Aircraft Accident Report

File i-0076

AIRCRAFT ACCIDENT REPORT

Adcpted: August 27, 1969

LOS ANGELES AIRWAYS, INC.

AUGUST 14, 1968

NAilONAL TRANSPORTATION SAFETY BOP43 DEPARTMENT OF TRANSPORTATION WASHINGTON D.C. 20591 KATIOXA3 'I?.A?<: POETATIO?< SsZm Z

synopsis ...... Probable 'Cause ...... Xistory of the ?Llg~t ...... Icjurles to Pers0r.s ...... D&na.ge to Aircraft ...... G tker Danage ...... Crew Ir.formaticn ...... Aircraft Infornation ...... Keteorolc~icalLrf'~.rlztior ...... Aids to Xavi~atLon...... Con~unications...... Aerodroae and Gro7~?d5'ac:litLes ... ?light Recorder ...... Wreckage ...... ?Ire ...... Survival Aspects ...... Tests and Research ...... Other ...... Analysis ...... Conclusions ...... ?indings ...... Probable Cause ...... Recommendations ...... File No. 1-9~16

ATIONAL P.ANSPORTATION SAFETY BOARD DEPARTXENT OF TRANSPORTATION AIRCFiAFT ACCIDZNT REPORT

Adopted: August 27L1969 LOS ANGELE~ S- 61s HELICOPTSR, $800~ COXPTON, CALIFORNIA AUGUST 14, 1968

Los Angeles Airways, Inc., S-61L helicopter, N300Y, crashed at Cornpton, California, on August 14, 1958, at approximately 1035 P.d.t. All 18 passengers and three crewmembers were fat.ally injured, and the aircrart was destroyed by impact and fire. The flight was en route from Los Angeles International Airport to the heliport at .4naheim, Califwnia, when the yellow blade, one of five maln rotor blades, separated at the spindle which attached the blade to the rotor head. Followi~gthe failure, the helicopter was uncontrollable and it fell to the ground. The Safety Board determines that the probable cause of this accident was the fatigue failure of the yellow main rotor blade spl~dle,causing separation of the blade which made the aircraft uncontrollable. The fatigue crack originated in an area of substandard hardness and inadequate shot peening. I. IhiTICATION 1.1 Xistory of the Flight Los *geles Airways, Inc., (LAA) Flight 417, was a regularly scheduled passenger fllght from Los Angeles Inter- natianal Airporz to Anaheim, California. The aircraft and crew had completed three round trips to various destinations in the Greater Los Angeles Metropolitan area beginning at 0607,l~' and departed the ramp at Los Angeles for Flight 417 at 1026. The flight, 0peratir.g under Visual Flight Rules (VFR) , was cleared by Los Angeles Eelicopter Control to take off and proceed eastbound at 1028:15. For the next few nlnutes, traffic coordination was accomplLshed on both the Relicopter Control and Hawthorne Tower frequencies. The captain also checked an alternate trznsmltter with Helicopter Control which reported difficulty hearing the flight. At 1029:30, the flight reported ts Hawthorne Tower that it was departing Los Angeles eastbound along Irn?erial Boulevard at 1,200 feet. At 1032:55, Helicopter Control advised, "LA four seventeen, seven miles $ast, radar service terminated." The flight acknowledged, Four seventeen thank you." This was the last known radio con- tact with the rllght. Statenents were obtained from 91 witnesses. A cocsensus of their observations indicates that the helicopter was proceeding along a normal rlightpth when a loud noise or unusual sound was heard. A main rotor blade was either observed to separate or was seen separated in the vicinity of the maln rotor disc. As the helicopter fell in variously described gyrations, the tail cone either folded or separated. In order to establish an approximate altitude for the flight, several sfmulzted flights were conducted In a sicilar helicopter. Most witnesses Ineicated that the flights at 1,200 to 1,500 feet appeared to be most accurate. The crash site coordinates were approximately 333541N latitude and 118°121~ longitude, and the elevation 97 feet m.s.1.

