies to an additional area of the pressure will not scratch good metal, to detect any indi­ bulkhead (Station 1037) and to a greater num­ cation of corrosion which may have developed ber of aircraft. A recent inspection of a Model on the forward side. If even slight indication 1049E airplane with 10,500 hours logged time of corrosion is found, conduct inspection 2. revealed extensive corrosion along W.L, 239 immediately. (approximately) between a wood strip and 2. Unless already accomplished per Lock­ pressure diaphragm at the lavatory seat level. heed wire FS/228233W or FS'228562W, Reported corroded area was approximately 27 within next 200 flight hours remove toilets, inches long by 5 inches wide. trim, plywood, insulation, paint, sealant, etc., Accordingly, on all aircraft that have or to espose all bulkhead, bulkhead ring and once had lavatories in this area, accomplish shell structure, both forward and aft side of the following: Station 1037, below the seat level and between 1. Unless already accomplished per Lock­ stringers 24 and 48 and thoroughly inspect both heed wire FS/229080-W, within the next 50 sides of the pressure bulkhead and ring. Par­ flight hours thoroughly examine the aft side ticularly close inspection shall be made to de­ of the bulkhead for corrosion in the area of tect any evidence of corrosion at the periphery W.L. 239 from a height of 2 inches above to of faying surfaces at the pressure diaphragm 2 inches below the eenterline of rivet or screw attachment to the bulkhead ring, the elevator- attachments across the full width of the bulk­ rudder cable pulley bracket attachment on the head. Probe the area with a blunt tool to lower left side and the Cannon plug attach­ detect advance stages of corrosion. If any ment. evidence of corrosion is found, conduct in­ 3. Replace any material or parts which show spection under step 3. immediately. evidence of corrosion damage and thoroughly 2. Unless already accomplished per Lock­ clean entire area, apply inhibitor, reseal, and heed wire FS/229080-W, within 400 hours, paint in accordance with standard maintenance inspect in accordance with step 3, or alter­ procedure. (See also 5.) natively as follows: 4. Inspect as in 2. and repair as in 3. at each Remove %-inch maximum diameter slugs block overhaul or at periods not to exceed 4,000 from the pressure diaphragm by means of a hours. This time may be increased to 8,000 hole saw or equivalent method. Take samples hours on those airplanes in which sealing and at approximately 6- to 7-inch spacing from drainage provisions equivalent to those out­ the back side of the bulkhead across its full lined in Lockheed Service Bulletin Xo. SB/597 width at approximately W.L. 239. Do not are incorporated. cut samples from diaphragm area covered by 5. If corrosion is found, flight operations stiffeners. If samples show any evidence of shall be restricted, pending repairs, as follows: corrosion, conduct inspection in accordance (a) Xd flight is permissible with significant with step 3. immediately. Holes in diaphragm corrosion damage to bulkhead ring, web, con­ may be plugged in accordance with negligible trol brackets or shell structure. damage repair shown in applicable structural (b) Unpressurized flight is permissible if repair manual. damage is confined strictly to the pressure 3. If corrosion is found as a result of steps diaphragm. 1. or 2., the following inspections shall be con­ (Lockheed wire FS/228562W, dated Septem­ ducted immediately. If both steps 1. and 2. ber 30, 1958, covers the same subject.) (Lock­ reveal no corrosion, the following inspection heed Structural Repair Manual, Report Xo. shall be conducted at the nest block overhaul 5886, covers acceptable repair methods.) or within 4,000 flight hours whichever occurs LOCKHEED L-29

first and at each block overhaul or 4,000-hour may be replaced by an identical part pending period thereafter. Remove toilet seats and final replacement of the guide assembly as other portions of installation as required. indicated below. Peel back trim and insulation to expose trim If no cracks are found the part must be strip and at least 2 inches of bulkhead web reinspected in the same manner at intervals above and below trim strip, completely across not to exceed 60 flight .hours. This reinspec- bulkhead within each lavatory compartment. tion procedure may be terminated upon re­ Remove trim strip and all paint, sealant and placement by P/N 318332. cement from the exposed area of web. Make Unless sooner accomplished, P/N 270197 close visual inspection for corrosion. must be replaced by P/N 318332 at the first 4. Replace any material or parts which show block overhaul after July 1, 1959, or in any evidence of corrosion damage. Strip to bare case no later than July 1, 1960. (Lockheed metal, apply inhibitor, sealant, and paint to Service Bulletins 49/SB-707 and 1049/SB- all exposed web areas. In applying this pro­ 2021 describe the installation of P/N 318332.) tection, -if the sealant and protective materials (FAA telegraphic instructions of January 30, noted in Lockheed SB/597 are used, further 1959, covered this subject.) special inspection at 4,000-hour intervals may 59-7-1 See Curtiss Propellers. be discontinued and normal routine inspections resumed. 59-7-3 Lockheed 5. If corrosion is found, flight operations Superseded by AD 62-1-2. shall be restricted, pending repairs as follows: 59-7-4 Lockheed Applies to All Models (a) Unpressurized flight is permissible if 049, 149, 649, 749 and 1049 Series Aircraft. corrosion damage is found on the diaphragm Compliance required as indicated. as a result of inspection per steps 1. or 2. Several nose landing gear actuating cylinder (Lockheed wire FS/229080-W, dated Octo­ attach bolt failures have been determined to ber 13, 1958, covers the same subject as this have resulted from fatigue. supplement.) (Lockheed Structural Repair On all aircraft which have accumulated Manuals, as applicable, cover acceptable repair 10,000 or more flight-hours, the following must methods.) be accomplished at the next block overhaul, 59-3-2 Lockheed Applies to All Models or 4,000 flight-hours, whichever occurs first, 049, 149, 649, 649A, 749, 749A, and 1049-54 and thereafter at intervals not to exceed 10,000 Aircraft Except Those Already Incorpo­ flight-hours. rating the Improved Main Landing Gear The two forward bolts, P/N 307403 and P/N Downlock Guide Assembly Per Lockheed 307404, which attach the forward end of the Service Bulletin 49/SB-707 and 1049/SB- actuating cylinder to the fuselage structure 2021. via a universal joint, must be replaced with Compliance required as indicated. new unused bolts. The following inspections and replacement Similarly, the aft bolt, P/N 307402 which have been established as a result of fatigue attaches the actuating cylinder rod to the drag failures in the fillet radius of the main land­ strut pivot must be replaced with new unused ing gear downlock guide stub, P/N 270201-3. bolts. Unless already accomplished, within the next 59-12-2 Lockheed Applies to All Models 150 flight hours inspect all Model 049, 149, 049, 149, 649, 749 and 1049 Series Aircraft. 649, 649A, 749, 749A and 1049-54 aircraft for Compliance required as indicated. fatigue cracks in the main landing gear down- The following inspections have been estab­ lock guide stub fillet radius, P/N 270201-3, lished as a result of recently found corrosion by magnetic inspection. and cracking on the wing Station 80 bathtub If cracks are found replace the entire main fittings, P/N's 251245 and 251246 on Model landing gear guide assembly, P/N 270197, 049, 149, 649, 749 Series aircraft and Model with downlock guide assembly P/N 318332. 1049-54 aircraft and P/N's 310008 and 310009 If P/N 318332 is not available P/N 270201-3 on the remaining Model 1049 Series aircraft. L-30 LOCKHEED

These inspections shall be accomplished on (4) Inspect the bathtub fitting end lugs for all aircraft which have accumulated 12,000 corrosion. Maximum permissible combined or more flight-hours. Inspect affected aircraft depth of corrosion on mating fitting lugs at the next block overhaul or within 4,000 should not be such as to increase the total gap flight-hours, whichever occurs first. between mating faces in excess of 0.020 inch. Inspect all aircraft for cracked bathtub Replace fittings which cannot be cleaned up fittings as follows: within this tolerance. The special inspection note above may be (1) Inspection may be made by removing extended an additional 12,000 flight-hours for the wing-to-fuselage fillet and dye checking each wing on which all fittings are replaced. the forward and aft edges on the neck of the Otherwise reinspection at 4,000 flight-hour bathtub fittings lugs of both the inner and periods or block overhaul whichever occurs stub wing fittings. first is required to insure detection of cracked (2) Replace any cracked bathtub fittings. or corroded Wing Station 80 bathtub fittings Inspect each inner wing and stub wing Sta­ or attachments. tion 80 fitting for corrosion as follows: (Lockheed Service Letter FS/231053 covers (1) Visually inspect the inner and stub this same subject.) wing Station 80 joint bathtub fittings adja­ 59-16-2 Lockheed Applies to All Models cent to the DD8 rivets and rivet attachments 18, PV-1, and PV-2 Series Aircraft Except taking particular care to note any imperfec­ Those Incorporating Spar Reinforcement As tions or paint defects. Probe further when­ Covered in Lockheed Aircraft Service Bulle­ ever defects in paint are discovered in order tin 18/SB-112. to detect any corrosion. Compliance required as indicated. (2) Replace any wing Station 80 bathtub Numerous reports have been received where­ fittings on which corrosion cleanup exceeds in fatigue cracks have been found in the a depth of 0.025-inch or a diameter of 0.70 horizontal stabilizer spars in the area of the inch (approximate diameter of a dime) vertical fin attachments. In order to deter­ around rivet attachments. Remove corrosion mine if this condition has developed, the fol­ if within the allowable and treat per Lock­ lowing inspection is required. heed Report 8882, (also 7789 and 5886) para­ Within the next 50 hours of flight and at graph 1-67N, revised July 15, 1957, or equiva­ 300-hour intervals thereafter inspect the hori­ lent. zontal stabilizer front and rear spar flanges (3) Inspect the stub wing and inner wing and webs for cracks in the region of the verti­ skin upper surface for corrosion around the cal fin attaching angles. If cracks are found, bathtub fitting screw holes. Also inspect the stop-drill, install spar flange and web doublers stub wing and inner wing upper skin lower and flange filler blocks extending beyond the surfaces between corrugations for corrosion. fin attaching angles. Add doubler plates on Maximum allowable skin cleanup without re­ the forward face of rear spar in region of sorting to a doubler repair is 0.020-inch deep rudder hinge bracket attachment holes. Visual or an area not exceeding one inch wide and inspections of the area with a 10-power glass three inches long, provided screw holes are are adequate. The 300-hour inspection may be not enlarged. Areas of skin corrosion ex­ discontinued after incorporation of the rein­ ceeding these allowable limits should be re­ forcements. One approved method of accom­ paired in accordance with applicable Struc­ plishing the above spar reinforcement is con­ tural Repair Manual procedures. Clean up tained in Lockheed Aircraft Service Bulletin and protect corroded areas per Lockheed Re­ 18/SB-112 dated September 18, 1944, pertain­ port 8882, (also 7789 and 5886) revised July ing to this same subject. 15, 1957, or equivalent. It must be determined that any corrosion is confined to the skin only 59-17-3 See Hamilton Standard Propellers. and does not penetrate into the corrugations. 59-18-4 Lockheed Applies to All Models Reinstall all screw attachments flush in to the 1049C, 1049D, 1049E, 1049G and 1049H cleaned up areas. Aircraft. LOCKHEED L-31

