oh-6a misshap experience report

8/11/2019 OH-6A Misshap Experience Report

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OH-6 MISHAP EXPERIENCE REPORT

uly 1967 hrough 30 une 1971

by LTC David L. Boivin

and M r. David T. Forbes, r.

LOH Division Directorate or Aircraft Accident Analysis nd nvestigation

USAAAVS .I. ADMVAalNCV FOR AVIATION BATY

COLONEL FRANCIS M AX McCULLAR Commander


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FOREWORD

Cause actors hich ontributed o ishaps nvolving he H-6A ircraft during he period uly 967 o 30 une 971 re dentified nd nalyzed n his report. ecognition nd nalysis f hese actors re mportant oday f better operating rocedures, aintenance echniques nd raining methods re volved for omorrow. tudy f hese actors an lso rovide tatistical ata seful in demonstrating eed or additional design nd quality ontrol equirements n

the uture. his umulative eport hould e f nterest o all f us n viation since ny hange n he bove elated ields ould erve o ffect nd mprove

our urrent lying operations. As videnced n his eport, ateriel nd perational roblems ere he wo

major oncerns nvolving H-6A ishaps uring his eriod. ateriel roblems were redominately aused y ngine ailures nd ngine alfunctions. perational rrors ere rimarily ttributed o ow evel perations esulting n he aircraft olliding with bstructions uch s ires nd rees. ther perational problems nvolved utorotation/emergency anding echniques nd iolation f regulations nd/or unit SOP's.

A eview of mishaps nvolved n ow evel operations which ere not equired by he ission r dictated y eather onditions ndicates any ishaps ould have een revented hrough roper upervision nd raining. ith his ind f knowledge, m onfident hat ommanders t ll evels n he rm y an eet the hallenge f nsuring n ffective ccident revention nd afety rogram within heir commands.

I rge ou o eview his eport nd pply he essons n t long ith our professional expertise o he betterment of he Army aviation program.

FRANCIS M AX McCULLAR Colonel Infantry

Commanding


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OH-6 MISHAP EXPERIENCE REPORT

JULY 967 THROUGH 0 JUNE 9 7 1

INTRODUCTION. his eport was prepared o aid commanders, aviation afety officers, mainte-

nance

fficers,

viators,

nd

elated

viation

personnel n ccident revention nd he reser- vation f ombat esources hrough eview f past H-6A ishaps nd heir ause actors. The erm mishap ncludes ccidents, ncidents, orced andings, nd recautionary andings s efined n R 85-40. Damaging mishaps re hose eported s major accidents, minor ccidents, nd ncidents. Nondamaging mishaps re orced nd precautionary andings. Aircraft osses or damages which were he direct result f ombat ction re ot ncluded n this eport.

SYNOPSIS. he OH-6A was nvolved n 1,554 mishaps rom uly 967 hrough 0 une 971. There ere 63 ccidents of hich 41 ere classified s otal osses), 57 ncidents, 87 forced andings, nd 447 recautionary andings. Based n ,229,271 lying hours eported uring this -year eriod, he ccident ate per 00,000 flying ours as 5.81. hese ccidents n- volved 3 atalities nd 62 onfatal njuries. There ere ix n-flight ires nd 4 ostflight fires.

ircraft amage ccurred n 20 f he

1,554 ishaps, costing bout 31,470,000.

Personnel actors ere nvolved n pproximately 55 percent of he accidents nd ncidents and

ateriel

actors ere

nvolved n 3

ercent

of he orced nd precautionary andings. The rimary ypes f rew rrors eported n

damaging mishaps nvolved practice autorotations and triking ires, rees, nd ther bjects. Engine nd ail otor roblems ere nvolved n the ajority f materiel ailure/malfunction ishaps hich esulted n damage.

CONCLUSIONS. uring his eporting period, Vietnam ccounted or 9 ercent f ll H-6A reported light ime 1,166,827 hours), 99 percent of he atalities 92), 7 ercent f he njuries (351), nd 8 ercent f he ccident/incident cost $31,023,000).

Crew error was eported as he principal cause for he ajority f amaging ishaps. ack f discipline on he part of the operatorsstretching the imitations of he aircraft plus ailure o use standard rocedureswas evident.

Supervision-related ishaps ere inimal. The upervisory actor ay e ne f mission rather han ommission. n ctive ommand- controlled rogram s equired o generate know- ledgeable, killful, isciplined aviators.

Mishaps aused y ateriel ailures nd al-

TABLE Number and Classification of Mishaps

FY FY FY FY Classification Total 1968 1969 1970 1971 Accidents 56 3 60 20 4 193 10 6 Incidents 35 7 16 12 4 124 93 Forced Landings 187 17 85 49 36 Precautionary Landings 44 7 44 10 3 113 18 7 Total 1554 137 51 6 47 9 42 2


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functions an be educed y dherence o estab- lished maintenance procedures, an effective quality control program, nd by nvolved upervisors.

DISCUSSION. able hows he number nd classification of OH-6A ishaps eported uring this eriod.

Of he otal ishaps eported, pproximately 36 percent were classified as ccidents. orty- two ercent f he ccidents ere lassified s total osses. iscal year 969 hows efinite increase n ll ategories f ishap lassifica- tions.

his ncrease ould e ttributed o:

(1) the otal number of aircraft deployed o RVN during hat year; 2) he ncrease n lying hour program; 3) the apid nflux f ewly rained aviators; nd 4) the nvironmental ondition n

which he H-6A as being operated. lthough the number of mishaps ncreased n FY 969, he accident ate ecreased y omparison o Y 1968.

Figure hows nnual 0H-6A accident ates, based n he umber f ccidents er 00,000 flying hours.

