Army Aviation Digest - May 1971

8/12/2019 Army Aviation Digest - May 1971

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USAARlSCfSUPPORTCENTERP O BOX 620577

RUCKER Al 36362 0577


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UNITED

OF ARMY AVIATION ACSFOROF THE ARMY

BG Will iam J. Maddox Jr .

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U . S. ARMY AVIATION SCHOOLMG Allen M . Burdett Jr .

COMDT U . S. ARMY AVIATION SCHOOLCOL Hubert S. Campbell Jr .

STAFFRichard K. Tierney Ed itorCPT Edward A . Bickel2LT Kenneth G . Kitzmiller2LT John H . ZwarensteynCW2 Mike lopezWilliam H . Smithl inda McGowanBrenda R. HarpBetty S. Wallace

ARTS SUPPORTHarry A . PickelDorothy l. CrowleyAngela A . Akin

U . S. ARMY BOARD FOR AVIATIONRESEARCH

COL Eugene B. ConradAND GRAPHICS DIV

Pierce l Wiggin ChiefWilliam E. CarterJack DeloneyTed KontosCharles MobiusPatsy R. ThompsonMary W . Windham

RMY VI TION

1GESJMAY 1971 VOLUME 17 NUMBEViews From ReadersThe Army Cheyenne Designed To SurviveCharlie And Danny's Write-InGeorgia National GuardEmergency ProficiencyAeromedic-Visual Il lusionsBeyond The BestMaintenance MattersRemember These Words Fire Mission OverInstrument CornerCrossword PuzzleOn Fire And Going DownCrew Chief-A Special SoldierEtiology Of A Midair CollisionBroken Wing AwardSubtle SymptomsGround TaxiThe GameToosoonoldt And ToolateschmartTwo VersionsMaintenance Mayday Or Maintenance Integrity?Crew ErrorWhose Error?Well DonesUSAASO SezHere Come The a nes Inside B

The mission of the U. S. RMY AVIATION DIGEST is to provide information of an operational or func1ional nature cocerning safety and aircraft occident preo;enfion, training, maintenance operatjons research and development aviatiomedicine and other related data .The DIGEST is an official Department of the Army periodical published monthly under the supervision of the Commodant U. S. Army Aviation School. Views expressed herein are not necessarily those of Department of the Army or the U.Army Aviation School. Photos are U. S. Army unless otherwise specified . Material may be reprinted provided credit is giveto the DIGEST and to the author unless otherwise indicated.Articles photos and items of interest on Army aviation are invited . Direct communication is authorized to : Editor U.Army Aviation Digest, Fort Rucker Ala . 3636 .Use of funds for printing this publication has been approved by Headquarters, Departmen1 of the Army 1 Octob1970.

Active Army un its receive distribution under the pinpoint distribution system as outlined in R 31 0-1. Complete D For12-4 and send directly to CO, AG Publications Center, 2800 Eastern Boulevard Baltimore Md . 21220. For any changedistribution requirements initiate a revised D Form 12-4 .National Guard and Army Reserve units under pinpoint distribution also should submit D Form 12-4. Other NationGuard un its should submit requests through their state adjutants general.For those not eligible for official distribution or who desire personal copies of the DIGEST paid subscriptions, 4 .5domestic and 5 .50 overseas, are available from the Superintendent of Documents U. S. Government Printing Office Wasington, D. C. 20402.


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F JEWSROME DERSSir:I read with dismay the article entitled

Good Safety Practices Do Pay Off inthe February 1971 edition of AVIATIONDIGEST.I am in full agreement with the use ofsafety equipment and maximum application of good safety practices; however,the article was about an incident that,from the facts presented, was both anunsafe act and tactically unsound. (I realize that criticizing in retrospect a tactical situation as unsound and/orconducted outside safety limits is alwaysrisky when you were not there to knowthe whole situation.) From the description of the incident, it appears that theAH-IG was not being employed withinestablished sound tactical or safety limitsbecause a gunship that is covered withmud has overflown its target and musthave been too low. There are. of course,times that the tactical situation wouldrequire such action but from the articlethis is not indicated.All in all, I believe it was a poor example of good aviation safety, not a seldomfound situation that promotes the valueof good aviation safety as claimed by thearticle. From the facts presented in thearticle this accident could have beenprevented and that is the best practice ofsafety.

Sir:

MAJ R. A. Neuwien Jr.Assistant Inspector GeneralU. S. Army Primary HelicopterCenter/SchoolFt. Wolters, Tex. 76067

I am a Marine major who was one ofthe first four Marines to go through theArmy Cobra training at Hunter AAFGa. I was truly impressed with the overall syllabus, especially the emphasisplaced on the cardinal rules of employ-MAY 1971

ment of attack helicopters. One of thoserules is: Do not overfly the target.On page 32 of your February issuereference is made to damage sustainedby a Cobra in a gun run when it flewthrough a secondary explosion. AlthoughI realize your article is attempting toemphasize the value of protective flightequipment, I think it would have beenmuch more effective if you had alsoquestioned the wisdom of the tacticswhich produced the damage.Your photos also imply that the pilotswere wearing utilities rather than Nomexflight suits. Is this a fact? f so, is this agood safety practice?I enjoy your magazine very much,especially because it deals so much withhelicopter problems. I especially appreciate your recent increase in emphasis onsupervision and command attention withrespect to aviation safety. I was the helicopter analyst at the Naval Safety Center in 1968 and am firmly convinced thatthese areas are the two remaining untapped sources for decreasing our accident rate and subsequently increasingour operational readiness.MAJ J. L. PipaMarine Corps Liaison OfficeCode 142Naval Weapons CenterChina Lake. Calif. 93555

The DIGEST has received numerous letters on this article. We couldn't agreewith them more. However, the article inno way endorsed the tactics involved.Rather it took the opportunity to point outthat the goo safety practices involved didpayoff. The aviators were wearing NomexHight suits during the flight; the photo wasposed for later.Sir:The article Accidents Are Stupid in

the February 1971 issue is great to pointout the stupid errors committed andthe disastrous results. The author left outone important step in the solution toprevent aircraft accidents . . . use ofperformance data charts to determineprobable aircraft performance.It is useless to compute the weight ofan aircraft and density altitude unlesssome kind of performance standard isused to determine aircraft capability. Themere fact that it is a hot day will indicatethat the aircraft will not perform as wellas it does on a standard day but this information, like density altitude, does nottell the degree of deterioration in performance. This information is found inchapter 14 of the operator's manual(dash 10 . After determining probableaircraft performance from performancedata charts, actual performance can beconfirmed at a. hover.

Sir:

CPT James P. Wall504 Morgan LaneOzark, Ala. 36360

I think you put out some bad information in the Instrument Corner. page27, March 1971 edition. The last questionconcerning reporting errors in estimateswas answered incorrectly. My referencein the 4 Feb 71 issue of FLIP. sectionII. tells me that this report is not necessary when in radar contact.How say ye to this?MAJ Raymond E. EvansCalifornia Army National GuardLong Beach, Calif. 90822

Yea verily. to err is human but to doso in print embarrassing, however legitimate in this case. Please see InstrumentCorner on page 30.


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The Army h e y e n n eOut of the advanced aerial fire support system AAFSS) pro-gram arose the AH-56A Cheyenne. Featuring the latest aerialequipment the Cheyenne can fly up to 26 000 feet day ornight and in most weather. The low level, high speed flightcapabil i ty coupled with i ts outstanding maneuverabilitymake the Cheyenne an extremely difficult aircraft to hit withground fire. The versatile weapons system and computerizedfire control enables the crew to engage most any target withhigh probability of first round hit. This article contains themost accurate information to date on the amazing Cheyenne

THE NEED FOR airmobileforces in the Republic ofVietnam was quickly established

and the concept of the 1950sbecame a proven success in the1960s. Although loss rates earlyin the conflict were less tha.lexpected, they were high enoughto bring sharply into focus ademand for improvements inhelicopter survivability. Of im-mediate concern was the reduction of vulnerability againstsmall arms fire in Vietnam, particularly for the attack helicop-ters.

Bolt-on armor plate and flakvests substantially lowered pilotand helicopter loss rates. Otherfeatures were later added thatfurther improved helicopter survivability. But how could heli-copters expect to survive inpotential1y less permissive combat environments of the 1970sand the next decade? It was forthis purpose that the Army di-rected its concern and attentionto designing survivability intothe AH-56A Cheyenne.

From the time the advancedaerial fire suppor t system(AAFSS) concept was conceivedin 1964 the Cheyenne was designed and developed to stringent protection requirements.2

Colonel Robert J. DillardThe intent was not only to makeorganic to the U. S. Army anaccurate and lethal direct aerialfire support system, operationaland effective in all potentialworld-wide natural and hostileenvironments, but also to makeit the most invulnerable aircraftto enemy fire in the history ofthe Army. It was from thesedemands that the exceptionalsurvivability features of theCheyenne evolved.

Future Combat EnvironmentThe decade of the 1960s endedwith definite indications of di-

minishing U. S. military involvement in Southeast Asia. TheArmy enters the 1970s with theresponsibility for maintaining aneconomical combat-ready posture for a spectrum of possiblefuture conflict situations. Potential world-wide actions couldrange from antiguerilla counterinsurgency to high intensity warfare against massive armoredforces equipped with the latestweapons. In addition to automatic small arms fire which is

the major threat to helicopters inVietnam, future aerial attacksystems must be prepared toencounter sophisticated antiair-craft threats-surface-to-air mis-siles (SAMs) and antiaircraftguns with high explosive HErounds in this spectrum ofpotential conflicts.

