Do You Want to Be an FAA Safety Inspector?

Do You Want to be an FAA Safety Inspector?

The U.S. Federal Aviation Admini- spectors that were available during stration (FAA) finally has convinced the early years of former U.S. Presi- the U.S. Congress that there is a dent Ronald Reagan. need for additional experienced aviation safety inspectors (maintenance) A related congressional concern is in the FAA field offices to closely compliance with safe maintenance monitor maintenance concerns of both practices by the air carriers and fixed aging and newer aircraft (see “Air- base operators which also is an as- craft Aging is a Growing Mainte- pect of safety that can be monitored nance Concern,” March/April Avia- by alert and qualified maintenance tion Mechanics Bulletin). This ac- inspectors. tion is in response to the strong concerns expressed by the public and Recognition of the critical role of the media related to the safety of the safety inspector as a key ele- public transport aircraft after recent ment in the safety of air travel brings incidents of apparent structural fail- along with it a heavy responsibility ures caused by corrosion and metal to those who follow this career path. fatigue. The newly hired aviation safety inspector faces the need to learn quickly The FAA intends to hire some 900 and “get up to speed” with the re- field inspectors. Although all of quirements of expanding traffic and this number cannot be funded at once, technology. He or she must be pre- an official noted that the current pared to face the fact that the newly hiring program will help assure that hired inspector may be regarded as proper maintenance standards are not possessing adequate experience maintained in the air transport in- in established aviation maintenance dustry. During the Fiscal 1988-90 practices. Further training must be budget period, the agency is expected accepted to ensure that the inspec- to hire about 300 additional inspector looking over the shoulder of a tors per year, and that by 1991 there mechanic on the job, who frequently should be double the number of in- is highly experienced, knows as much

FLIGHT SAFETY FOU NDAT ION ¥ AVIAT I ON M ECH ANICS BU LLET I N ¥ JUL Y /AUGUST 1989 1 if not more than the technician he is observing. NEW PRODUCTS

The inspector also must quickly gain Information on the following prod- the insight to sense when an opera- ucts, services and literature is pub- tor, through his mechanics, may be lished in the interest of improving cutting corners on maintenance and aviation safety through a well-in- emphasizing economics to the det- formed, better-equipped aviation riment of safety. mechanic. The need, the recognition and the rewards are there for maintenance Wrap Protects safety overseers. The FAA—and Hoses and Wires the traveling public—expect reliable aircraft, and the Congress has awak- Spirally cut cable wrap called Heli- ened to the need to stimulate the Tube¨ from M. M. Newman Corp. expansion of the means to assure applies like tape to hydraulic lines, the attainment of this goal. Mechanics hoses and wires to protect them are a critical cornerstone of avia- from abrasion. The product also can tion safety; safety inspectors help be used to bundle, insulate and keep that cornerstone aligned with dampen vibration effects on these maintenance standards and abreast components. of new developments and techniques so necessary to keep up with the The wrapping material is available increasing challenges. in six sizes for bundles from 1/16 inch to 5 inches outside diameter, Aviation safety inspectors currently and operates in temperatures rang- earn up to $53,000 per year, have ing from -232 degrees C to 260 de- opportunities for advancement, are grees C (-450 degrees F to 500 de- afforded benefits that include up to grees F). It is non-flammable and is 26 days of paid vacation a year, chemically inert. plus sick leave and retirement benefits. U.S. citizenship is required at the No special tools are needed to in- time of application. If you are in- stall Heli-Tube, which conforms to terested in becoming an FAA avia- MIL M-20693, AMS 3651B, AMS tion safety inspector, send a post- 3653, AMS 3654, and AMS 4655. card with your name and address Aircraft applications include damp- to: FAA, P.O. Box 26650, Dept. ening vibration for electrical wires PPAO4, Oklahoma City, OK 73126 and as a chafe guard on high tem- U.S.♦ perature, steel-braided teflon hoses