Compliance required as indicated. 59-21-2 Lockheed Applies to All Model 188 The following inspections have been estab­ Series Aircraft. lished as a result of recently found cracking Compliance required as indicated. in the inner wing rear spar web at Wing Sta­ Due to repeated loosening of wing leading tion 458. edge attachment screws between the fuselage At the next block overhaul or 4,000 flight- and the outboard nacelles, the following in­ hours, whichever occurs first, on all aircraft spections shall be conducted: (regardless of accumulated flight time) inspect (a) At each 50 hours of service time, vis­ the inner wing rear spar web at Station 458 ually inspect the leading edge attachment for cracks in the upper and lower notched screws, top and bottom, from the fuselage to web area shown in Lockheed Drawing 555353. the outboard nacelles, paying particular atten­ Inspection is applicable to both left and right tion to screws adjacent to nacelles. Tighten wings. any screws found loose. If cracks are discovered incorporate the re­ inforcements shown in Lockheed Drawing (b) At 300-hour intervals retighten all af­ 555353, or equivalent. fected screws to 25 to 40 inch-pounds torque. If no cracks are discovered, the reinforce­ The above inspection program may be dis­ ments shown in Lockheed Drawing 555353 may continued upon the removal of the NAS 517-3 be incorporated. Otherwise, reinspection at screws from all leading edge attachments, top 4,000 flight-hour periods or block overhaul, and bottom, and the installation of LPHT whichever is less, is required to insure detection 517-3 screws. Torque all new leading edge of cracks. attaching screws to 45-55 inch-pounds. (Lockheed Service Letter FS/231094 covers (Lockheed Service Bulletin 88/SB-334 cov­ this same subject.) ers this same subject.) 59-20-2 Lockheed Applies to All Model NOTE: LPHT-517 refers to Lockheed Speci­ 1649A Aircraft. fication for a Long-Lok, Polyvinyl insert, High torque screw. Compliance required on items (1) and (2) by October 15, 1959; compliance required on 59-25^1 Lockheed Applies to All Model item (3) by December 1,1959. 188 Series Aircraft—Serial Numbers 1002 As a result of a recent accident involving a Through 1072. suspected explosion of a wing tank, the follow­ Compliance required as indicated. ing shall be accomplished to prevent the pos­ Insufficient clearance between the generator sible recurrence of such an explosion: feeder wires and the leading edge rib at wing (1) Remove the static wick on the inboard Station 221 together with deflection of the lead­ wings adjacent to the tank vents. ing edge has resulted in abrasion of the insula­ (2) Install temporary placard at engineer's tion on the generator feeder wires and ground­ station reading as follows: "In order to main­ ing of the generator feeder. tain a nonexplosive rich mixture in tanks, do (a) Inspect for evidence of abrasion not not use fuel out of auxiliary tanks Nos. 5, 6, later than the next 8 hours' time in service and 7 below 50 gallons. In operations which with a light and mirror through fillet access involve use of fuel from main tanks only, the doors N125 and N126 left and right without, 50 gallons of residual fuel1 in the auxiliary lowering the leading edge section. If the in­ tanks must be replaced with 50 gallons of fresh spection shows evidence of abrasion, additional fuel or mixed with at least 150 gallons of fresh spacers must be installed prior to the next fuel at' the end of every 12 flight-hours or 5 flight to obtain a minimum 0.38-inch clearance flights, whichever occurs first." with the flange of the leading edge rib. If no (3) Install P/N 634014-1 or equivalent flame evidence of abrasion is present, the inspection arrestors in the tank vent outlets. must be repeated at intervals of 60 hours' time After installation of flame arrestors de­ in service but not to exceed 250 hours' time in scribed in item (3), item (2) may be disre­ service when additional spacers must be in­ garded. stalled to provide at least a 0.38-inch clearance. L-32 LOCKHEED

Functionally test the generator differential (b) Models 1049-54 and 1049C aircraft. protection system in accordance with Lock­ (1) Remove and inspect by the dye pene­ heed Maintenance Manual, Section 24-1-0, trant method the upper and lower aft P/N page 201. 291925 and/or P/N 308236 brackets of the P/N (b) Within the nest 250 hours1 time in serv­ 291940 and P/N 338239 upper and loweT aft ice inspect all wiring in the leading edge and latch assemblies of the P/N 308269 and P/N powerplant sections for actual or incipient 308269-600 forward passenger door assemblies abrasion of wires. If abrasion of wires or for cracks in the fillet radius of the attach insufficient clearance is found, the conditions flanges of the brackets. are to be corrected prior to the nest flight. (Lockheed Field Service Letters FS/222746 (Lockheed Electra Alert Service Bulletin and FS/220393-W pertain to this subject.) 376 covers this same subject.) Cracked latch brackets must be replaced. The replacement part may be either a new 59-26-7 Lockheed Amdt. 73 Part 507 Fed­ bracket of the same part number, the improved eral Register December 19, 1959. Applies to latch assembly P/N 554278-3, P/N 554289-1, Models 649 and 749 Aircraft, Serial Num­ or P/N 554289-3, whichever is applicable, or an bers 2518 Through 2524, 2529 Through 2535, equivalent item. 2548, 2549. 2554 Through 2556, 2610, 2611, (2) Check door rigging and condition of 2614 Through 2618. 2642, 2653, 2659, 2660, safety bar and hooks. 2662 Through 2673, Model 1049-54 Serial When the improved latch assemblies (iden­ Numbers 4001 Through 4024 and Model tified above by part number) are installed, 1049C, Serial Numbers 4523 Through 4538. this inspection procedure may be terminated. Compliance required as indicated. When the replacement bracket is identical to As a result of cracks discovered in forward the originally installed bracket, this inspection passenger door latch brackets the following procedure is to be reestablished upon accumu­ shall be accomplished on the above serial lation of 10,000 flight-hours on the replace­ numbered aircraft which have accumulated ment brackets. flight time of 10,000 hours or more. (Lockheed Service Bulletins 49/SB-882 and Unless already accomplished, within the nest 1049/SB-3052 describe the installation of the 200 hours of service time and at each succeed­ improved latch assemblies mentioned above.) ing 1,000 hours of service time the following 60-1-5 Lockheed Amdt. 74 Part 507 Fed­ inspections are required: eral Register January 6, 1960. Applies to (a) Models 649 and 749 aircraft. All 188A and 188C Aircraft- (1) Remove and inspect by the dye pene­ Compliance required as indicated. trant method the top and bottom P/N 291924- Continuing investigation of the propeller de- 2 and -3 brackets of the P N 291941-2 and icing power transfer relay has shown the de­ -3 top and bottom latch assemblies of the P/N sign of the relay is such that properly tight­ 290S09 forward passenger door assembly for ened terminals cannot be assured for a practi­ cracks in the fillet radius of attach flanges of cal interval of time due to cold flowing of the brackets. plastic relay body. (Lockheed Field Service Letters FS/222746 Upon arrival at the next station where main­ and FS 220393-W pertain to this subject.) tenance personnel are available, deactivate the Cracked latch brackets must be replaced. propeller deicing system by pulling the control The replacement part may be either a new circuit breaker on the main and essential direct bracket of the same part number, the improved current bus at the forward load center. Pla­ latch assembly P N 554278-1, P N 5543S9-1 card the propeller deicing system inoperative. or P N 5542S9-3, whichever is applicable, or On arrival at main base disconnect 8-gage an equivalent item. power wires from the priority A and B bus to (2) Check door rigging and condition of the propeller deicing power relay. Tape and safety bar and hooks. stow at priority bus end. LOCKHEED L-33

With the propeller deicing system deacti­ ing gear ribs and near the forward edge of the vated, aircraft may be dispatched into known plank. This inspection may be discontinued icing conditions if Icex compound (B. F. when an approved reinforcement designed to Goodrich Company Adhesive Depressant No. prevent cracking is installed.1 6) is applied to all propeller blade fairing (b) If cracks are found, FAA approved re­ heater boots and spinners under the following pair and reinforcement must be accomplished1 conditions: After initial application, Icex com­ prior to the operation of the aircraft except pound shall be reapplied after cumulative ex­ that the aircraft may be ferried to the base at posure to not more than six hours precipitation which the repairs and reinforcement may be during flight or after 50 hours elapsed time, performed. Upon installation of an approved whichever occurs first. reinforcement and repair the aircraft may be (Lockheed Alert Bulletin No. 403 wired to returned to service, and the daily inspection all operators on November 27,1959, covers this discontinued.2 same subject.) (c) An approved reinforcement shall be in­ The propeller electrical deicing system may stalled prior to February 1,1960. be returned to operative status when the origi­ This supersedes AD 59-16-6. nal propeller ice control relay (Lockheed P/N 60-3-5 Lockheed Amdt. 95 Part 507 Fed­ 613649-1, Leach P/N 9202^516) has been re­ eral Register February 2, 1960. Applies moved and a new relay (Lockheed P/N 613422- to All Model L-188 Aircraft. 17, Hart man B124-GL) has been installed in Compliance required by April 1, 1960. the circuit and physically located in the main Loss of the top cowl panel over the engine transfer relay box in a manner approved by tail pipe has occurred in flight due to insecu­ an authorized representative of the Adminis­ rity of the cowl latches. To prevent recur­ trator. When the propeller electrical deicing rence of this difficulty, the following modifica­ system has been reactivated in this manner, tions must be accomplished: Icex compound will no longer be required for (a) Modify latch assemblies by replacement aircraft dispatching into known icing condi­ of snap ring retention with clevis or shoulder tions. pin design and safety in place. (Lockheed Alert Bulletin No. 403 wired to (b) Install position pins and locators to all operators on November 27 covers the de­ provide more positive alinement of the cowling activation of the original Leach relay and the with the latches when in the closed position. use of Icex compound. Lockheed 188 Service (Lockheed Service Bulletins Nos. 188/295 Bulletin No. 403, effective December 15, 1959, and 188/365 cover this same subject.) describes a satisfactory and approved means of installing the replacement Hartman relay.) 60-4-3 Lockheed Amdt. 100 Part 507 Fed­ This airworthiness directive sent by tele­ eral Register February 9, 1960. Applies gram to all operators of Lockheed 188A and to All Model L-188 Airplanes Equipped 188C aircraft on December 8, 1959. With Lord Engine Mounts Number LM- 60-1-6 Lockheed Amdt. 85 Part 507 204A-SA4. Federal Register January 16, 1960. Applies Compliance required as indicated. to All Model 188A and 188C Aircraft Ex­ As a result of two incidents of front Lord cept Serial Numbers: 1001, 1044, 1088, 1090 engine mount fatigue failures on units of old and Up, For the Wing Station 167 Area In­ design the following must be accomplished: spections; 1001, 1044, 1057, 1066, 1068 and (a) Inspect mounts for cracks particularly Up, For the Wing Station 209 Area Inspec­ in the web and fillet areas upon next arrival at tions. scheduled stop where maintenance facilities Compliance with the following is required. are available and repeat this inspection at in­ (a) A daily visual inspection of the No. 4 tervals not to exceed 50 flight hours. Any left and right upper wing surface planks for 1 Lockheed Service Bulletin No. 88/SB-306 contains an ap­ proved reinforcement for the wing Station 209 area. spanwise cracks. The affected areas are adja­ 2 Eastern Air Lines sketches 62059 and 62259, revised June 25, 1959, contain an approved reinforcement and repair cent to the Nos. 2 and 3 nacelle attach angles in the wing Station 299 aTea. Lockheed sketch ALS 82959, Change A, contains an approved reinforcement and repair above wing Stations 167 and 209 main land­ for the wing Station 167 area. Lr-34 LOCKHEED