F ro m Vie tn a m we havelearned that the attack helicoptercan withstand considerable punishment from fire delivered bylight automatic weapons. However the survivability of thesesame attack helicopters is re-duced when encountering groundforces equipped with the largercaliber weapons.

While current attack helicop-ters can be adapted to accommodate limited additional weaponryappropriate for the higher intensity conflicts, survivability in asophisticated threat environmentis not so easily ascertained. Thekey to long range preparednessis to develop a survival philoso-phy at the inception of an attackhelicopter program which is of

COL Dillard was the advanced aerial weapons sys-tems project manager with USAAVSCOM, St. Louiswhen he wrote this article. A Senior Army aviator,he qualifies in both fixed and rotary wing aircraft

U. S. ARMY AVIATION DIGEST


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i g n e o urvive

equal importance with all otherdesired attributes. Then designin survivability as an integralpart of the overall aerial weaponsystem. The Cheyenne evolvedunder this integrated weaponsystem approach.he ttack Helicopter

It was prior to the deploymentof U. S. combat troops in theVietnam conflict that the Army's

th Air Assault Division (T)developed and demonstrated therotary wing airmobile concept.By the time U. S. Forces inMAY 1971

Vietnam were energetically engaging a fleeting enemy in earchand destroy missions, it becameapparent that a new dimensionhad been added to modern warfare. Transport helicopters werebeing frequently engaged byenemy ground fire. This situationcreated an immediate need toarm the transports for both selfand mutual protection. The re-pon e to this requirement was

adapting helicopters to accommodate door gunners with lightmachine guns.

The armed helicopter soonbecame an established vehiclefor combat. Separate armed heli-copter units were created andproved themselves as effectiveescort . The success of thearmed helicopter against hostileground forces in these missionsclearly indicated the need for anexpansion of tasks to includeattacking ground targets in proximity to engaged U. S. troops.This type of discriminating fire,delivered at the behest of theground commander and called

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direct aerial fires (DAFs) , as distinguished from close air support, soon proved to be thedecisive contribution to the success of many firefights. TheArmy learned that traditionalmethods of fire and maneuvercould be vastly improved byusing its most mobile combatvehicle-the helicopter- to deliver effective firepower.

Unfortunately the forced ]anding and loss rate of theseaggressive combat vehic]es ,while acceptable , were higherthan desired. The Army nowbegan in earnest to study aircraftsurvivability problems and in theinterim provide the current combat helicopters with some meansof passive protection.I t was in the mid 1960s thatthe first attack helicopter wasintroduced into the Army inventory , the AH-1G HueyCobra.For the first time the Army hada helicopter specifically designedfor the direct aerial fires mission. The Cobra, a modificationof the successful UH-1 series ofhelicopters , was equipped withantipersonnel weapons in a chinmounted turret and capable ofcarrying 2.75-inch folding finaerial rocket (FFAR) pods. Butof equal importance to increasedfirepower , the Cobra also offeredseveral vulnerability reduction4

Figurefeatures-bolt-on armor for vita]engine components , crew seatarmor and self-sealing fueltanks. These features , for thepurpose of defeating or negatingthe effects of small arms fire,were the result and the initialimplementation of Army p]anning for improving helicoptersurvivability.

Cheyenne CharacteristicsThe Cheyenne advanced at

tack helicopter is the realizationand culmination of the ArmyAAFSS requirements initiated inthe mid 1960s. The Cheyennecompound helicopter is currentlyunder development. It is themost advanced, fully integratedrotary wing weapon system inthe world figure 1). t is capableof carrying and delivering largepayloads of lethal ordnance.Dead]y accurate fires are accomplished with the finest computerized fire control system of itstype ever developed. A swiveling gunner's station with a 360degree field of view and containing a stabilized periscopic sightis tied into all aircraft armaments through the computer.

Basic armament figure 2 include : 1) TOW ant i tankmissiles externally mounted inpods on the wings , 2) 30 mmcannon in the belly turret with a360 degree field of fire that can

deliver dual purpose rounds(antipersonnel/light armor) withdemonstrated accuracies thatequal or exceed the accuraciesof any aircraft flying today and(3) an c c u r t e 40 mmantipersonnel/grenade launcherlocated in the nose turret. A 7.62mm automatic gun serves as analternate weapon for the noseturret.Additional onboard systemsthat further enhance the devastating firepower of the Cheyenneare the self-contained Dopplerinertia] navigation system and agunner's night vision system foraround-the-clock combat operations.

A Matter Of SurvivabilityBefore reviewing the specificsurvivability features of the

Cheyenne, it is p p r o p r i t ~ tofirst clarify the term survivability. Survivability in the aircraftcontext is a capability to survivehostile fire during the conduct ofits mission. How well a vehicleaccomplishes this goal is themeasure of survivability . Thatwhich is to be measured is theefficacy of the active and passivedefense features of the aircraftfigure 3).

The overt actions of any aircraft during approach, deliveryof fire and departure from enemy target engagements are of-



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ten referred to as active defense. features. The active defense features of any aircraft are: (1) thecombat tactics and safety offlight options available to thepilot, determined by the maneuvering capabilities of the aircraft; and (2) the ability to avoidor neutralize enemy fire that canthreaten achievement of firemission objectives-a functionof the acquisition, fire controland armament system which isintegral to and harmonized withthe aircraft.

Aircraft protection by design(or modification) of airframe andon board systems is referred toas passive defense features.Methods for survivability im provement of this type include:minimal visual, radar and in frared signatures; and improvedinvulnerability. Decreasing thevulnerability is by far the mostwidely used technique , but alsomost often incorrectly a sumedto be ynonymous with the degree of overall aircraft survivability.

urvivability FeaturesAircraft survival during a

combat mission depends on thesuccess of: (1) avoiding beinghit- low detectability, minimumexposure and threat suppression;(2) withstanding a hit- low vulnerability; and (3) continuedoperation with a high level ofsafety when flown and landed ina damaged condition.

voi being h i ~ l i g h t tacticsused to attack hostile groundtargets can significantly affectthe survival of the aerial supportsystem. Assuming a midintensityarmored conflict with U. S. airsuperiority, an attack aircraftshould expect to encounter aspect rum of threa ts Thesethreats include: (1) optically controlled antipersonnel and highexplosive antiaircraft weapons,(2) radar controlled antiaircraft

Figure

weapons of similar caliber , (3)small arms fire and (4) surfaceto-air missiles.

Predictable antiarmor attackmaneuvers , such as straight-indives , may be prohibitive in thisthreat environment. Incomingthe aircraft would be exposed tosurface-to-air missiles and theoptical and radar controlled highexplosive incendiary antiaircraftfire. Following commencementof the attack the aircraft wouldbe exposed to optically trackedantiaircraft weapons and automatic small arm fire as it fliesclose by or over the target.

The Cheyenne would employits unique characteristics in performing the required attack tasksby attempting to operate belowthe radar horizon and below theminimum SAM altitudes. We areall familiar with a helicopter'sability to fly at low speeds closeto the terrain, referred to as napof-the-earth flight. The AH-56Acompound helicopter will use itsstabilized fire control systemwith a 360 degree field of viewand a 2 power periscope to detect and identify designated targets and protecting threats. Thenby taking advantage of its heli-

copter flight regime to remainclose to the terrain , the crew caneither visually-or by using thepinpoint accuracy of its demonstr ted l ser r a n g efinder/navigation system- fix ,record and recall the targetlocations . The Cheyenne cansubsequently select a spectrumof attack modes , dependent onthe type of target. Against mechanized and light armored vehicles , for example , the Cheyennecan deliver a ustained 360 degree field of fire , accurate atlong ranges with a 30 mm cannon. One method of employingthe Cheyenne in a TOW missileattack against even the heaviestof enemy tanks would be a popup maneuver from behind terrainand then entering a sidewardflight maneuver until missileimpact. Tank kills with TOWmis ile have been demon tratedin AH-56A flight tests at standoffdistance beyond the effectiverange of many antiaircraft weapons and all small caliber ground weapons.

The AH-56A also ha s theunique capability of maneuvering and engaging multiple targetssimultaneously. For example ,


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AH 56A CHEYENNE PASSIVE DEFENSE FE TURESItem

CrewFuel and oil systemFlight controlsEngineHydraulic system

Electrical system

Rotors/propellers

Transmission and drive

Airframe

the TOW missile could be delivered against a tank by the gunner while the pilot engages othertargets , thus protecting againstthe armored threat with the 30mm cannon and/or the 40 mmgrenade launcher. The primarytarget, the tank, is engaged bythe gunner using the swivelinggunner s station with the stabilized periscope sight. The pilot ,simultaneously , employs hishelmet sight to suppress antiaircraft threats with the flexible 30mm belly turret or 40 mm grenade launcher in the no e turret.

ithstand hit-UH-I Hueygunships and AH-I G HueyCobras operating in the Rupublicof Vietnam have clearly demonstrated the effectiveness of theattack helicopter. Some of the6

FactsTwo crew members; armor protectionSelf-sealing; fire suppressant; fuel pump inside tank;gravity feed outboard tanks to main tankDual separated push-pull rods; armor protectionArmor protectionDual independent systems; automatic shifting primaryto secondaryDual components; automatic switching; sectional wirebundlesPrimary structure designed to withstand a direct hit; helicopter backup flight modeDrive shaft designed to withstand direct hit; gears andbearings have oil retainers 30 minutes of flight withoutoil coolingSafe flight with loss of anyone primary load-carryingstructural element; safe flight with any three of fourbolts used for all major attachments; safe flight with lossof anyone main transmission support bulkhead member

Figure

hrst attempts to design protection into helicopters are found inthese rotary wing aircraft. Theyhave performed their tasks welland valuable Ie sons werelearned which were not lost onthe Cheyenne. Recognizing thatthe AH-56A could be expectedat any time in the future to conduct its support function in amuch less permissive environment than Vietnam , the Armydemanded of the Cheyenne unprecedented protection againstloss by hits from potential heavyenemy fire. Low vulnerabilitywas one of the key buildingblocks for design of the Cheyenne.