The accident ate has gradually declined rom 66.7 ccidents er 00,000 lying ours n Y 1968 o 36.8 accidents er 00,000 lying hours in Y 971.

uring Y 971, he lying our program nd umber f ircraft n he rmy n- ventory ere also educed.

Of he ,554 mishaps eported, pproximately 89 percent, or 1,382, occurred n Vietnam. hese mishaps by classification and ocation are hown

in able 2.

TABLE

Types of Mishaps by Location

Classification

Total CONUS Vietnan

23 54 0 25 33 2 26 161 98 34 9

17 2 1382

Accidents

63

Incidents

57

Forced Landings 87 Precautionary Landings 47 Total 554 As hown n able , 55 ersonnel ere

injured r illed uring his -year period. a- tality ates er 00,000 lying hours re hown in igure .

he verall atality ate or he

4-year period was 7.56 per 100,000 hours.

TABLE Injuries

Location Total Fatalities Injuries CONUS 12 1 11 Vietnam 443 92 351 Total 455 93 362

The otal ost f all ishaps hich esulted in amage uring his eriod as 31,470,000. Figure hows he otal ishap ollar ost, plus he dollar cost per light hour, or each iscal year. pproximately 98 percent $31,023,000) of he otal ost esulted rom ishaps hich occurred n Vietnam.

Table hows he number of cause actors y type ishap. Mishap ause actors utnumber

F Y 8 RATE FLYING HOURS

F Y 9 F Y 0 FY 1

FIGURE Accident Rates Worldwide


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TABLE 4 Mishap Cause Factors

All Total Forced Precautionary

Cause actors Mishaps Losses Accidents Incidents Landings Landings Materiel fail/mal) 84 8 123 130 44 16 8 383

Flight crew 66 8 16 9 24 0 237 8 14

Unknown/other 144 6 20 10 4 1 13

Maintenance 104 14 20 5 28 37

Supervision 76 28 42 5 1 0

Weather 58 20 16 17 0 5

Facilities 47 14 18 13 1 1

Training 21 11 10 0 0 0

Design 17 8 7 0 0 2

Ground rew 8 0 3 2 1 2

Command 4 3 1 0 0 0

Total 1995 396 50 7

427

208 457

the otal eported mishaps. his s sually he case because mishap nvestigation often eveals that ore han ne ause ontributed o he mishap.

Materiel actors ccounted or pproximately 42 ercent f ll auses, nd rew rrors c- counted or approximately 33 percent. f mishaps which esulted n amage ere rouped ogether (discount orced nd recautionary andings), cause factors would ealign as crew error approximately 9 ercent nd ateriel s 22 ercent.

Table hows ignificant ateriel nd rew error auses. ause actors esulting n ajor accidents ere, in rder f requency: engine

malfunctions, nsuccessful mergency utoma- tions, ractice utorotations, nd ail otor system alfunctions nd trikes aircraft truck trees, ire evetments, ntennas, tc.). f he 409 crew accidents including otal osses), 94 (48%) esulted rom ingle phase of operation- autorotation. here were 95 practice autorotation accidents nd 9 mergency utorotation cci-

dents. In table 5, the ine antitorque control efers

to ishaps dentified ith he arning ote n

chapter f M 5-1520-214-10, hange , oncerning brupt urn aneuvers. he roblem, normally called tail spins, can result from

< l- <

FY 8 RATE FATALITIES

FY 9 FY 0 FY 1

FIGURE Annual atality Rates


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TABLE

Materiel and Crew Error Causes

Causes Mishaps Losses Accidents Incidents Landings Land Materiel

Engine ystem 390 79 89 17 119 86 Tail otor ystem 146 32 36 13 34 31 Flight controls ystem 12 6 0 0 3 3 Chip detector ights 136 0 0 0 0 136 Main otor ystem 43 0 3 0 3 37 Battery 43 0 0 5 5 33 Other 78 6 2 9 4 57 Total 848 123 130 44 168 383

Crew Strikes trees, wires, etc.) 14 1 27 22 90 0 2 Practice autorotations 117 10 85 22 N/A N/A Emergency autorotations 104 35 64 5 0 N/A FOD nto main or ail otor 49 8 5 36 0 0 Improper anding technique 43 9 16 18 0 0 Improper takeoff technique 42 6 8 28 N/A N/A Lost control 41 17 13 11 0 N/A Antitorque control tail pin) 15 10 4 1 0 N/A Fuel exhaustion 25 10 12 1 2 N/A Other 91 37 11 25 6 12 Total 668 169 240 237 8 14

abrupt ight r eft urns, erformed ownwind t low ltitude, ow irspeed, nd specially when

the aircraft s over maximum gross weight. ight turns to he pilot's ide) end o cause he problem much more often han eft urns. When abrupt

uplift s nduced n he orizontal tabilizer, tendency o pin o he ight ccurs. n CP has been approved o replace the ail otor blades (P/N 69A1710) with ew all-metal blades P/N 369A1613). These ew ll-metal lades ave

12

10 i/> z 2 8

2 \

O u < o

4 -

2 -

12 600 000

23.96

2 160 000

FY 0 Y 8 Y 9 COST PER FLYING HOURS C ST

IGURE

Accident/Incident Dollar Cost

FY 1

36 n

32 o H

28 TJ m 24 70

n 20 i-< 1 6 z 12 X

o 8 c 7

\

4 o r > 50


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modified amber, ncreased hord, nd n n- creased ail otor hrust f at east 5 ercent. The ncreased hrust will o much o educe he occurrence f he roblem, ut viators ould

eliminate all f them by voiding operation within he ombination f onditions hat reates the roblem.

Table urther dentifies ateriel ishap causes.

