Army Aviation Digest - Jan 1972

8/12/2019 Army Aviation Digest - Jan 1972

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UNITED

DIRECTOR OF ARMY AVIATION ACSFORDEPARTMENT OF THE ARMY

BG Wil l iam J . Maddox Jr .

COMMANDANT U . S. ARMY AVIATION SCHOOLMG Allen M . Burdett Jr .ASST COMDT, U . S. ARMY AVIATION SCHOOL

COL Hubert S. Campbel l Jr .DIGEST STAFF

Richard K. Tierney, EditorCPT Tom GreeneCW2 Mike lopezWil l iam H . Smithl inda McGowanBetty S WallaceJudith A . ClassenDianne Horne

GRAPHIC ARTS SUPPORTHarry A . PickelDorothy L. CrowleyAngela A . Akin

COMMANDING OFFICER U . S ARMY AGENCYFOR AVIATION SAFETY

COL Eugene B. ConradUSAAAVS PUBLICATIONS AND GRAPHICS

Pierce l . Wiggin ChiefWill iam E. CarterJack DeloneyTed KontosCharles MahiusPatsy R ThompsonArnold R. lambertEugenia M . BertaOwen B. England Jr .Mary W . Windham

ABOUT THE COVERA flare from an Army aircraftflushes out a tank during daynight maneuvers of air combatcavalry br igade tests at Ft.Hood, TX. A related story onhelicopter employment in conventional warfare appears onpage 6 . Photograph by CPT

Tom Greene

RMY VI TION

1GESJJANUARY 1972Views From ReadersNot By Reputation

VOLUME 18 NUMBE

The Role Of Helicopters In Conventional WarfareCharlie And Danny's Write-InProximity Warning Devices Versus Midair CollisionsAeromedic-Flying FatigueWhy USAASO Sez?Maintenance MattersComputer Assisted MaintenanceInstrument CornerThe Crew ChiefThril l Addicts And YouHelicopter Terrain CollisionsGestalt, Awareness, And The ASISlicks And ThingsIMC-Fr iend Or Foe?Aviation Accident Prevention ForumThe Crack In Our MirrorUSAASO SezUnit Rotary Wing Instrument Training Inside B

The mission of the U. S. ARMY AVIATION DIGEST is to provide informat ion of on operational or funct ional nature cocerning safety and aircraft accident prevention, training, maintenance, operations, research and development . aviat imedicine and other related data .

The DIGEST is on official Deportment of the Army periodical published monthly under the supervision of the CommandanU. S. Army Av iation School. Views expressed herein are not necessarily those of Deportment of the Army or the U. S. ArmAviation School. Photos are U. S . Army unless otherwise specified . Material may be reprinted provided credit is given to tDIGEST ond to the author unless otherwise indicoted .

Articles photos and items of interest on Army aviation are invited. Direct communication is authorized to : Editor U.Army Av iation Digest Fort Rucker Ala . 36360 .Use of funds for printing this publication has been approved by Headquarters Deportment of the Army 1 c t o ~ 197Act ive Army units receive distribution under the pinpoint distribution system as outlined in AR 310 1. COlmrJIt.lII_

124 and send directly to CO AG Publications Center 2800 Eastern Boulevard Baltimore Md . 21220 .distribution requirements initiate a revised DA FOr m 124 .

No t ion a l Guard and Army Reserve units under pinpoint distribution also should submit DA Form 12 4 . Other NotionGuard units should submit requests through their state adjutants general.For those not eligible for official distribution or who desire persona l copies of the DIGEST paid subscriptions, 4 .domestic and 5 .50 overseas, are available from the Superintendent of Documents U. S . Government Printing Office Wasington, D. C. 20402 .


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VFR

JEWSROME DERS

Getting out soon? Consider Reserveomponent aviation. Write the DIGESTfor a list of units in your state

tir:As you remember, I pve the DIGESTat my RVN neaatives while I

at Rucker '69 to '70 because I knowaviators use instama tic slidesof us specialize in black3S mm.You have used several of my shots

31 and 33 of the November 1971I'm just as proud of those two

DeCW4 Don JoyceNewport News, VA. 236 1

The DIGEST would Uke to apoloalze fornot credltlna CW4 Joyce for the photos onpaae. 31 and 33 of the November I ue.The DIGEST I. Intere.ted In obtalnlnl loodphotoaraph. deplctlnll Army aviation andInvite. reader. to lend copies of their pho-tos or nellatlves to:EditorU. S. ARMY AVIATION DIGESTP. O. Box JUSAAVNS

Ft. Rucker, AL 36360Pleale be sure to write the photographer'sname and address on the back of the pho-tOlraphs so that proper credit may bealven when published.

Photolraphl by CW Don Joyce

The DIOEST thanks CW2 Peter J Smith,aviation safety officer 165th AviationGroup Combat) for the following:The skies over the Republic of Viet-nam are no longer darkened by hugeswarms of helicopters and fixed wingaircraft as they were a few years ago.This is a matter of great significance. Nolonger can an aviator transmit a Maydayand have instant response from dozensof aircraft. Not so long ago if you wereforced to autorotate you could normallyexpect to spend only a few minutes onthe ground, provided of course you wereable to get off a distress call.But this has all changed. As the num-ber of troops, pilots and aircraft beingwithdrawn increases, your chance for aninstantaneous rescue decreases. Thisaccents the importance of flight follow-ing. f we don't tell someone where weare lIoing plus how and when we will getthere they won't even know where tostart looking for us if we turn up missing.A big item in safe flying in Vietnam,and one that can never be emphasizedenough, is knowing your position at alltimes. Waiting until the engine quits ismuch too late to try and figure out whereyou are. You'll need two heads and fourhands just to keep the aircraft undercontrol, warn the passengers, turn theContinued on page 17


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ot y ReputationCounting on reputations can backfire just s it did for Wild BillHickok when he met Wesley Harding right). In fact, counting onreputations can prove fatal. I t did for Custer and i t can for you iyou misjudge the reputation of your aircraft, yourself or the enemy

TH E MOTION PICTUREabout General George Patton came as a surprise to me. Idid not know that the generalwas one of us . By that Imean I always have had recollections of previous lives, butdid not know that General Patton shared that awareness.I recall some of my earlierlives more clearly than parts ofthis one. When people ask mehow it feels to have this awareness, I want to ask them how itfeels not to have it. When theysay D o you believe in reincarnation? I want to say thatit is not a question of belief- i tis one of knowledge. Either youknow it or you don't. It 's thatsimple.

Usually when one is giftedwith this awareness he also isgifted with the knowledge tokeep his mouth shut. I have onlyhalf the gift, and thus I'm writing this. But I have a purpose.I wish to make a point of safety, and if I do perhaps my follywill be justified. I want to explain how it is that men are susceptible to a certain kind ofaccident. It all has to do withreputations, and if I may takethe liberty of a little nostalgia I

2

Bob KuenstlerDepartment of the Army Civilian

think I can make my point betterthan if I stated it briefly.

In all rfly observations of people in the several lives I recall,men have lived partly by theirdeeds in the present and partlyby their deeds in the pas t -bytheir reputations. It ' s nice tohave done things so well in thepast that you can coast along onyour reputation. Bill Hickok, thefamous marshal of Abilene, didthis.I remember I'd driven the trailup to Abilene with a herd ofsteers from Beeville, TX. Ouroutfit had been joined by ayoungster named Wesley Harding. I'm not sure where Wes hadspent his life up til that time,because he'd never heard ofHickok.

You see, Hickok had had hisbelly full of drovers shooting upthe saloons there in Abilene. Ithad become his custom to senda party of men out to meet usand to collect our sidearms before we entered town. Wes toldthem that if Hickok wanted hisgun he'd have to come get it inperson. Well, we all knew thereputation of Hickok, and weexpected to see him ride out andmeet us as soon as he got Wes's

message. But to our surprise henever showed up, and Wes roderight into town wearing his gun.As if that weren't enough, hewas still wearing it that nightwhen we were in the Silver Dol-lar. tHickok owned, or had i n t r s ~in, most of the saloons there nAbilene at the time and the Sil-ver Dollar was the nicest. It hada fulltime piano player and fid-dler, and there was a little stagebuilt over on one side wheresome of the better looking girlswould dance and sing. It wasn'ta good show, but out there andunder the c i rcums tances i tcouldn't have been more enjoyable if it had been what they nowhave in Las Vegas.

We were all havin' a goodtime, and it was right after acouple of the saloon girls hadfinished s ingin ' a new songcal led Buffa lo Gal thatHickok walked in. There was ahush went over the room because everyone knew Hickokand his reputation. That is tosay, everyone except Wes Harding knew it. Wes was leaning onthe bar and concentrating hisattention on the stage. But thenext entertainment was to com

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from Hickok and Harding , andeveryone knew it except thechief performer Wes Hardinghimself Well , the whole thingwas over before it began .Hickok walked up and said ,

Cowboy , we 've got a rule inthis town- no guns to be wornby anyone . .