It is estimated that the AH-56A is almost invulnerable tohits from small arm s fire and can

significantly reduce the lethaleffect s of larger antiaircraftrounds. Numerou passive defense features , never beforecollectively designed into anyaircraft, were employed in theAH-56A design concept. Thecurrent Cheyenne configurationensures the lowest probability ofkey system and airframe failurefrom damage received fromenemy fire possible within thepresent technology. Note inchart 1 the comparative im provements in U. S. Army attack helicopter passive defensemeasures.

The passive defense featuresto be found in the Cheyenne in-clude: 1) self-sealing fuel cellprotection, 2) component protective positioning, 3) redundan-



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ehflrlie flnrl1)flnnY s Write-InD EAR CHARLIE: Why does the dash CL forthe U-SD have procedures for landing withone gear up? The aircraft can be landed gear-upwith little damage if the landing gear malfunctions.

CPT C. L. R.Charlie s answer: The dash CL is a condensed formof the normal and emergency operating procedureschapters in the operator s manual (dash 10). It contains only the sequence of events of a procedurewithout any instructions, warnings or cautions. Itspurpose is to remind a pilot, qualified in the aircraft, of the steps outlined in the operator s manual. It is not intended to be used as an instructionmanual. The U-8D manual clearly states (page 4-11) that i all three landing gear cannot be fullyextended and locked, the landing should be madewith the landing gear retracted. Procedures arealso given in the event a gear(s) cannot be retracted. These procedures appear in the dash CL incondensed form. A pilot must know his aircraft anduse the procedure applicable to the emergency.Dear Danny: What is the correct procedure if youlose transmission oil pressure in the oR B? Ihear conflicting stories. lLT S. B. F.Danny s answer: Your TM 55-1520-219-10, page 4-7, paragraph 4-36 explains this situation. It says toland at the nearest safe landing area and no furtherflight until the cause of the light has been determined and proper corrective action taken. Do notmake an autorotative descent. You want your engine turning your transmission on the descent.Some aviators have attempted an autorotative descent under these conditions and their rotor bladesstopped turning prior to reaching terra firma. Youcan well imagine the end results.Dear Danny: What is the correct emergency fuelfor the OH-6A? I say any aviation type fuel wiIJdo; others say it must be a jet type fuel. Who iscorrect? lLTR. R. S.Danny s answer: Your answer is partway correct.S

TM 55-1520-214-10, page 7-1, patagraph 7-1.1holds your answer. I t says that MIL-G-5572 aviation fuel without TCP) (80/87, 100/130, 115/145can be used under the following conditions: The electric fuel pump must be on at all times. The use of emergency fuel is limited to a totaof 6 hours between TBOs. .Dear Danny: In the OH-5SA manual, in chapter 3it says to turn the anti-ice switch on when OAT is4 degrees C. 40 degrees F.) or below, and chapter 10 says OAT 5 degrees C. 41 degrees F.)Which is correct?

CW2 S. D. F.Danny s answer: Chapter 3 in the TM 55-1520-228-10 is correct. Change 1 to the manual, which is indistribution, corrects this error between the twochapters.Dear Danny: In the event of a hydraulic failure inthe TH-13T, does the waste gate control in thesupercharger become inoperative?

CW3 P. M. SDanny s answer: The notes of pages 2-19 and 4-7 oTM 55-1520-226-10 provide you with the answeryou desire. Hydraulic pressure will be provided tothe waste gate control if there is a loss of hydraulicpressure. If the pressure line to the waste gate ruptures, then of course hydraulic pressure will be losand the waste gate will go to the full open positionand horsepower available is reduced.Dear Danny: What is the proper use of the electric fuel pump in the OH-6A? Some of the guyssay it s on all the time. I disagree. lLT R. R. SDanny s answer: You, sir, are correct. I suggesyour friends read page 2-18, paragraph 2-58 of TM55-1520-214-10, change 4. It states the electric fuelpump is on and provides fuel to the engine pumpduring engine starts since it operates automaticallybecause of its electrical connection with the startingcircuit. Other than starting it should only be usedduring high altitude or high temperature flighconditions, which is 15,000 feet MSL or 45 degreesC. 113 degrees F.) OAT/fuel temperature.



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WHAT DID YOU SAYWAS frU ND LOCKED?

Dear Danny: The normal gear warning horn setting in the U-8D is 4 inches Hg. During transition at Ft. Rucker, Ala., I was taught to make mynormal pattern descent at 5 inches Hg. t appears to me that this procedure makes the horninva id as a warning device, as the horn will notsound in the event of a "gear-up" approach untilthe aircraft is over the threshold and the power isfurther reduced for landing . This may be too late.

CW2 G. G . D.MAY 97

TM-55- i}: 10j ~

Danny's answer: Too late is correct I wonder howmuch good a horn will do when Peter Pilot doesn'tuse his checklist during the BEFORE LANDINGcheck and arrives on final with his head and gear"up and locked." However, you may be happy toknow that this information has been passed on toU. S. Army Aviation Systems Command engineering and the setting of the warning horn will bechanged to 16 inches Hg. This will appear in achange to TM 55 1510 201 20 which will be published in the near future.

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With the slowdown of the warin Southeast Asia, and thelessening of our materiel andlogistic requirements in thecombat zone, many new piecesof equipment are finding theirway into the National Guardand Reserve Component inven-tory. The Georgia NationalGuard is one of the first com-ponents of our nation s back-bone of defense to receivenew, modern equipment.Photo left: Georgia NationalGuardsmen monitor infraredreceivingequipment in its termi-nal station as a National GuardMohawk above right) flies nearStone Moun ta i n Ga.


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phy plus electronic surveillance and reconnaissance.Training fl ights, designed totest the abilities of flight crewsand ground support personnel ,were conduc ted by theGuardsmen at night as well asduring daytime operations.

Acquisition of the Mohawkbegan with the reorganizationof the Georgia Army NationalGuard on 1 January 1968. Atthis time Georgia accepted theassignment of the two air surveillance companies and thecomplicated mission of recruiting personnel with special aptitudes to qualify in the manyhard skills necessary to successful ly man such complexunits.

N pilots discuss route offlight prior toflying mission

Although it was 2 years afterreorganization before the aircraft were first delivered, theunits attended training at Ft.lewis, Wash ., with active Armysurvei l lance units in 1969.Training in a critical MOS 7 l(ai rborne sensor operator wasdelayed due to a lack of schoolspace. However, some weretrained prior to their annualactive duty, allowing missionsto be accomplished with fullyqualified crews .The first two Mohawks werepicked up factory fresh fromthe Grumman Aircraft Company, Stuart, Fla., in January1970 by two Georgia ARNGOV-l pilots and flown to Win-der. Four more were flown to

Georgia during the next 6months.The allied ground equipmentnecessary for the functioningof the two aerial surveillancecompanies has been deliveredin stages since January 1970.Not until the units arrived inSavannah, however, did theyget some of their essentialequipment. There the aviationcompanies were well supported by technical representatives of the U. S. ArmyElectronics Command.

With the direct and personalinterest of Major General Fran-cis S Greenlief, Director ofthe Army National Guard, Na-tional Guard Bureau, the Geor-gia Mohawk aviators have beengiven a high priority. The general has visited the unit sev-e r a I t im e s, f low n i nt eMohawk and has challengedthe Georgians to master thecomplex aircraft and its so-phisticated capability.

Another interested visitor tothe field training at Savannahwas Major General John M.Finn, deputy commanding

Film developing (below left andimage interpreting (below) bothcomplement the Georgia NG stactical surveillance capabilities


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Sophisticated data terminalstations receive surveillance in-formation from the Mohawks

general of Third U. S Army forReserve Forces. General Finntoured the f light l ine afterbeing briefed on the missionand training progress appear-ing confident that the Georgians were well on their way tobecoming combat ready.To personally see that train-ing of the aviation companieswas progressing satisfactorily,Major General George J

Hearn, Adjutant General ofGeorgia spent part of his annual field training time withthe aviation personnel at theSavannah airport.The first working day afterarrival at Savannah, eachcompany flew a mission. Thiswas accomplished only after amaximum effort at all levels.Each morning and afternoonthereaf ter , the 158th and159th flew two missions eachfor a total of 80 missions dur-ing the 2-week period of inten-s i ve t r a i n i n g . Pho totechnicians and imagery inter-preters were kept busy. Skilledpersonnel recorded incomingdata from airborne Mohawksand were processing photos bythe time the aircraft landed.Total Mohawk flying time dur-ing their Savannah trainingwas 130 hours accomplishedby six pilots. Missions includedsupport of National Guardunits and active Armmands in several states.

M Greenl ief above le f tdiscusses the Mohawk trainingexercises with members of theguard while M Finn left) receives briefing on the trainingfrom Georgia N commanders

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~ t t E R G E N y


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Quick react ions do not a lways imply safe react ions. Fol lowinga few simple rules could possible save your l i fe in a givenemergency situation. Use your head first then react

M ELVIN CONSIDEREDhimself a top-notch Armyaviator , proficient enough tohandle any emergency.