The phase f operation during which he mishap began s hown n able . pproximately 66 percent f the mishaps occurred during cruise flight. When only accidents (including total

losses) re onsidered, ruise light emains predominate t 2 ercent. he ajority f cruise light accidents occurred during ow evel flight here here s ittle argin or rror r

inattention. The eriod f peration uring hich he

mishap occurred s hown n able . A s expected, he reatest umber f mishaps

(92 ) occurred during he day. owever, he 4 mishaps ccurring uring wilight ours dawn an d dusk) re ot n proportion o exposure ime and arrant ore ttention n viation ccident prevention rograms.

TABLE Materiel y stem Causes

All Total Forced Prec. Mishaps Losses Accidents Inci dents Landings Landings

Engine ystemtotal 390 79 89 17 119 86

Fuel Control 96 19 17 6 36 18

Bearings Compressor FOD

27 23 15

6 3 5

7 11

7

2 0 0

4 2 3

8 7 0

Other 104 6 17 2 29 50

Unknown 125 40 30 7 45 3

Tail otor ystem- -total 146 32 36 13 34 31

Drive shaft 45 13 7 8 15 2

Coupling

Blades

25

25

5

1

10

2

2

0

7 3

1 19

Gearbox 17 2 7 1 5 2

Pitch control 5 3 1 0 0 1

Other 11 1 6 1 1 2

Unknown 18 7 3 1 3 4

Main otor ystem -total 43 0 3 0 3 37

Transmission 25 0 3 0 3 20

Blades 10 0 0 0 1 9

Dampers Other

3 5

0 0

0 0

0 0

0 0

3 5

Flight control system-total Cyclic Swashplate

Collective

12 3 3

2

6 1 2

1

0 0 0

0

0 0 0

0

3 1 0

0

3 1 1

1 Other 3 1 0 0 2 0

Unknown 1 1 0 0 0 0

All Metal Shor t/ Mishaps Pa rticles Broken W ir e Other Unknown

Chip detector ights-total Main otor

136 73

67 38

13 7

4 2

52 26

Engine Tail otor

41 22

18 11

4 2

2 0

17 9


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TABLE Phase of Operation

All Total Forced Precautionary Phase of Fli gh t Mishaps Losses Accidents Incidents Landings Landings Cruise 1023 18 4 16 6 16 6 12 2 385 Autorotation 17 1 16 100 24 27 4 Landing 15 0 27 27 42 21 33 Takeoff 97 12 19 37 18 16 Static 98 0 9 81 2 6 Hover 8 0 5 Other 7 2 2 Total 1554 24 1 322 357 18 7 44 7

Problem reas EIR's). SAAAVS ecords indicate that only 360 EIR eports were ubmitted against he 48 ateriel ailures nd alfunctions n which EIR's hould have been ubmitted. This, owever, s nly mall ortion f he complete IR icture or he ears.

f he

total IR's ubmitted gainst he H-6A o U S A AV S C O M , hose f ignificant alue ere assigned n VSCOM ase umber nd ere reported s eficiencies n he epartment f the rm y echnical ulletins TB 50-992 series), Equipment mprovement eport nd Maintenance igest. everal f he IR eficiencies ublished n he igest re eing e- peated ere or nformational urposes nd s reminder o ommanders, upervisors, nd aintenance ersonnel f pecific H-6A roblem areas nd hat orrective ctions ere aken r are being aken o liminate hose eficiencies.

For dditional etailed nformation egarding any f he IR eficiencies isted elow, efer to he ppropriate B 50-992, eferencing he USAAVSCOM ase number.

TITLE: Tail otor /atfes-USAAVSCOM ase

number A-60-190-369A1710. DEFICIENCY: Tail otor blades cracking. Skin cracks occur at all locations and fiberglass bonding eparates t eading nd railing dges of blades. ACTION TAKEN: An ll-metal ail otor lade is currently being developed by Hughes Tool Company. New blades will also improve tail rotor hrust.

TITLE: Tail Rotor rive fta/fs-USAAVSCOM case number SA-90-585-369A5518. DEFICIENCY: Tail otor rive haft hears n

flight, r s ound wisted. ACTION AKEN: CP 672 as pproved or retrofit y ttrition hrough pares eplacement which provides ore ugged drive haft eatur- ing n ncreased all hickness. his haft s identified s P/N 369A5518-601.

TITLE: ail Rotor Drive Shaft Couplings-USA- AVSCOM case number SA-90-070-369A5501.

TABLE

Period of Operation

All Mishap Classification Mishaps Dawn D ay Dusk Night Total oss accident 241 224 6 10 Major accident 32 2 3 30 0 12 7 Incident 35 7 4 33 0 18 5 Forced anding 187 2 169 7 9 Precautionary anding 447 3 41 0 18 16 Total 1554 13 1433 61 47


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DEFICIENCY: Tail otor drive haft ouplings, P/N 369A5501, reak n light, esulting n oss

of ntitorque control. ACTION AKEN:

a. roperly him drive haft per M 55-1520- 214-35, ection , hapter , nd nspect ouplings nd rive hafts or damage s pecified in M 5-1520-214-20, hapter , ection I, Special nspections.

b. CP 2672 was approved for retrofit through attrition by pares eplacement which s art f the more ugged drive haft assembly.

TITLE: ail otor ransmission-USAAVSCOM case umber A 80-190-369A5401. DEFICIENCY: ail otor ransmission ousing cracks nd breaks n light, allowing output shaft support ection f ousing, ogether ith t- tached utput haft nd ail otor ssembly, o separate rom ircraft, esulting n oss f ntitorque ontrol. ACTION AKEN: ause f roken ousings s generally esult f n nbalanced ondition f tail otor lades s esult f oss f brasion strip. ughes ool ompany s eveloping n all-metal ail otor lade hich hould elp eliminate his problem.