MOUNTS WITH CRACKS MUST BE REPLACED IMME­ (B) INSPECTION AND REWORK: DIATELY WITH LM-204A-SA5 'LOCKHEED P'X (1) Ultrasonic shear irave detection 632182-9. method. THIS PROCEDURE MAY BE USED ON (B) REPLACE ALL LM-204A-SA4 MOUNTS WITH CYLINDERS WITH PISTON AND OIL IN THE CYLINDER LM-204A-SA5 MOUNTS WITHIN 300FLIGHT HOUR S OR THE CYLINDER ONLY. REWORK IN ACCORDANCE AFTERFIRST INSPECTIO N REQUIRED BY (A) BUT NOT WITH (C) (2) MUST BE ACCOMPLISHED WITHIN LATER THAN MARCH 1,1960. 4.000 HOURS' TIME IN SERVICE IF THE ULTRASONIC (C) ALL SPARE QUICK ENGINE CHANGE UNITS METHOD IS USED. MUST BE MODIFIED TO INCLUDE THE NEW SA5 (2) Magnetic particle detection method. MOUNTS PRIOR TO INSTALLATION IN AIRCRAFT. THIS METHOD REQUIRES REMOVING AND DISMAN­ (LOCKHEED SERVICE BULLETIN XO. 228 COVERS TLING OF THE STRUT ASSEMBLY. REWORK IN AC­ THIS SAME SUBJECT.) CORDANCE WITH (C)(2) MUST BE ACCOMPLISHED WITHIN 4,000 HOURS1 TIME IN SERVICE IF THE MAG­ THIS AIRWORTHINESS DIRECTIVE SENT BY TELE­ NETIC PARTICLE METHOD IS USED. GRAM TO ALL OPERATORS OF IBS AIRCRAFT ON JANU­ (3) Radiographic method. THIS METHOD ARY 11, 1960. REQUIRES THE REMOVAL OF THE PISTON FROM THE 60-4-4 LOCKHEED AMDT. 101 PART 507 FED­ CYLINDER AND COMPLETE 360° COVERAGE. REWORK ERAL REGISTER FEBRUARY 13. 1960. REVISED IN ACCORDANCE WITH (C) (2) MUST BE ACCOM­ BY AMDT. 127 FEDERAL REGISTER APRIL 9.1960: PLISHED WITHIN 3,000 HOURS" TIME IN SERVICE IF AMDT. 200 FEDERAL REGISTER SEPTEMBER 15, THE RADIOGRAPHIC METHOD IS EMPLOYED. 1960. APPLIES TO ALL .Models TN^, U9, 649, (C) REPAIR AND REWORK INSTRUCTIONS: AND 749 SERIES AIRCRAFT WHICH HAVE THE (1) OUTER CYLINDERS WITH CRACKS IN THE CLEVELAND PNEUMATIC-MODEL 8298 SERIES RADIUS DESCRIBED IN (A) AND FOR A DISTANCE OF MAIN LANDING GEAR STRUTS INSTALLED WITH 0.5 INCH BELOW THE RADIUS TANGENCY POINT CIR- THE REMOVABLE SIDE BRACE ATTACHMENT CUMFERENTIALLY AROUND THE CYLINDER MAY BE COLLAR. REPAIRED BY GRINDING OUT TO A MAXIMUM DEPTH OF 0.017 INCH. COMPLETE REMOVAL OF CRACKS COMPLIANCE REQUIRED AS INDICATED. MUST BE VERIFIED BY MAGNETIC PARTICLE INSPEC­ DUE TO FATIGUE FAILURES FOUND IN THE ABOVE TION OR EQUIVALENT. IF CRACKS ARE COMPLETELY MAIN LANDING GEAR OUTER CYLINDER, THE FOLLOW­ REMOVED AS VERIFIED BY SUCH INSPECTION, REMOVE ING INSPECTIONS AND REWORK MUST BE ACCOM­ AN ADDITIONAL 0.008 INCH OF MATERIAL FROM THE PLISHED ON ALL MAIN LANDING GEARS WHICH HAVE REPAIRED AREA. REWORK MAY BE ACCEPTABLE ON ACCUMULATED 25.000 OR MORE HOURS" TIME IN OUTER CYLINDERS WITH CRACKS THAT CANNOT BE SERVICE. REMOVED BY GRINDING TO A DEPTH OF 0.017 INCH. (A) UNLESS ALREADY ACCOMPLISHED IN THE LAST SUCH CASES MAY BE SUBMITTED TO THE FAA FOR 1,000 HOURS' TIME IN SERVICE, WITHIN 400 HOURS' EVALUATION OF THE EXTENT OF CRACKING AND TO TIME IN SERVICE INSPECT FOR CRACKS IN THE MAIN DETERMINE IF REWORK IS POSSIBLE. REWORK AC­ LANDING GEAR OUTER CYLINDER SURFACE, AT THE COMPLISHED SUBSEQUENT TO SUCH AN EVALUATION 0.125-INCH RADIUS OF THE SHOULDER AGAINST WHICH MUST BE IN ACCORDANCE WITH FAA APPROVED THE DRAG STRUT-SIDE BRACE COLLAR RETAINING NUT REPAIR INSTRUCTIONS. BEARS, BY MEANS OF ONE OF THE THREE METHODS (2) ON ALL CYLINDERS, WHETHER CRACKS ARE IN (B). REINSPECT EVERY 1.000 HOURS' TIME IN FOUND OR NOT, REWORK THE AREA DESCRIBED IN SERVICE THEREAFTER, UNTIL THE REWORK IN (C) (2) (C) (1) AS FOLLOWS: IS ACCOMPLISHED. OUTER CYLINDERS WITH CRACKS (I) CLEAN AND POLISH THE ABOVE CYLINDER MUST BE REPLACED PRIOR TO FURTHER FLIGHT. AREA TO REMOVE ALL TOOL MARKS AND CORROSION. CRACKED CYLINDERS MAY BE RETURNED TO SERVICE (II) SHOTPEEN THE ABOVE AREA USING STEEL AFTER REPAIR AND REWORK IS ACCOMPLISHED IN AC­ SHOT 0.019^).033-INCH DIAMETER TO AN INTENSITY

CORDANCE WITH (C). REWORK ON ALL UNCRACKED OF 0.012-0.016 A2 ALEMEXT (REFERENCE OUTER CYLINDERS MUST BE ACCOMPLISHED IN AC­ LAC PROCESS BULLETIN 217M, REVISION 1). CORDANCE WITH (C)(2) NOT LATER THAN THE TOTAL (D) UPON COMPLETION OF THE REWORK DE­ ACCUMULATED HOURS" TIME IN SERVICE INDICATED SCRIBED IN (C)(2), ALL MODEL 8298 CYLINDERS IN (B). SHALL BE REINSPEETED FOR CRACKS AT PERIODS NOT TO LOCKHEED L-35 exceed 9,000 hours' time in service using one of (b) Install fire sleeves over all flammable the inspection methods noted in (b). Cracked fluid-carrying flexible hose lines in zones 3 and cylinders must be replaced prior to further 3A in the inboard engine nacelles. flight. Cracked cylinders may be returned to 60-8-4 Lockheed Amdt. 132 Federal Reg­ service after repair and rework is accomplished ister April 14, 1960, revised by Amdt. 192 in accordance with (c). Federal Register August 19, 1960. Applies (Lockheed Service Letter FS/239304 covers to All Models 1049 Series and 1649A Air­ this same subject.) craft. Compliance required as indicated. 60-5-2 Lockheed Amdt. 110 Part 507 Fed­ As a result of several cases of rudder torque eral Register March 4, 1960, revised by tube failure (P/N 306525-2 and P/N Amdt. 139 Federal Register May 4, 1960; 306525-3), attributed to stress corrosion, the Amdt. 183 Federal Register July 29, 1960; following inspection must be accomplished: Amdt. 198 Federal Register September 10, Within the next 300 hours' time in service 1960. Applies to All Models 1049C, D, E, on all aircraft which have accumulated 5,000 G and H Airplanes. hours' time in service, visually inspect for Compliance required by August 1, 1961, for cracks, using a 10-power magnifying glass, items (a)(1) or (a)(2); July 1, 1961, for the lower attachment portion of the upper item (a) (3); and by September 30, 1960, for rudder torque tube and the upper attachment item (b). portion of the lower rudder torque tube. If An accident occurred in which fire originat­ cracks or crack indications are found, reinspect ing in the engine section burned underneath the above area using dye penetrant or equiva­ the nacelle and entered the wheel well area lent. (The cracks progress along the longi­ rupturing flammable fluid lines and causing tudinal direction from the edge of the tube to extensive damage. An incident also occurred the first row of bolt holes and beyond. The in which fire originating in the power section cracks may also emanate from the second row blistered the paint on the landing gear wheel of bolt holes.) well doors. An examination of the burn pat­ Replace the torque tube prior to further tern on the landing gear doors indicates that flight if the tube is cracked beyond the first the circumstances surrounding this incident %-inch bolt attachment hole or if the tube is were quite similar to those of the accident but cracked at the second row of %6-inch bolt with less severity due to the lower exposure attachment holes. time. To correct fire protection deficiencies in If the tube is cracked from the edge to the the wheel well area, the following modifica­ first %-inch bolt hole a repair may be used tions are considered necessary: provided the repaired tube is reinspected in (a) To prevent fire from entering the wheel the above manner every 300 hours until re­ well area, accomplish one of the following: placed. The repair must be made prior to (1) Replace the present aluminum skin on further flight and consists of the addition of the forward landing gear doors with fireproof two i/4-inch blind lockbolts or Jobolts, located material. one on each side of the crack, spaced halfway (2) Cover the present aluminum skin on between the existing %-inch bolt holes and in the forward landing gear doors with fireproof line with these bolts. The maximum number material. of cracks permitted is two. If the crack (3) Coat both inside and outside of the progresses beyond the %-inch bolt attachment present aluminum skin on the forward land­ hole, with the repair installed, replace the ing gear doors with a material that will with­ torque tube prior to further flight. stand a flame of 2000° F. for 15 minutes. If no cracks are found, reinspect visually Product Techniques Inc. Coating PT-209, every 1,300 hours' time in service. If torque 0.015-inch thick on each side of the door is tubes are replaced with new parts (P/N considered satisfactory when applied in ac­ 306525-5 or P/N 306525-7), no further special cordance with PTI Process Specifications inspections are required. (Lockheed Service PTP 40-22. Letter FS/237201 covers this same subject.) L-36 LOCKHEED