Having thus established Melvin qualifications, we can joinhim a he hovers his UH- I Hueybetween two rows of revetments . He still ha about 100feet to go before he reaches theend of the row of parked aircraftwhere he will have to execute a90 degree right turn to reach theactive runway.

Melvin had hovered down thisrow so often that he could do itblindfolded. He reache down toput his tran mit/selector switchon position 2 just a he arrivesat the end of the taxi way. SinceMelvin was sitting in the leftseat he had to place hi left handon the cyclic and his right handon the transmit/selector switch.Upon applying right pedal tomake his turn, the tone of theengine rises sharply and the air-craft yaws to the right in aclimb.

In pite of the trange positionof his hands, Melvin reactsquickly. As his left hand reachesthe collective, he immediatelyapplies pitch which raises theaircraft to approximately 60 feetin the air. He snap the throttleto flight idle, leaving the collective up under his armpit and therotor rpm is now decaying rapidly. Melvin big problem isthat the aircraft is almost out ofcontrol.

The aircraft begins falling andMAY 97

CW2 J . M Adk ins

Melvin s reaction is to lowercollective. As his rate of descentbegins to increase , it crossesMelvin s mind that stopping theaircraft at the bottom is going tobe tricky. He increases throttlebut the rpm doesn t seem to beresponding. At about 5 feet offthe ground he attempts to cushion the aircraft onto the ground.

As he applies col1ective theengine rpm catches and beginsto increase. This causes the air-craft to spin, then hit the groundand roll over into a revetmentwall. Luckily Melvin survives.

The experience of his accidenthas influenced Melvin a greatdeal and helped him developgood safe flying habits. t onlycost the Army approximately350,000 to turn Melvin into agood safe pilot.

f Melvin would have followeda few simple rules he could haveprevented the loss of an aircraftand would not have placed thelives of his crew in danger. Thefirst mistake was in assumingthat one emergency procedurecan be applied under al circumstances. The correct procedureto follow must be modified tocope with the position of theaircraft (i.e., air speed, altitude,wind, load and pilot proficiency).A professional pilot will realizethat emergency procedures aspublished in the dash 10 are onlya guide. He will also anticipatepossible solutions to differentemergencies and thus cut reaction time when it counts.

In determining possible variat ions to an emergency , anaviator is wise to consult otherpilots who have experienced thatparticular type of emergency. fno one is available with first-hand knowledge, a round-tablediscussion about symptoms andresults will do a great deal toreduce reaction time and in crease a pilot s awareness ofhow to recognize a particulartype of emergency.

Melvin s second mistake wasin developing a complacent attitude toward his flying. No onepilot is good enough to copewith any possible emergency inal possible configurations, andno pilot ever reaches a pointwhere he can afford to close hismind to new ideas or techniques.

Melvin s third mistake was intaking his hands off the controlsto tune the radios. He apparently did not use the prescribedaircraft checklist in his runupwhich provides for the tuning ofaircraft radios as well asfailed to utilize his copilot. Theman in control of the aircraftshould focus his attention onflying and fol1ow standardizedprocedures.

As Melvin tried to cope withhis emergency, he got furtherand further behind the aircraft.Consequently, his degree of control diminished until in the endhe had no control at all.

Melvin wasn t such asho t af ter all , butlucky.

5


18/68

Due to space considerations thisarticle was condensed for publication in the September 1969 US. Air Force Medical ServiceDigest. The original report,SAM-TR-67-28 was published inApril 1967 under the title Visual Illusions and Aircraft Accidents. Names of investigatorswho reported findings at variouspoints in the article have beendeleted but are available in theabove cited references

N A MAJOR overseas command it was found thatspatial disorientation was thecause of 4 percent of all flyingaccidents and 4 percent of allfatal accidents. Investigators isolated one of the visual factorswhen they stated that the primary cause of undershooting orovershooting nonemergency accidents was faulty distancerate-of-closure on the part of thepilot.

The U. S. Air Force is notalone in accidents caused by illusory phenomena. Disorientationwas credited as the most common probable cause of fatal acin the Royal Air Force.6

l llUSIONSMore recently the Military Airlift Command (MAC) has illust ra ted that landing-shortaccidents have not shown animprovement in the 10-year period between 1955 to 1964. Thus,aircraft accidents caused by illusory phenomena resulting fromvisual, emotional or vestibularfactors constitute a major portion of all U. S. Air Force accidents.It is the purpose of this articleto analyze some of the visualfactors which contribute to disorientation or faulty distancejudgment in an effort to provideinformation which may be usedin the analysis and correction ofaircraft accidents.It is evident that during thelanding phase the pilot is busierthan during normal flight, but atthe same time he is usually moreattentive to the required procedures for landing. Many of theseprocedures require visual surveillance prior to the pilot making decisions regarding thesafety of the landing.

There is always the danger ofconfusing approach and runwaylights. When a double row of

approach lights joins with theboundary lights of the runway,pilots have reported confusion indetermining where approachlights terminate and runwaylights begin. The beginning ofthe runway must be clearlyshown. This can be solved byhaving radically different runwayand approach lights or speciallights separating the approachfrom the runway.Approach lighting systemsshould be designed so that theydo not give illusory or false information. When flying into agradually thickening fog on approach, the pilot feels that he isclimbing; in compensating, hedescends too low. Under certainconditions approach lights canmake the aircraft seem higherwhen it is in a bank than whenits wings are level.

The intensity of the approachand runway lighting system isimportant. For example, pilotshave the impression that theyare in a bank when they are actually flying level if one row ofrunway lights is brighter than theother. Attention has been calledto a rather unique illusion. f a



19/68

er )medicProvided by the Societyof u S Army Flight SurgeolU The Society of U. S. Army Flight Surgeons wishes to call at

tention to the reprint of this particularly informative articleon a subject easily overlooked by air crewmen. It appearedin the December 1970 issue of the U. S. Air Force INTERCEP-TOR. The information, though pertaining to fixed wing flight,is appl icable both to fixed wing flying and to rotary wingflight. A sequel with an Army aviation slant will appear in afuture AVIATION DIGEST. Our thanks to the author, LTC DonaldG. Pitts, USAF (Ret), and to the U. S. Air Force's INTERCEPTORmagazine for granting permissIon to reprint the article

Lieutenant Colonel Donald G Pittscombined with a standardizedimproved approach lighting andglide-slope system should eliminate or drastically reduce thefalse or illusory information received by the pilot. t must beremembered that as long as thehuman subsystem is operatingthe aircraft, there is the possibility of human error.

USAF asc Ret)

single row of lights is used alongthe left side of the approachpath, a pilot misinterprets theperspective and corrects hisglide path to the right. Thus, thetouchdown point would be far tothe right of the runway as theaircraft crosses the runwaythreshold.The approach and runway

MAY 1971

lighting problem has receivedextensive research in recentyears to minimize these illusions. As improvements aretested and evaluated, changesare incorporated into presentsystems. It is important to notethat a standardized approachlighting system has not beenadopted; therefore, one of themajor hazards in approach andglide-slope systems is that differ-ent airfields use different syst ems and con s equen t l ycomplicate the pilot's task ofmaking height and distance judg-. ments on approach and landing.Instrument approach systems

A normal approach glide pathis illustrated ih figure 1 Actualor physical height (x) corresponds to apparent height y),and the resultant glide slopeprovides a safe landing. Illusorycues may be provided by a runway that is narrower or widerthan the normal runway towhich the pilot is accustomed.Additionally, the runway slopeand terrain around the runwayapproach can induce visual illu-sions. We shall attempt to illus-trate these factors which serveto provide illusory visual cueson landings and approaches. In

17


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most of these illustrations , x willrepresent the normal glide pathheight; y will indicate the appar-ent height due to illusory cues;and x will represent the com-pensatory glide path which thepilot uses so that the glide pathwill appear normal to him.

Illusions can result when arunway is narrower than thatusually experienced by the pilot(figure 2). The actual height ofthe aircraft for a narrow runwaywidth is h + h . For a narrowrunway, the pilot feel s as thoughhe were at h + h when he isactually flying at a height of h ;

therefore , the apparent heightdoes not correspond to realheight but is somewhat less.Thus , the glide slope results in alow approach and the tendencyto undershoot or land short ofthe runway. An approach of thistype could re sult in a seriousaircraft accident.

While landing on a wider thannormal ;unway , the pilot feels asthough he were flying at h whenhe is actually at a height equal toh + h (figure 3) . Again , the ac-tual height does not correspondwith the apparent height. Theapparent height is somewhat

Figure 1 Normal approach glide slope

greater than the real height. Theglide slope would result in a highapproach and the tendency toovershoot or land down therunway. This would not be a se-rious illusion if the runway werelong enough for safe braking .