2 FLIGHT SAF ETY FOU NDAT I ON ¥ AVI AT I ON MECHANICS BU LLET I N ¥ JUL Y /AUGUST 1989 and hydraulic lines. showing at aviation technology schools or lunch-break viewing at The spiral tape is priced according maintenance facilities. to size and quantity requirements and is available from M. M. New- The video tape is available free with man Corp., 24 Tioga Way, P.O. Box a charge of $6.95 to cover the cost 615, Marblehead, MA U.S. 01945 of packing and mailing. It may be (Telephone 617-631-7100; FAX 617- ordered from: Bowman Distribution, 631-8887). Barnes Group, Inc., 850 East 72nd Street, Cleveland, OH 44103 U.S. Video Tape Describes (Telephone 1-800-877-8800). Fastener Safety Brochure Describes Corrosion Protection A 12 1/2-minute video presentation explores the nuts and bolts of fas- A full-color brochure from Sermat- tener safety. Titled “For Safety’s ech International, Inc., describes a Sake: The Fastener Audit,” the video diffused aluminide coating, SermaLoy tape was produced by Bowman J, designed to protect gas turbine Distribution, a direct-to-user dis- hot section components from hot tributor of maintenance and repair corrosion and oxidation. The coat- products. ing is made of diffused aluminide The video presentation instructs the with a silicon-enriched outer layer, viewer on methods of protection designed to protect gas turbine hot against the hazards of inferior quality section components at temperatures and counterfeit fasteners. (In rec- up to 1204 degrees C (2,200 de- ognition of the prevalence of the grees F). bogus parts problem, Flight Safety Foundation is preparing a detailed report on the subject.) The film deals with mismarked and misrepresented Photograph not available. bolts, nuts, washers and other fasteners being sold to manufacturers and maintenance services.

The distributor of the video tape claims that both the buyer and in- staller of fastening devices can benefit According to Sermatech, the mecha- from it. Possible uses can include nisms of high-temperature metal

FLIGHT SAFETY FOU NDAT ION ¥ AVIAT I ON M ECH ANICS BU LLET I N ¥ JUL Y /AUGUST 1989 3 degradation in older turbine engines Rigid Borescope Offers were isolated within different stages Safer Inspections of of the hot section and could be ad- dressed separately. In the newer, Hard-to-Reach Areas hotter and more efficient engines, however, low-temperature hot cor- A rigid fiberoptic borescope from rosion (LTHC) and high-tempera- the Lenox Instrument Company is ture hot corrosion (HTHC) are no intended to replace slow, tedious longer segregated within the en- feeler gauges for surface inspections. gine but now occur on the same Measurement of grooves, rings, slots, part. The air-cooled blades and holes, and other internal surface vanes in these engines experience features of parts and equipment is drastic temperature gradients and said to be more accurate and faster require special protection, accord- than with conventional inspection ing to Sermatech. methods.

The silicon in the coating is claimed to prevent thermal fatigue cracking caused by unequal rates of heating and cooling between the surface and interior of a component, a Photograph not available. common cause of cracking when using coatings without this protection.

SermaLoy J is applied by an international network of coating facilities operated by Sermatech Techni- cal Services division. According to The borescope was developed for the company, one operator using Pratt measuring O-ring grooves in bear- & Whitney PT-6 engines reported ings where tolerances are in thou- savings of up to $20,000 per engine sandths of inches and is available as a result of a reduced need for with features that allow it to be parts after using the coating adapted to high-tolerance gradation.

Further information is available from Different models are available with Sermatech International, Inc., 155 variable magnification (zoom) and South Limerick Road, Limerick, PA interchangeable micrometer eye- 19468 U.S. (Telephone 215-948- pieces. Viewing sections are avail- 5100; Telex 84-6335). able in lengths from six inches to

4 FLIGHT SAF ETY FOU NDAT I ON ¥ AVI AT I ON MECHANICS BU LLET I N ¥ JUL Y /AUGUST 1989 more than 50 feet. The unit can be used with closed-circuit television systems, motion picture cameras and many formats of still cameras including 35 mm, 2 1/ 4-inch square and 4-by 5-inch. It is available in diameters ranging from 3/16-inch through 2 3/4- inch and with vari- Photograph not available. ous directions of view.