TITLE: Tail Rotor 7Yansmi'ssion-USAAVSCOM

case

umbers SA 80-020-369A5408

nd SA 80-

372-369A5400. DEFICIENCIES:

a. ail otor ransmission output hafts, /N 369A5408, eveloped xial nd/or xcess adial play, enerally causing high requency vibration.

b. ail otor ransmissions re eing rema- turely emoved ue o nternal ailures, ormally indicated y chip detector lluminations. ACTION AKEN: CP 890 eplacement f u- tomotive ype earings ith igher apacity aircraft quality earings t ext verhaul eriod should orrect both deficiencies.

TITLE: Support, Pusft-Pu//-USAAVSCOM case number A 01-020-369A3506. DEFICIENCY: Push-pull upport rames, /N's 369A3506, 69A3507, nd 69A3588, ere ound to be wearing excessively round ush-pull ube grommets, P/N 369A3509. ACTION TAKEN: In an effort to reduce tail boom rame ear, lass I CP as pproved which dds a 0.020-inch-thick teel oubler o

tail oom rames.

TITLE: Main Transmission-USAAVSCOM case

number A 70-381-369A5167. DEFICIENCY: Main ransmissions f 69A5100 series re ccasionally ound ontaminated ith

water fter lying n ain. ACTION AKEN: nvestigation eveals hat water ay nter ransmission ear op hrough transmission eal 369A5167). roduct m- provement rogram ill e nitiated ith rime contractor to develop an mproved seal assembly.

TITLE: Main Rotor Blade P/ns-USAAVSCOM case umber A 05-190-369A1004. DEFICIENCY: Main otor blade pins 369A1004) are cracking and corroding in pivot area of handle. ACTION AKEN: roduct mprovement rogram has been nitiated with he prime contractor to edesign his tem. uring he nterim, on- tinue o nspect ins aily nd ccasionally apply ight oat f urbine ngine il o an- dlebarrel ut ating urface nd am ortion of handle. Do not il expanding bushing portion.

TITLE: Main Rotor /acfes-USAAVSCOM case number A 05-020-369A1100. DEFICIENCY: Main rotor blades (369A1100) eroding at eading edges, ometimes o he oint where brass eights re visible. ACTION TAKEN: Apply or eapply ntierosion tape er M 5-1520-214-30, ection I, hapter 8, whenever operating in rain or an abrasive environment.

TITLE: otor Sysfems-USAAVSCOM ase umber A 50-790-369A1400. DEFICIENCY: omplaints ave een eceived concerning otational rag heck n ain otor dampers.

vailable reakaway ype orque

wrenches re ot ffective n his pplication. ACTION AKEN: M 55-1520-214-20, aragraph 8-8b(3), ill e hanged o equire ial ype

torque rench or his heck. orque rench,

FSN 120-288-8865, as een stablished s special ool or he OH-6A nd hould be equisitioned y all units upporting OH-6A helicopters.

TITLE: Oil Pressure Senders SAAVSCOM case number A 09-374-369A4534. DEFICIENCY: Inaccurate oil pressure readout attributed o efective r nternal ailure f il pressure ender, P/N 369A4534. ACTION AKEN: The il pressure ending unit


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has een edesigned, liminating alibration provisions f il nit. IP rogram ill e initiated o einstate eans f calibration. n the nterim, when nstalling a new black) sender

and he ockpit auge s nown o e ood, scrape lack aint f ender ody t rounding strap o nsure ood round nd ook irect reading auge nto il ystem. eep rying dif- ferent enders ntil ne s ound here oler- ances f auge nd ender ancel ach ther and cockpit eadout s easonably accurate.

TITLE: lower Scro/Js-USAAVSCOM case number A 07-190-369A5306. DEFICIENCY: lower croll ssemblies f 369A5306 eries re racking, ainly t ttaching oints. ACTION AKEN: racking nd old-flow f plastic arts t ttachment oints re enerally indications f astener vertorque. lso, he prime ontractor as ound his ype f lastic susceptible o amage y ot urbine ngine il and s n he rocess f eveloping uitable coating. his oating ill e ncorporated n subsequent pare parts.

TITLE: Engine ower-Out arning nit-USA- AVSCOM ase number A 09-374-26530332. DEFICIENCY: Engine power-out warning unit

(26530332)

becomes

unserviceable

due

o

ntern-

al ailure. ACTION AKEN: he rime ontractor s urrently developing an mproved engine-out warning which rovides n arlier ndication, oupled with n automatic estart device.

TITLE: uel uantity ransmitters-USAAVS- CO M ase number A 09-374-369A4245. DEFICIENCY: nternal ailures f uel quantity transmitters f 69A4245 eries, sually e- tected y rroneous ow uel ight llumination. ACTION AKEN: ailures re ainly ttribut- able o horting, aused y etting nit ith water, nd o orrosion. he rime ontractor has eveloped 603 ersion f he 69A4245 tank nit hich as ealant pplied o over terminals nd iring o liminate horting nd corrosion. ew ersion ill be mplemented n an attrition basis. s n nterim ix oncerning this matter, efer o he above USAAVSCOM case number n hange f B 50-992-4, ated July 971.

TITLE: uel hut-Off alve ontrol SAAVS- COM ase number A 10-497-369A8136. DEFICIENCY: uel hut-off alve ontrol s- sembly usts t ockpit nd nd ecomes m- movable r ails o ctuate hut-off alve rom full ff o ull on. ACTION AKEN: he rime ontractor s urrently edesigning ntire uel ystem. n he interim, ubricate nd ig ontrol ssembly er TM 55-1520-214-20, ection V, chapter . heck and ycle daily.

TITLE: Helicopter OH-6A)-\JSAAVSCOM ase number A 01-381-369A2030-1. DEFICIENCY: Water as een ccumulating n fuel ank over (369A8130), creating orrosion problems. ACTION AKEN: Adding asket etween he access cover, P/N 369A2030-1, and he argo floor ill eliminate water entry.