60-9-3 Lockheed Amdt. 134 Part 507 Fed­ and operation with autopilot engaged is limited eral Register April 20, 1960, revised by to speeds at or below 225 knots. Amdt. 174 Federal Register June 24, 1960. (2) Modifications are made to the auto­ Applies to All Model 188 Series Aircraft. pilot system as described in Part II and Part Compliance required as indicated, LTI of FAA approved Lockheed Alert Service (a) Post following two placards in full Bulletin No. 453 as amended December 21, view of pilot: 1960. Under this condition, the "altitude- (1) Following operating speeds shall be hold" function is operative and the above Serv­ observed, V normal operating speed equal to ice Bulletin No. 453 Part II speed restriction is removed, ((b)(1) (2) revised by telegram 225 knots CAS or MACH number 0.55: V December 31, 1960.) never exceed speed equal to 245 knots CAS (d) Supersede by AD 60-13-3. or MACH number 0.55. This airworthiness directive sent by telegram (2) Feather propeller in event the torque- to all operators of 188 aircraft on March 25, meter indicator should go to zero or full scale 1960. in Sight. This placard may be removed from the aircraft when all its installed engines are 60-10-4 Lockheed Amdt. 138 Part 507 equipped with midbearing torquemeter, P/N Federal Register May 3, 1960. Applies to 6823900 identified by a Vrineh by 24-inch All Models 049, 149, 649, 749, 1049, and blue stripe on forward bevel of housing as 1649 Series Aircraft. described in Allison Commerical Engine Bul­ Compliance required as indicated. letin No. 72-113. In case of aircraft having A crack was found in the segment ring of one or more, but not all, engines equipped with the fuselage aft pressure bulkhead. The crack, midbearing torquemeters, the placard may be approximately 37 inches long, was in the top suitably altered to indicate those engines so left section of the ring, extending from a equipped, which are exempt from compliance point right of center. As a result of investi­ with its provisions. gation of the failure, the following must be The placard described in (a) (1) may be re­ accomplished on all aircraft with more than moved when the provisions of Lockheed Serv­ 30,000 hours* time in service. ice Bulletin No. 88/SB-500 have been accom­ (a) Within the next 180 hours' time in plished. The torquemeter placard described in service, unless already accomplished within (a) (2) may be removed when the provisions of the last 4,500 hours' time in service, and every AD 60-21-1, effective November 9,1960, which 4,500 hours' time in service thereafter, inspect requires installation of the midbearing torque­ the entire peripheral ring of the aft pressure meter housing assembly, has been accomplished. The placard on aircraft having one or more bulkhead at the bend radius adjacent to the but not all engines equipped with midbearing skin using one of the following methods or torquemeters may be suitably altered to indi­ equivalent: cate those engines so equipped which are ex­ (1) Radiographic inspection. empt from compliance with its provisions. (2) Pressurize the cabin to a minimum of (Revised by telegram December 31, 1960.) 2 p.s.i. Apply soap solution to the rear face of the ring and examine for leakage. This (b) Until modifications outlined below have will require removal of the sealing compound. been accomplished, the autopilot shall be de­ (b) If cracks are found, they must be re­ activated. Operation of the autopilot is per­ paired in accordance with FAA approved man­ missible under either of the following condi­ ufacturer's instructions. Pressurized flight is tions: prohibited until cracks are repaired. (1) Modifications are made to the auto­ (c) When any part of the aft pressure pilot system as described in FAA approved bulkhead peripheral ring is replaced by a Lockheed Alert Service Bulletin No. 88/SB- new part, inspection of the new part per (a) 453 Part II as amended December 21, 1960, is not required until the new part has accum­ (reactivation of autopilot). Under this condi­ ulated 30,000 hours' time in service. (Effec­ tion, the "altitude-hold" function is inoperative tive July 11, 1961.) LOCKHEED L-37

(d) Upon request of the operator, an FAA Through 10036, Manufactured By Sargent maintenance inspector, subject to prior ap­ Engineering Corporation. proval of the Chief, Engineering and Manu­ Compliance required as indicated. facturing Branch, FAA Western Region, may As a result of two failures of the main land­ adjust the repetitive inspection intervals speci­ ing gear drag strut cylinder, P/N 471035-3, fied in this AD to permit compliance at an es­ the following inspections and rework are re­ tablished inspection period of the operator if quired, unless already accomplished. the request contains substantiating data to jus­ (a) Within the next 425 hours' time in tify the increase for such operator. service inspect the root of the 6%6-inch (Lockheed Service Letter FS/240954 covers diameter thread and thread relief area in the this subject.) cylinder, P/N 471035-3, for cracks using one Revised March 9,1962. of the following inspection methods: (1) Dye penetrant method. 60-10-5 Lockheed Amdt. 145 Part 507 (2) Magnetic particle method (liquid Federal Register May 10, 1960. Applies to suspension only). All Model 188 Aircraft. (3) Eddy current method. (b) If no cracks are found, reinspection is Compliance required as indicated. required as follows, except that such reinspec­ There have been reported instances of the tion will not be required if the parts are main float closure port of the fuel tank vent reworked in accordance with the rework in­ valve remaining closed due to slight pressure structions in (c). in the tank. These pressures are considerably (1) If inspection method (a) (1) or less than the 1.75 p.s.i. setting of the pressure (a) (2) is employed, reinspection is required relief poppet. There is also a possibility of every 1,000 hours' time in service. sticking of the pressure relief poppet in the (2) If inspection method (a) (3) is em­ P/N 634056-1 tank vent valves. As a pre­ ployed, reinspection is required every 4,000 cautionary measure, underwing refueling must hours' time in service. be accomplished with the overwing fuel caps removed until the following action has been (c) Rework instructions: taken. As soon as possible but no later than (1) Remove 0.020-inch material by re- the next periodic inspection: machining new Acme threads and new thread relief in the cylinder, taking care to prevent (a) Drill a ^g-inch hole in the suction relief heating of the cylinder material which may flapper approximately halfway between the affect its strength. Grinding or rolling proc­ center of the flapper and the flapper seat. esses must not be used for making the threads. (b) Manually determine that the pressure (2) Cadmium plate the machine surfaces relief poppet action is free. in accordance with aircraft practices for heat- Upon accomplishment of above action nor­ treated steel. mal underwing fueling procedures may be (3) A new nut, Lockheed P/N 557466-1, resumed. or equivalent, must be used to replace the exist­ (Lockheed message to all Electra operators ing nut. dated April 18, 1960, covers this same subject.) (4) Reassemble the strut assembly and This airworthiness directive sent by tele­ proof test to 12,300 p.s.i. (Lockheed 1049 gram to all operators of 188 aircraft on Service Bulletin 3112 covers these rework in­ April 19, 1960. structions.) (d) Parts found cracked must be replaced 60-10-6 Lockheed Amdt. 150 Part 507 prior to further flight. Parts in which a heat Federal Register May 13, 1960. Applies to affected zone is indicated by inspection method All Model 1049 Series Aircraft Equipped (a) (3) must be reworked in accordance with With Drag Strut Assemblies With Ground (c) within 1,000 hours' time in service. Acme Threads, P/N 469080-5 and -6, Serial (Lockheed Service Letter FS/240867L cov­ Numbers 6001 Through 6363 and 10001 ers this same subject.) L-38 LOCKHEED

60-11-3 Lockheed Amdt. 159 Part 507 60-13-2 Lockheed Amdt. 175 Part 507 Federal Register May 24, 1960, revised by Federal Register June 24, 1960, revised by Amdt. 205 Federal Register September 29, Amdt. 280 Federal Register May 6,1961, and 1960. Applies to All 188 Series Aircraft. Amdt. 405 Federal Register March 9, 1962. Compliance required as indicated. Applies to All Aeroproducts A6441FN-606 Due to loose attachments and cracked quick Propellers Installed On Lockheed 188 Series engine change upper cowl panel longerons the Aircraft. following inspections are required. Canceled May 12,1962. Prior to dispatch from a terminal where in­ 60-13-3 Lockheed Amdt. 176 Part 507 spection facilities are available, unless already Federal Register June 24, 1960. Applies to accomplished within the last 300 hours' time in All 188 Airplanes Not Equipped With Fuel sen-ice, and thereafter at every 300 hours" time Tank Pressure Relief Overflow Valves. in service, inspect the top cowl panel upper Compliance required as indicated. longerons and the attachments at the rear fit­ tings for cracks or loose attachments, Service experience indicates that a check of (a) Replace loose attachments in the longe­ the fueling system valves at a high fuel level ron fittings. Acceptable replacements are: point should be made when filling tanks to (1) One-sixty-fourths-inch diameter over­ capacity. This check is necessary to determine size Hi-Lok (P/N HL 56-6 pin, P/N HL that the system is functioning properly since 61^-6-5 pin, P/N HL 85-6 collar). failure of a fueling valve to close fully may (2) Thirteen-sixty-fourths-inch diameter subject the tank to high fuel pressure which NAS type close tolerance screw, minimum heat could cause not only tank rupture but struc­ treat 160,000 p.s.i. Ream to oversize hole tural damage. To prevent possible fuel tank limits of 0.212-0.2192-inch diameter. overpressurizing, the following actions are re­ (3) Seven-thirty-seeonds-inch diameter quired commencing not later than 10 days NAS type close tolerance screws; minimum after publication of this airworthiness direc­ heat treat 160,000 p.s.i.; minimum edge dis­ tive in the Federal Register. tance, 1V£ diameters. Ream to oversize hole limits of 0.2181-0.2192-inch diameter. (a) Conduct a check of the fueling system at the start of each fueling operation in ac­ (4) It is satisfactory to mis Huck bolts cordance with the placard located on the fuel­ and Hi-Lok fasteners, but it is not acceptable ing panel. to mis NAS type screws with Huck bolts or Hi-Lok fasteners. (b)(1) On all outboard tanks and on ex­ tended inboard tanks, when installed, conduct (b) Cracked longerons must be replaced or a second check of the primary and secondary an FAA approved repair incorporated before next flight. controls between 8,000 and 10,000 pounds fuel per item 2 on the placard. The preceding inspections may be discon­ tinued after the incorporation of the modifica­ (2) When standard inboard tanks are in­ tions contained in Lockheed Service Bulletin stalled, conduct a second check of the primary 88/SB-500. (Effective May 13,1961.) and secondary controls between 4,500 and 6,500 (Lockheed Alert Service Bulletin No. 467 pounds fuel. covers this same subject.) (c) Any malfunctions indicated by the This airworthiness directive sent by tele­ checks required by items (a) and (b) of this gram to all operators of 188 aircraft on April airworthiness directive must be corrected prior 29, 1960. to continuance of pressure fueling to that tank. (d) The fueling panel will be monitored 60-11-5 Lockheed Amdt. 165 Part 507 Federal Register May 28, 1960, revised by during the entire fueling operation. Amdt. 172 Federal Register June 24, 1960. This supersedes paragraph (d) of AD Applies to All 188 Series Aircraft. 60-9-3. Canceled September 21,1962. 60-17-1 See Aeroproducts Propellers. LOCKHEED L-39