1.2 Injuries to Persons InJuries Crew Others Fatal -3 0 Nonfatal 0 None 0 2 All times herein are Pacific daylight, based on the 24-hour clock. -3- 1.3 Dama~eto Aircraft The aircraft was destroyed by impact and fire. 1.4 Other Dama~e None, 1.5 Crew Iriformation All crewmembers were properly qualified for their respective assignments. (see Appendix A for details.) 1.6 Aircraft Information The aircraft had been maintained in accordance with Federal Aviation Administration FAA) requirements, and was roperly loaded for the flight. See Appendix B for details. P 1.7 Meteorological Information Witnesses in the area described the weather as very good, with clear vislbillty below a layer of clouds which were higher than the helicopter was flying. The wind was light, generally froin the southwest. 1.8 Aids to Naviuation Not applicable.

I j Communications LOS Angeles Helicopter Ccntrol advised that it was having dlfficulty reading Flight 417 shortly after takeoff, but subsequently reported another transmitter as "loud and clear." 1.10 Aerodrome and Grcund Facilities Not applicable. 1.11 Flight 3ecorders No flight recorders were installed or required. 1.12 Wreckage The aircraft crashed in a recreation park located in a residential industrial area. The entire fuselage, both engines, maln rotor head assembly, four main rotor blriies, and the pylon assembly were located in the main impact area. The fifth main rotor blade (yellow) including the sleeve and part of the spindle, was located approxlmately one quarter of a mile northwest of the main wreckage site. Minor parts associated wlth tiis rotor blade were scattered over a three-block area northwest of the park. Examination of the yellow blade spindle (S/N ~~19)revealed a fatigue fracture in the shack of the spindle adjacent to the shoulder at the Inboard end of the shank. (see Attachment 1. ) 1.13 -Fire There was no evidence of in-flight fire; however, an intense ground fire occurred at impact. The fire was extinguished by the Compton Fire Department. 1.14 Survival Aspects This was a nonsurvivable accidenc 1.15 Tests and Research

A stereomlcroscope examination of spindle AJ-19 revealed that the nucleus of the fatigue fracture was on the trailing side of the spindle, one-eighth of a~ Inch below the centerline, approximately at the shank tangency point, with the 0.125 inch radius at the shanwfork junction. The crack had origi~ated in the base metal surface at the interface with the nickel plating, and propagated through approximately 72 percent of the shank cross-section prior to the fallt=e= Additicnel laboratory studies revealed the followlrg factors associated with the development of the fatigue crack: Incomplete shot peening of the spindle shank before plating. Adequate shot peening umld have increased the fatigue strength of the spindle and reduced the detrimental effect of the three following factors. Low hardness of the steel in the area of the shank/ fork junction where the fracture occurred. The general hardness was k \low the minimum specified for the spindle and, in addition, there were localized variations in hardness associated wlth a banded microstructure in the steel. The fatigue nucleus was In one of the softer bands. A small surface flaw, similar tc a corrosion pit, my have been present at the fatigue nucleus. Such a pit would Lncrease the stress concentration normally present in the shank/fork fillet. (4) The nickel plating may have had a detrimental effect on the fatigue strength of the unpeened base metal. 1.16 Other The spindle is part of the assembly which attaches the main rotor blade to the main rotor head, and about which the blade rotates to provide pitch control. The spindles are forged by independent contractors whose quality control of the parts includes chemical analysis, magnetic particle inspection, and hardness testing. One forging selected from each "heat batch" Is subjected to 35 separate Brinell hardness checks along the longi- tudinal axis. Each remaining spindle is checked through use of a standard Brinell hardness tester. The receiving inspection at Sikorsky consists of (1) comparison of the chemical and physical properties listel on the certification sheets with the procuFe- ment specifications; (2; verifying that necessary Inspections have been conducted by the contractor; (3) testing of a sample of the forging lot to verify that the chemical and physical properties meet specifications; and (4) on the basis of statistical sampling dimensional inspection, nondestructive tes~ing (magnaf lux) , and hardness checks. Prior to the accident, the hardness test on the basic forging sample at Sikorsky was accomplished on the shank end. If the sample failed to meet the hardness, magnaflux, or certain dimensional checks, the entire lot of forgings would be rejected. During the manufacturing process, each spindle was magnetic pzr- ticle inspected, and tested for hardness and dimension following each pera at ion. The hardness check after the machining operation was made at the fork end of the spindle. Normally only one reading per spindle was made unless the value was near the acceptable tolerance. In this instance, additional readings wouid be taken to insure that the hardness was acceptable. Subsequent to the accident, Sikorsky instituted a new procedure requiring that a star.dard Rockwell hardness test 5e accomplished in the transition area adjacent to the radlus at the shank/fork junction. As part of the main rotor head, the spindles are overhauled every 1,200 hours to inspect the bores in the ears. 2nd the out- side diamete~of the shank for scoring, scratches, fretting, corrosion, gouges, or other damage. They are also magnetic particle inspected at every overhaul. The initial three over- hauls of spindle Aj-19 ?:ere routine and completed in December s63, October 1964, and August 1965. During the fourth overhaul In June 1966, the magnaglo inspection indicated the presence of The magnetic particle Inspection includes either magnaflux or magnaglo. nonmetallic inclusions 3/ on spindles AJ-19 and AL-82. They were sent to Sikorsky Aircraft for determination of their airworthiness, and were returned with the notation, ". . . no evidence of nonmetailic inclusions which could impair the serviceability of the parts." LAA then sent both spindles along with three others to Modern Plating Company (MPC) for salvage. 4f