TITLE: il oo/er-USAAVSCOM ase umber SA 7-381-369A8302. DEFICIENCY: il cooler assembly eaks, ainly t nlet boss. ACTION AKEN: eaks are generally he esult of wisting nlet ose hen emoving/installing mating heck alve. se pecial rench VS- 5236) when erforming his peration nd ollow procedures ontained n M 5-1520-214-35, section V, chapter 5.

TITLE: verrunning lutch-USAAVSCOU ase number A 04-381-369A5350. DEFICIENCY: verrunning lutches f 69A- 5350 series are eaking oil at output haft, ometimes ollowed y moke n abin nd hearing of utput haft. ACTION AKEN: reviously, il eaking ast engine haft eals 6854086) ould ill lutch housing ntil il ould eak ut op f lutch. This il ould ash rease ut f earing (R20FOILO), ausing t o verheat nd hear output haft. B 5-1520-214-20/38, ated 9 September 970, as ssued o orrect his n- satisfactory ondition.

TITLE: Landing Gear Dampers-USAAVSCOM case number A 02-374-369A6300. DEFICIENCY: Landing ear ampers of 69A- 6300 series are experiencing internal failures characterized y collapsing or extending beyond


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normal imits. ACTION AKEN: he ontractor s urrently redesigning ampers o ncrease ervice ife and orrect current deficiencies.

TITLE: amper ssembly-Landing ear-USA- AVSCOM ase number A 02-247-369A6300-501. DEFICIENCY: ampers ere eing eceived n the ield ith ars f ap ssemblies t 0 angles o ach ther. ars ust e arallel or proper nstallation f damper assembly. ACTION AKEN: anding ear amper ssemblies eceived n bove ondition an e or- rected y ttaching ower nd f amper o landing ear trut s irected y M 5-1520- 214-30, hange , page -32A. nsert olt nto top ounting earing hole nd urn trut lockwise until cap ssembly ears re parallel. trut should be urned lockwise o prevent oosening of end caps on damper.

TITLE: orizontalStabilizer-\JSAAVSCOM case number A 01-070-369A3600. DEFICIENCY: utboard ections f orizontal stabilizers of 369A3600 series ear off n light. ACTION AKEN: tructural ailure f hese stabilizers s he esult f ibration-induced fatigue, esulting ainly rom ail otor mbal- ance. Under product mprovement program, he

contractor as esigned ew trut o eplace the present 369A2001 trut. n he nterim, main- tain ail otor alance er M 5-1520-214-35, section II, hapter , nd mphasize tabilizer

and

trut

heck

n

ach

reflight

s

equired

y

TM 55-1520-214-10, hapter 3, ection I.

TITLE: ower Vertical Stabili z er-USAAVSCOM case umbers A 1-750-369A3650 nd A 1-

730-369A3650. DEFICIENCY: BC djustable olts resently used n ounting oles f ower ertical tabilizers f 69A3650 eries llow tabilizers o

vibrate, esulting n ailure f BC olts nd in-flight oss of the tabilizer. ACTION AKEN: WO 5-1520-214-30/36 as initiated or correction of his roblem.

TITLE: roop eat nd Harness itting-USA- AVSCOM ase number A 17-020-369A3037/9. DEFICIENCY: roop seat nd houlder harness fittings n irframe 369A3037-1, 2 nd 69A- 3039-1, 2) re earing ut ince ating eat and arness ittings re f arder etal. e- placement arts ould ot e btained hrough

supply. ACTION

AKEN: hese ittings ave een

resource oded nd an ow e equisitioned and replaced. Refer to TM 55-1520-214-34P.

Selected Accident Briefs

ACCIDENT O. -Aircraft as lying n arginal eather n ission o arry aps nd other apers. ilot alled or nd eceived special FR clearance o ield. eather was reported as XM17 W. efore arrival t he field, ight nowshowers ere ncountered. Navigation o he ield nd over GCA unit was accomplished.

y his ime, he ight now-

showers ad urned eavy nd he ircraft as at 5-20 eet nd 0-30 nots. he ilots e- cided o and near he GCA unit nd n doing o all isual eference as ost ue o lowing snow. Both ilots xperienced ertigo nd he

aircraft it ard ith light earward otion and eft ide ow. he wo ilots ustained minor njuries nd he ircraft as estroyed.

The rimary ause actor as isted s oss f ground ontact ue o eavy nowshowers nd blowing now ro m otorwash. uspected actors were 0 ind hift, ilot isorientation, ot making a go-around, and pilot's inexperience.

Editor's note: as his rip eally necessary? Hardly, ith now nd cing onditions, nexperienced ilots, nd n ircraft ot FR n- strumented.


14/21

ACCIDENT NO 1-Both pilots experienced ertigo n blowing snowmM^w i:

ACCIDENT O. -Two ircraft esponding o a istress all a and ehicle ad it ine and ersonnel ere njured) ried o ccupy he same pace t he ame ime. ne ircraft as flying t 00 eet n ight urn ooking or he vehicle.

he econd ircraft pproached he

zone n ast descending ight urn nd olli- sion ccurred.

here ere ive atalities nd

both ircraft ere destroyed. aused y ailure of oth ilots o roperly lear hemselves.

Editor's note: he day as absolutely lear, too

ACCIDENT O. -One ircraft n light f two adioed hat rouble xisted n ontrolling excessive ngine pm. or 0 inutes his excessive ngine pm roblem ontinued hen finally he ilot aid, I hink ust ost every- thing. itness tatements ndicated hat he engine nd otor ad evved p. his as ollowed y elative ilence. he ain otor severed he ail oom nd he ircraft ell ro m approximately ,500 eet, pinning lockwise, nose ow nd erratic. round mpact howed he rotor o e early, f ot ompletely, topped.