60-20-3 Lockheed Amdt. 202 Part 507 Fed­ block assembly from terminals Tl, T2 and T3 eral Register September 28, 1960, revised by of relay No. 2. Amdt. 231 Federal Register December 8, (h) Modify the terminal block assembly be­ 1960. Applies to All Model 188 Series Air­ tween the externa] power feeders and relay No. craft Serial Numbers 1002, 1004 Through 6 to remove plastic in compression. 1102,1104 Through 1126,2001 Through 2014. (i) Within the AC Bus Transfer and Dis­ Compliance required within 1,000 hours' time tribution Box, route the control wires for the in service after September 28, 1960. generators separate from all power wires. Insufficient resistance to flammability of (j) Relocate the essential bus alternate components of the AC Bus Transfer and Dis­ feeder circuit breaker to a housing to be tribution Bos has resulted in a fire. Tempera­ attached to the left side of the AC Bus Trans­ tures within the AC Bus Transfer and Distri­ fer and Distribution Box. bution Box and within the main electrical serv­ (k) Provide forced air cooling of the elec­ ice center higher than that for which some of trical load center by installing: two destratifi- the equipment in these locations is designed cation fans; ducting from the fans to the AC contributes to over-temperature of the equip­ Bus Transfer and Distribution Box; ducting ment. and controller to regulate overboard dumping Accomplish those portions of Lockheed of heated air; ventilation holes in the AC Electra Alert Service Bulletins 408 and 287, Transfer and Distribution Box. Install a revision 1, summarized below or equivalent: shield to cover hydraulic connectors between (a) Within the AC Transfer and Distribu­ fuselage Stations 540 and 549.5. tion Box, replace the black vinyl covered flex­ (The portions of Lockheed Electra Alert ible bus assemblies, which interconnect the cir­ Service Bulletins 408 and 287, revision 1, not cuit breakers, with jumpers made of MDLr-W— summarized above are also approved.) 7139 wire. 60-20-4 Lockheed Amdt. 203 Part 507 Fed­ (b) Replace, with MIL-W-7139 wire, all eral Register September 28, 1960, Applies size 6, 8, 10 and 12 vrires which route within to 188 Aircraft Serial Numbers 1002, 1004 and between sections of the AC Transfer and Through 1102, 1104 Through 1126, and Distribution Box except power wires to pro­ 2001 Through 2015. peller deice power relay. Compliance required by the next 300 hours' (c) Apply a fire retardant coating, Magna time in service after October 28, 1960. Coatings and Chemical Co. Laminar X-500, Leaking lavatory tank ground drain valves to the exposed and accessible portion of the have permitted drainage to the exterior sur­ inside and outside of the following impreg­ face of the aircraft in flight, resulting in ice nated fiberglass boxes: AC Bus Transfer and formation which came off and struck the Distribution Box and its covers; forward load stabilizer. Since such ice formation is hazard­ center bus box and cover; forward load center ous to aircraft in flight and to persons on the circuit breaker shrouds; flap asymmetry con­ ground, all lavatory tank ground drain valves trol panel cover; hydraulic pump shroud boxes. must be modified to incorporate LAC seal No. (d) Replace, with moulded melamine ter­ 838228-1 or equivalent. (LAC 88/SB-407 minal blocks, the stepped terminal block as­ covers the intent of this change.) semblies which serve as busses in the three This directive effective October 28, 1960. upper compartments of the AC Bus Transfer 60-21-2 Lockheed Amdt. 207 Part 507 Fed­ and Distribution Box. eral Register October 7, 1960. Applies to (e) Remove the short bus bars which serve All Model 18 Aircraft Which Have Been as extensions for terminals Tl and T3 of re­ Converted to the "Learstar" Configuration. lays No. 1 and No. 3. Compliance required as indicated. (f) Replace the bus bar assemblies on ter­ Flight tests have disclosed that excessive minals T2 of relays 1 and 3 with a type which temperature stratification at the carburetor air does not have plastic in compression. screen exists during operation with partial (g) Remove the short bus bars and terminal carburetor air preheat. This stratification re- L-40 IJOCKHEED suits in erroneous readings on the cockpit car­ 60-24-1 Lockheed Amdt 222 Part 507 Fed­ buretor air temperature gage and may, under eral Register November 15, 1960. Applies icing conditions, cause ice formation on the to All 188 Aircraft. cold portions of the air screen and in the car­ Compliance required within 5,000 hours' buretor. While full preheat is available if time in service after the effective date of this needed for ice elimination, only partial preheat directive. should be used for continuous operation under To provide protection against possible over- certain temperature conditions in order to pressurization of fuel tanks during refueling, avoid exceeding the engine manufacturer's car­ the following modification is required unless buretor air temperature limit of 38° C. The already accomplished: following action is required: Install pressure relief overflow valves in (a) Effective November 15, 1960, Learstar each fuel tank. Lockheed overflow valves aircraft shall be restricted against operation P/N 634114-7 or -9 are satisfactory for this in known icing conditions until modifications purpose. (Lockheed Service Bulletin 188/SB- to the air preheat system covered in para­ 422 covers this subject.) graph (b) are accomplished. The following This directive effective December 13, 1960. placard shall be posted in full view of the pilot: 60-25-2 Lockheed Amdt. 229 Part 507 Fed­ "OPERATION INTO KNOWN ICING eral Register December 2, 1960. Applies to CONDITIONS PROHIBITED." All Model 188 Series Aircraft. The limitations section of the FAA approved Compliance required as indicated. Airplane Flight Manual is hereby amended to As a result of reported cracked aileron incorporate this limitation. counterweight attaching angles, the following (b) The operating restriction into known is required: icing conditions shall continue until modifica­ (a) At intervals not to exceed 300 hours' tions are accomplished to the carburetor air time in service, inspect for cracks in the angles preheat system which will result in conserva­ which attach the aileron balance-weight tive C.A.T. indications for the prevention of brackets to the aileron spar at aileron Stations 13.85, 30.95, 48.01, 82.16, 116.31, 150.46 and ice formation on the carburetor screen and 184.61. Cracked angles must be replaced be­ engine induction system at all preheat posi­ fore further flight. tions. Such modifications shall also permit operation with preheat under varying power (b) The replacement of angles found to be cracked must be made in accordance with and ambient temperature conditions without either (1) or (2). resulting in excessive C.A.T. A satisfactory modification to meet the requirements is cov­ (1) Original angles may be replaced with ered in FAA approved PacAero Engineering parts having the same dimensions as the orig­ inal parts but fabricated from 0.090-inch Corporation Service Bulletin No. 14, dated thickness AISI 8630 or AISI 4130 steel heat- August 26. 1961. An FAA approved airplane treated to 150,000-170,000 p.s.i. ultimate tensile flight manual revision setting forth recom­ strength, cadmium plated and baked. Lock­ mended procedures for safe operation of the heed Process Specifications Nos. 522, 491, and system will be supplied by PacAero with the 170 or FAA approved equivalent must be used modification kit. Any deviations from the for the respective processes indicated. modifications or procedures set forth in the (2) Original angles may be replaced in service bulletin and airplane flight manual accordance with the instructions in the kits revision must be approved by FAA, Region outlined in Lockheed Service Bulletin 88/SB- Four, Engineering and Manufacturing Branch, 451 or FAA approved equivalent. This serv­ Los Angeles, California. ice bulletin also contains detailed instructions (c) Upon compliance with paragraph (b), for accomplishing this modification. the operating restriction set forth in para­ (c) After replacement of the original parts graph (a) is cancelled. in accordance with the instructions in (b), LOCKHEED L-41

subsequent inspections of replaced parts may- ance weight due to cumulative free play in then be made at normal inspection periods. joints of balance arm linkage. If movement This supersedes AD 60-11-4. of balance weight due to cumulative free play