Wes just looked around andsaid , Oka y, marshal. Withthat he reached down and pickedhi gun out of it s holster asthough to hand it to the marshal.But uddenl y, to ev e r yone ' ssurprise . We s wa holding thegun leveled at Hickok ' s chest , asthough to hold him at ba y. I'lltake your guns , marshal , hebreathed in a barely audiblevoice as he carefully removedone , then the other of Hickok ' spearl-handled revolvers fromtheir holsters and placed themon the bar. He then orderedHickok out of the building andHickok left.

Harding finished his drink andthen ordered the music to con tinue. It did but the atmospherewas a bit strained until Harding ,not willing to push a good thingtoo fa r , vanished out the back4

into the alle y before Hickok hadtime to return.

Hi ckok enjoyed a good reputa-tio n , but here was a case wherehe wa no t kn ow n b y it. He hadfoo l hl y rel ed upon it , and suf-fered a little embarra ss ment as ares ult.

Now I'm not saying that thewhole idea of reputations is bad.Sometimes a reputation canserve a good purpose . Like during the Civil War. I was in aninfantry outfit then . We weremoving through the wood oneday when a rabbit jumped upand ran away. The fellow nextto me said , If I didn ' t ha v ean y more reputation t o upholdthan he has I d be running too.It was no joke. His desire forreputation kept him there to do ajob that had to be done . It was agood thing.

When it comes to ta lk ingabout reputations , no discoursewould be complete without themention of George ArmstrongCuster . I was with Custer, youknow . Oh , yes , I know you'llthink I'm like the proverbial oldtimer who claim he was with allthe greats - Roosevelt at San

he rabbit didn t have to hangaround to protect a reputation

Juan Hill , etc. But , I really waswith Custer as a Department ofthe A r m y c iv i l i an s cou tWhether or not there is anyconnection between my being aDAC in that life and in this oneI ca n ' t say.I knew Custer well ; he was afine man. He was hell for gettin'the job done and he was allduty , you can be assured ofthat. There was just somethingabout him that you couldn't helpbut like and admire. His men,except for the few who wereenvious and hated him for thatrea on , would have followedhim right into hell and been gladfor the opportunity to do so. Infact , that's what we did that dayat the Little Bighorn.The Lit t le Bighorn real lwasn't as big a mistake as history recorded it. A mistake ,yes- jus t not quite like it ' beenremembered. You might say itwas a calculated risk , and notsuch a bad calculation at that.You see , Custer had run thesame risk with good results atleast twice before.

Once at the Battle of theWashita Custer split up hiscommand into four units , surrounded a village at night andattacked and wiped it out atdaybreak-only to discover thatthe village he attacked was theend of a long line of villages andgreat hordes of hostiles were allover the area. His supply wagons were several miles backdown the trail , and he was afraidthey'd be discovered and cap-

he Indians were confused whenCuster mounted up the regimentand held a parade in front of them

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tured. f they had been we dnever have gotten out alive . Sowha t did Cu t e r do? H emounted up hi regiment andwith the band playing conducteda dress parade up and down theline of village . Thi divertedand confu ed the Indian a thathis wagon were able to arriveunnoticed. The remaining ho tilechiefs came in to urrender andto promise to return to the reser-vations. In his attack on that onevillage Custer had established areputation by which he defeatedalmost an entire Indian nation.Thus, the savages too had estab-lished a reputat ion with him.Custer thought them to be aneasily confused lo t unable to

regroup and fight effectively af -ter an initial setback.

t wa a mi guided opinion,yet further confirmed one day ona scouting expedition . We hadcamped along ide a fairly wideriver and everything eemedpeaceful a night came. All nightthere wasn t a much a an at -tack by a hungry rna quito.

But dawn of the next morningbrought a urpri e. The oppo itebank wa lined with ho tile .They were elevated above ourpo ition and began firing at us.We took cover and began firingback. Our best sharpshooterstook heavy toll of their ranks,but we also lost eight to directhit from the savages r i f le

Soon both sides were undercover and the niping took alower pace . They began cros -

ing the tream on both ide ofour po ition.

You d think Cu ter wouldhave ordered an immediate with-drawal, seeing their uperiornumber and willingness to fight.But not so. When new of theircro ing came to Cu ter he wadelighted and said he hopedthey d all cro s over. He splitthe command into five eparateunit and placed each in a sepa-rate pOSItIon a dictated by thecontour of the terrain. He couldpass vi ual signals to each unitfrom his central position. Our

Continued on page 32


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he Role f elicopters


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In Conventional Warfare

I T IS DIFFICULT for many torecall that just a few yearsago airmobility was not universally accepted, even within theU. S. Army. t was not until thetests conducted with the thAir Assault Division [later designated the 1st Cavalry Division(Airmobile)] at Ft. Benning, Ga.,during 1963 and 1964 that airmobility gained a glimmer of respectability. And, it was notuntil its later baptism of fire inthe Republic of Vietnam that theairmobility concept was proven.

Similarly, today there aremany n t g o n i ~ t s who recognizethe desirabiiity of employinghelicopters in an environmentsuch as the Republic of Vietnam, but maintain that they willhave only limited use in mid- tohigh-intensity warfare. The arguments on both sides are endlessand, in the final analysis, regardless of convictions all beliefs areunsupported by facts becausesuch a war using helicopters hasnot been fought. But, of course,this does not justify waiting for awar to start before developing ahelicopter force capable of operating effectively in mid- to highintensity warfare conditions.

Each new advancement inwarfare has seen its share ofcontroversy and has been initi-ated with a certain degree ofskepticism. Indeed, many criticsprophesied that helicopters couldnot survive in Vietnam. PlacingJANUARY 1972

Colonel DeLyle G edmond

weapons on such an unlikely,unstable platform as a helicopterin the late 195 s and early 196 swas greeted with something lessthan wild enthusiam and universal acceptance. But, the Armyhas been successful in this endeavor and continues to look tohelicopters to satisfy its everincreasing tactical mobility re quirements. What must be determined is the ex ten t of useenvisioned for helicopters sothat appropriate organizationscan be s tructured, equipmentcan be developed and trainingprograms initiated. Prior to determining future requirements itmust be clearly established justwhat helicopters will be expected to accomplish in any future warfare.

OperationsHelicopter operations will be

primarily defensive in nature.Large-scale penetrations overheavily defended areas will beunlikely. This does not meanthat helicopters will be employedonly in a defensive role. On thecontrary helicopters will be usedto exploit success and bring thebattle to the enemy wheneverpossible; however, helicopterswill be used to inflict maximumdelay on enemy forces, particularly in the initial stages of afuture war.

Defensive action must placeheavy reliance on front line

trip-wire units inflicting signif-

icant damage to delay the enemyuntil troops can be withdrawn orreinforced by airmobile assaultor more conventional groundmeans. Main and airmobile re serve forces also must be capable of swift movement to anyarea of the battlefield. All forcesmust have the means availableto them to stop the enemy inadvance. In all instances heavyreliance must be placed on helicopter units armed with air-toground missiles.

In defeat ing a conventionalarmy success hinges in the ability to stop enemy a rmor t hevanguard of the assault. Of primary importance, therefore, isthe employment of helicopters ina tank-killer role. Attack helicopters must be capable of decisively engaging and defeat ingenemy armor. They must havean all-weather day and nightcapability and be available insufficient numbers to blunt anenemy offensive. Used with theU. S. Army/V S. Air Forcecombined arms striking force,attack hel icopters can significantly contribute to the outcomeof any battle.

Attack helicopters also mustbe capable of employing variousweapons systems to accomplishother missions. Included in thisrole are the specific tasks ofpreparatory fire, suppressivefires, counterpreparation, diversionary and fires against targets

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of opportunity. Many targetsmay be better suited for engagement with rockets of machineguns than with air-to-groundmissiles. Helicopters must havethe capability for complete interchangeability and selectivity ofweapons so that commanderscan engage targets with appropriate armament with the leastpossible delay.

The success attained by usingaviation is attributable in nosmall degree to responsivenessto the desires of the groundcommander. He must have helicopters able to accomplish a variety of tasks and no singlehelicopter can satisfy all of hisrequirements. Therefore, there isa definite need for specializedtypes of hel icopters . For in stance , a large helicopter cannotpossibly function as an observation helicopter. The very natureof the mission calls for a small,fast , highly maneuverable aircraft. Similarly , because of suchdiverse factors as the enemy situation, configuration of terrain,speed of flight , dis tance toobjective or any number of reasons, a small transport helicopter capable of carrying a squadof infantry would be preferredover a large transport helicopter.At other times the reverse willbe true.Likewise, to anticipate making

a mUltipurpose attack helicopterwith a button-on armamentsystem double as a transport isfallacious thinking. An attackhelicopter must be designed andbuilt for specific purposes andits configuration is not compatible with that of a transport. Thisdoes not mean that the Armyshould have a great number ofdifferent types of helicopters(which greatly increases anyorganization's problems) butthere must be enough observation, attack, medium and heavytransport helicopters to attainthe flexibility required by theground commander.