The LAA purchase order for the salvage of the five spindles was accompanied by a drawing which set forth the rollowing procedure: Grind bearing Journal to 4.523/4.524 Magnaflux Inspect after grind Shot peen reworked area No. 170 Shot per MIL-S-13165 Intensity - .010/.012~ Mask retenrion "Yt Threads and washer land Nickel Sulfamate plate to 4.530 diameter Finish grind to 4.5271/4.5281

Mask spindle ear bores awl threads, Cadmium plate per &&-P-416 CL 11 type 11 These instructions were in accordance with the salvage prsce+dre recommended by Sikorsky Aircraft except that LAA did not specify hardness criterla or amplifying instructions for the Nickel Sulfamate platin . The Sikorsky procedure assigned a 9lating process (sS 811147 which requires s rni~irnum hardness of Rockwell c 47. The Quality Control Manager for MPC testified at the public hearing that his company subcontracted for the shot peening of the spindles with Astro-Peen Company. Following this operation they are given a visual Inspection for peening and then plated. He advised that his plating procedure would produce a hardness In the range of Rockwell C 30 fo 35. 3 Nonmetallic inclusions - Particles of nonmeballic Lmpuritles, such as oxides, sulphides, and silicates, in a steel. 4/ Sikorsky overhaul instructions refer to the herein described rework procedure as salvage. The owner of Astro-Peen Compa~yreported that he had shot peened the spindles on a manual machine because it has loaded with 170 shot, whereas the automatic machine big enough to accommodate the spindle was loaded with smaller shot. He per- fomed the work in accordance with ~i1-~-13165. During the fifth overhaul (~ovember1956), s3indle AJ-19 was examinet?, along with three other spindles from the same rotor head, by representatives from Sikorsky. They determined that the fretting of nickel plate was due to insufficient hardness of the plating, and recom~endedthat the spindles be reworke'd in zccordance with previously provided engineering instructions. On May 9, 1967, these four spindles and %he firth, which had not been plated as yet, were shipped to Sikorsky fcr salvage. Instructions on the LAA 3urchase order, the shipping document, Sikorskyts RMA (~eturnMaterials ~uthorization) document, customer checkoff list, and overhaul and repalr order relating to the shipment and subsequent processing of the five spindles specifically outlined each operation to be accomplished, as follows: (I) Strip previous nickel plate (2) Replate and grind (3) Nickel Sulfamate plate per SS 8414 (4) Shop peen per ~1~-~-13165,No. 170 shot intensity 10-12A. The work order operation sheet disclosed that the requirement to shot peen was deleted, and therefore not accomplished during this salvage of the five spindles. The operator who perforned the plating of the spindles stated that since they appeared to have been shot. peened, he did not shot peen them at that time. The Suftervlsor of Planning and Production Control ,estifled that, . . . it was not called out as a separate step cn the operation sheet since it is covered in the standards for plating and at that time when the part was stripped it would be checked." He also reported that as a result of this inspection it was determined that spindle AJ-19 had previously been shot peened, and therefore that step of the procedure was deleted. The Chief, Quality Assurance and Reliability for Sikorsky Aircraft stated, "As the original manufacturer and designer of the helicopter, we possess technical capabilities. It is not LTCO~TCT. to set, ar, orde'r IT. fr3.7; a custmer kith nequlreaents tkzt ire not reqxired. Slzce we do 2ossesz t?.ls techxlcal capablllty, xe WOG~~?lace the Ltexs Ln prcper perspective. IR this ?-star-ce, tte lcspector in thls ares, and the operator, are weil acqcaintec wlth (22 5414). They are workL~gwith it ail. :he time, asd tke docx-rient is, :; the area. 'iherc are xary, many ;arts whlc!: we grccess tk~oul;~cur sjrste:~after havisg been shot pee~edorcz. 91rce there is ro requlrecezt to re-shot peen, upcr, exa.;..irat:or that a shot pecniri: operatlor. kaC keen conpleted at are ~0:r.t in tlxe, tb~eywo~'d proceed to i~.dcc~ the ?art into the nlckel sulfarnate process. Eowever, te:ore tkey would perxit the part to ;c into tke p1atir.c operatlor:, tkey would have cat:si':i.d thexcelves tt.at tti! pal.: had ir :act beez shot pecfiec. !'