Most runways are level , butthose few which have some de-gree of slope provide tricky vi-sual cues to the pilot. For theupslope runway (figure 4) thepilot feels as though he is at yheight above the terrain; there-fore , in an attempt to fly a nor-mal glide path, his compensatoryglide path at x results in landing

Figure 2. The effect of a narrower as against a normal width runway on landing an aircraft: AB is the width of a nor-mal runway; A B is the width of a narrow runway; h is the height for a narrow runway; h + h is the height for anormal runway. At the same point in the approach the pilot feels as though h is the same as h + h . A normal glideslope height h would result in the tendency to undershoot and land short of the runway

8 U . S. ARMY AVIATION DIGEST


21/68

- . --- - - - - - - , A ::E__ --- E S\..V1A __ .. GUo h------------. ; t ' O ~ 'Tt

B-------....JBFigure 3. The effect of a wide runway as against a normal width runway on landing an aircraft: AB is the width of anormal runway; A B is the width of a wide runway; h is the height for a normal runway; h h is the height of aircraft for a wider runway. At the same point in the approach, h h is thought by the pilot to be equal to h. Thus,the normal glide slope of the aircraft results in an overshoot or landing down the runway

-------- -- - Figure 4. The effect of runway upslope on glide path: With an upslope, the normal glide path will appear to be toosteep. Flying in a glide path that appears more normal could result in an approach which lands short of the runway

short of the runway. A similarsituation occurs when there is adown slope in the approach ter-rain , i.e. , the compensatory glidepath results in landing short ofthe runway (figure 5).

The downslope runway pro-vides illusory cues which makethe pilot believe that he is lowerMAY 1971

(y) than his actual height (x). Tocompensate for this phenome-non , he flies a compensatoryglide path (x ) which will resultin landing long or overshootingthe runway (figure 6). Upslopeterrain in the approach zone cre-ates a similar visual illusoryeffect (figure 7).

I f a pilot is in doubt concern-ing the runway and approachterrain slopes, he should dragthe landing strip and be aware ofthe illusory effects which can beinduced. It should be empha-sized that a pilot usually encoun-ters mult iple i l lusory cuesinstead of the simplified single

19


22/68

Figure 5. The effect of terrain downslope in the runway approach on the aircraft glideslope: When the terrain slopes downward the pilot will believe the aircraft to be onlow flat approach and there is a tendency to land short of the runway

Figure 6. The effect of runway downslope on the aircraft glide slope: With a down-slope the glide path will appear flat; there is a tendency to overshoot the runway

cues mentioned above. Combinations of these cues may serveto lessen or increase the totalillusory effect. A severe illusionmight result from a narrow upslope runway and downslopeapproach terrain. Conversely anupslope runway could be canceled as an illusory problem byupslope terrain or a wide run-20

way or both. Inclement weatherand poor ambient luminancewould most probably increasethe effect of these illusions.

t may be of value to be awareof other changes in experiencedor accustomed visual cues whichmay result in poor height anddistance judgments or give falsecues for landing. For example

landing over water reduces vi-sual cues to a minimum. Pilotsnot accustomed to landing overwater tend to land too low orshort of the runway. Externalobjects on the approach pathmay serve as false cues toheight. f a pilot were accustomed to landing with an ap-proach over large evergreen or



23/68

Figure 7. The effect of terrain upslope on glide slope of an aircraft When there is an upslopein the runway approach zone the aircraft appears to be above the normal glide path. ocompensate the pilot would try to fly a glide slope which can result in a long landing

spruce trees and were requiredto land in the Aleutian Chain, hemight misjudge his height anddistance from the runway because the spruce trees in theAleutians are small and scrubby.One of the best means ofeliminating or reducing aircraftaccidents from these types ofvisual illusory cues is throughcareful briefing of the aircraftcrew prior to the flight. A pilotshould be cognizant that distance and height judgments canbe affected by changes in experienced visual cues and shouldsimulate a landing before makingthe actual landing. The combination of good air crew briefingand discipline is required to result in safe approach and landingprocedures over all types of terrain and landing field configurations.

SummaryStandardized runway andapproach lighting and instrumentlanding systems aid the pilot inthis apparent height and distancejudgment by providing nearlyidentical visual cues for eachMAY 97

landing. Thorough briefing before flying into a strange or unfamiliar airfield is necessary.Under certain conditions imposed by weather, repair, etc., apilot should drag fly over) thelanding strip at least once beforelanding to provide himself andthe rest of the air crew a familiarity with the approach andrunway. A portable self-poweredapproach lighting system wouldbe desirable at remote airfieldsto aid in maintaining the properglide slope.A pilot must trust his instruments and cross-check thosewhich give him information onaircraft attitude. It is seldomthat all instruments fail at thesame time, and pilots should betrained to rely on their instruments although their informationmay be opposite the seat-ofthe-pants orientation cues.Therefore, instrument performance should continue to be anintegral part of each annualcheckride.

t is recommended that investigation teams for aircraft acci-

dents compile data relative torunway conditions, i.e., width,length, lighting and surroundingterrain. These terrain and humanfactors would probably revealthe factors responsible for certain types of accidents. Corrective measures could be taken byeach major air command commensurate with their accidentexperience.At the time the article was written LTC Pitts was assigned tothe U S. Air Force School ofAerospace Medicine Brooks AirForce Base Tex. as the Assistant Chief of the Physical-Physiological Optics FunctionOphthalmology Branch. He wascommissioned in 1950 and servedas a clinical optometrist until1957. He was the first Air Forceoptometrist to receive the Ph.D.degree in Physiological Optics.His assignments since 1957 havebeen in research and teaching atWright-Patterson Air ForceBase Ohio and the U S. Air

, ~ r c e School of e r o s pcine. _2


24/68

Beyond The BestCaptain Edward A Bickel

I was a pilot not a body to be delegatedthe dubious honor of sitting shotgun

ELL SIR, YOU'VE been around a longtime and I 'm sure you'll agree life as a copilot is death. Really could you imagine a more

boring existence? After all I was a pilot, trainedand proficient, not an extra arm of the man flyingthe machine and certainly not a body to be delegated the dubious honor of "sitting shotgun."

to smile, to keep a good wit, but I began

to loathe the word copilot. I felt as though all mytraining was for naught. I was a natural a realace of the skies. f it had wings and an engine Icould make 'er perform. What coordination Anda control touch that was smoother than silk.When I flew there wasn't any need for an "extra"to handle my radio calls, to monitor my engineinstruments or keep his eyes peeled for "the oth-



25/68

ers. My tuned ear could analyze any problemthe minute an engine coughed and, if worse didcome to worse, I'd just have to exercise my expertise on short field work to make an uncanny,but miraculous, forced landing. So what if I ha9only logged 260 flight hours. Half of that time wasspent polishing my already fantastic techniques.Why I can even remember my first flight instructor throwing up his hands and saying, You'rereally something, Ace. That man was a coolhead. He recognized my inherent abilities, but Imust admit he was pretty good himself. I supposehe already placed me in the same class with Ricken backer and Von Richthofen, the Red Baron.

But time dragged on , sir. Day after day I assumed the right seat. One flight was all I neededwith a man to tell whether he could really hackit. Inside of 2 weeks I'd flown with 1 of 'emand had 'em all pegged. Most of them flew onlyonce with me, but I could tell by the way they allavoided me after hours that each and everyonehad placed me on a plateau Above The Best.When one of the other boys did come around itwas for consultation. The look of awe on theirfaces belied the great admiration they had for me.

And it seemed that I was forever answering questions such as How did you ever manage?

Would you run that by us once more butslowly? Tell us again about the timeEveryone laughed with me whenever I relatedhumorous exploits about how I handled seeminglyoverwhelming situations.

And then finally today my chance came. Onlymonth incountry and they were ready to let medemonstrate how a real pro could handle it. twas just a short mission and the company standardization instructor pilot was y copilot. Although we hadn't had the opportunity to knockaround the skies together before, I 'm sure everyone had told him about the days when they werefortunate enough to have me along . This morningmy U-6 literally bounded into the blue. She responded beautifully to every control movement ah, si r- i t was as if she knew who was mastertoday, but then-eh, wel l - don't let me bore youwith the rest. t was an accident-just one ofthose things that happens to the best of us. Sirsir, now I do have one question, When do Iget to dazzle the others with my skill in handlingreal feathers? St. Peter, St. Peter, sir. . . . . . .

\..\ 1//C :J5=- \

MAY 1971 23


26/68

Removing Engine Fuel Pump OnU-6A: When removing the engine-driven fuel pump from theR-985 engine, be sure to placethe fuel selector valve in theOFF position. Make a sign ortag and place it on the valvestat ing, Fue l l ine disconnected. (Reference: TM 55-1510-203-20, chapter 5, paragraph 5-204, page 5-36)Beaver Caburetor Air Filter: Besure to stay abreast of all technical manuals. Washing the airfilter of the -6A and immersingit in a lubricating oil mixture after drying is no longer the approved method of cleaning. TM\S

aln enance

SO LOOK ORTIPS E CH MONTHON THESE P GES

55-1510-203-20 12 Aug 70), paragraph 5-28, CLEANING statesthat the only method authorizedis tapping the filter. Place thedirty face of the filter down andtap until all the dirt and dust isremoved.Save The Cannon Plugs): Whenremoving larger electrical cannon plugs that have a habit ofsticking and the proper tool isnot available, use a small strapwrench. This will do the jobeffectively and will not damagethe cannon plug.FOD: When working on an aircraft equipped with a gas turbineengine, always use a bucket orsome other means to collect allcut safety wire to prevent FOD.Turbine Engine MaintenanceMalpractice: Turbine engine repair and replacement has beenone item that has almost putmodern aviation out of business.

The cost of turbine engine repaiand replacement operations inVietnam has become a matter ograve concern by the Department of Defense. f we continueto opreate without a decrease incost for turbine engines, it wilbe extremely difficult to predicour future and the future oArm y aviation.