Pilot as illed nd ircraft as estroyed. Fuel ontrol alfunction aused n verspeed, but he- pilot ailed o and ollowing umerous indications f alfunction. uspect ailure of main otor ynamic top r ontrol ystem om- ponent aused ail boom chop.

Editor's ote:

. RADMAC nalysis id not gree ith he onclusion hat ngine ad oversped.

t as oncluded hat he urbine

wheels did not exhibit overspeed stretching.

They ecommended hat astellated ype uts (with otter in) e sed on he ower urbine governor and uel control adjusting evers.

2. e uspect here was ome overspeed and the ilot sed igh otor lade itch ngle o minimize he otor overspeed.

he ngine uit

or as topped mmediately ollowed y ross blade tall, oupled with a arge alt cyclic nput that aused he ail oom hop nd practically stopped he blades.

ACCIDENT O. -Aircraft eparted n taff reconnaissance mission. t was ater een o be descending t bout 0 ngle. t rashed n a ooded rea, xploded, nd urned. he our occupants ere illed. uspect ircraft as n autorotation ue o ome ailure, erhaps uel control r ail otor malfunction.

ACCIDENT NO. -Aircraft ifted ff hip bout 1925 ours ith our eople board. urviving witness ndicated hey ook ff traight p, turned 0 o he ight, ccelerated orward, nd struck he water about 00 meters ro m he hip.

Two occupants were killed, one ustained ajor injuries, nd ne s issing. ircraft as destroyed. uspect arginal eather bscured horizon nd ilot, nexperienced n ight hipboard operations, allowed disorientation to occur.

Editor's note: hipboard night operations t upper imit gross eights ith arginal eather conditions re emanding f ven he ost x- perienced viators.

ntrained viators hould

not e used.

1 0


15/21

ACCIDENT O. -Gunner as ropping rag- mentation renades rom ircraft n ttempt o destroy ootbridge. xplosion ccurred n passenger ompartment nd ompartment as engulfed n lames. xplosive orce

nocked pilot's eet off pedals nd broke out chin bubble. Emergency anding as ade nd ilot nd observer scaped.

ircraft as onsumed y

fire ith he unner till n is eat. here was ne atality nd ne ajor njury. ircraft was destroyed. aused y unner dropping ive grenade on passenger compartment loor.

ACCIDENT O. -Pilot ccepted ircraft rom maintenance nd as eturning t o is arent organization.

hortly fter akeoff bout 730

hours, ircraft truck uy ire ttached o 00- foot adio ower nd isintegrated. he

hree occupants ere illed. uspect ilot as ot familiar with he ocation of he owers nd hat the angle of the un caused un blindness.

ACCIDENT NO. -Aircraft was lying ow evel down highway and hit lambretta. Damage to

ACCIDENT NO 4-Ttie ou r occupants of this aircraft were killed.

lambretta nd njury o assengers re unknown. Major amage o ircraft. aused y nneces- sary ow-level light.

ACCIDENT

NO.

-Pilot

ccepted

ircraft

with-

out isually hecking mount f uel board. Fuel quantity gauge was known o be naccurate. Sometime nto he ission, ilot eported- 80 pounds of uel emaining, after which he lew or approximately inutes, hen anded or -3 minutes.

his ime e eported 0 ounds f fuel nd ook off heading home. he light home was t 90 knots ow evel. ngine topped ust after yclic limb o lear ow f rees. ilot entered autorotation nd aircraft hit nose ow n left ide t n stimated 0-50 nots.

here

were wo atalities nd ne ajor njury. ircraft as estroyed. aused

y mproper reflight, mproper udgment n aking ff ith 0 pounds f uel, nd unnecessary nd erratic ow level light.

uspect nsufficient utorotation

training. ecommendations were: 1) Terminate flight ith 0 ounds f uel ndicated, 2) flight ime imit ased n ngine ime, nd (3) emphasize utorotational roficiency.

ACCIDENT O. 0-Aircraft anded nd rew chief and observer exited. ilot rictioned down the collective control nd exited. ircraft ifted off

he

round

nd

ilted

orward.

ain

otor

blade truck ilot n he hest, ausing ajor injuries. ircraft ame o est gainst evetment. hile eing ling oaded, H-6A egan to oscillate, as eleased, rashed nd urned. Cause of accident was isted as unknown.

ACCIDENT NO. 1-Aircraft was one of light on n arly orning mission. bout 0 minutes after aunch, pilot called nd eported his engine chip etector ight as n nd hat e as e- turning o ase.

he ast adio ransmission

heard as hat he OT as out f ight,aircraft as ibrating everely, nd hat e n- tended o and at he closest helipad. witness stated hat he aw he ircraft circling with he landing ight n nd hat lames ere oming out he ear. he lames topped nd he engine quit. he aircraft hit 60-foot ree, crashed nto a hut, nd ank n bout eet f ater. he three occupants were killed nd he aircraft was destroyed. he econd tage ompressor otor blade fractured from fatigue, causing engine

1 1


16/21

failure. uspect o. ain bearing roze, re- ating vibrations nd atigue of otor blade. ilot pulled itch xtremely igh, ausing ow otor

rpm.

Editor's ote:

he nvestigation evealed there were other landing areas afer than he one

selected. ody dentification as hindered because og ags were not worn.