The fixCh overk.aui of splndle A:-15 was cszpleted 5y Los Anzeles ;.irways 'n ,u?e 1463, at wk.ick tlzc Lt had Seen operzted for 5, $1,. 2.3 hours . :Jo crack- usrs detcctec c~rlr.~ t?.e .mgna~lolnspectlon cor'ducted at this tine. The splr,dl~ W.iS then reIr,stallcd or. !;30CY, zsd resa1r.e~there ur,tll the ti~e0; tke accident. The spindle had a total ti-c of 7,371.i5 hours prL3r to the estlnwted 3.17 fllckt nomc 0:: the day of the acclde~t.

2. AXALYSIS AhQ CONCLUSIONS 2.1 Analysis Zxam1:-aticr, or the wreckaze early in the Ir.vestisatlan revealed W-;.,t z faii;ue fracture Ir, the sl-.ank of the yellow blade spindle resulted in separatlcn of the yellox maln rotor blade, and zausec 102s or control of the aircraft. It wac s~bsequentl~~determined that no otcer factors relatsd to the operatl~nof the flizht were Involved. Corsque~tly,the nain thrust of t:?e Investi~atior,focused or. the circ~nstances swromdl~: the cause of the fatLzue crack and the faiLure to detect lt. The fracture i;as of a ty~egecerally describea es a hi~h- CYC~C. low-:tress fatigue f:*aciu-.~. A crack was Initiated by stresses weil bei~wthe srsss yield ztrecstk of the steel and p-opa~atcdby rnany +,.Llousar.ds of load cycles before the spiridle railed coapletely. It is believed that this crack was presert and lar~eerough tc be detected during the magnaglo inspection that was conducted at tke llzst overhaul cf the sp:r.cle, The magnaglo equipment operatea 5y LA;. should be ca-+.:le of detecting cracks as smll as C.SX i~chIn lenztk- under plating of the thiclmess orA s9inale AJ-15. It Is not kr,oi*r, why the crack was not detected.