The measuring borescope can be retrofitted to existing borescopes, fabricated in the unusual configu- rations for special uses, and is ra- diation-resistant. Light sources include incandescent and fiberoptic with AC or rechargeable DC electrical power. An explosion-proof fiberoptic light is available for ap- safety of a steady platform to pre- plications that require this protection. vent tipping the operator or damag- Offset eyepieces are available. ing an adjacent aircraft.

Details are available from the Le- Designated the Bally/Lift/Two by the nox Instrument Company, 265 An- manufacturer, Ballymore Company, drews Road, Scottsville Industrial the unit is equipped with three-speed Park, Trevose, PA 19047 U.S. hydraulic hand pumps for quick, easy (Telephone 215-322-9990). lifting or a choice of AC and DC electric drive motors. Platform-mounted pushbutton power controls are included with the electric-drive models. Personnel Lifts Built New features incorporated in the For Steadiness, Safety Bally/Lift/Two include built-in access ladders, adjustable leveling sta- A newly designed line of hydrau- bilizing jacks at each corner of the lic-powered personnel/maintenance base and work platforms that are lifts is intended to offer the avia- enclosed on all sides by steel rails tion mechanic the capability to lift for operator safety. as much as 300 pounds to working heights of up to 21 feet, with the The angled access ladder used to

FLIGHT SAFETY FOU NDAT ION ¥ AVIAT I ON M ECH ANICS BU LLET I N ¥ JUL Y /AUGUST 1989 5 reach the platform when it is in the ally dry out the moisture on metal fully lowered position is constructed surfaces and penetrate into the base with three-inch-deep, anti-skid lad- of the corrosion cell. It is an ultra- der steps and side-mounted hand- thin compound applied under high rails. Self-storing leveling jacks are pressure. A powerful attraction for positioned at each corner of the base metal causes the compound to spread of the lift to provide convenient lev- and penetrate into fuselage skin laps, eling and stabilization on uneven around rivets and screws and blind surfaces. spots not directly sprayed. It is said to separate water from metal, leav- Three models of the platform are ing an ultra-thin insulating layer that available, including one with a can- prevents further oxidation through tilevered platform. The units con- electrolytic action. form to OSHA standards and ANSI A92.3 19890 codes.

For more information contact the Ballymore Company, 220 Garfield Ave., West Chester, PA 19380-0397 U.S. (Telephone 215-696-3250). Photograph not available. Anti-Corrosion Agent Blocks Electrolysis

Marketed by Corrosion Block, Inc., the anti-corrosion chemical ACF- 50 is claimed useful on moving parts According to the supplier, ACF-50 as well as for entire airframes. The remains effective for about 18 months material separates metal from mois- and gradually disappears as it is ture and is said to block the action chemically consumed, leaving no of the electrolytic process that pro- residue. The product is available duces corrosion that can lead to struc- for spot treatment in 13-ounce aerosol tural failure of aircraft parts and cans or one- and five-gallon con- structures. tainers with hand sprayers.

Although common waxes can seal More information is available from moisture into corrosion pits and al- Corrosion Block, Inc., 4901 Keller low the destructive process to con- Springs, Suite 108, Dallas, TX 75248 tinue, ACF-50 is claimed to actu- U.S. (Telephone 1-800-638-7361.

6 FLIGHT SAF ETY FOU NDAT I ON ¥ AVI AT I ON MECHANICS BU LLET I N ¥ JUL Y /AUGUST 1989 Disposable Urinal Aids One portable, disposable urinal is the Brief Reliefª distributed by Pilot , Mechanic Alike American Innotek, Inc. The product is claimed to be convenient to The safety aspects of a portable urinal use, leakproof and tough enough, are easily evident for the pilot flying even when full, to sustain rough han- an aircraft without on-board facilities, dling that includes being dropped especially when the use of such an aid from a height of six feet or being helps avoid an unplanned landing in stepped on. the middle of a flight just when the weather is at its worst. Its benefits to the aviation mechanic are less obvi- ous, but nevertheless offer a measur- able contribution to his ability to keep the aircraft in top shape.