Because of the probable nature of any future battlefield,helicopter units must be employed from dispersed locationsand be capable of operat ingfrom field positions for prolonged periods. They now havea limited capability for operatingfrom field locations but mustconcentrate their forces arounda large rather immobile, groundoriented logistical tail. To beeffective these units must be selfsufficient and capable of maintaining aircraft in the field underall-weather conditions .While the situation and terrainwill dictate the degree of dispersion required it is important thathelicopter forces be able to bemassed at any given time so that

the commander can concentratedecisive forces and helicopterfirepower sufficient to stop armor at his discretion.

OrganizationFuture airmobile organizations

should be formed on the buildingblock concept. Each organizational part of team can operate independen t ly or anynumber of teams may be joinedto form a larger unit. Centralizedcontrol is required to provideoverall direction and supervisionof the teams. This concept willnecessitate only minor revisionof present day forces. There willstill be a requirement for divisional, nondivisional and aircavalry helicopter units.

In mechanized or armor divisions more emphasis will beplaced on the use of attack helicopters than on troop transports.These divisions must be givensufficient transports to airlift acompany size unit to provide adegree of flexibility to the commander. Medium and heavy heli-copters also must be available tosatisfy part of the division'st remendous logistical supportrequ i remen ts . Both air andground vehicles will be used toprovide a responsive means ofsupplying fast moving mechanized or armor striking forces .

Infantry divisions will be airmobile oriented. The airmobiledivision as we know it today isan excellent starting point to satisfy this requirement . In thistype unit air cavalry, infantry,artillery, attack helicopter, trooptransport and medium helicopterunits are all combined to providea force capable of rapid movement and decisive action. Onesuch organization proposed for a

fireteam of AH IG departsa staging area during CCStests of techniques and heli-copter tact ics being ex-plored at Project M SSTER



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IRC V LRY COMB T BRIG DE

IRCAV

~ I

'-- -'SQON

'igade size unit is an air cavalry_ombat brigade figure 1). Thisunit employs the elements essential to an airmobile force of theuture.

The Army commander musta general support aviationHe will then be able

o shift his helicopter assets tomass forces and provide support

required . .All helicopter orgamust not be organic toor separate units. All

the majorty of medium helicopter support

be provided by a separateThis comis also necessary to pro

overall aviation expertisesupport to the theater com.

Air ,cavalry is currently recons ance and survei l l nceand has only a limited

and firepowerfinding the

in a future war will notas important as having the

JANUARY 1972

HH

immediate capability of destroying him. Hunter-killer helicopterteams capable of stopping enemy armor should consist of at tack helicopters. Little is to begained by using helicopters in anobservation only capacity andthen having to call on other helicopters to destroy a target. Thelonger the period of t ime between sighting and engagement,the more likely the target willeither disappear or the helicopters will themselves be exposedand taken under fire.

The basic element of futurehelicopter units will be teamsconsisting of various numbersand combinations of types ofhelicopters . Teams will be essentially platoon size organizationsof eight to ten helicopters . Eachwill use helicopters for resupplyand be capable of independentoperations.

Helicopter companies willconsist of three to five teams.Administrative and other support

AHC

requirements will be provided bythe parent company headquarters.

The dispersion of forces willcreate local security problemssince large numbers of troopscannot be committed to satisfythis requirement , helicopterteams must rely on mobili tyrather than numbers. They mustselect areas providing the mostsecurity and move frequently.Of course , it is impractical toanticipate that all hel icopterunits will be completely mobile ,and this creates a requirementfor a base area. This area neednot be elaborate but it must contain the necessary manpower,communications, parts and supplies to sustain the teams . I t willrequire a degree of security butlocating it with other elementsreduces the overall requirement.

TrainingNo longer will the Army avia

tor fly number five or numberContinued on page 5


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C Jorlie onri DonnY s Write-InDear Danny : In the U-21manual, TM 55-1510-209-10/1, I note the presence of twofuel tables which don ' t agree.The information contained in themoment columns in the table onpage 12-9 (figure 12-2, sheet 5)differ from the one shown onpage 12-10. Obviously one tableis incorrect , so which chartshould be used?

SP6 W. W. B.Danny's answer: Those in theknow advise that both charts arecorrect but apply to differentconfigurations of the airplane.When the manual was printed aminor notation was inadvertentlyomitted explaining that the charton page 12-9 is to be used only inconnection with U-21A and RU-21A. The chart on page 12-10 isto be used with U-21A configuration II (U-21G) aircraft only. Inaddition it is not necessary to calculate fuel usage by using the in structions on page 12-9, merelyuse the combined fuel tab leshown on page 12-10. Propernotations to this effect will appearin a change that is now beingprepared for distribution.Dear Dann y : Change 5 to TM55-1520-227-10 (CH-47B and C)changed the normal operatingrpm to 235 for the CH-47C withL-7C engines and MWOs 55 -1520-227-50/15 or 55-1520-227-50/16 applied. The change statedthis increase in normal operatingrpm was necessitated becausethe minimum tuning range of thetuning vibration absorber is 233.The question arises in chapter 4 ,page 4-2, paragraph 4-6 where itstates, On the CH-47C with T55-L-7C engines , set rpm at 230at all gross weights. This page10

is marked change 1. Was this anoversight or was it intended tobe this way?

CW2 BellDanny's answer: Change 4, dated22 Oct 70, removed page 4-2 ofTM 55-1520-227-10 and replacedit with a new page 4-2 and a page4-2A. However, that portion towhich you refer remains unchanged. By the time this comesout in print we should have beensuccessful in having it changed toinclude a note or reference concerning those helicopters modifiedby the above s ta ted MW Os.Please refer again to the W ARNING on page 1 of change 5 andthe last two sentences of paragraph 2 which read, Again,these instructions apply only tohelicopters modified by the aboveMWOs. Instructions for theunmodified CH-47C with T 55-L-7C engines remain unchanged.Dear Danny: In TM 55-1520-219-10 and TM 55-1520-210-10 , adiscrepancy appears in refenence to the maximum engine oilpressure. Both the B a n d Dmodels indicate 25 psi minimumoil pressure at flight idle. Theyboth give 60 to 80 psi for continuous operation. The B modeldash 10 has 80 psi for maximumoil pressure and the D modeldash 10 has 90 psi for maximumengine oil pressure. Please givethe reason for the difference .

CW2 SmithDanny's answer: Someone goofed;the maximum oil pressure forboth the B a n d D model UH-l is80 psi. This will be corrected inan early change to TM 55-1520-210-10. Your interest and alertness is appreciated; keep up thegood work.

Dear Danny: We have been having a discussion on the emerg e n c y p r o c e d u r e f o rtransmission chip detector andloss of transmission oil pressureon the CH-47 aircraft (referenceTM 55-1520-227-10; chapter 4Emergency P rocedures . tstates that after a loss of oilpressure or when a chip detect



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ATTENTION-ALL AVIATION OFFICERSCharlie and Danny has a l imited supply of U. S ArmyAviation School T-42 checklists. A l imited number ofchecklists will be sent to aviation officers upon request

light illuminates to make a landing as oon as practicable usingminimum power. This sounds alittle ambiguous. Does it mean tomake a landing with minimumpower uch as an autorotativelanding? Our thinking on this isto make a landing with minimumpower redu tion and to keep' lower applied until touchdown.JANUARY 1972

Most transmission seizures occur w h en torque applied to atransmission with a loss of pressure or a chip light on is reducedand then reapplied.

CW2 J. T. M.Danny 's answer: Thanks for theQuestion. t does get you to thinking what is minimum power. Ihad one fellow say, "Minimum

power? Autorotate " Don't getsucked in, friend, best thing to dois to keep power applied to thedriver t ra in. We have recommended that paragraph 4-70 beretained as is with one change.Change last sentence to read,"Should the caution light illuminate during flight, land as soon aspracticable using power."


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Proximity Warning evicesVerses da ir oli isions

aptain Lee W. Jurney

W H E N MAN FIRST bega nto y h e h a d th e k ypr e tt y mu ch to himse lf. Bu t th a twa c ha nged b y two world warsw hi ch spaw ned m a ny tec h no logica l a dv a n ces in a ll ph ases o f12

avia tio n . A v ia to r are now con-fr o n te d w ith v irtua ll y the sa mepo tentia l f o r colliding as are au-tom obil e .

T he F ed e ra l Avia tio n Admin-i tra tio n FA A , ge ne ra l av iation

and the military have all beenhard at work trying to preventmidair collisions. The use ofe l e t r o n i ~ devices seemed a logical solution , but problems rang-ing from prohibitive costs toexcessive weight kept croppingup . So measures such as theredesign of airways , controlzones and procedures were stud-ied and met with limited suc-cess . But the midair collisionproblem cont inued to becomemore critical and Army aviationfelt the impact.