TM 55-1520-220-35, chapter 5section II, paragraph 5-11 whichpertains to turbine engines)states: Caution: do not usecadmium plated tools for anyprocedures outlined in this section. Cadmium plating will chipf any of these chips enter theengine they will contaminate thelubrication system and cause

deterioration to magnesium engine parts. This is good informat ion f o r ma in tenancepersonnel assigned to the engineshop. Prevent them from usingimproper tools. What it fails todo is let the crew chief or mechanic assigned to a PE teamunderstand how easy it is tocontaminate the oil system of aturbine engine, transmission andgear box in other ways .Electro cadmium plating isone of the most inexpensiveplatings used by industry today.Many items normally transported in a mechanic's tool box,on a key chain or in his pocketwiIJ be cadmium plated. Whenthe mechanic uses his handy



27/68

beer can opener (which he carries day and night) or a platedscrewdriver to open a can of oil,he doesn t realize that he hascontaminated the new oil he isusing to service the aircraft.Cadmium plating chips or acadmium plated surface thatcomes in contact with the synthetic base turbine oil presentlyutilized is dissolved by a chemical action contaminating the oil.The present spectrometic oilanalysis system utilized by theArmy tests for seven differenttypes of metal wear contaminat ion; but , cadmium platingdoesn t happen to be amongthese. It s up to you to keepcadmium plated items and oilaway from each other. Remember, i you are a honcho, it isimperative that all of us checkour maintenance p e r s o I n ~ toensure that they have been properly educated on this subject andutilize the proper tools especiallywhen servicing oil system reserviors.

Food for thought: Would youfly a mission tomorrow if youthought there was any chance ofoil contamination?Overgreasing? When lubricatingthe UH-t tail rotor crossheadbearing, it should be noted thatoverlubrication will cause contamination of the 90-degree. gearbox. Hand pack when grease fit-MAY 97

ersting is not installed. When usinggrease fitting limit lubrication totwo shots from hand grease gun.Lubrication should be accomplished in accordance with chapter 2 of the appropriate dash 20.Check Those Pins: Double-checkto make sure hose quick disconnect indicator pins are fully extended after reconnecting hoses.Do It Up Right: Installation oflockwire- the following rulesapply when using lockwire toprevent the loosening of boltsarid general hardware used onaircraft: Use carbon steel wire, zinccoated Federal specification -W-461 for all normal lockwireoperations. Use steel corrosion resistingwire Federal specification -W -423 Condition A for specificapplication where heat resistingproperties are desired, except ininstances where instrumentationis adjacent then use W -423Condition A nonmagnetic type(any 300 series specified). Install lockwire so thatwhen wired bolts, screws orthreaded items begin to loosenthe wire will apply a restrainingforce in the tightening direction.Remember, do not overstressthe wire. .

Apply the recommendedtorque to parts to be securedand align holes before attempt-

ing to proceed with the installation of lockwire. New lockwire will be usedfor each application. Removal oflockwire for any reason willnecessitate its replacement. A void causing kinks orsharp bends in lockwire. The length of the pigtail atthe twisted end should be f4 to1 2 inch or 3 to 6 turns.Note: When safetying ventedplugs, caution should be used toensure that the safety wire is ofsuch a diameter that it will notcompletely block the vent hole.

Safetying Emergency D e v i c ~ s :Use 0.020 inch diameter copp erwire Federal specification -W-343 for security of itemswhere easy accessibility must bemaintained by breaking the wire. When emergency devicessuch as canopies, exits and thelike require securing with lockwire, use 0.020 inch diametercopper wire. A 0.020 inch diameter copper wire is also used to securenonstructural parts such asemergency valves, oxygen regulators and the like. Secure first-aid kits, portable fire extinguishers and itemsrequiring lockwire with 0.020inch diameter copper wire. Sealwith a lead seal. This aids thedetermination of use and ensurescompleteness of contents.


28/68

6

~ e e 6 e J -

AeJe1J/qJ t/J --------The artillery committee of the U S. Army Aviation School at Fort Rucker Alabama providesthe following commentary on the infrequent andsometimes nonexistent use of artillery assets byArmy aviators in the Republic of Vietnam. Ourthanks to Captains Robert B. Armstrong JamesV Cronkhite David L Greer Clyde HamiltonPaul H Eaves and Alfred G Snelgrove

E ACH OF THE four militaryregions in the Republic ofVietnam presents unique problems to the Army aviator. Theyhave been, however sharing onerather perplexing situationthat being the infrequent, almostnonexistent use of available ar-tillery fire support.

Far too often the aviator ha sthought only in terms of gunships when reque sting fire support. The fact that artillery canbe employed faster with equalaccuracy, hasn t deterred theaverage aviator from relyingalmost exclusively on aerial support. Unfortunately, the principal reason for this infrequentuse of artillery ha s been a lack

of confidence in his ability torequest fire.

The following stories, eachfrom a different Vietnam mil-itary region, illustrate some ofthe problems avia tors havefaced. Some are psychological,some contrast with situations inother areas; nevertheless, theyall are serious.

ilitary Region IThis area (formerly I Corps)

has been saturated with a wideassortment of artillery units.Control in the northern sectorwas delegated primarily to U. S.Army units; around Da Nang theU. S. Marine Corps becomesresponsible; Korean and ArmyRepublic of Vietnam units con-



29/68

FireMissionO'Ver

trol areas south of Da Nang; andonly a few miles further southU. S. Army units again exercised primary control.

In the north most targets observed by aviators have beenneutralized by either aerialrocket artillery or gunships. Butsuch targets as troops in theopen heavily fortified bunkerssampans and truck convoys generally were neutralized moreeffectively with artillery fire thanwith armed helicopters. Aircraftcan deliver only the type ordnance on board. Artillery batteries have numerous shell andfuze combinations allowing thecommander to select the mostappropriate for a specific target.MAY 97

Too often 2.75-inch rockets havebeen unsuccessful used againstbunkers that could easily havebeen destroyed with less ammunItIOn if artillery rounds withdelay action fuzes had beenused.

In the central region aroundDa Nang the general rule forengaging enemy personnel onthe ground has been to use tactical air support or helicopter gunships. Artillery fire is used onlyif these are not available.

There were numerous delaysencountered when artillery wasused. For example it took twoor three times as long to get abasic clearance for artillery firethan one for air support even

when the target was a bunkercomplex with no personnel in-volved. Also limitations wereimposed upon artillery whenfriendly troops were nearby. Inthis region artillery clearancesalso were difficult to obtain because of the uneven distributionof various sectors .

Estimates from the field indi-cate the average aviator requiredabout a week to familiarize himself with these various sectorsand then feel comfortable callingand adjusting artillery fire.Unfortunately artillery hasbeen primarily used againstsmall point-type immobile targets or in precision fire missionroles in region I

27


30/68

Military RegionExtensive use of artillery byaerial observers has been com

mon in military region II (IICorps). The majority of theseobservers were either Englishspeaking South Vietnamese , U.S. forward air controllers (FAC)or the aviators themselves. Asone might expect , the ARVNobservers preferred calling theirown ar t i l le ry . However , itwasn't always available.

An AR VN observer was adefinite asset because he couldcommunicate directly to theSouth Vietnamese , thus avoidingnumerous communications problems. This observer could obtainclearances from his unit whilethe U. S. aviator could do likewise with his.Generally, artil lery supportwas limited to "live" targets dueto shortages of ammunition. Inthe absence of shortages theobserver could request fire onbunkers on suspected enemypositions. Often he would utilizethis support to recon by fire.28

Upon arrival incountry thenew aviator can expect a minimum of five or six missions before he becomes proficient inrequesting fire support. A wordof caution: be alert to the artillery fire of allied units. You'llfind that it often isn't reported tothe clearance authority. Thus itis extremely important to monitor the artillery frequency , aninsurance step that should keepyou out of artillery fire sectors.

Military RegionOn 21 November 1969 at approximately 2000 hours two

aviators were returning from aroutine mission. The aircraftcommander (AC) was experienced with 1 months incountry,while the copilot was a recentarrival having been in Vietnamonly 2 weeks. Approaching theheliport the AC requested landing instructions.

The tower operator advisedhim not to land because the airfield was receiving mor tarrounds. The AC immediatelystarted a 180 degree left turn.Just as the ship was completingthe turn the copilot announcedon the intercom, I see the mortar tube flashes " The AC initiated a circling climb while thecopilot kept the flashes in sight.Then he called operations , requesting an AH-IG HueyCobragunship to silence the mortar.

Thirty minutes later the Cobraarrived, but it was too late tosilence the mortar crew whichhad vanished into the darkness.The point is not why the gunshipwas late, but why was it requested when heavy artillerywas readily available and couldprobably have silenced the mortar within a few minutes? Itcould easily have been that theAC , like the average aviator,lacked confidence in his abilityto request and adjust artilJeryfire. All aviators should have atleast a basic know ledge of artil-

lery procedures , including whenit could best be used to neutralize targets. Had the AC used hibasic understanding of artilleryhe undoubtedly could have neutralized the target.

Other problems existed in region III , congestion being aprincipal one, with Saigon representing the major populationcenter of Vietnam. In additionthis area was divided into numerous sectors of allied responsibility , making it difficult todiscuss artillery utilization patterns . However , if one examinesthe 1st Cavalry Division Airmobile) concept of artillery andaviation support he can get anidea of the difficulties encountered in each area.The ai rmobi le concept isbased in part on the ability toprovide immediate fire supportto maneuver elements. Therefore, with an artillery battalionin direct support of each maneu-


31/68

ver brigade, plus other assetsprovided by the corps artillerycommander, fire support usuallywas readily available.