Regzr4ding tine cause of the f'at:;=t;e crack, as previously noted, the basic metal stock of the splKdle had a bar.ded zlcro- structure, indicatlr-.: lack of ur-if ornity ir. tk,e distrlSutZo~ of certain constituents of the steel. The segregatioc of tk-ese elenents in the lrgot from whlch the spir,dle was manufacture?, affected itt response t~ heat treatment and resulted :n hardr-ess readings as lcw as 28 OK the Rockwell C scale. Xicrohardr,ess tests bdicated that the l~calhar~ness lr. the softer bands was even lower. Thus, the hardness of the steel at the polrt where tne faticue crack lr,ItIa~edwas well below the razge of 3U to 3f? Rockwell C specified or, the spindle n~anufactur:ng drawing. The rough cc~relatlonbetkeer the hardness and fatigue stren~thof the steel indicates that the fatigue strength of sgindle AJ-15 was considerably lcwer than that of others conplying with all of the spe~ifl~zati~nrequirements. In additlor, if the slight pit5ing otserved at the fatime nucleus was present prior to the irLitiation of the crack, it would have tended to further reduce the resistznce of the spindle to fatL@;i;e faikure. The effect of the plating itself is difficult to evaiuate, but pickel plating normally produces some residual tensile stress in the steel suzface wh!ch would tend to reduce the fatigue strength of the spindle and th~siRcrease the detriaer.tal effect of the other factors mentioned above. However, it should be r~otedthat the 3.2 &414 plating process :vas selected to minimize the detrimental effects of clckel platir,g. Incom~leteshot pceni~gundoubtedly was an ImpcY~ant facYor because t5e peening had not been effectiv5 in the critlcal area of tiie shanufork i'illet wP,er.e the fatise crzck originated. Adequate shot peening of the fillet would have extended the fatiwe life of the spindle by increasing the fatisue strength in the area here the general hardness was low and where localized soft spots were present. It probably would have eliminated any detrimental effect of' swll pits or othez* mall zurface defccts that migkt have been present. Some infomtior or the effect cf shot peen:^^ was 0ktalF.ed from two spindies tkat had Seen salvaged, Sut not shct ?eezed, simulating the conditlor. of A:-1:. These were iscl~ce5:z a fatigue test progar, cor,d~ctedby SZkcrsky after the accident. Results were that tr,e fatigxe l:fe or these two s?lr,dles was 0nl.y about one-fifth to c~ne-tenth cf the zean life cf spi~ciles that had been shot peezed dur:~~the saivage ope~atic?~. Flnally, thou~hv:~tualiy I~pssiSleto elther assess or explain, is the overall effect ot the salvage procecure or tr.e part. It is appzrezt from the fat:,y~e testi7.s co~dcctedty Sikorsk~that there is extrezely wiue scatter in the relative fat:gue strengtk of salvs;ez spir.5les. The fa:lque pattel- of reworked sa~piesraz:ed froz those witn the shortest fatig~e life to those tkat were ~etlredwzthoct fa:ling (two cf which were from 33KY . The fcl1owir.g possikll:ties, ir-.dlvld~ailyor in combLratioc cxld expla:n tPls a~~oaaly:

(1) Frettin5 or other service da.nage to the base aetal which 1s not elix:n?.ted prior to plating.

(2 Variations in degree of shot peening (3) 3ifferences In tensile stress froa the plating (4) Coincidental norm1 variation IF the fatigue properties of the base metal. There were two itens of corollary interest discovered durlng the Investigation. The first was the apparent failure of LAA to insure that plating of the proper hardness was used in tht initial salvage of AJ-15. However, i~asmchas this plating was replaced with proper plati~g,presumably before initiation of the crack, it had no bea~ingcn the accident. The second area is sore difficult to accurately assess, but conceivably did have a direct effect on the acc1der.t. Zikorsky, Sased on their unique expertise, elected to deviate from the Specific instructions of the:? customer and their own written procedure in that they did not shot peen spindle AJ-15 during their salvage of that part. Inasmuch as inadequate shot peening in the shanwfork radius area of the spindle cortriSuted to the InitiatLon of the fatigue crack, it must te concluded that this omission had a direct bearing or, the accident. 1. The aircraCt gross weight and center of gravlty were w:thin limits.

2. The cremembers were qualified for the fii*t.

3. The yellow rnalr, rotor blade separated ifi fllght rendering the aircraft azcontrsllable. 4. "lade separation was due to fatigue failure of ikA4 sp:r.dlc. c,. The fatigue crack was a high-cycle, low-stress type which propagated over a long period of time. 6. The crack Inltlated beczcse of a co~blnationof the followil?g factors: (aj Xetal hardness below speclflctitlons associated with a banded rnlcroetructure.

(b, Improper peenhe of the base metal surface.

!c) Possible detrlrncntal effect of residual tensile stress from the piatlng.