Between January 1966 andMarch 1968 16 lives were lostand 3 aircraft were destroyed inmidair coll isions at one postalone. t is conceivable thatmost if not all of these mid airscould have been avoided with aworkable warning device whichwould have alerted pilots thatother aircraft were nearby. TheArmy quickly went to work onthe midair collision problem. InNovember 1967 the U . S . ArmyElec t ron ics C o m m a n d , FtMonmouth , N . J. , published arequest in the F E D E RA L RE GI STER for proposals from commer-cial industry to provide a devicefor testing and evaluation at nocost to the government . Fivecompanies expressed interest inthe program and promised toproduce a device and supplyengineering support for an evalu-ation prior to May 1968.

Competi t ion was soon nar-rowed to two companies and thefinal evaluation was conductedby the U. S . Army Aviation TestBoa rd at Ft. Rucker. The evalu-a tion conce pt required th a t theproximity wa rning de vice wouldbe a tra n ponde r-type y ternwhich ma in ta in co ntinual con tact with ot he r sy te rn th a t a rewithin ra nge 300 fee t of a ltitude a nd within 1,000 , 2 ,000 or3,000 feet horizonta ll y as de te r-mined b y a se lector in th e cock-pit . The sys t e m tr a n s mit s it.

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altitude to all other proximitywarning device ystem withinrange by sending out a series ofpulses. f the data processingindicates that the alti tude requirement of 300 feet has beenmet, then a reply ignal i generated and tran mitted back to thesystem that wa doing the interrogation. The proximity warningdevice then de te rmines thelength of time that had elapsedbetween the transmi ion of thealtitude data and th receipt ofthe reply. f the range is equal toor less than the range set on therange selector switch, then analarm occurs, an audio alarmsignal will come on , and also alight that indicates the relativeposition of the intruding aircraft.

As a result of the comparativeevaluation the Army began negotiations with Honeywell Aerospace Division , Minneapolis ,Minn ., for the purchase of 222proximity warning device . The;ontract for the devices plusnecessa ry suppor t and tes tequipment was signed on 30June 1969. Delivery of the ysterns began that December andmarked the beginning of a seriesof operational evaluations of theHoneywell YO 1054 proximitywarning devices. The first wasconducted within Ft. Rucker sbasic helicopter instrument training area by scheduling TH-13Tsequipped with the device in adjacent training areas. The reportwas highly complimentary of thesystem-based on more than 200contractor instructor pilot evaluation and 400 flight hours . Afterthe complet ion of the operational u er evaluation, a complete profile with preplannedintrusions (intentional midaircourse) wa flown with 100 percent per reliable results.Acting upon the favorablereport of the evaluations andrecommendation made by thelsers , a more advanced ystemJANUARY 1972

was brought to Ft. Rucker undercontract for evaluation. The device was ba ical1y the same asthe original with an azimuthcapability added. The result ofthe 30-day eva luation of theazimuth device mounted on aUH-J D helicopter wa not asfavorable a that of the originaldevice ; however , with additionalengineering re earch and te tingit could be an effective aid in theprevention of midair colli ion .

In July 1970 the final shipmentof 222 device arrived at Ft.Rucker for in tallation. An additional 63 devices were needed tocompletely equip the TH-13Tfleet and make the sy tern effective within that particular portion of training. A contract forthe 63 devices was signed inDecember 1970 and shipmentsbegan in May 1971 . The e proximity warning device were de-igned for the TH-13T and the

Ft. Rucker e nvironm ent andhave been performing satisfactorily in that capacity. This hasno t , however , restricted researchinto more advanced systems forhigher performance aircraft ordifferent environmental situat ions These include xenonlights , radar, laser beams andeven atomic clocks . But the devices alone will not solve themidair collision problem. Theycan only aid the pilot in preventing midairs. The final responsibility rests with the entire crewof each and every aircraft.

EDITOR S NOTEAt the t ime of this writ ing thepost that experienced the mid airshas recorded only one midair collision since the first proximitywarning devices arrived in December of 1969. That midair wasbetween two fixed wing aircraftwhich were not equipped with thePWD (no fatalit ies, and onlyminor damage).

PW with all azimuth lights operating

PW azimuth forward above warning

PW aZImuth center quadrant warning


16/68

Provided by the Society of U S rmy Flight u r g e o n ~

Major Nicholas E. Barreca M . D.

FLYINGF TIGUE

Aviation has fatigue-producing stresses.Commanders f l ightsurgeons and air crew-men must recognizeand control these i fthey are to be averted


17/68

M ILITARY AIR CREWMENare familiar with skill fa tigue. They have experiencedthe tired, haggard weariness re sulting from long, vigilant anddiligent labors in a basicallystressful aviation and militaryenvironment. They have recognized the deterioration in perf o r m a n c e or e f f i c i encyassociated with varying states offatigue. And, they can testifythat the familiar "head-bobbing"often experienced during a longuninteresting auto trip on today's superhighways is nothingcompared to the mul t iplestresses of concentration andboredom encountered simultaneously in the aviation environment.H ow can one r e c o g n i z epotentially disabling skill fatigueand prevent it from occurring?Can it be measured? In a sophisticated laboratory the physical

nd chemical effects of stress_an be measured when baselineor control observations are madefor comparison. Under operational conditions this is not practical and most likely impossibleto accomplish for any length oftime. Thus, there is no simplemeasurement such as a singlesymptom, sign or test that willlend itself to use and interpretation in the field. Instead, onemust learn to recognize fatigueeffects while they are developing. And, most importantly, onemust recognize those stresseswhich commonly result in fa tigue so that they may be minimized or modified in advance.

The aviation environment hasmany fatigue-producing stresseswhich may operate alone or incombination. Each must be recognized and controlled if skillfatigue is to be averted. Pilotsand crews must cope with somer all of the altitude stresses:JANUARY 1972

hypoxia , decompression sickness, gas expansion and hyperventilation.

T h e r e a l so are the l es saviation-oriented, yet prominent,physical stresses: acceleration,noise, vibration and temperatureextremes. Speed also imposesthe stress of workload as well asthe pressure of split-second timing. In addition, there are theconfinement and constraints ofcockpit design which from ahuman factors standpoint canimpose stresses.

The u n p r e d i c t a b i l i t y ofweather and instrument missions, the l imitations of nightoperations and differing aircraftcharacteristics also place degreesof stress upon each air crewmanregardless of his training andexperience.

Our day-to-day medical statusis a potential stress in itself anddetermines our ability to handleother stressful factors. Organicor physical conditions, especiallythe common ones, exert theirinfluence. Then there are thepsychological or emot iona lstresses which become intertwined with one 's level of re sponsibility, competence andexperience. Further, there are avariety of self-imposed stresses,those we may bring upon ourselves: poor eating habits andoverweight, smoking, drugs, al-coholic overindulgence, overexertion, a lack of physical activityand off-duty activities includingsocial obligations and moonlighting

Other conditions determine orinfluence our response to aviation stresses. These too can freq u e n t l y be c o n t r o l l e d ormodified. There are the stressesof aviation mission scheduling:work-rest cycles and circadianor diurnal rhythms. Ideally,work-rest ratios should correspond to 8 hours on and 16hours off, an arrangement to

which most working people havebecome accustomed. Circadianrhythm has to do with our biological clock. The t iming ofsleeping, eating, digestion andelimination generally follow a24-hour pattern. f upset by dislocation across several t imezones, our basic body processesbecome unsynchronizedand fatigue results.

Lastly, there are the organizational stresses. Leadership, ad ministration and maintenancewill have a positive or negativeinfluence on an individual's ability to cope with stress and oftendetermine whether or not signifi-cant fatigue will result and interfere with performance.All of the factors outlinedabove can be categorized intotwo types of fatigue, each ofwhich can be characterized differently. cute sk ll fatigue istemporary and ordinarily rel ieved by a night s s leep .Chronic sk ll fatigue is more serious and incapacitating and generally is not simply relieved byshort periods of rest.

The characteristics of acuteskill fatigue have been observedand studied. Most of us haverecognized some of them ourselves or in a fellow air crewman:

Tired air crewmen a reincreasingly willing to acceptlower standards of accuracy andperformance ("I 'm 200 feet offmy altitude So what? Is thisTimes Square or something?").

Fatigue causes errors intiming or loss of ability to keepapace of sequenced events .("Prelanding check? But, I 'vealready landed ").

With fatigue there is a lossof control smoothness and poorcoordination of flight controls("Sorry 'bout that Guess there'stoo little friction on the cyclic.What was that about the needleand ball?").

5


18/68

Tired air crewmen developdiminished ranges of attention.They become more forgetfulwith a tendency to be easily distracted. Thus, they require alarger stimulus to produce agiven response ("What was thatabout aircraft my area?Damn that cigarette is out again. . . boy, that Chinook s a largeaircraft, hard left ").