Usually, the maneuver battalion commander would overseeeven the smallest airmobile operation when his elements wereinvolved. His staff included anartillery liaison officer who generally controlled supporting firesunder direction of the groundcommander. Thus, the aviatorrarely became directly involved.

However, in the aviation section of each maneuver brigade adifferent situation existed. Normally these units operated adaily minimum of one reconnaissance team, i.e. two lightobservation helicopters. Theteams checked intelligence reports and bomb damage assessments. The avia tors in thissection became very adept . atusing artillery firepower to engage targets of opportunity.Despite the deviations fromstandard artillery procedures,the overall results were impressive.

In Vietnam the 1/9th CavalrySquadron was generally responsible for providing visual reconnaissance in the division area ofoperations. Generally, a lightobservation helicopter and anAH-1G escort gunship composedeach recon team. Often operating outside artillery coveragerange, these teams usually employed organic weapons to engage targets. Consequently,when they operated within artil-MAY 97

lery support range the reconteams, accustomed to previoustactics, generally overlooked artillery fire capability in favor oforganic weapons.

The aviators in the division saerial rocket artillery battalionemployed conventional artilleryin lieu of expending onboardordnance, depending on the target. The obvious advantage wasthe preservation of the onboardordnance until it was absolutelyessential to use it.

Generally speaking, if artillerywas employed as indicatedabove the result was quite satisfactory. The aviation school sbasic instruction in artillery procedures is sufficient but it is upto each individual aviator tobecome proficient and confidentonce he arrives incountry.

ilitary Region VIn military region IV (formerly

IV Corps) ARVN forces lackedorganic artillery, a fact whichprobably helped account for theinfrequent calls for fire. Also,permanent fire support baseswere not used because of rangelimitations and the large area ofoperations. Consequently, gunswere moved with respect to theground commander s priorities,assuming he also dictated eachfire base location (ARVN forcesoften moved from site to siteeven when operating in the samearea).

Even when artillery was available it wasn t used as much as itshould have been. Usually,communications posed the majorobstacle. f an aviator made anattempt to communicate withoutgetting the desired results, hewould likely avoid contactingARVN troops on subsequentmissions. And, obtaining clearances through ARVN channelswas extremely time consuming ifintelligence channels report negative activity.

In many cases the ammunition

supply itself limited the numberof fire missions. Aviation support directly affected artillerysupport. For example, CH-47Chinooks can haul only so muchcargo, and if the mission calledfor artillery relocation the menof that battery may not be resupplied until the next relocationmove.

Delta region airmobile operations normally involved two tofour gunships. When artillerysupport was unavailable, theirmission was to recon the landingzone, escort the lift ships andremain onstation to provide direct fire support for the groundforces. After the insertion thegunships either could reconahead of the maneuver elementsor deploy as a blocking force.What happened when thesetroops got into a fire fightwho provided supporting fires?Gunships had l i t t le effectagainst well prepared positions.f the enemy had several automatic weapons positions withlarge fields of fire the air mis

sion commander (AMC) stood agood chance of losing some gunship support. Once the gunshipsbegan delivering ordnance onto aspecific target, the AMC alsohad to face a rearming problem.

Situations like this became therule rather than the exception. Itwas also apparent that a pilot, if


32/68

unable to call gunships to neutralize a target, would generallygive that target up as a lostcause. Pilots justified this actionby stating they didn t have theproficiency to accurately placefires onto a t rg t so theyavoided artillery support altogether. However they enthu-

siastically adjusted AH-l GHueyCobras or pinpointed a target location to a FAC. I f thesepilots had expended the sameeffort calling artillery fire theycould have received more fire-power over a greater period oftime. In a life or death situationit makes a difference.

INSTRUMENT ORNERLEAD TIME required for submission of articles for print inthe VI TION DIGEST coupled .with the rapid changes occurring in Army aviation, may cause some information toincomplete or erroneous by the time i t reaches the reader Asan example, the Instrument Corner in the March issue statedthat a report is required when an estimate previously submit-ted is in error in excess of 3 minutes even under radar con-tact. This is no longer true with the publication of DOD FLIP,section II, effective 4 Feb 71. In an effort to keep the readeras informed and current as possible, future answers to ques-tions in the Instrument Corner will contain the effective dateof the referenced publication. So please bear with us.Q. Having been radar vectored to the final approach andcleared for the approach, to what altitude may descent bemade?A. AIM's Part 1, page 1-59, paragraph 1a(1) states: Whenestablished inbound on the final approach course, radar separation will be maintained and the pilot will be expected tocomplete the ppro ch utilizing the ppro ch id design tedin the cle r nce (lLS, VOR radio beacons, etc.) as the primary means of navigation . . . After passing the final approach fix (outer marker, radio range, etc.) on final approach,aircraft are expected to proceed direct to the airport andcomplete the approach. . . . U. S. Standard for TERPS,chapter 10, Radar Procedures, paragraph 1013, FeederRoutes and Initial Approach Segments states: Navigationalguidance may be provided by ASR, other navigational facilities or a combination thereof When other navigationalfacilities are used .. the criteria specified in chapter 2, sections 2 and 3 shall apply as appropriate. The terminal ATCManual 7110.88, paragraph 1360c states: If terrain or trafficdoes not permit unrestricted descent to lowest published alti-tude specified in approach procedure prior to final approachdescent, controllers shall Then it goes on to tell whatthe controllers' actions are. Therefore, when cleared for theapproach and in the absence of any restrictions issued by thecontroller you may descend to the lowest altitude specified inthe procedure [low station altitude at FAF (final approach fix)]prior to final descent. The criteria for the altitudes, lateralseparation, etc., are found in TERPS. Compliance by the aviator is simply a matter of flying the altitudes as published onthe appropriate approach chart (AIM dated February 1971).

30 U. S. ARMY AVIATION DIGEST


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CROSSWORD PUZZLEACROSS 2 3 4 5 6 7 8 9 1

I Horizontal cyclone7 Consolidate 12 1412 Move through air13 Enthusiastic reformer15 Type of bread 1516 Solemn pledge17 Fall behind18 Not none19 Arabian leaders2I Faucet23 Functions24 Technical inspection: abbr25 Entertaining 2428 Municipal investment: 2 wds.30 Post office: abbr3I Compass direction 2832 Symbol for volts33 Strong winds35 Barometric depression39 Old horse40 Scrambled transmissions45 Type of approach46 Top grade47 Foot extremity49 Group Fire Distribution 40Center: artillery abbr50 Aircraft that has touched

down has 4S53 Flight surgeon: abbr54 Climbed 49

Answers on inside back coverDOWN

I AVIATION DIGEST letters II Units of energy 36 Power switch: 2 wdscolumn 14 Universal time: abbr 37 Air defense artillery: abbr2 International amateur games 18 Stone charm 38 College degree: abbr3 A whiskey 20 Earthly 4I Unit mail clerk: abbr4 Temperature: abbr 2I Losing l ift 42 Ailments5 Frugality 22 The ego 43 Air route6 Produces rays 26 Therefore 44 High explosive: abbr7 Escorting 27 Emergency signal 48 Musical poem8 Not applicable: abbr 29 Towards the center 5I Aircraft commander: abbr9 Engine running slowly 30 Secures a tent 52 Department of the Navy:10 Rips 34 Endured abbrMAY 1971 31


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O n 19 MARCH 1969 I wasflying as a UH-l H aircraftcommander on a 196th InfantryBrigade resupply mission in theRepublic of Vietnam. Most ofthe morning had been spenthauling wounded infantrymen tothe rear following a heavy nightaction in the Thien Phouc Valley. Now, however, the missionwas to resupply D Company.I had been into the DCompany area just recently andhad not received any fire goingin and only a little small armscoming out. Suddenly hostile fireappeared to be coming from allsides of ' the unit and we had tomake a very tight , high overheadapproach. As the aircraft descended it received minor smallarms fire but no hits.

After offioading and pickingup three ground troops (two ofwhich were minor casualties) ,we took off on a heading of 220degrees as had been recommended by the ground troops.After gaining some air speed webroke to the right. (The battaliollS-3 air had told me that a NorthVietnamese Army regiment was

in the area, and to break leftwould have put me nearer theirlocation.)

Just after I broke right the aircraft began receiving intenseautomatic weapons and .50 caliber fire , taking numerous hits.With each hit the aircraft shuddered violently and seemed tojump about 1 feet. noted theinstruments were vibrating, buteverything appeared to be holding together. Then either mycrew chief or gunner cried out,"We are on fire Get it on theground "

immediately started an autorotative pescent, and turned theselector switch to companyUHF to get o lt a Mayday call,"This is 16, am on fire andgoing down."

Someone answered saying," 16 , where are you1"I replied , "About five klickssouthwest of Thien Phouc."remembered something in thedash 10 about reducing air speedwhen on fire, so held about 60knots going down. had to pu]]a little pitch at the bottom toclear a small hedgerow and then

On Fire AndoingOownCaptain William D Bristow Jr

32

landed the aircraft.While on short final the flames

had reached me, and by the timewas on the ground the cockpit

was engulfed in flames. knewhad to shut it down but couldn'teven see the main fuel or batteryswitches, so decided to leave italone and exit the aircraft. Un

k l i n the seat belt and shoulde t harness , looked to myl e f t -my armor side plate wasstill forward and the door wasstill Closed. The fire to my leftwas the worst, so dove overthe pilot's seat and out his opendoor.