This directive effective December 2,1960. in system exceeds y8-inch inspect each joint 1960. in balance arm linkage and reduce the free play by bolt and/or part replacement at one 60-26-4 Lockheed Amdt. 234 Part 507 Fed­ or more of these joints so as to reduce total eral Register December 14,1960. Applies to free play movement of the balance weight to All 188 Aircraft. % -inch or less prior to further flight. This Compliance required as indicated. 6 inspection must be repeated every 450 hours' Failure of the clamp or flange of the swirl time in service. When provisions of para­ straightener assembly resulted in at least two graph (c)(1) are accomplished, this special cases of overheating the nacelle area causing inspection may be discontinued. extensive damage to the nacelle. In addition, (b) Within the next 300 hours' time in there have been a number of failures of the service, unless already accomplished within the retaining clamp and cracks in the flange area last 700 hours' time in service, and following of this assembly caused by dynamic loads im­ any occurrene of inflight elevator or control posed by the sugar scoop deflection of exhaust, column oscillations, inspect the elevator booster gases. control valve viscous damper diaphragm, The following modifications shall be accom­ Lockheed P/N 813612-1 for evidence of rup­ plished to correct the above conditions at the ture. See Lockheed Electra (Model 188) first engine change after December 14, 1960. Overhaul Manual Section 27-1-10 Page 1 for (a) Remove the present sugar scoop and the information on evidence of rupture. If such lower bell mouth. Install a new lower bell- evidence is found the airplane shall not be re­ mouth of extended length to mate properly turned to service until the diaphragm is re­ with the engine after removal of the sugar placed with a new part, or compliance with scoop. When this rework has been accom­ paragraph (c)(2) has been accomplished. This plished, it will be necessary to relocate the fire inspection must be repeated at periods not to sensing elements on the structural shroud. exceed 1,000 hours' time in service until the (b) Tack-weld the vanes to the clips located provisions of paragraph (c) (2) have been ac­ on the perimeter of the straightener assembly. complished. (c) Add rubbing strips on the tailpipe (c) The following must be accomplished shroud door and drill holes in the nacelle cool­ within the next 1,000 hours' time in service. ing duct assembly to cool the bellmouth. (1) Install a spring-loaded cartridge, (The above items must be accomplished in Lockheed P/N 840404-1, in the elevator coun­ accordance with Lockheed S/B No. 430, which terweight linkage in the manner described by covers the same subject.) Lockheed Service Bulletin 88/SB-524. This directive effective December 14, 1960. (2) Replace the elevator boost control 60-26-5 Lockheed Amdt. 236 Part 507 Fed­ valve viscous damper, Lockheed P/N 813608-3, eral Register December 22,1960. Applies to with an orifice type damper, Lockheed P/N All 188 Series Aircraft. 492508-3, in accordance with Lockheed Serv­ Compliance required as indicated, ice Bulletin No. 88/SB-524. (a) Within the next 150 hours' time in (3) Rework the elevator booster assem­ service commencing on November 22, 1960, bly in accordance with Lockheed Service Bul­ unless already accomplished within the last letin No. 88/SB-524 to incorporate an orifice 300 hours' time in service, inspect the elevator valve assembly, Lockheed P/N 804551-1, and counterweight installation, Lockheed Drawing modify the booster piston rod end installation No. 829912, at airplane center line for evidence to incorporate two retaining washers, Lockheed of free play as follows: with elevator blocked P/N 839756-1, in accordance with Lockheed at extreme down position apply up and down Service Bulletin No. 88/SB-498. force to balance weight Lockheed P/N (FAA approved Lockheed Service Bulletins 827020-1, and measure total movement of bal­ 88/SB-198 and 88/SB-524, Lockheed Electra L-42 LOCKHEED operating information letter Xo. IS dated (1) Within the next 25 landings and every November 1, I960, Lockheed Alert Bulletin Xo. 50 landings thereafter, inspect the main land­ 524 dated December 1, 1960, cover portions of ing gear drag strut attach plates, P/N 112900, this subject.) or P/N 12665, in place on the aircraft for This supersedes AD 60-24-2. cracks and looseness.1 Dye penetrant or FAA This directive effective December 22, 1960. approved equivalent must be used for crack detection. If the drag stmt attach plate is 61-3-3 See Hartzell Propellers, loose, then it must be visually inspected for 61-3-4 Lockheed Amdt. 244 Part 507 Fed­ elongation of the bolt holes and the attaching eral Register January 27, 1961. Applies to bolts visually inspected for cracks, or deforma­ All Model 1649A Aircraft. tion. If cracks or elongation of the bolt holes Compliance required as indicated. are found in the drag strut attach plate, it One of the following modifications to the must be replaced prior to the next flight. Deformed or cracked bolts must be replaced vent system must be accomplished within 400 prior to the next flight. hours of time in service after the effective date of this directive. (2) Within the next 25 landings, unless al­ ready accomplished within the last 125 land­ (a) Modify only the right-hand vent float ings and every 150 landings thereafter, remove valve of the Xo. 7 tank (LAC P/X 634024-3, the main landing gear drag strut attach plates, Aero Supply Mfg. Co. P/X 22-1845-002) to P/N 112900, or P/N 12665, and conduct an a combination pressure relief and suction relief X-ray or dye penetrant, or FAA approved valve by removing the float assembly so that equivalent, inspection for cracks. The bolt only the pressure and suction relief features holes in the drag strut attach plate must be remain operational. Replace the valve spring visually inspected for elongation and the at­ (P/X 22-0228-1) with spring (P/X 22-0337- taching bolts inspected for cracks or deforma­ 1) having a higher cracking pressure. tion. If cracks or elongation of the bolt holes (b) Replace only the original right-hand are found in the drag strut attach plate, it side valve assembly on Xo. 7 fuel tank with must be replaced prior to the next flight. De­ a new valve assembly LAC P/X 634024-5 formed or cracked bolts must be replaced prior (Aero Supply Mfg. Co. P/X 22-1845-003). to the next flight. (Lockheed Letter dated August 22, 1960, (b) The special inspections contained in this directed to all 1649 operators completely covers AD may be discontinued after the Howard the details of this modification.) Aero, Inc., replacement main landing gear This directive effective February 13, 1961. drag strut attach plates, P/N 5-302006, or 61-4-4 Lockheed Amdt. 251 Part 507 Fed­ FAA approved equivalents, are installed using eral Register February 10, 1961. Applies 180,000 p.s.i. minimum ultimate tensile strength to All Models PV-1 and B-34 Aircraft "With attaching bolts. Main Landing Gear Drag Strut Attach This directive effective March 14, 1961. 112900 Plates, P/N or P/N 12665. 61-9-1 Lockheed Amdt. 279 Part 507 Fed­ Compliance required as indicated. (It will eral Register April 28, 1961. Applies to be necessary for operators to maintain a record All 188 Series Aircraft Which Incorporate of landings in order to ascertain compliance Hydraulic Damper Housing P/N's 840655-1 with this AD.) and 475645-1 (rudder, elevator, and aileron Investigation has shown that failure of the control systems) Installed Per Lockheed main landing gear drag strut attach plate. Service Bulletin 88/SB-524 and 88/SB-532. P/N 112900 has caused the main landing gear Compliance required not later than the next to collapse. The B-34 main landing gear drag 50 hours' time in service. strut attach plate, P/X 12665, is the same as the PV-1. As a result of this service experi­ 1A method of inspection for looseness is to check for gap­ ping of 0.010 inch or greater, between the drag strut plate ence the following shall be accomplished: and the backing plate at a point approximately 4.5 inches (a) Inspection in accordance with either (1) above the lower edge of the attach plate. Insert a feeler gage between the attach plate and the backing plate from or (2) is required: the outboard side to make this check. LOCKHEED L-43