Mechanics have found that the use of makeshift toilet facilities aboard Photograph not available. aircraft can present insidious threats to safety. The problem is with the effects of acidic urine that can come in contact with aircraft structure and systems through leakage or acciden- tal bursting of an inappropriate con- tainer that may have been pressed into service. The insidious action of acid on aluminum, electronics or electrical and mechanical mechanisma, to say nothing of upholstery, could The unit is a specially designed spill- eventually degrade structural integ- and splash-proof plastic bag filled rity or operational viability. with a non-toxic, absorbent powder that changes the liquid into an odorless One of these would be good insur- semi-solid on contact. A plastic ance in a mechanic’s tool box. It closure slide seals the opening after could come in handy for that time use. The company claims that the of need when the technician is work- bag, with a built-in funnel, is de- ing on an airplane parked far from signed so that even if the closure a restroom and he doesn’t want slide is lost and the bag is acciden- to leave his valuable toolbox un- tally stepped on, the gel will not be protected. squeezed out.

FLIGHT SAFETY FOU NDAT ION ¥ AVIAT I ON M ECH ANICS BU LLET I N ¥ JUL Y /AUGUST 1989 7 The product is usable by men, women for cleaning and protecting alumi- and children, and each bag will hold num surfaces. The manufacturer states up to 16 ounces of fluid. Each bag that they are non-toxic and are not folds flat for ease of storage and irritating to skin or eyes. measures 4.5 inches by 6.5 inches. Instructions are printed on each bag Contact Novus, Inc., 10425 Hamp- and a non-alcoholic washup towel- shire Ave., So., Minneapolis, MN ette is included. 55438 U.S. (Telephone 612-944- 8800). More information is available from American Innotek, Inc., 334 Via Vera Aeronautical Cruz, Suite 251, San Marcos, CA Dictionary 92069 U.S. (Telephone 619-471- 1549). Aviation mechanics seem to keep run- ning into new words and phrases in maintenance and overhaul manuals, Polish Improves Vision technical literature and trade publica- Through Windshields tions. They, as much as pilots, need to keep abreast of industry terminol- Two products from Novus, Inc. are ogy to avoid unsafe conditions designed to rejuvenate and protect plas- brought on by communications tics such as aircraft windows. misunderstandings.

Plastic Polish 1 is a cleaner, shiner One way to keep up with the latest and protector. Designed to be ap- terms is to consult the 1989 edi- plied in one operation, the highly tion of the Dictionary of Aeronau- concentrated formula polishes to tical Terms. Along with their nor- an even glaze that is said to resist mal library of maintenance manu- fingerprints and dust buildup, and als, many maintenance technicians to be antistatic and antifogging. The keep this type of aeronautical ref- other product, Plastic Polish 2, re- erence work near at hand. The pub- moves fine scratches and haze. It lication defines more than 5,000 is a polishing compound that re- aviation terms used in engineer- stores and protects damaged plas- ing, avionics, maintenance and gov- tics, and when it is used the manu- ernment documents. facturer recommends that it be fol- lowed up by application of Plastic The dictionary is available from ASA Polish 1. Publications, 6001 Sixth Ave., S., Seattle, WA 98108 U.S. (Telephone The two products are also useful 206-763-0277).♦

8 FLIGHT SAF ETY FOU NDAT I ON ¥ AVI AT I ON MECHANICS BU LLET I N ¥ JUL Y /AUGUST 1989 porate pilot, flight instructor me- NEWS & TIPS chanic examiner, and an accident prevention counselor. He has spo- Maintenance ken at many aviation conferences Technician Honored in the United States and has pub- lished articles in a number of avia- in Michigan tion magazines.