Fatigued air crewmen fail tointegrate instruments as a unit.Their panel crosschecks are inconsistent and more attention ispaid to individual components orinstruments ("No sweat on thealtitude . . good ole altimeteronly down a notch ").

Fatigued air crewmen tendto neglect secondary tasks andperipheral instruments ("What'sthat, Doc? What chip detectorUght?").

Fatigued air crewmen tendto be unaware of errors and error accumulation ("How did Iman a g e to mi s s t h o s echeckpoints?' ).

With fatigue air crewmentend to split complicated tasksinto component parts ("First Ipull in power, then a little leftpedal, then some forward cyclicpressure . . . ' ).

With fa t igue there is agrowing inability to interpretkinesthetic sensations of motion,weight and position correctly ( Ididn't realize you could roll anLOH ").

A state of irritability andlack of patience builds up as fatigue increases ("Roger, tower,wheels down and locked for thesecond time . . . stay awake willyou ").

Fatigued air crewmen project their mistakes on the equipment, aircraft or environmentalconditions ("Damn bird, if it hadwings I wouldn't have had acompressor stall "). Air crewmen become lesscapable of evaluating their own6

compromise or unreliabilitywhen fatigued. They cannot appraise their own disability ("Postage stamp LZ watch melick it ").

Fatigued air crewmen makemany mistakes performing simpie, well-learned tasks, particularly toward the end of a missionand most commonly in the landing sequence ("Field In sight. Nosweat Simple straight-In approach behind that C-141.' ).

Recognizing the signs of acutefatigue is important. When an aircrewman recognizes them, usually in another individual. he canat least recommend that he coolit for awhile. t is more important though to prevent. or atleast minimize, acute skill fa tigue. Here are some ways ofaccomplishing this.

There must be a limitation ondaily flying and working hours.AR 95-1 states that crew duty(beginning 2 hours before takeoff) will not exceed 12 hours (14hours with an augmented crew).This is a start in the right direction.

Commanders must avoid pilingstressful missions on top of oneanother Miss ions must bespread out and fairly dividedamong all unit members. Theyalso must be undertaken withinthe capacity of the unit's abilityto perform them.

Every reasonable attemptshould be made to lighten orlimit the burden placed upon aircrewmen. The copilot is onemeans of accomplishing this forthe aviator. This has been effectively used in Army aviation.Cockpit design with the use ofsupporting electronics and in struments are another means.Then, there are "luxuries" suchas environmental control andprotective devices.

Finally, all air crewmen mustbe given the opportunity foradequate rest and natural sleep.

AR 95-1 states that a crew reminimum of 12 hours prior tothe start of crew duties is advisable. Often air crews experiencerestless sleep due to the effectsof alcohol or well-intentionedsleep medication. (This subjectwas discussed in a previousAeromedic. AVIATION DIGESTMay 1970.) Natural sleep. if itcan be initiated. is the best deterent to acute skill fatigue.

While acute skill fatigue is ourmost common enemy, chronicskill fatigue becomes a not uncommon intruder. particularlyduring combat operations. Manyof the stresses responsible foracute skill fatigue contribute tochronic skill fatigue. Usuallychronic skill fatigue results whenthere has been inadequate resolution of acute skill fatigue. Invar iably the individual aircrewman does not recognizechronic skill fatigue readily so itis important for other air crewmen to recognize its characteristics:

Slowed reaction time ("Sir,it was almost as if he was preoccupied. We were the last ship inthe formation. He knew the LZwas tight, yet he reacted lateand sluggishly in decelerating theship. That was too close forcomfort. This wasn't the firsttime. For the last few weeksI 've had to alert him to bogiesthat I'm sure he saw it's asif he was operating on a different time scale. ')

Poor judgment ( I don'tknow what has gotten into him.He's always been so careful andexacting. Yesterday we wereloaded to max gross windsand DA were high. Just aftertakeoff we took fire and hits. Heelects a 180 right back to thebase . . . we take more fire . . .and really tear up the landing.Last few days he didn't seem to

Continued on page 2U. S. ARMY AVIATION DIGEST


19/68

Continued from p ge

JEWSROME DERS

necessary switches to the correct positions, find a suitable forced landing area,establish an autorotational glide and getoff a Mayday. There is no time to figureand pinpoint your location. And it s awfully, awfully hard to locate one smallOD painted helicopter on the groundunder the best conditions-even when itsgeneral location is known.

Another matter of vital importance toyour welfare is your survival equipment.Having a survival radio on your p rsongreatly enhances your chances to be rescued. And of course smoke grenades,flares, strobe lights, et c ., all improveyour chances to make it back.

We all have been well schooled in theproper procedures and are provided withthe tools and means to fly safely in aombat environment. But we must us

.he assets at our disposal.Sir:

The word safety comes up more andmore every day in Army aviation . Butwhat does the word really mean to us asArmy aviators? The Webster s Dictionary defines it as: being safe from un dergoing or causing hurt or loss; a deviceon a military apparatus (as a mine ormissile) that prevents it from being firedaccidentally; a football play; a memberof a defensive backfield in football in thedeepest position; and, last and perhapsmost important to us as aviators , to protect against failure, breakage or accident.

The first step is being safe from undergoing or causing hurt or loss. To methis phase following your dash 1 checklist as described in AR 95-\ ensures youof a prelight which will prevent you fromundergoing or causing hurt to yourself aswell as to your crew. How embarrassingit would be if you didn t check your fueland 15 minutes after you take off youhave fuel starvation. Filling out the 12correctly will help prevent the loss offlight time and pay. Plus, the -13 is veryimportant because it lets you know ifanything is wrong with the aircraft. I fyou find anything wrong with the aircraftwrite it in the book; it lets the next guywho flies the aircraft know what is

rong also. How would you like it if the

JANUARY 1972

crew before you did not write up bindingin the pedals and the antitorque push-pulltubes jammed on you in flight? I f there sanything wrong with the aircraft, no matter how little or big , write it in the book;it covers you and helps the next guy.The biggest help would be to fly the aircraft the way it s designed to be flown.Most commanders want live pilots, notdead showoffs.

The next phase touches equipment asdevices on a military apparatus (mines ormissiles) that prevents them from beingfired accidentally. Here the meaning ofsafety is very important. Think of all theexplosives that are carried on Army aircraft. Imagine that you re the aircraftcommander of a slick or cargo plane andyour load was 500 pounds of explosivessuch as hand grenades, smoke grenades,WP, etc. Would you check to see ifthere were any loose grenades and makesure that the firing pins are secured andwouldn t come loose? Keeping looserounds of ammunition in a container willprevent them from getting lodged in yourcontrols. It s hard enough to fly an aircraft with good controls, but it s evenharder when you have something stuckin them.

but feed your ideasto the VI TION DIGEST

Another important area is the deviceon a piece of equipment to reduce hazard; this meaning of safety has a greatimportance to us . I f we ensure that allsafeties are fastened and secured, theywill function more effectively. By beingin a hurry and skipping over your preflight you might not notice a brokensafety wire on the damper arm of themain rotor blades, or a missing cotter pinin the rudder trim. When carrying cargomake sure it s fastened down and se cured; I d hate to make a turn and havethe cargo shift. The most important pieceof equipment in any flying job is you.Wearing your flight suit, gloves, helmetand boots properly will help to protectyou from a flash fire, cuts and any unnecessary injuries. Keeping yourselfphysically and mentally fit will help too.

Let s face it, safety and flying goalong like bread and butter. I f you flysafely you have a better chance of making it to your destination than flying unsafely. Filing a flight plan is a goodpolicy. I t lets people know where youare going, plus which route you are taking. Like in football it s no fun makingtwo points for the other team. Morale ishigher if you make a touchdown for yourown side, particularly if it s safe andsound.

Much like the member of a defensivebackfield in football in the deepest position, you re the guy your crew dependson to get them back safely and in onepiece. Don t take unnecessary chances;one mistake could end your crew s livesand yours.

Perhaps the most important phase ofsafety is Webster s last definition: to protect against failure , breakage or accident.No one can prevent all things from goingwrong with your aircraft, but knowingyour emergency procedures as written inyour aircraft s dash 1 will allow you toget the aircraft on the ground safely andintact. Doing your job as efficiently andsafely as possible will help you to a longand safe flying career which means following all the rules established for Armyaviators. I f you have any better suggestions submit them so we all can benefit.Rules were made to keep you safe and ifyou follow the established proceduresyou ll have a better than average chanceof collecting your retirement. A primarybasic is to ensure that you and your aircraft are capable of performing the miss ion. Don t let your ego of pridesubstitute for safety because your egodoesn t give the engine more powerwhen you need it. My best advice issafety first above anything else for a longflying career .