(d, Pitting whlch may have been present In the base aetai surface. 7. it is belleved that the crack was present at the last magnaglo lnspecti~nof the part, and It is not h.own why It was not detected. (b) Probable Cause The Safety Board determines that the probable cause of this accident was the fati~~efailure of the yellow maln rotor blade spindle, causlng aepaxwatlon of the blade which made the aircraft uncontrollable. The fztigue crack originated in an area of substandard hardness and inadequate shot peening. Initial findings cf the investigatim revealed that there was strcng evidence of a aetal fatigue type failure in tk.e rotor blade splndle assembly. Acco~d'ngly on August 16, 1961, the folZcw1ng recommendatio~swere nade to t3e FAA:

"i3ased OR Lts prellzinary findings in the Cmpton crast. I~vestigat:on, the Safety Zoard today is recon'~~endi~gtc the Federal Aviation Aministrator that he {I)require an :.mediate fleet inspection of all Si~0r;kyS-61 hellcopter spindle its; (2, aaopt a more preczse and freque~t;r.spection to preclude future spindle urtlt failures; and (3, study tne need ror establ2shin& a ret:resent Life for this vital part." Or the sane date ;he FAA lssuec a telegraphic Airworthiness Directive whlck required the following actior,: Eefore Yurther f li?ht, remove nain rotor Slade spindles P, 3s 56116-23325-1, 26110-23325-2 and ~6112-23025-1 that elther have been "salvaged" . . . or have accumulated 2,4C3 or more haws tine In service OK the effectlve date of this AD, and replace with blade spindles of the same part nunber that have not beer. "salva&eci" and that have less than 2,400 hours time IR service. Replace mail; rotor blade sp1~5lesP/Ns ~6110-23325-1, S611G-23325-2, and ~6112-23025-1, tkat have not been "salvaqed' and have less than 2,430 hours tlae in servic~~or: t?~.effective date of this AD, before the accunu~~t:.ozof 2,4GC hours time in service with main rotor blade spindles of the same part number that have not Seen ''salvaged" and have less than 2,40C hour- time i~ service. On February 27, 1962, tne Safety Board forwarded a recom,~endationto the % which stated ir part: he spindle, &s orl&nally designed an3 tested, was certificated as as cnllnited life ite? by the FAA. As testified to at the recent hearing held in cormectlon with this accide~t,this certlflcation was based on data submitted by the Si~arskyAircraft Corporation and approved by the BAA. No suck data were submitted In regard to reworking a spindle. Further, It appeared, from testimony given at the hearing by FAA personnel, that the FAA was not aware of the rewo-k procedure until after the accidents."

"~tthe t:~e spindle rework was developed by Sikorsky, It is apparent that the criteria for determln- ing what constituted a major.or a minor change, allowed the rework to be classifled a minor change. Under such a classirlcation, no r.otificat?on to the .-'AA by the nzanufact.urer was necessary and no substantiating and descript2ve data were required."

Under these circuastances the spindles continued to be con- sidered as unllaited life items. Although it Is quLte posslble that the FAA may have accepted a Slkorsky proposal indicatlng the rework would not appreciably affect the service life of the spindle, the recornmendation pointed out that the FAA should have been made aware of a change to such a critlca: part. Accordingly, the letter of recom~enda~ionconcluded: ". . . the Safety Board recommends a re-evaluation of the FAA procedures and criteria involved in carryifig out the Intent of FAR Part 21, Subpart D (changss to type certificatesj. The procedures and criteria should insure that all changes affecting a part critical to the safe operation of the aircraft come %o the attention of the agpropriate FAA inspector so that proper actioii may be taken. " The reply to this recornrcendation wss received from the FAA on March 26, 1569, and state3 in part: 'Subsequent to the accident, we reviewed the procedures and criteria internally and with the nanufact~rers. It is our opinion that, when properly followcd, the requirements will assure that an epprop~iateevaluation Is mde of any changes to ty+ decign. However, we have requested that our regions review the procedures used by the manu- facturers, operatcrs, repair stations, and the FAA in categorizing and evaluating major and minor repairs and desLgn chanses, and recommend any changes needed in procedures.