Peter G. Tanis received the annual Minnesota General Aviation Main- tenance Technician of the Year Award at the General Aviation Maintenance Photograph not available. Conference in Minneapolis this spring. Sponsored by the Minnesota Department of Transportation (Mn/ DOT) and the U.S. Federal Aviation Administration (FAA), the award rec- ognizes the importance that mainte- Peter G. Tanis (r) receives the Minnesota nance technicians play in the role of Maintenance Technician of the Year aviation safety. Award from Raymond Rought, Director of the Office of Aeronautics, Minn. DOT. Tanis, a pilot and aircraft mechanic since 1959, was nominated for the Do You Understand award for his many contributions to aviation safety and for his inven- The New MEL Rules? tion of an aircraft preheater system. The patented device allows an air- The U.S. FAA’s most recent ruling craft to take off with little delay in concerning minimum equipment lists cold weather. (MELs) permits certain aircraft to be operated with inoperative instru- In addition to operating a small comments and equipment not essential pany and distributing thousands of for the safe operation of the air- preheaters in 49 states and seven craft. Amendment Numbers 43-30 foreign countries, Tanis maintains and 91-206 to the U.S. Federal Avia- and performs annual inspections on tion Regulations (FARs) permit ro- aircraft in his local community of torcraft, nonturbine-powered air- Glenwood. planes, gliders, and lighter-than-air aircraft, for which an approved master A former teacher of aviation me- minimum equipment list (MMEL) chanics, Tanis also has been a cor- has not been developed, to be op-

FLIGHT SAFETY FOU NDAT ION ¥ AVIAT I ON M ECH ANICS BU LLET I N ¥ JUL Y /AUGUST 1989 9 erated with inoperative instruments b. At the next required inspection, and equipment not essential for the the inoperative instrument or item safe operation of the aircraft. of equipment is repaired, replaced, removed or inspected as appropri- These amendments also allow gen- ate. eral aviation operators of small air- planes, gliders and lighter-than-air Copies of these amendments are avail- aircraft, for which an MMEL has able from the U.S. Government Print- not been developed, the option of ing Office, Superintendent of Docu- operating either under the MEL or ments, Washington, in accordance with the provisions DC 20402-9325 U.S. (Telephone 202- of the new rule, as follows: The 783-3238). pilot-in-command, owner or operator will be required to identify the in- Where Credit is Due … operative instruments or equipment, consult the aircraft’s approved flight In the January issue of this publica- manual or owner’s handbook, and tion, the article on page 15, “U.S. review FAR Part 91.30[d]. After Maintenance Technician Receives the pilot ensures that an inopera- Recognition,” omitted mention of tive instrument or equipment is not the National Business Aircraft required, the aircraft may depart Association (NBAA) as a cospon- provided: sor of the program. In fact, that or- ganization chaired the 25th awards a. The inoperative instrument or ceremony. item of equipment is deactivated or removed, the cockpit control of Are You Looking For the affected instrument or item of equipment is placarded with the ACs or NPRMs? word “Inoperative,” and the dis- crepancy is recorded in the aircraft’s A number of our readers have re- maintenance records (If the inop- quested information on how to re- erative instrument or item of equip- ceive FAA Advisory Circulars (ACs) ment is being removed from the and Notices of Proposed Rule Mak- aircraft or if deactivation requires ing (NPRMs). To receive these pub- maintenance, a certified and ap- lications, write to the Department propriately rated maintenance per- of Transportation, Distribution Re- son will be required to accomplish quirements Section, M-494-1, 400 the removal and maintenance task.); 7th Street, S.W., Washington, DC and, 20590 U.S.