CWO Earl K. BauchDSfT, Systems EngineeringFt. Rucker, AL 36360

7


20/68

hyU5AA5 5e ?Colonel George Rog rs

COL Rogers was director of the U. S. ArmyAeronautical Services Office USAASO)when he wrote this article. The article con-tains information of the services that are

I N TODAY S Army there arefew soldiers- from private togeneral officer-who have notflown in military aircraft . Formany , flights taken were in andout of the fire bases and tacticallanding sites in the Republic ofVietnam. For others , the logisticsupport or administrative flight ismore familiar . Almost all flew toand from Vietnam on contractaircraft. Flying in the military ,as in the civilian community , hasbecome a way of life an d , likemost other commonplace experiences, little attention is given tothe systems supporting that wayof life.

One of the more important ofthose systems supporting airtravel , be it around the world bycommercial air or a 10-minutehelicopter flight into a tacticallanding zone , is the air trafficcontrol system. In some form oranother air traffic control is involved in just about every flightmade , and yet surprisingly littleis known about the system evenby aviators themselve s, muchless the passengers.

18

available through USAASO

What is air traffic control? Theingredients of an ATe systemcan best be depicted schematically , as shown in the accompanying chart.

On a national level the FederalAviation Administration (FAA)is charged with development andoperation of the entire system.However , by Federal law andbecause they are major users themilitary departments are activelyinvolved in both the developmental and operational phases.A major effort is routinely expended by all interested partiesin keeping this system-which isso vital for safe and efficient airtraffic-current with the changing needs of the users.

For the U. S . Army , responsibility for the air traffic controlsystem is vested in the U. S .Army Aeronautical ServicesOffice (USAASO) , a little knownorganization located at CameronS ta t i on , Alexand r i a , Va.USAASO is a class II activityunder the Assistant Chief ofStaff for Force Development andoperates within the parameters

of AR 95-23 as the Departmentof the Army Executive Agencyo n

Airspace and air traffic regulation , control and procedures.

Related ground support fa cilities and procedures.

Flight information.Very little public notice has

been given to the Army s participation in the national programand one may ask the question asto just how this involvement isconsummated. The Army s involvement is accomplished primarily by cooperative agreementand by the timely exchange ofinformation. Frequent formaland informal consultations be tween action officers of the FAAand members of the Departmentof the Army and other militaryservices result in discussions andsubmission of proposals andcomments on major issues .Through this media the Armyassists in shaping national policies and plans of the FAA forthe growth and development ofthe national aviation system.

The Department of DefensU. S. ARMY AVIATION DIGEST


21/68

In darkened room at the busyTan Son Nhut RVN airportArmy air traffic control lers ofCapital Center flight follow hun-dreds of aircraft daily

and the epar tmen t of theArmy s management of thiscooperat ive effort is formallyaccomplished through an establ ished advisory commit tee onFederal aviation which in turn,is supported by working groups.The assistant Chief of Staff forForce Development is the De partment of Army s principalmember of this committee andthe Director of Army Aviationserves as the alternate member.USAASO is the Army s execut ive agency on airspace, airtraffic regulation, rules, procedures, related ground supportfacilities and systems, and onflight information. The directorof this activity serves as theprincipal Army member of theworking group of the DOD advisory committee on Federal aviation.

With th is background aninquiring but cursory look at theUSAASO and its assigned mission should generate provocativequestions about this relationship.

To fulfill the mission relativeto airspace, air traffic regulation,con t r o l and p r o c e du r e sUSAASO conducts daily liaisonand coordination with the FAA.Additionally, organic residentoffices are located at eight FAAregional headquarters.

The Department of the Armyhas about 200 separately designated areas of special use airspace located throughout theContinental United States. Ofthese, 114 are classified as re -tricted airspace and range in

JANUARY 1972

size from 2 square miles to over1200 square miles. Additionally the Army has 4 controlled firingareas. Associated with Armyflight facilities are the controlzones and transition areas topro tec t the in s t rumen t approaches and departure procedures as well as air traffic in theterminal areas. As a major userof airspace the Army has a cont inuing requirement to justifyretention revision or establishment of new areas to supportthe Army s mission.

In the utilization of navigableairspace consideration must begiven to our nation s philosophyof the public s right of freedom

of transit, and to ensuring thesafety and efficiency of flight forprivate and commercial as wellas militar y aircraft. From a par -tisan point of view, considerat ion must be given to specificrequirements of each militaryinstallation and protection of itsoperational interests relative tospecial use airspace which maybe hazardous to flights of nonparticipating aircraft. AdditionalIy, the Army will continue tohave requirements wherein thecoordination of national airspaceis necessary. Examples are construction proposals by the mili-tary establ ishment when theproposed structure will penetrate

9


22/68

the navigable airspace and, conversely, when like structures areproposed by civil agencies whichmay be in the vicinity of militaryinstallations. Each such construction proposal must be negotiated and approved by theFAA.

During fiscal year 1971 over,000 Federal airspace propos

als and studies were reviewedand processed by USAASO. Ofthese, 2,000 actions related tothe structure or restructure ofexisting or programed airways ;approximately 1,000 actionswere proposals for new civil airport facilities; and the remaining8,000 related to the structure oftowers , buildings or like facilities that would penetrate thenavigable airspace. Even thoughonly a small percentage of thestated proposals have a directimpact on Army operat ions,each must nevertheless be reviewed to safeguard military in-terests.Air traffic con t ro l e n -compasses actions pertaining tothe development of Army policyand criteria for instrument flightprocedures. This includes thereview, approval and publicationof actions on each standard in-strument flight approach procedure and standard instrumentdeparture for all Army airfieldshaving approved terminal facilities.

At both the tactical and nont c t ic l Army airf ields theground controlled approach ra dar is the Army s primary instrument weather landing system.Nondirectional beacons and terminal VHF omni ranges alsoprovide for approaches to Armyairfields. Air-ground communications equipment plays a majorrole in the control of terminaland enroute traffic. Altogetherthere are over 50 separate majoritems of equipment used in theArmy air traffic control system.

The operators of this equip-20

ment are the ATC tower operators (MOS 93H) , the ATCground control approach (GCA)specialists (MOS 931), the ATCenroute specialists (MOS 93K),and the air traffic control chiefs(MOS 93L). Training for thesespecialists is conducted at the U.S. Army Aviation School , Ft.Rucker, Ala., and current lythere are about 2,500 on theArmy s rolls. Maintaining thissophisticated equipment in theenlisted fields are the radar repairmen (MOS 26D) trained atFt. Monmouth, N. J., and theavionics communication equipment repairmen (MOS 35L) theavionics navigation equipmentrepairmen (MOS 35M) , and theavionics equipment supervisors(MOS 35P) trained at Ft. Gordon, Ga. About 1,100 of theserepairmen are required to mainta in the Army s wor ldwideequipment inventory . USAASO s involvement and responsibilities in this area encompassthe establishment of policies andcriteria on the requirements for,and the installation, operationand certification of , air trafficcontrol facili t ies. Worldwideengineering assistance on designand installation of ground support facilities is provided byorganic technicians who currently are stationed worldwide.

When service and supportrequirements exceed the capabilities provided in the areas ofoperation cited, technical assistance is augmented by technicians from the home office on aTDY basis. USAASO technicians are exceptionally qualifiedto perform these functions andhave extensive background andexperience in the field of groundavionics. Augmentation of or ganic capabili t ies in technicalassistance is provided by a current contract budgeted for andmanaged by USAASO. Anothersource of technical assistancecomes from a national agree-

ment with the FAA. Upon request , and on a reimbursablebasis, the FAA provides onsitetechnical engineering aid. Looking to the future, extensivestudy and research by the Combat Developments Command andthe Office, Chief of Researchand Development in conceptsand hardware are a continuouseffort to meet Army requirements in air traffic regulation andcontrol.

USAASO determines and validates Army requirements forflight information and coordinates with other services andother governmental and international agencies for publication inappropriate flight informationmedia. Action officers are deeplyinvolved in the acquisition, validation and editing of over 200operational items of informationor informational change eachweek in the 43 separate flightinformation documents in whichthe Army provides input. Distribution control of these documents is a perplexing task ofUSAASO s. To effectively carryout a worldwide flight information program for over 1,300 subscribers , USAASO has threeaeronautical services detachments. The detachment locatedin Hawaii assumes responsibilityfor the entire Pacific area. Thedeta Chment at Heidelberg is responsible for the European,Mediterranean and Near Eastareas of operation, while a de tachment in the Canal Zonehandles the Central and SouthAmerican areas. Responsibilityfor the North American area ishandled by the home office.

The enlisted specialist at theunit and installation level responsible for the overall coordination of flight information datais the flight operations coordinator (MOS 71P). About 1,900 ofthese specialists are coordinatingthe traffic created by over 26,000Army aviators flying more tha



23/68

12 000 aircraft for a total of 6.1million flight hours in fiscal year1971. These flights are con ducted from over 500 airfieldsand heliports employing approximately 800 fixed and tacticalATC and N A VID facilities inthe worldwide Army aviationprogram.