ACCIDENT O. 2-Weather as elow ini- mums or akeoff rom Z, nd he n oute nd destination eather as nknown o he ilot. He ook ff nd isappeared hrough mall hole n he louds. e eported lear t ,700 feet nd hen ater ransmitted ayday all that he had ost control. ircraft was next een at 90 eet where he ail boom eparated. ight spin eveloped nd round mpact as ear vertical and hard. ilot sustained major njuries and ircraft as estroyed. nvestigation e- vealed hat he ilot xperienced ertigo nd panicked.

he n he ircraft roke ut f he

clouds, he ilot bruptly owered ollective and ade ight ear yclic ovement.

he

main otor blades evered he ail oom. ilot failed o aintain FR n n ircraft ot equipped or FR.

ACCIDENT NO. 3-Aircraft was n cruise light when ail otor rive haft ailed. ail oom chop ccurred nd ircraft rashed nd urned. Pilot was killed. Suspect incorrect torquing

resulted n roken rive haft nd mproper cyclic nput chopped ail boom.

ACCIDENT NO. 4-In-flight ire occurred during

maintenance

est

light

nd

ircraft

rashed.

Pilot nd wo passengers died of burns. ircraft was estroyed. uspect asket/seal or uel tank ccess over as eaking ue o mproper maintenance. wo assengers hould ot have been on board during est light.

ACCIDENT O. 5-Engine topped hile ircraft as n ow urning pproach o anding. Aircraft rashed nto rees nd as estroyed. One occupant was killed and two sustained major injuries. blade of the engine urbine assembly broke.

ot tart as isted s he ause or

the lade ailure.

ACCIDENT O. 6-Tail. boom eparated n cruise light t 00 eet. ircraft rashed nd was estroyed.

ilot ustained inor njury.

Cause nknown.

ACCIDENT NO. 7-Aircraft truck rees uring low-level light, rashed, nd urned. he wo crewmembers ere illed. aused y han- nelized ttention.

uspect upervisor rdered

flight beyond apability of aviators.

ACCIDENT O. 8-Engine topped n traight and evel light t ,000 eet nd ilot ntered

ACCIDENT NO 6 Gunner dropped ive grenade on passenger ompartment loor

12


17/21

autorotation.

uring pproach or ouchdown, incorrect ollective ontrol abrupt own) nd excessive ateral ontrols ere sed. ircraft struck round, olled ver, nd as estroyed.

Observer as illed hen is ead it he r- mored eat. ngine topped ecause f uel exhaustion.

Editor's ote: he ilot actors ead s: faulty light plan, iolation f light iscipline and navigation rror old wind blast, nd over- confidence. atigue and leep eprivation ere suspected.

ACCIDENT O. 9-Aircraft as aking teep, low-level urn. ilot pplied brupt p ollective nd xcessive orces esulted. ircraft struck

oulders nd

urned. ne

ccupant as

killed nd he ther ustained ajor njuries. Pilot elected wrong course of action nd ailed to use accepted procedures. uspect upervisor ordered light beyond capability of aviator.

ACCIDENT O. 0-While ircraft as n he ground

oading nd nloading assengers,

another person ot boarding aircraft walked nto tail otor nd was ecapitated. aused y nat- tention nd ailure o se ccepted rocedures.

ACCIDENT O. 1-Tail otor rive haft sheared uring limbing urn. irectional ontrol as neffective or ouchdown nd ircraft hit ard nd as estroyed.

here ere our

minor njuries. he ind aught nsecured poncho rid lew t ut f ircraft nto ail

rotor haft.

ACCIDENT NO. 2-In esponse o equest by the attalion ergeant ajor, ircraft as o assist n aising 5-foot lagpole djacent o the operations enter. he ntent of he aneu- ver as o aise he lagpole ro m n nclined position o n pright osition y se f opes held n he ockpit. pon eaching high over, aircraft huddered iolently, rashed, nd as destroyed. here ere wo ajor njuries nd one minor njury. ccident eport stated: Main rotor blades came n contact with n obstacle i.e., he lagpole.

ACCIDENT O. 3-Aircraft as t pproximately 00 eet urning ight ase or anding when ngine topped. ilot ook ontrols rom passenger, n 4, nd ttempted o nter utorotation.

ntry o utorotation as omewhat

late and rotor rpm was not regained. Exag-

ACCIDENT NO 7Aircraft struck guy wire attached o 400 foot radio ower

13


18/21

gerated lare llowed ail otor o trike round and ircraft rashed nd urned. ilot nd passenger ustained major njuries. eason or engine toppage s pending analysis.

ACCIDENT O. 4-Aircraft as hutting own on anding ad hen light f H-lH's anded close by. ecelerating rotor blades dipped down and evered ail oom. otorwash rom H-1H flight upset H-6A otor blades nd aused ail boom hop.

ACCIDENT O. 5-Fifteen-minute light as made fter assenger efueled ircraft.

fter

another passenger was embarked, engine topped at n nspecified ltitude t 0 nots uring takeoff. ircraft anded ard, olled ver, nd was estroyed. here

ere wo ajor njuries and ne inor njury. uspect uel ontami- nation. ACCIDENT O. 6-Aircraft ost ower uring low-level econ ission. rom 0 eet nd 0 knots, ilot ttempted o maneuver hrough dead trees o small tream clearing. ail boom truck dead ree nd ircraft crashed lightly ose ow and olled ver. uel cell uptured upon mpact and ilot as inned n ircraft hen t olled

over. aliant efforts by crewmembers reed pilot. Shortly hereafter, pilled uel gnited nd burned wreckage. here as ne ajor nd wo inor injuries. Cause f ngine ailure is nknown.

ACCIDENT NO. 27-Engine quit at approximately 400 eet uring akeoff limb. assenger blocked light ontrols uring utorotation nd aircraft ouched own ard. anding ear trut broke nd evered uel ose, esulting n ost- crash ire. ircraft as estroyed. wo ccu- pants ere illed nd ne ustained ajor n- juries.

ain earing ailure aused ngine

stoppage. Suspect passenger panicked.