10 FLIGHT SAF ETY FOU NDAT I ON ¥ AVI AT I ON MECHANICS BU LLET I N ¥ JUL Y /AUGUST 1989 The ACs are issued to make public two crew members were the only many announcements concerning or occupants. explaining new rules or procedures, and they affect almost everyone who As the aircraft approached the des- has anything to do with the opera- tination, the captain, a company train- tion or maintenance of aircraft. ing pilot, told the company dispatcher that prior to landing he would give NPRMs are notices of proposed some instruction to the copilot, who revisions to Federal Aviation Regu- was scheduled to upgrade to cap- lations (FARs) or new ones, and tain status the following month. The they usually offer the opportunity aircraft entered a holding pattern to respond with comments and to at the airport's non-directional beacon influence the outcome. (NDB) and the pilot announced over the radio that they would execute Ask to receive all ACs and NPRMs an NDB approach. He subsequently that pertain to general aviation or reported that they were in the pro- transport aircraft. Request all issu- cedure turn inbound to the airport. ances if your area of activity is within the scope of both categories. Approximately three minutes later, two other pilots who were flying a de Havilland Twin Otter nearby and MAINTENANCE ALERTS who had seen the DC-3 in the holding pattern and outbound for the ap- The following information on acci- proach, witnessed the cargo aircraft dents and incidents is intended to diving steeply with the left wing provide an awareness of problem areas folded upwards beyond 90 degrees. through which such occurrences may The DC-3 continued its descent in- be prevented in the future. verted and crashed into the mus- keg surface at a descent angle of Misread X-Rays about 70 degrees. The two pilots were killed instantly. The nose and The Douglas DC-3, operated by a fuselage sections sustained massive Canadian carrier, was used primar- damage, and the tail assembly had ily for cargo work in northern com- twisted sharply but was relatively munities. After its last hauling job intact. Both engines were torn from of the day, delivering a cargo of their mounts. The left wing was fuel, the aircraft was returning to found 650 feet away and had landed Pickle Lake, Ontario. The late af- flat, sustaining very little damage. ternoon weather was clear and the There was no fire.

FLIGHT SAFETY FOU NDAT ION ¥ AVIAT I ON M ECH ANICS BU LLET I N ¥ JUL Y /AUGUST 1989 11 Investigators later determined that ¥ All the radiographic exami- the left wing had failed under nor- nation reports, except for mal flight loads as a result of a fa- the one performed by a dif- tigue crack in the center section lower ferent company on Febru- wing skin. The final report that ary 25, 1980, stated that there was produced by the Canadian Avia- were no apparent defects; tion Safety Board also stated that “Anomalies in the radiographs (X- ¥ The visual inspection done rays) taken during mandatory NDT by the operator following [non-destructive testing] inspections the February 1980 inspec- were not correctly interpreted.” tion, which stated there was a crack indication at sta- Among the report’s conclusions were tion 127.750, was not docu- the following: mented in the aircraft log books; ¥ A 15-inch fatigue crack was visible in radiographs taken ¥ The requirement of a Feb- at the normal inspection ruary 1966 service bulle- cycle, 297.8 hours of flight tin was not fulfilled on this time before the accident, but aircraft and on some other was not interpreted by the DC-3s operating in Canada. radiographer; The service bulletin (SD263), subsequently re- ¥ The radiographs taken at the vised, from McDonnell Dou- normal inspection cycle glas, responded to DC-3 showed that three bolt fas- wing cracking problems by teners and an adjacent rivet stipulating dye penetrant were missing from the bot- checks in conjunction with tom of the front spar in the radiographs of certain ar- vicinity of station 127.750, eas including station where the fatigue failure had 127.750; occurred; ¥ There were no recorded in- ¥ Had a thorough visual instances of hard landings or spection been completed fol- flight through turbulence that lowing a radiographic inspec- could be considered contribution on November 23, 1986, tory to the accident; during subsequent peri- odic inspections, a number ¥ The structural failure was of missing fasteners would not the result of aircraft have been detected; system malfunction or