Another time-consuming taskis the necessary routine liaisonand representation on variousDepar tment of the Army Department of Defense, nationaland internat ional commit tees .Current ly membership is provided on 26 formally establishedcommit tees , working groupsand/or working parties .

The most recent addition tothe tasks assigned to this officeis its designation as the Department of the Army point of contac t for the fo l lowing ATCequipment , s ystems and staffactions:

AN/TRN-30-NondirectionalbeaconAN/TSQ-71-GCAAN/TSQ-70-Control towerAN/TSQ- )-Control towerLanding systemsA N / G R C 1 7 1 U H F TransceiverAN/GRR-23 - VHF receiverAN/GRR-24-UHF receiverAN/GRT-21 - VHF transmitter

AN/GRT-22- UHF transmitterA N / T S C 6 1 - F l i g h tcoordination centerFAA coordinationDA po in t of c o n t a c t a tPANAG ECOM position andnavigation group)AN/GRN-6- NondirectionalbeaconA N / F ~ N 4 0 G C ATB 95-1 implementationKorean ATC updateJoint ATC actionsRadar target simulatorsAN /APM-305 transponder testsetFrom a standpoint of policy

which has Army-wide impact

lements of the Army s air traffic control system

JANUARY 1972

ENROUTECONTROLSYST M

TCSYST M

2


24/68

Whether in the visual above) or theradar air traffic control environmentbelow), USAASO provides service

to Army units throughout the world

USAASO s proponency for 2Army regulations is one of itsmore important tasks. Of equalimportance is the participationwith other services and the FAAin the development of joint andfederal regulations pertaining toair traffic control. Additionally,USAASO has primary responsi-bility for input into certain tech-nical manuals, technical bulletinsand army subject schedules per-taining to ATC.

USAASO is first and foremosta service activity and is in thebusiness of selling service. Itcan assist installation command-ers or individual unit command-ers by providing direct supportwherein onsite technical assist-ance in the operation and main-tenance of ATC equipment isprovided. Also, it can afford as-sistance where and if desired toimprove overall ATC manage-ment of aviation facilities either

by tailoring a team of specialistfor a specific requirement or byproviding a full team of special-ists to conduct a survey of facili-ties to identify weaknesses inATC personnel or equipmentperformance.

e r sonne l a s s igned toUSAASO represent the entireArmy aviation family referred tothroughout this article as theycoordinate ATC actions at toplevels of command and as theyparticipate in the business of the26 separate committees andworking groups on which theyserve. AR 95-23 authorizes indi-viduals, worldwide, to communi-cate directly with this USAASOin matters related to its func-tions . To increase the efficiencyand effectiveness of the Army sair traffic control system, theefforts, the ideas and the sugges-tions of each interested personare earnestly solicited.


25/68

eromedicContinued from page 6care what we flew over or atwhat altitude )

Irritability. ( "Now lookhere , Sonny-boy, I flew theBurma Road when you wereimpressing your parents withyour ability to hold your headup. You don't give me lessons inflying. What's more, don't chatter while I fly and chief,you and the gunny stop shiftingyour we i gh t a r o u n d b a c kthere ")

Poor appetite. ( Doc, Idon't feel sick . . . I just don'twanna eat. The food doesn ' ttas te as good an ymore . . . Idon't know why. Besides, Idon't feel much like . . . doin'anything ")

Weight loss. ( Yeh, I 'velost a little weight. You'd loseweight too if oh, Idon't know. ")

Sleeplessness and indulgence in alcohol. ("Doc, he justtosses and turns all night. Keepsme awake, too But that doesn'tworry me as much as the booze.He doesn't usually drink much

only socially. Lately thoughhe 's on a l iquid diet till 0200hours. ")

Many might say the individualis depressed . . . not acting likehimself. Often the flight surgeonmust be called upon for thetreatment of this type, of fatigue.However, chronic skill fatiguecan be prevented. If acute skillfa t igue is dea l t with oftenchronic skill fatigue will beavoided. The following measureswill often minimize the likelihood that chronic fatigue willbecome prevalent:

Ensure adequate tralnLngWith good leadership the men ofa unit will be prepared, disciIlined and trained to undertake aJANUARY 1972

given mission. This will maximize their performance in theface of known stress and inevitable fatigue. Without training,discipline, leadership and asense of esprit de corps a unitand its members are ill-preparedto confront even the simpleststresses of the aviation and military environment.

Limit flying hours. AR 95-1recommends that commandersconsider the following forfixed wing aircraft, 30 hours/7day period and 100 hours/30 dayperiod . . . for rotary wing aircraft, 25 hours/7 day period and90 hours/30 day period. In thecombat environment this wasnecessarily extended but onlyunder close and continued command and medical supervision.

Have provisions for regularleave and R R. This measuremust be carefully utilized. tmust be applied before seriousfatigue is apparent . Once thedepressed fatigue state is established . . . as with combat fa tigue taking the individualaway from it all, frequently reinforces his state of disability.

Improve working conditions.One needs no practice in themiserable. Groveling in the mudfor the sake of tradition traditionally results in discomfort,di ssidence, disease and sometimes disaster. Every effort mustbe made to maximize man'seffectiveness by avoiding unnecessary stresses.

Establish set and limitedtours of duty. The prospect ofultimate relief enables one totolerate more stress. This hasbeen one of the reasons for thedecrease in psychiatric casualtiesin Southeast Asia.

Encourage good physicalconditioning through beneficialforms o f recreation. Physicalconditioning not only preparesone for the enduring tasks athand but improves mental out-

look. t increases the likelihoodthat sleep will be natural andprotective. Minimize the self-imposedstresses. While largely an individual task, great strides can bemade by a commander by settingthe example and discouragingconditions which would enablethe easy development of badhabits. Recognize accomplishmentsthrough awards and decorations.Man, while intelligent, is basically vainglorious and proud.Without recognition of his ac complishments he soon loses hismotivation.

The administrative provisions(AR 95-1) for flying hour limitations are somewhat arbitrary.They can be misleading and easily result in a false sense of security. Each individual differs inhis tolerance to stress and theextent to which he will becomefatigued. Because of the multiplecomplex stresses involved inaviation and fact that i t ' shuman nature not to realizewhen you're too tired for efficiency and safety, flight surgeons and commanders mustkeep an eye on pilots and otherair crewmen for signs of fatigue.To accomplish this commandersand flight surgeons must have anintimate knowledge of their men.This only can be achieved byfrequent participation in theirduties and missions and closesurveillance of their responses tostress. Commanders must recognize the safe l imits of humanperformance and the uniquenessof individual capaci ty. Flightsurgeons must be alert for thesubtle reflections of compromised performance and marginalreserves. Air crewmen must beaware of their individual capabilities and avoid overextendingthemselves at the expense ofsafety, efficiency or the compromise of future mission accomplishment.

23


26/68

Preservation Of Fuel Control:The fuel control should not beleft unpreserved T -53 seriesengines) for a period longer than48 hours. Moisture present inJP-4 fuel will corrode internalparts of the fuel control, causingserious damage. Reference TM55-1520-210-20, page 5-116)Component Disassembly: Whenremoving or dissassemblingcomponents exercise care toprevent dirt or other foreignmatter from entering the engine.Caps, plugs or temporary coversshould be used to close all exposed openings.Installation Of Aircraft NickelCadmium Battery: Installation ofthe particular aircraft nickelcadmium battery will differ fromaircraft system to aircraft system. For installation proceduresof each different aircraft nickelcadmium battery refer to themanual covering the aircraft.Also, observe the following:

Battery positioning andsecurity. Ventilation of gases. Voltage regulation.Note: For a battery to be used

for the first time, e sure thatthe battery has been prepared

inten ncefor service by higher category ofmaintenance personnel as annotated on the battery service record card.Transmission Wafer Oil FilterSeal: Many problem areas arepeculiar to a specific series aircraft. One that has been experienced several times was failureof the UH-l series helicoptertransmission wafer oil filter seal.Frequently this problem occurswhen a transmission is changedor disconnected to facilitatetransmission mount changes. Ineach case excessive maintenancemanhours were required fortrouble-shooting. On each occasion the problem occurred assoon as the engine started andthe transmission was turning.Excessive oil pressure blew thetransmission oil wafer filter seal.The problem was often due toan unserviceable quick disconnect in the transmission to oilcooler pressure line, or just agood case of improperly in stalled quick disconnect. Thequick disconnect is located inthe forward transmission welland is extremely difficult to install and/or to detect improperinstallation.Oxygen Gaseous) Servicing: Cau-

tion: Only qualified personnelshall be authorized to operateequipment for servicing of anaircraft oxygen system. Oxygenservicing requires the utmostprecautionary measures due tothe highly explosive and flammable capabilities of oxygen.

a. Prior to servicing an aircraftoxygen system, personnel shalfamiliarize themselves with thesystem, precautions and instructions for handling gaseous oxygen, operat ion of servic ingequipment and potential hazardsinvolved.

b. Aircraft shall not be serviced with oxygen when any of

the following conditions prevail:1) i rcraf t e lect r ical

switches are on.2) Ground-powered equipment is operating within 50 feetof the servicing area.3) Aircraft is being servicedwith fuel, oil or anti-icing fluids.4) Any combustible materials, fluids, etc. , are evidentaround oxygen servicing equipment.c. When an aircraft is beingserviced with oxygen within 50feet of an area where smoking ispermitted, NO SMOKIN signsshall be placed at a 50-foot radius around the servicing area.