ACCIDENT O. 8-After efueling, ircraft took off o - o 7-foot hover, ith ross eight of 2,542 pounds. ilot ttempted 80 eft urn from over nd ost ontrol. ircraft

rashed, rolled ver, nd urst nto lames rom uptured fuel ell. wo ajor njuries nd ne inor injury esulted. ause was isted as vergross weight.

Editor's note: he high hover, ver alternate gross weight, nd extra power demands of a eft turn ndicate hat ower equired xceeded power available.

ACCIDENT NO. 9-Aircraft tarted unning nto

ACCIDENT NO 9-Result of mproper preflight ow fuel and unnecessary and erratic ow evel light.

14


19/21

small atches f ow louds bout idfield n downwind eg or anding t irport. escent did ot lear louds nd ilot tarted eft urn. Aircraft as ow n he louds nd ttitude indicator idn't ppear o ork. ircraft ame out of clouds n diving urn. lare ppeared to e onducted t bout 50 eet, ollowed y impact n SP axiway. nitially, ircraft skidded 3 eet, hen became irborne gain or about 100 eet. ilot emembers pinning. fter second mpact, ircraft raveled pproximately 250 eet irborne, mpacted nto ide f parked C-47, nd as destroyed. ilot ustained major injuries. ilot experienced vertigo n he clouds and as n n nrecoverable ttitude oming out f the clouds.

ACCIDENT NO. 30-Pilot was hovering o efuel when he heard oud oise nd experienced om- plete oss of directional control. ircraft began to pin n lockwise irection. ilot losed throttle and made hovering autorotation. ircraft rotated bout wo nd ne-half imes efore t struck he round, ith ajor amage. ailure of orward lexible oupling f ail otor rive assembly as aused y corrosion nd ossible

improper himming.

ACCIDENT O. 1-During ow-level ruise flight, ircraft egan ight urn, ecame ncon- trollable, rashed, nd as estroyed. ne occupant as illed nd wo ustained ajor injuries. Cause undetermined. ACCIDENT O. 2-Hard anding t onclusion of ractice ouchdown utorotation evered ail boom.

aused y ilot pplying ollective

pitch oo early.

ACCIDENT O. 3-While ruising ow evel o remain clear of ow clouds, ircraft truck wire, crashed, nd burned. here were wo atalities. Caused y ow-level light n imited isibility conditions nd ossible istraction r nat- tention.

ACCIDENT O. 4-IP as emonstrating straight-in ractice utorotation. ircraft it on eels f kid nd ain otor lades lexed down nd evered ail boom. P misjudged ltitude nd ad xcessive ft yclic pplied t initial ontact.

Selected ncident Briefs

M an alked nto ain otor lades nd as killed.

Sudden gust of wind caused hovering helicopter to rift nto water ower.

Pilot as bserving esults f P renade thrown by his observer and lew nto ree.

During hutdown, SM C CH-46 hovered earby

and otorwash aused lade o lap own nd strike ail boom. During hutdown, ust f ind aused ain

rotor lades o lex own nd trike ail oom.

Pilot tarted engine with ne main otor blade tiedown till attached.

Pilot melled moke n cruise light. nvestigation evealed art f he attery as urned and charred. Results are pending analysis.

Aircraft was hutting down when person tand-

ing n earby evetment lipped, ell nto otor blades, nd was killed.

Tail otor truck rees during ow-level ruise flight.

Pilot as ruising ow evel hen ain otor blades it ole. ilot as istracted y right light.

Main otor blades truck rees during ow-level cruise light.

Aircraft vibrated everely during cruise light. Tail otor rive haft heared rom n ndeter- mined ause nd kids ere amaged uring touchdown.

Pilot anded n SP or assenger ickup. During akeoff, ight kid hooked SP nd ose pitched own.

ilot ulled ft yclic, dded

power, nd kid eparated rom ircraft. ilot later anded on andbags.

15


20/21

Selected Forced Landing Briefs Engine an ough uring nitial tart. t as shut own nd o echanical ifficulty as

found.

hen ircraft eached ,000 eet fter takeoff, ngine uit. uel as ontaminated with ater.

Amperage xceeded imits nd ilot ecured battery nd enerator witches. ockpit illed with moke nd pilot anded. aused by voltage regulator ailure.

Pilot melled moke uring limbout nd nitiated anding. t 0 eet, verrunning lutch failed.

Pilot as aking ow-level ractice utorota-

tion. oom limb as nitiated nd hrottle rolled o light dle. ngine uit nd ctual autorotation esulted. uel ontrol inkage had not been properly adjusted.

Engine nd ail otor drive haft ailed lmost simultaneously uring cruise light. ilot uto- rotated uccessfully. ause f engine nd ail rotor drive haft ailure s undetermined.

Engine topped uring utorotation. ause unknown.

Aircraft was on inal t 00 eet nd 60 knots when ail otor rive haft heared. ilot lew aircraft home nd made unning anding.

Selected Precautionary Landing Briefs Throttle roze during akeoff. Caused y irt. Pilot eard loud oise nd elt evere ibra-

tions. Tail otor ip came off. Pilot thought he had experienced tail rotor

failure ecause f estricted irectional ontrol and landed o nvestigate. Minigun rass as. found under ail otor control pedals. Brass was removed nd ission continued.

Battery horted out n cruise light nd part of battery urned.

All mergency arning ystem ights llumi- nated uring light. attery ack/mount ad broken, llowing battery o hort out.

Fuel quantity auge ent o zero during light and pilot anded. Gauge malfunctioned.

TOT tarted o ise, ower as educed, nd pilot anded. Reason or high OT s unknown.

Transmission hip etector ight ame n. Metal article was ound on magnetic plug.

1 6


21/21

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