12 FLIGHT SAF ETY FOU NDAT I ON ¥ AVI AT I ON MECHANICS BU LLET I N ¥ JUL Y /AUGUST 1989 pilot-induced maneuvers; were illuminated during the pre-land- and, ing checks, found everything was all right, and executed a normal ¥ The aircraft weight and landing. center of gravity were within prescribed limits. During the rollout after touchdown, the nose continued to lower beyond Gear Mechanism the normal position and the propellers hit the runway surface. The A Boeing 747 pilot had to declare aircraft came to rest on the center an emergency during the approach of the runway on its nose, which for landing at Sydney, Australia, when along with the propellers and pitot a landing gear malfunction occurred. tubes, was damaged. The flight was en route from Hono- lulu, Hawaii, and Auckland, New Upon later examination, the nose Zealand. gear actuator showed a number of defects. No electrical continuity The aircraft made a safe landing and was found across the leads from there were no injuries. Witnesses re- the microswitch assembly regard- ported that a piece of wing material less of the microswitch plunger fell off as the aircraft landed and position. An internal examination that there was some fuel leakage. revealed that the two microswitches Some hydraulic fluid also was re- that made up the assembly were ported to have leaked, but there was serviceable, but that all the leads no fire. The aircraft was towed to were damaged at the point where the international terminal where the they entered the base. Also, the O- passengers deplaned through the nor- ring seal under the lock piston had mal exits. been cut and showed signs of hav- ing extruded. After inspection, it was found that a mechanism which controls the main Tripped by Corrosion pivot in the starboard main landing gear had failed, producing localized The Boeing 727 was being towed damage that resulted in the punc- from a passenger loading gate at tured fluid lines. Stapleton International Airport, Den- Frayed Wires? ver, Colo, U.S. when the left main landing gear collapsed. The 113 The pilot of the Cessna 404 checked passengers and seven crew mem- that the landing gear down lights bers exited without injury.

FLIGHT SAFETY FOU NDAT ION ¥ AVIAT I ON M ECH ANICS BU LLET I N ¥ JUL Y /AUGUST 1989 13 Investigators found that the acci- The design of the main gear operat- dent was caused by metal fatigue in ing mechanism on this aircraft util- a trunnion assembly that had cor- izes a hydraulic actuator that incor- roded. The trunnion had been sched- porates an internal mechanical lock uled for inspection in the summer which engages as the gear mecha- of 1990 and had never had been nism reaches the fully extended po- removed from the aircraft, which sition. Upon gear retraction, the was eight years old. locking mechanism is disabled by hydraulic pressure. There is a mi- Three Greens croswitch on the side of the hydraulic No Good gear actuator that, through the action of a plunger, senses the fully The Cessna 404 was being test flown extended position of the gear and to check the repair of defects noted serves two purposes; it sends a sig- during a previous flight for the re- nal to illuminate the green “locked- newal of the certificate of air- down” light in the cockpit and, in worthiness. According to the pilot, conjunction with similar switches one of those defects was that the on the other gear legs, turns off the right main gear green light remained hydraulic pump. As the landing gear on despite four retractions. extends, the last gear leg to reach the down and locked position is the The gear was recycled twice during one to stop the hydraulic pump. the test flight and the cockpit indi- cations from the gear “locked-down” The right gear actuator, found in and “unsafe” lights operated prop- the partially retracted position, was erly. When the aircraft was returned sent to an overhaul facility for a at the end of the test flight, the pilot tear-down inspection. There it was got three green gear lights and made found that the switch operating a normal touchdown. Shortly, how- plunger was jammed by corrosion. ever, the right wing lowered and the propeller on that side struck the Investigators reasoned that the right runway. The pilot stopped the air- leg was the last to extend and, with craft without losing directional control the switch operating plunger stuck and saw the three green lights still in the “locked-down” position, a glowing. Later examination showed premature signal was sent to the that the right main gear had par- hydraulic pump. When the second tially collapsed, but there was no of the three gear legs locked in the apparent mechanical failure that could down position, the hydraulic pump have caused it. was turned off, stopping pressure