As a result of an incident involving elevator (c) Upon request of the operator, an FAA booster hydraulic damper malfunction, hy­ maintenance inspector, subject to approval of draulic damper housing P/N 840655-1 and the Chief, Engineering and Manufacturing P/N 475645-1 not identified with blue anodized Branch, FAA Western Region, may adjust the color must be replaced with new parts identi­ repetitive inspection intervals specified in this fied with blue anodized color as received from AD to permit compliance at an established in­ spection period of the operator if the request the manufacturer or reworked to the following contains substantiating data to justify the dimensions; increase for such operator. (Effective July (a) Length of skirt 0.312 inch plus or minus 26, 1961.) 0.010 inch. (Lockheed 1049 Service Bulletin No. 2935 (b) Bore of body 1.3800—1.3817 inches. pertains to this subject.) (c) Clearance between piston and damper This directive effective July 17, 1961. housing 0.0015—0.0040 inch. (d) Identify the reworked housing with 61-15-4 Lockheed Amdt 309 Part 507 Fed­ blue dye or blue paint. eral Register July 21, 1961. Applies to All The reinstallation of new or reworked 188 Series Aircraft Incorporating A Lounge damper housings must be accomplished in ac­ Using Hardman Seats. cordance with instructions in Lockheed Serv­ Compliance required as indicated. ice Letter FS/251702-L dated February 14, Reports have been received that grommets 1061. are missing in some of the aft lounge safety belt cable guide brackets. Grommets are re­ (Lockheed Service Wire to all operators quired in these brackets to permit the cable to dated April 7, 1961, applies to this same sub­ withstand the design load. Within the next ject.) 100 hours' time in service inspect the safety This directive becomes effective upon publi­ belt cable guide bracket, Hardman P/N 5072-1, cation in the Federal Register for all persons of the left and right aft lounge seats for pres­ except those to whom it was made effective ence of nylon grommets. It the nylon grom­ immediately by telegram dated April 7, 1961. mets are missing, install nylon grommets, P/N 61-14-5 Lockheed Amdt. 307 Part 507 Fed­ 295957-1OA (United Carr Fastener Corp.), or eral Register July 11, 1961. Applies to All equivalent, or restrict occupancy of the left Model 1049 Series Aircraft. and right aft lounge seats during takeoff and Compliance required as indicated. landing until such time as grommets are in­ As a result of numerous occurrences of loss stalled. of main landing gear doors, the following in­ (Lockheed Service Bulletin 88/SB-541 re­ spections and rework are required. fers to the same subject.) (a) Within the next 30 hours' time in serv­ This directive effective August 2, 1961. ice after the effective date of this AD and every 30 hours' time in service thereafter, con­ 61-19-3 Lockheed Amdt. 338 Part 507 Fed­ duct a visual inspection for cracks or loose eral Register September 20, 1961. Applies fasteners in the front main landing gear door to All 049, 149, 649, 749, and 1049 Series assemblies paying special attention to the Aircraft. front ribs and front hinge fittings. If any Compliance required as indicated. defects are found, they must be repaired or As a result of findings during investigation replaced prior to further flight, except that a of a recent Lockheed Model 049 aircraft fatal ferry flight may be authorized in accordance accident, it is necessary to require the follow­ with CAR 1.76 to a base where the required ing corrective action. replacement or modifications are to be made. Unless already accomplished within the last (b) When doors incorporating the modifica­ 50 hours' time in service, the following special tions outlined in Lockheed 1049 Service Bul­ inspection is required at the first layover or letin No. 2935, or FAA approved equivalent, stop where qualified maintenance personnel are installed, the special inspections described and facilities are available and the inspection in (a) may be discontinued. can be conducted without undue delay but not L-44 LOCKHEED to exceed the next 25 hours' time in service mate tensile strength is less than 150,000 p.s.i., after the effective date of this AD. Inspect the strut must be replaced with a similar part to ensure that the 5 bolts, nuts, and cotter pins heat-treated to 150,000 to 170,000 p.s.i. or by a in the parallelogram linkage between the ele­ strut, P/N 125715 or equivalent, prior to fur­ vator boost valve and boost mechanism are ther flight, except for ferry flight in accord­ properly secured and safetied. ance with the provisions of CAR 1.76. This directive effective September 20, 1961, NOTE: Strut, P/N 125715, originally designed for for all persons except those to whom it was the PV-2 type aircraft is an acceptable alternative for made effective immediately by telegram dated stmt. P/N. 112CKH, and a hardness test on this strut is not necessary. If the P/N is missing or obscured, the September 8,1961. struts may be identified by the following: The PV-2 61-21-5 Lockheed Amdt. 342 Part 507 Fed­ strut, P/N 129715, weighs approximately 15.5 pounds and the PV-1 strut, P/N 112004, weighs approxi­ eral Register October .3, 1961. Applies to mately 10.5 pounds. The PV-2 strut tube has a wall- All Model 188 Aircraft. thickness of 0.25 inch whereas the PV-l part has a Compliance required as indicated. wall-thickness of 0.156 inch. The wall-thickness can Several instances of inadvertent tripping of be measured by laying a stratght edge along the tube and measuring the perpendicular distance between the compass circuit breakers have occurred due to straight edge and the end fitting. bumping the ganging bar by the occupant of the observers seat. Due to the effect of the (b) Spare lower drag struts, P/N 112004, loss of heading information upon operational must comply with the hardness test and re­ safety, accomplishment of the following is placement provisions of (a) prior to installa­ required: tion. Within the next 100 hours' time in service This directive effective November 3, 1961. after the effective date of this AD, inspect the 61-22-6 Lockheed Amdt. 351 Part 507 Fed­ pilot's and copilot's compass circuit breakers, eral Register October 21, 1961. Applies to and if the circuit breakers are ganged together, AH PV-1, B-34, and 18 Series Aircraft Hav­ either remove the ganging bars, or install a ing Elevator Control Mast Assembly Cast­ protective guard which precludes inadvertent ings P/N 11467 or 56045. operation of the ganging bar. (These circuit Compliance required within the next 100 breakers are located in the lowest circuit hours' time in service after effective date. breaker panel beside the observers seat on the left side of the flight deck.) As a result of reported cracks in the elevator control mast assembly castings, the following This directive effective November 2, 1961. inspections and installation procedures are re­ 61-21-6 Lockheed Amdt. 343 Part 507 Fed­ quired unless already accomplished: eral Register October 4, 1961. Applies to (a) Inspect the elevator control mast assem­ All PV-1 and B-34 Type Aircraft Having bly casting prior to removal, for mating marks Main Landing Gear Lower Drag Stmts P/N to insure correct assembly. If none exist, de­ 112004. termine the proper position of the cap on the Compliance required as indicated. mast and mark the assembly with a paint During investigation of a PV-1 main land­ stripe or equivalent to insure future correct as­ ing gear failure, the main landing gear lower sembly of parts. drag strut, P/N 112004, was found to be under- (b) Remove the elevator control mast assem­ strength because it was not in the specified bly casting and inspect both the control mast heat-treated condition. As a result of this and the cap castings for cracks in the attach service experience, the following is required: holt lugs using dye penetrant methods or equiv­ (a) Within the next 50 hours* time in serv­ alent. If any cracks are found, the casting ice from the effective date of this directive un- must be replaced prior to further flight. les already accomplished, determine by the (c) Install the four AN 5-16A bolts in the Brinell, Rockwell, or an equivalent hardness casting in place on the aircraft, with the lock- test method whether or not the struts, P/N plate between the cast cap and the easting on 112004, are heat-treated to an ultimate tensile the aft side, and with the mating marks strength of 150,000 to 170,000 p.s.i. If the ulti­ matched. Torque the two bolts which go LOCKHEED L-45 through the lockplate to 50-70 inch-pounds, Aircraft Incorporating Clevelend Pneumatic then the other two bolts to the same range of Tool Company Main Landing Gear Cylin torque values. Measure the gap between the ders, P/N's 9040-2, 9040A-2, 9106-2, 9291-2, forward side of the castings. Fabricate an 9291B-2, 9291B-2B, or 9291D-2. aluminum alloy shim, +0.002 to +0.005-inch Compliance required as indicated. greater than the measured gap. Eemove the As a result of failures of the cap weld on forward bolts, install the shim, replace the main landing gear cylinders which have been bolts, and torque all bolts to 100-140 inch- returned to service following compliance with pounds. Ensure that the shim does not con­ the provisions of AD 59-7-3, as amended, all tact the surrounding structure. aircraft shall be inspected and/or modified as This directive effective November 21,1961. follows: (a) Within the next 400 hours' time in serv­ 61-24-4 Lockheed Amdt. 367 Part 507 Fed­ ice after the effective date of this AD, unless eral Register November 14, 1961. Applies already accomplished, all landing gear cylin­ to All Models 049, 149, 649, 749, and 1049 ders with cap welds which previously have Series Aircraft Having 25,000 Or More been inspected by the double-wall gamma Hours' Time In Service. radiographic technique in compliance with AD Compliance required as indicated. 59-7-3 shall be reinspected in accordance with As a result of reports of numerous cases (c), or shall be replaced with cylinders which of cracking in the horizontal stabilizer rear have been inspected in accordance with (c) spar-to-fuselage attachment, the following in­ and found to exhibit no evidence of cracks. spections must be accomplished within the next (b) Within the next 1,200 hours' time in 400 hours' time in service after effective date service after the effective date of this AD, un­ of this AD, unless already accomplished less already accomplished, all landing gear within the last 4,300 hours' time in service and cylinders with cap welds which previously at intervals of 4,700 hours' time in service. have been radiographically inspected by a Inspect the rear spar web (P/N 271488-4) method other than the double-wall gamma for cracks in the 0.38 inch radius adjacent to technique in compliance with AD 59-7-3, shall the stabilizer-to-fuselage fitting on both the be reinspected in accordance with (c), or shall left and right sides of the airplane. If cracks be replaced with cylinders which have been in­ are found, they must be repaired prior to fur­ spected in accordance with (c) and found to ther flight in accordance with Lockheed Serv­ exhibit no evidence of cracks. ice Letter FS/250615, or FAA approved equiv­ (c) The inspection techniques and proce­ alent. dures to be applied to all cylinders noted in The above inspection may be discontinued (a) and (b) shall be those prescribed by Sec­ upon incorporation of the repair or reinforce­ tion B of Lockheed Field Service Letter No. ment provisions of the Lockheed Service Let­ FS/254049L, dated August 29, 1961, or FAA ter, or FAA approved equivalent. engineering approved equivalent. The entire periphery of the cap weld shall be inspected. Upon request of the operator, an FAA maintenance inspector, subject to prior ap­ (d) Any cylinder with a cap weld which is proval of the Chief, Engineering and Manu­ found to exhibit any evidence of cracks when facturing Branch, FAA Western Region, may inspected as required by (a) or (b), shall be adjust the repetitive inspection intervals speci­ replaced prior to further flight of the aircraft. fied in this AD to permit compliance at an es­ Cracked cylinders are not eligible for any fur­ tablished inspection period of the operator if ther use in certificated aircraft. the request contains substantiating data to jus­ (e) The cap welds on all cylinders which tify the increase for such operator. have been installed or which have been in­ spected, found to exhibit no evidence of cracks, This directive effective December 14, 1961. and returned to service in accordance with (a) 62-1-2 Lockheed Amdt. 384 Part 507 Fed­ or (b), shall be reinspected in accordance with eral Register January 9, 1962. Applies to (c), at periods thereafter not to exceed 5,000 All Models 49,149, 649, 749, and 1049 Series hours' time in service. The first periodic re- L-46 LOCKHEED inspection of any cylinder in service which, surface skin to allow lifting the skin for the prior to the effective date of this AD, was purpose of inspecting the aft outer surface inspected in the manner prescribed by (c) of the rear spar upper cap in accordance shall be accomplished within 5,000 hours" time with (a). in service following the date of that inspection. (d) Repair all corrosion damage in accord­ (f) Cylinders with the cap welds which ex­ ance with Lockheed Report 8882, figure 2-25 hibit any evidence of cracks during any of and paragraph 1-67N, or FAA approved these periodic reinspeetions shall be replaced equivalent. If no corrosion is found on the prior to further flight of the aircraft. aft outer surface of the rear spar upper cap, Cracked cylinders are not eligible for any fur­ coat it with zinc chromate. ther use in certificated aircraft. (g) Upon request of the operator, an FAA (e) All rear spar upper caps which have maintenance inspector, subject to prior ap­ been inspected and repaired in accordance proval of the Chief, Engineering and Manu­ with (a) through (d) shall be reinspected facturing Branch, FAA Western Region, may and repaired in accordance with (a) through adjust the repetitive inspection intervals speci­ (d) at periods thereafter not to exceed 5,000 fied in this AD to permit compliance at an es­ hours' time in service or two calendar years, tablished inspection period of the operator if whichever occurs first. The first periodic the request contains substantiating data to jus­ re inspect ion of any rear spar upper cap tify the increase for such operator. which was inspected and repaired in the (h) When the cylinders described are re­ manner prescribed in (a) through (d) prior placed with new cylinders, TPC Co. P/N's to the effective date of this AD, shall be 9040A-2A, 9106-2A* and 9291D-2A. incorpo­ accomplished within 5,000 hours' time in rating flash welded caps, the inspections speci­ service or two calendar years, whichever oc­ fied in (a) through (g), may be discontinued. curs first, following the date of that inspection. (Lockheed Field Service Letter FS/254049L (f) Upon request of the operator, and FAA covers this same subject.) maintenance inspector, subject to prior ap­ This supersedes AD 59—7-3. proval of the Chief, Engineering and Manu­ This directive effective January 9, 1962. facturing Branch, FAA Western Region, may adjust the repetitive inspection intervals speci­ 62-16-3 Lockheed Amdt. 461 Part 507 Fed­ fied in this AD to permit compliance at an es­ eral Register July 12. 1962. Applies to All tablished inspection period of the operator if Models 1049-54,1049B, 1049C, 1049D. 1049E, the request contains substantiating data to jus­ 1049F, 1049G, and 1049H Series Aircraft. tify the increase for such operator. Compliance required as indicated. (Lockheed Field Service Letters FS/249582L As a result of corrosion found on the wing dated November 4, 1960, and FS/250141L rear spar upper cap exposed surfaces which dated December 20, 1960, cover this same exceeded the negligible damage limits the subject.) following is required: This directive effective August 13, 1962. (a) Within the next 700 hours" tune in service after the effective date of this AD, 62-19-2 Lockheed unless already accomplished, inspect the ex­ Amdt. 477 Part 507 Fed­ posed surfaces of the rear spar upper caps eral Register August 23, 1962. Applies to from wing Station 80 to wing Station 45? All Models 49,149, 649, 749, and 749A Series using a wood or micarta pick as a probe and Aircraft Incorporating Cleveland Pneumatic a good light source to illuminate the area. Tool Company Main Landing Gear Pistons, P/N's 8298-4, 8298B-4, 8298C-4, 8298C-4A, (b) If no corrosion is found, coat the 8298D-4 or 8298F-4. spar cap with zinc chromate primer. The aircraft may then be returned to service. Compliance required as indicated. (c) If corrosion damage is found on the As a result of one complete fatigue failure exposed surfaces of the rear spar upper cap, and subsequent cases of cracks in numerous remove enough rivets from the aft upper pistons in the area immediately above the weld LOCKHEED L-47