The crew and passengers wereall in a hedgerow just a few feetfrom the aircraft so told themto get away before the aircraftexploded. We crossed the hedgerow and an adjoining rice paddyand took cover in the next hedgrow. The aircraft then explodedin a ball of fire and smoke as theflames reached the fuel cells.A quick check of the weaponsrevealed an M-16 and two .38pistols with about 30 rounds foreach weapon. told everybodyto stay down and keep quiet


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since the enemy was between usand the friendlies. Our bestchance for survival was to re-main undetected.I then checked for casualties.One of the ground troops hadhurt his back pretty badly andwould not be able to move. Ibriefed the gunner that when therescue aircraft came we wouldhave to carry the wounded menout. After approximately 10

minutes the first aircraft arrivedoverhead. There was no diffi-culty in locating the aircraft asblack smoke was billowing up inthe sky. Our problem was to lethim know where we were without also informing the enemy.

We did not have a survivalradio because of the criticalshortage of them in the unit.Only a few aircraft had the ra-dios on board. Not only couldwe have more readily effectedour rescue with a radio but alsowe could have directed the gunship strike.I cut my white T-shirt out

from under my Nomex jacketand chicken plate and then hungit on a small shrub. Actually theT-shirt was so small and discolored due to sweat and dirt thatit was impossible to see from theair

My gunner had crossed therice paddy and was waving hisrifle at passing aircraft but I hadto tell him to get down since hehad no cover whatsoever. Mortar rounds started coming innear our location at this time. Itwas later discovered that t h ~ swere probably short rounds thatwere meant for D Company.


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nFire nd Going own aircraft circling overhead andthe Charlies were certain that wehad all perished in the explosionand fire. We could also haveused, however a survival radioand red flares.

Charlie probably didn t know wewere alive.

By this time the aircraft orbitswere getting larger and manyaircraft were onstation in areasfar away from us. I felt aroundon my chicken plate to see whatI had to speed up rescue. I wasparticularly looking for penflares, but there were none. Ithen found the strobe light, butcould not unsnap the carryingcase. We had to cut it out of thecase. I gave the strobe light tothe pilot, who laid on his backand tried to catch the attentionof one of the aircraft.

I t was starting to get dark andchances of rescue were gettingslim. Each time an aircraft triedto make a low level pass overthe burning aircraft it receivedintense small arms and .50 caliber fire. The gunships had determined the .50 caliber positionand had set up a daisy chain,attacking the enemy with miniguns and 2.75-inch rockets. Thethird ship in the chain was themaintenance aircraft equippedwith a free gun M-60 on eachside in addition to the door guns.

I began to plan for spendingthe night. I knew we would notbe able to move due to the manwith the back injury. Also, theenemy was all around us (wecould see them to our front andhear them tramping through thebush to our rear and ourchances for rescue were far better near the aircraft.

Suddenly the hedgerow wasstrafed by tracers. The roundswere coming in from above andto our rear, so we couldn t tell ifit was an aircraft or the enemyfiring from higher ground. Wecouldn t move but everyone didget a little closer to the ground.Finally, one of the gunshipsflashed his landing light to indi-34

cate that he had seen our strobelight.Now the problem was how to

get an aircraft in and out safely.The gunships began a strikeabout 100 meters to our north-they were going to make theirattempt.

On the hill the Muskets wereattacking I saw three North Vietnamese soldiers dressed ingreen uniforms with a long largeweapon. It looked like either a.50 caliber or a recoilless rifle .Each time one of the gunshipswould make a run the enemywould duck out of sight, likeinto a bunker or foxhole and asthe gunship broke off they wouldbe back up aiming their weapon.

At approximately 1900 hours,after a long 1 hour and 1 minutes on the ground a Minuteman aircraft appeared out ofnowhere. I had not heard orseen him coming down, and itwas not until he was on 1 footfinal that I realized what washappening. Both his door gunners were putting out maximumsuppressive fire but we couldnot hear it due to the mortar andthe gunship strikes. The gunnerand I carried the man with theback injury, and we all jumpedon board and prayed.Fortunately, we got out ofthere with no problems. To saythat all of us are thankful to theMinuteman crew is quite anunderstatement. The professionalism and calm they displayedwere tremendous. Enroute to thehospital, the crew chief on therescue aircraft applied first aidto the burns on my crew chief sarms and head and also to theground troop who had beenburned.

We owe our lives to the strobelight, without it we would havebeen given up for dead. Both the

My Nomex flight suit savedme from severe injuries in thefire. I wore no gloves becausenone were available and wasvery lucky just to be singed onthe backs of my hands. My visorwas down which saved my facefrom possible burns.I learned that in a situationsuch as ours the only thing thatcomes out of the aircraft is whatyou have on. Weapons emergency kits etc. went up withthe aircraft.

The Department of Aeromedical Education and Training, U.S Army Aviation School at Ft.Rucker, Ala., reviewed this ar-ticle and provided the following comments:On l y those i t ems ofsurvival, signaling and personal protection which are attached to the body are goingto be conveniently available tothe air crew member underemergency condit ions of allcontingencies. Following emergency landings there is a needfor rapid egress from the air-craft because of the potentialof a postcrash fire or enemyactivity. This creates a needfor an integrated survival sys-tem. Provisions have beenmade for an item of this type:vest, survival, SRU-21/P, hotclimate FSN 8465-177-4819).The basis for issue is one survival vest per each air crewmember in the Republic ofVietnam only. This vest incorporates many items of survival,emergency signaling and per-sonal protect ive equipment.The purpose and contents ofthis piece of equipment arefound in TM 55-8465-215-10.



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O N MY FIRST TOUR in theRepublic of Vietnam, Iserved with the 240th AssaultHelicopter Company at BearCat. This is where I first encountered a very remarkablebreed of soldier: the crewchief. The 240th supportedground units all over III Corpsfrom Song Be to Binh Phoucand during May 1970 movedtroops into Cambodia. With the240th averaging 3,000 hours amonth, each crew chief had toperform an in termediateinspection every third day.

Up each morning by 0500hours flying all day and thenworking until midnight gettingthe aircraft ready for the nextday the crew chief had hishands full. Plus whenever theflight shut down during theday the crew chief seized theopportunity to clean his helicopter. Daylight is valuabletime to any crew chief andevery minute was used to thefullest extent.

Performing maintenance wasnot the crew chief s only re-sponsibility. In the air he keptthe pilot informed of other aircraft in the vicinity, clearedthe tail rotor when entering orleaving a l n d i ~ g zone lZ),manned a door gun helped inloading and unloading, etc.On a resupply mission forthe 199th Infantry Division Ihad to rely completely on mycrew chief to clear the aircraft.0 Company had broken contact with the enemy at 0430hours and needed suppliesand medevac in order to con-

tinue pursuit. No equipmentwas available to prepare an lZjthe most they could do was toprovide smoke so we couldwork our way down.

e came to a high hoverover the 200-foot jungle andbegan the descent. I lost intercom with my door gunner inMAY 97

the first 50 feet, and then itwas completely up to my crewchief to get us in and out.Verbally he would give directions to guide the aircraft in.At times there was less than afoot between the trees and thetail rotor. One wrong move andall of us would spin 200 feet toour death. As the aircrafttouched down all gave a sighof relief.Then I looked up and sawthe small hole in the junglewhich we had jus t come

through and I couldn t believeit. But we made it in and, witha little more work made i t out.Our day did not end until wereturned three more times.The mission was finally finished after 9 hours of continous flying. Then as soon as wereached Bear Cat the crewchief started performing hisdaily inspection; the aircrafthad to be ready for the nextday. Maybe there would be aneasier mission, maybeit had to be ready.

HIEF

ASPECIALSOL IER


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Etiology. ofa

idair ollision

CW Jose A SuarezData enterUS B R


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ETIOLOGYA science or doctrine o causation or o the demonstrationo causes a branch o science dealing with th causeso particular phenomena all th factors that contributeto th occurrence o a disease or abnormal condition

T HE DAY HAD been long and tiring. Theflight leader called the tower on the way homeand requested permission for a flyby. Alwaysgood for mora'e, he thought. The five slickslocked in right echelon. Before reaching the endof the runway, Chuck 4 collided with Chuck 3.The results included four fatalities and two postcrash fires.

Members of the aircraft accident investigationboard agreed the major cause of this accident waspilot error because the pilot of Chuck 4 misjudgedhis distance when it was his responsibility aswingman to maintain adequate separation fromChuck 3 Considerable investigation and deliberation by the flight surgeon revealed several factorsthat played an etiological part in contributing topilot error.

One of the major factors was an attitude ofoverconfidence, with subsequent carelessness onthe part of the pilot of Chuck 4. He was one ofthe most experienced aviators in the unit, withmore than 1,500 hours in helicopters and 1,336hours during his current I1-month tour. He hadbeen averaging more than 120 hours monthly andhad no previous accidents. After considerablediscussion with him and his fellow aviators, itbecame obvious he considered himself an exceptionally capable aviator and undoubtedly tookgreat pride in his flying record and prowess. Hisplatoon leaders and others had noted he wasrather resistant to suggestions regarding his flyingtechniques and habits. He had been admonishedon several occasions that he was flying too close .during formation flights. On the day of the accident, he had been told twice, once earlier in theday and again just prior to the accident, that hewas flying unusually close. t would seem his overconfident attitude allowed him to become , unusually careless about keeping his proper distancebetween helicopters.Faulty attention was another factor which

played an important role in this accident. t wasmanifested by a low level of

Army Aviation Digest - May 1971

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Transcript of Army Aviation Digest - May 1971