As a result of a. quality assurance audit in Zanuary 1968, the Sikorsky Q~~alltyControl Manual 1101 was revised to make it clear that any Materials Review Board (MRB) disposition in which there Is any doubt that the non- confcrming production part involves other than a minor cha~gem~st be referred to FAA Engineering for evaluation. MR8 dispositions are spot checked by the FAA to determine whether FAA approval has been obtained for majcr. changes. in addition, we have reviewed with Sikorsky repair station personnel the criteria for categorizing repairs as major or minor and procedures for evaluatmg these repairs. They have instituted procedures to Insure that Sikorsky En~ineerIn~continues to evaluate instructions for all Fepairs processed through thelr repair station. "

JOHN H. REED Chairman

OSCAR M. LAUREL Member

-FRANCIS H. McADAMS Member

LOUIS M. THAYER Member - APPENDIX A

Crew Information Captain Kenneth L. Waggoner, aged 32, held airline transport pifot certificate No. 1486141 with rattngs in rotocraft- hellcopter, S-55 (V~Ronly), S-51L (unrestricted) and commercial grivileges airplane multl-engine land, S-58, and instruments. He had accumulated 5,877:23 total flying hours, of w:llch 4,300:27 hours were in the S-61~. He satisfactorily completed IFR and VFR proficiency checks on February 15, 1968, and March 8, 1968, respectively. His last FAA first-class medical certificate was Issued July lo, 1968, wit;? no lirnitations.

Copilot F. Charles Prac~er,;r., aged 27, hela c~~~merclal pilot certificate No. 1628290 with ratlngs in rotorcraft- helicoyter, V-107 I1 and instruments. He had accumulated 1,661:18 total flying hours, of which 634:18 hours were in the ~61~.He satisfactorily conpleted his last proficiency check on May 22, 1968. His FAA first-class medical certificate was issued on August 1, 1968, with no limitations.

Flight Attmdant,James A. Black, aged 30, was employed by LAA on May 2, 1958, and had served on S-61~aircraft since March, i962, when they were first placed In service with the company. His last check as a flight atten nt was satisfactorily completed on March 6, 1968. Aircraft Information N300Y, a Sikorsky S-61~helicopter, serial No. 61031 was the prototype for the ~-61~,and had accumulated 11,863.64 tatal flying hours prior tb>the day of the accident. It is estlinated that approximately 3.17 hours were flown on August 14, 1968. The aircraft was equipped with tw~General Electric ~~58-140-1turboshaft engines installed as follows:

Position Time Since Overhaul Total Time No. 1 280-131~~ 1,231: 52 5,762:49

The aircraft was serviced with 1,000 pounds of JP-4 fuel and had a takeoff gross weight of 17,185 pounds, which was below the maxim^ allowable takeoff weight of 19,000 pounds. The computed center of gravity at the the of the accident was 260.111 inches from datum, whlch is 267.4 inches forward of the main rotor hub centerline. The allowable limits are from 256.0 to 278.7 for a gross weight of 17,000 pounds. The estimated gross weight at the time of the accident was 17,118 pounds. APPENDIX C

Investigaticn and Hearing i. Investigation The Board received notification of the accident at approximately 1100 on August 14, 1968 from the Federal Avlatlon A&ninistratlon. Pn investigating team was im- mediately dispatched to the scene of the accident. Work- ing groups were established for operations, witnesses, human factors, structures. systems, powerplants and main- tenance records. Icterested parties included the Federal Aviation Administration, Los Angeles Airways, Inc., Sikorsky Aircraft, Air Line Pilots Association, and General Electric. The on-scene ir~vestigationwas completed on August 24, 1968. 2. Hearing

A public hearing was held at Marina Del Rey, California cn December 11-12, 1968. Parties to the Investigation included the Federal Aviation Administration, Los Angeles ALr- ways, Inc., Slkorsky Aircraft, and the Air Line Pilots Asso- ciation. 3. Preliminary Reports

A s ry of the testimony which was taken at the public hearing was published by the Board on Jar'uary 16, 1969. ATTACHMEKT I MAIN ROTOR SPINDLE PART N2. S6il0-23325-2B

CCNNECTS T3

LOS ANGELES AIRWAYS,INO. C~ECTSTO S-6 1 L N3COY M41N ROTOR BLADE COMPTON. CALIFORNIA AUGUST i4,1968