14 FLIGHT SAF ETY FOU NDAT I ON ¥ AVI AT I ON MECHANICS BU LLET I N ¥ JUL Y /AUGUST 1989 to the right gear actuator before it after a small fire broke out in the extended that leg to the fully down aircraft’s auxiliary power unit (APU) and locked position. For the same which supplies power for heat and cause, the switch with the jammed lights while the aircraft is on the plunger sent a signal that illumi- ground. nated the respective green light, in- dicating to the pilot that all was Although the incident involved only well. a minor fire, the passengers were taken off by use of the emergency Cessna has since distributed a serv- chutes and window exits as a pre- ice newsletter that deals with the caution. The fire was quickly ex- problem of moisture affecting the tinguished and only one minor in- mechanism, and describes a means jury was reported. of sealing the switch. Total Power Loss Door Opens in Flight The flight instructor was conduct- As the Boeing 737 was approach- ing a dual check ride of the private ing an airport in northeastern India, pilot. After all internal and exter- a door opened, depressurizing the nal preflight checks had been com- aircraft. Four persons were injured pleted, they started the engine and before crew members were able to taxied out for takeoff. The power close the door. check of the Piper PA-28 Warrier’s engine was all right and they took After landing, the injured passen- off. gers were taken to a hospital for treatment and the aircraft again took At a height of between 50 and 100 off. The door again opened and the feet the aircraft suffered a total power aircraft returned to the airport where loss. When the instructor took con- maintenance was accomplished. The trol and lowered the nose, the en- aircraft later was put back into ser- gine surged to full power but quit vice with no further reported prob- again after about four seconds. With lems involving the door. little altitude and few alternatives, the aircraft was landed in a plowed Fire in the Hole field. The main gear dug in and the nose gear collapsed after touchdown, Shortly before takeoff, with 122 following which the propeller passengers and a crew of six aboard, struck the ground. The right main the Boeing 737 had to be evacuated gear sank into the soft earth,

FLIGHT SAFETY FOU NDAT ION ¥ AVIAT I ON M ECH ANICS BU LLET I N ¥ JUL Y /AUGUST 1989 15 causing the right wingtip to contact had gone unnoticed because the main the ground with enough force to bend fuel selector valve had been in the the wing back. The three occupants, “off” position, creating an air lock who were wearing shoulder harnesses, and causing fuel drainage from the were uninjured other than for bruises Curtiss valve to cease after a short suffered by the occupant in the right time. Some initial fuel draining from front seat. They all were able to the filter may occur when the drain leave the aircraft with no difficulty. valve is opened even with the fuel selector in the “off” position. Later inspection revealed that the fuel tanks were about three-quar- After opening the fuel selector valve, ters full and that the electric fuel the pressure loss associated with an pump properly supplied fuel to the open drain valve may not be enough carburetor. However, it was no- to prevent fuel from reaching the ticed during recovery of the aircraft carburetor and supplying the engine that fuel was flowing from the fuel normally until the pressure at the filter drain valve — the quick drain filter inlet is reduced used to drain the filter during pre- somewhat by takeoff and climb fuel flight checks. This was the Cur- flows. Therefore, the engine can tiss-type valve that is opened by be started and run, apparently nor- pushing in on a cross-bar against mally, with the drain valve open, spring pressure; it can be locked in but it can suffer fuel starvation to the open position by twisting the the carburetor during takeoff and cross-bar into the “shelf” formed climb. by the “L” shape of the slot along which the cross-bar travels. A number of similar instances had occurred to PA-28 aircraft that were This valve normally is opened for attributed to the locked-open con- only a few moments during the pre- figuration of the drain valve, and a flight inspection while the pilot al- recommended modification of the lows the required amount of fuel to valve was accomplished by filing drain and then is released to close. off the shoulder of the “L” channel The evidence indicated that the drain to remove the step that locked the valve of the accident aircraft had valve’s cross-bar, thereby render- inadvertently been left locked open ing the locking feature of the unit after the check, and the oversight inoperative.♦

16 FLIGHT SAF ETY FOU NDAT I ON ¥ AVI AT I ON MECHANICS BU LLET I N ¥ JUL Y /AUGUST 1989