that retains the metering pin bulkhead, accom­ adjust the repetitive inspection intervals spe­ plish the following: cified in this AD to permit compliance at an (a) Within the next 800 hours' time in serv­ established inspection period of the operator if ice after the effective date of this AD, and the request contains substantiating data to jus­ thereafter at intervals not to exceed 2,000 tify the increase for such operator. hours' time in service, inspect the main landing (Lockheed Field Service Letter No. FS/ gear pistons, Cleveland Pneumatic Tool Com­ 256603L dated January 24, 1962, covers this pany, P/N's 8298-4, 8298B-4, 8298C-4, 8298C- same subject.) 4A, 8298D-4, and 8298F-4, for cracks in the This directive effective September 24, 1962. area immediately above the weld that retains the metering pin bulkhead. In those cases 62-21-4 Lockheed Amdt. 489 Part 507 Fed­ where an inspection in accordance with the pro­ eral Register October 3, 1962. Applies to cedures described in this AD has been accom­ All Model 1649A Aircraft. plished within the last 1,200 hours' time in Compliance required as indicated. service as of the effective date of this AD, As a result of chordwise cracks on the wing that inspection may be considered as the initial lower milled skin at wing Station 590, the fol­ inspection, and the repetitive reinspection in­ lowing shall be accomplished: tervals shall then start no later than 2,000 hours' time in service from that date. This (a) Within the next 400 hours' time in serv­ inspection may be made by dye penetrant, mag­ ice after the effective date of this AD, unless netic particle or ultrasonic methods. already accomplished within the past 600 hours' (1) Pistons with cracks which exceed a time in service, and at periods thereafter not depth of 0.050 inch as measured from the pis­ exceeding 1,000 hours' time in service follow­ ton inner wall surface shall be modified in ing that initial inspection, inspect from wing accordance with paragraph 4(b) of Lockheed Station 580 through wing Station 600, the ex­ Field Service Letter No. FS/256603L, dated ternal lower surface of the aft skin panels, January 24,1962, or an FAA approved equiva­ P/N 472066, for any evidence of cracks ema­ lent in order to be eligible for further use- nating from the aft edge of the panel through Pistons with this modification are redesignated the rear beam attachment holes. Inspection shall be by close visual or dye penetrant means. Cleveland Pneumatic Tool Company P/N's 8298C-4B, 8298C-4C, 8298D-4A, or 8298F-4A. (b) Any cracks shall be repaired prior to (2) Pistons with cracks which do not exceed further flight in accordance with Lockheed a depth of 0.050 inch as measured from the 1649 Service Bulletin No. 73, Section 1, "Modi­ piston inner wall surface shall be repaired in fication Data," and Lockheed Drawing SED accordance with paragraph 4(a) of Lockheed 61-9004, or an equivalent method approved by Field Service Letter No. FS/256603L, dated the Chief, Engineering and Manufacturing January 24, 1962, or an FAA approved equiva­ Branch, FAA Western Region. lent in order to be eligible for further use. Re­ paired pistons shall be identified by stamping (c) The periodic inspections may be discon­ a letter "R" in front of the part number. tinued following repair per (b) or when an (3) Pistons showing no evidence of cracks uncracked skin panel has been reinforced in and pistons repaired in accordance with (a) accordance with Lockheed 1649 Service Bul­ (2) may be returned to service subject to the letin No. 73. 2,000 hours' repetitive reinspection intervals. (d) Upon request of the operator, an FAA (b) When modified pistons, P/N's 8298C- maintenance inspector, subject to prior ap­ 4B, 8298C-4C, 8298D-4A, or 8298F-4A, or proval of the Chief, Engineering and Manu­ FAA approved equivalent are installed, the pe­ facturing Branch, FAA Western Region, may riodic reinspections of (a) may be discontinued. adjust the repetitive inspection intervals spe­ (c) Upon request of the operator, an FAA cified in this AD to permit compliance at an maintenance inspector, subject to prior ap­ established inspection period of the operator if proval of the Chief, Engineering and Manu­ the request contains substantiating data to jus­ facturing Branch, FAA Western Region, may tify the increase for such operator. 1^48 LOCKHEED

(Lockheed Field Service Letter FS/240893L, 62-26-4 Lockheed Amdt. 514 507 Federal dated April 14, 1960, and Lockheed 1649 Serv­ Register December 5, 1962. Applies to AH ice Bulletin Xo. 73 cover this same subject.) Model 188A and Model 188C Aircraft. This directive effective November *2, 1962. Compliance required as indicated. To permit early detection of cracks in both 62-26-3 Lockheed Amdt. 512 Part 507 Fed­ the closed and open section type elevator eral Register December 6, 1962. Applies to balance weight arms and to assure rework of All Models 49,149,649, 64SA, 749,749A, and uncracked arms and replacement of cracked 1049-54 Series Aircraft Incorporating Main arms, the failure of which could cause jam­ Landing Gear Crossheads, P.N 307866 or ming of the elevator or adversely affect pro­ P/N 288982 Which Have Accumulated tection against flutter, the following shall be 10,000 or More Hours' Time In Service. accomplished: Compliance required as indicated. (a) Unless already accomplished within the To detect fatigue cracking in the 0.25-inch last 75 hours' time in service prior to the radii adjacent to the one-inch diameter bearing effective date of this AD, all elevator balance surfaces on main landing gear crossheads, the weight arms of the closed (square tube) type failure of which would prevent normal exten­ shall, within the next 100 hours' time in service sion and retraction of the main landing gear, following the effective date of this AD and at the following shall be accomplished: intervals thereafter not to exceed 175 hours' (a) Within the next 700 hours' time in serv­ time in service from the last inspection, be ice after the effective date of this AD, unless inspected in the manner prescribed in (c). already accomplished within the last 1.800 Any closed type arm found to be cracked hours' time in service prior to the effective shall be replaced prior to further flight with date of this AD, and thereafter at intervals an uncracked closed type arm of the same part not to exceed 2,500 hours" time in service from number, with an uncracked open type arm the last inspection, inspect all crossheads as of the proper part number as prescribed by follows; Lockheed Field Service Letter FS/249931L or with an FAA engineering approved replace­ The crosshead shall be removed from the ment arm. The replacement shall be accom­ aircraft and inspected by the magnetic particle plished in accordance with Lockheed Service method or FAA approved equivalent for cracks Bulletin 88/SB-567, Revision 1, or FAA en­ in the 0.25-mch radii adjacent to the one-inch gineering approved equivalent. diameter bearing surfaces. All cracked cross- heads shall be replaced with sound ones before (b) Unless already accomplished within the the aircraft is returned to service. Crosshead last 250 hours' time in service prior to the replacement for 1049-54 aircraft shall be P/N effective date of this AD, all elevator balance 307866 only. Crosshead replacement for 49, weight arms of the open (C—section) type 149, 649, 649A, 749. and 749A aircraft shall shall, within the next 100 hours' time in serv­ be either P/X 307866 or P /X 288982. ice following the effective date of this AD and at intervals thereafter not to exceed 350 hours' (b) Upon request of the operator, an FAA time in service from the last inspection, be maintenance inspector, subject to prior ap­ inspected in the manner prescribed in (c). proval of the Chief, Engineering and Manu­ Any open type arm found to be cracked shall facturing Branch, FAA Western Region, may be replaced prior to further flight with an adjust the repetitive inspection intervals spe­ uncracked arm of the same part number or cified in this AD to permit compliance at an es­ with an FAA engineering approved equivalent tablished inspection period of the operator if arm. The replacement shall be accomplished the request contains substantiating data to jus­ in accordance with Lockheed Service Bulletin tify the increase for such operator. 88/SB-567, Revision 1, or FAA engineering (Lockheed Field Service Letter FS 251565L. approved equivalent. dated March 31, 1961, covers this same sub­ (c) Conduct close visual inspections of all ject.) external exposed surfaces of both types of This directive effective January 7, 1963. arms and of the inner surfaces of open type LOCKHEED L-49 arms in areas where external surfaces are 62-27-7 Lockheed Amdt. 521 Part 507 Fed­ hidden by clips. The close visual inspections eral Register December 27,1962. Applies to shall be made with a magnifying glass or All Models 1049C, 1049D, 1049E, 1049G, and magnifying mirror of at least 3X magnifica­ 1049H Series Aircraft Which Have Ac­ tion, with the elevator in full up position and cumulated 20,000 or More Hours' Time in with all elevator access doors at the trailing Service and to Aircraft With Less Than edge of the horizontal stabilizer, in the open 20,000 Hours' Time In Service, Upon the position. Accumulation of 20,000 Hours' Time In Service. (d) Within 350 hours' time in service after the effective date of this AD, all balance Compliance required as indicated. weight arms inspected per (a) and (b) and As a result of fatigue cracking of the wing found to be uncracked shall, unless already front spar lower cap and web at wing Station accomplished, be reworked in the manner de­ 325, accomplish the following: scribed by paragraphs B(2) through B(6) of (a) Unless already accomplished within Lockheed Service Bulletin 88/SB-567, Revi­ 1,100 hours' time in service prior to the effec­ sion 1, or in an FAA engineering approved tive date of this AD all aircraft shall be in­ equivalent manner. spected and repaired or reinforced as necessary within the next 400 hours' time in service fol­ (e) Closed type replacement arms installed lowing the effective date of this AD, and at per (a) and closed type uncracked arms re­ periodic intervals thereafter not to exceed 1,500 worked per (d) are subject to the inspection hours' time in service as follows: for cracks in accordance with (c) at intervals not to exceed 175 hours' time in service. Open (1) Use X-ray film of the AAM type in a type replacement arms installed per (a) or (b) double loaded holder. Place the film on the and open type uncracked arms reworked per front beam cap horizontal leg on each side of (d) are subject to the inspection for cracks in wing Station 325 and as close to wing Station accordance with (c) at intervals not to exceed 325 as possible. Use a minimum of 60 KV 350 hours' time in service. {FAA engineering and 5 milliamps at 36 inches focal distance approved equivalent replacement arms installed with an exposure time of approximately 3 min­ per (a) or (b) will be subject to such special utes. The exposure is to be taken at 90° to the inspections as may be prescribed by FAA in wing lower skin. All sealing compound in the conjunction with the approval of the use of area to be inspected must be removed prior to such arms.) inspection. (i) If no cracks are detected in the for­ (f) Upon request of the operator, an FAA ward horizontal leg by the X-ray inspection, maintenance inspector, subject to prior ap­ inspection of the spar cap and lower main proval of the Chief, Engineering and Manu­ beam web is not required. facturing Branch, FAA Western Region, may (ii) If a crack is detected in the for­ adjust the repetitive inspection intervals spe­ ward horizontal leg by the X-ray inspection, cified in this AD to permit compliance at an inspection of the spar cap and lower main established inspection period of the operator beam web is required. All sealing compound if the request contains substantiating data to in the area to be inspected must be removed justify the increase for such operator. prior to inspection. Inspection of the aft (Lockheed Field Service Letters FS/ horizontal and vertical leg and inspection of 249931L dated September 9, 1960, FS/ the lower main beam web shall be accomplished 250044L, dated November 28, 1960, and Serv­ by use of either radiographic or dye penetrant method. ice Bulletin 88-SB-567, Revision 1, cover this same subject.) (2) All aircraft that are inspected in ac­ cordance with (a) (1) (i) and are found not to This supsersedes the Airworthiness Directive be cracked may be returned to service. Any on the same subject issued and made effective cracked spar caps or webs shall be repaired in by telegram dated November 23, 1962. accordance with Lockheed Structural Repair This directive effective December 4, 1962. Manual, Report No. 8882, or FAA approved L-50 LOCKHEED i equivalent prior to returning the aircraft to (c) Upon request of the operator, an FAA service, Repairs made in this area must be maintenance inspector, subject to prior ap­ sealed against fuel leakage in accordance with proval of the Chief, Engineering and Manu­ Lockheed Report No. 5909 or FAA approved facturing Branch, FAA Western Region, may equivalent. adjust the repetitive inspection intervals speci­ (b) The periodic re inspection may be dis­ fied in this AD to permit compliance at an es­ continued on aircraft: tablished inspection period of the operator (1) on which the spar caps are found not to be cracked if such spar caps are reinforced if the request contains substantiating data to in accordance with Lockheed 1049 Service Bul­ justify the increase for such operator. letin No. 3110, dated March 31, 1961, or FAA (Lockheed Field Service Letter FS/240885L, approved equivalent; and dated April 15, 1962, covers this same subject.) (2) on which the cap and web are repaired and sealed in accordance with (a) (2). This directive effective January 28,1963. L-51

LUSCOMBE

(For Model 8 Series, see SUvaire) (For Model 11 Series, see Temco)