27/68

tterswhen servicingoxygen systems

JANUARY 1972

Caution: Oxygen equipmentshall be kept clean at all times.No organic matter or flammablesubstance of any nature shall bealJowed to contact oxygen. Ensure that all components of thesystems are free of moisture, oiland grease at all times. Oxygenis a nonflammable gas; however,it supports combustion and lowers the flash or ignition point ofall combustible materials. Oxygen shall be handled as a flammable gas.

d. To prevent overfilling oftanks personnel shall observeaircraft oxygen system gauges atall times during servicing.e. Personnel shall be stationedat the oxygen servicing unit atall times during servicing operation to shut off unit valves immediately upon receiving acommand from personnel watching aircraft system gauge.f. Service aircraft from cylinders clearly labeled DRY orA V I A T O R S BREATHING

OXYGEN. Other oxygen mayhave moisture which could causeflow stoppage at temperaturesbelow freezing.g. Always use a pressure-reducing device when servicinglow pressure oxygen systemfrom high pressure bottles.

h. Fill oxygen system slowlyto prevent explosion resultingfrom heat generated by fillingtoo fast.

i An aircraft oxygen systemnot eq uipped with -shutoff devices at cylinders shall be completely discharged of all pressureprior to removing components.All electrical power shall beturned off during oxygen discharge operations.

j Refer to applicable aircraftmaintenance manual for additional information and maintenance procedures. (ReferenceTM 55-1500-204-25/1, page 1-16

We received a maintenancequestion on calibration of theJ2 or AN/ASN-43 gyro magnetic compass. Our researchfinds that the calibration procedures for the J2 compassare found in TM 11-6605-200-35 and the AN/ASN-43 is inTM 11-6605-202-35.


28/68

26

Computer ssistedaintenance anagement

Major Harold L Jones

Al though computers are now being used more andmore t the d i rec t suppor t c t iv i t y leve l in theaviat ion support structure their value in providingassistance to maintenance is often being over looked

U S ARMY AVIATION DIGEST


29/68

UIC

HOURS\ HOURS AVGP : TO P DAYS

DUEt DUE TO P_ /

56 UH-1D 65-9565 25 3912 .3 3913 0 o l - l l lE10979 0

56 UH-1D 65-10050 27 3574.6 3577 2 .9 l - l l lE10071 0

56 UH-lD 65-9708 25 4392.1

56 UH-lD 66-17078 32 3108.1

BANK TIME - 1254

THE VALUE OF computersto supp ly opera t ions iswidely known. Computers whichhave been specifically developedto aid in maintaining stock rec-ord ledgers and to completefunctions which otherwise wouldbe tedious, time consuming andvery much subject to humanerror are now found at directsupport supply activity level inthe aviation support structure.

4401 8 3.6 l-l1 lE10818 0

3207 98 43 .8 l - l l lE10663 0

Figure 1

The only known widespreaduse of computers in maintenancemanagement involves the compi-lation and presentation of datafor the DA Form 1352. the Air-craft Inventory, Status andFlying Time Report. Hunter isno different from other largefleets in this respect in that datafor this report is accumulated ona daily basis in some cases andchecked and consolidated at theend of the month, pr inted bycomputer and then distributed.

Working with the 1352 data.however, and with a minimalamount of additional input dataHunter has developed a differentdata presentation felt to be muchmore useful at this lower levelof management. As shown in the

656

10

860

907

TO H\ DUE/ DUE-

4006 93

3742 167

4701 308

3303 194

41.5 4883

74 .5 4754

137 .5 5131

86.6 3399

solid circles in figure 1. this pre-sentation called the ScheduledM(lintenance Projectior usesseven bits of information alreadysubmitted for 1352 report pur-poses. The bits of informationshown in the broken circles onlyfour are required to be sepa-rate ly suhmitted by the unitsowning the aircraft ; the com-puter does the rest. It subtractsthe Tota l Airframe Hoursf rom Hour s PE (per iodicinspection) Due and arrives atHours to PE Due . I t then

completes the same computationto arrive at a figure for Hoursto H E (hot end i n spec t ion)Due.

Then in a slightly more com-plex computation the computer

Although computers are in -creasingly being used in the sup-ply field, their value in providingassistance to maintenance hasbeen largely overlooked. In theAircraft Maintenance Brigade,Hunte r Army Airf ield , Ga . ,maintenance management infor-mation systems are being devel-oped which, hopefully, willprovide a beginning in rectifyingthis oversight. Even though thedata presentations now in useare aimed specifically at Hunt-er's problems and are primarilyfor staff and support planningpurposes, the principles involvedhave wide application. Hunter'ssystems could very possibly beadapted for use in many otherareas.

Figure 2

JANUARY 1972

TOTAL HOURSFLOWN INMONTH

30 DAYS+ IN THEMONTH

NUMBER OFAIRCRAFT IN.THE UNIT

AVERAGE HOURSPER AIRCRAFTPER D Y

27


30/68

REMAINING HOURS TO PE :CFT

SERI LNUMBER

2222233333444445555566666777778888899999o 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 10065-9565

65 -1005065-9708 8

66-17078

B NK TIME - 1254

recalls the total number of hoursflown by this particular unit inthe previous month and , afterdividing the total by 30 days inthe month to arrive at the average unit daily flying hours , thecomputer again divides - thistime by the number of aircraft inthe uni t - to arrive at the averagenumber of flying hours per dayper aircraft (figure 2) .This factor, which normallyranges from 2.0 to 2.4 hours perday at Hunter, is then dividedinto the number of Hours toPE Due and into Hours toHE Due to arrive at Average

Figure 3Days to PE and AverageDays to HE '.

After the data is accumulatedfor each of a given unit 's aircraft , it is sorted and put intosequence in re la t ion to the

Hours to PE Due with theaircraft which is closest to PEbeing first and the aircraft farthest from PE being la st. Thenthe data is printed.

This pre sentation results in adepiction of every unit in relation to it s s cheduled maintenance workload for the comingmonth. I t has the potential with

98

skillful use to make it possible toidentify peak workloads a weekor two in advance of their occurrence. Conversely , the Scheduled Maintenance Projection canidentify a unit with a relativelylight scheduled maintenanceworkload a week or two in ad vance of that situation. This information can then be used inscheduling especially heavyflying commitments or to allowthe unit to pull early or deferredmaintenance.

As an additional computationthe presen ta t ion shows the

Bank Time for the unit. ThisWorking with engine workload projection sheet, engine shop s platoon

leader coordinates parts requirements with his supply supervisor


31/68

gure results simply from theaddition of the number of hoursremaining to PE for each of theunit's aircraft. Under optimumscheduling conditions BankTime would be the number ofaircraft in the unit multiplied by50 hours each. For example , in aunit with 20 aircraft one aircraftshould be 5 hours from PE, an other 95; the second closest toPE should be \ 0 hours out andthe second farthes t 90 hours;each aircraft set should averageto 50 hours. Optimum BankTime for this unit would be 20x 50 or 1 000 hours. The actualBank Time figure might be750 hours , indicating a heavierthan average maintenance load,or it might be 1 250 hours, indicating a light workload. Byprinting out the Bank Timefigure for each unit the user ofthe data presentation is providedwith a quick and dirty indicator of the unit's scheduled maintenance workload.

Use of the data presented inthe Scheduled MaintenanceProjection led quickly to thedevelopment of a spinoff presentation of extracted information.This spinoff, seen in figure 3, isentitled Tabl o RemainingFlying Hours Before PeriodicInspection. Its use and purposeis relatively apparent . Onceagain it sequences a unit 's air-

ACFT SERIALUIC TYP NUMBER

63 UH 1D 64 13723

39 TH 1G 66 15286

68 UH 1D 65 9665

63

JANUARY 1972

craft in relation to their nextscheduled PE and prints them inthat sequence, s howing thenumber of hours remaining tothat PE. By drawing a line diagonally from t h e ' ' 0 Hours Remaining point for the firstaircraft to the \00 Hours Remaining point for the last aircraft, an optimum schedulingline is establ ished. It is thenvery easy to identify workloadpeaks and val leys . Effortsshould then be made to alleviatethe problems represented by either of these two conditions.

The third computerized maintenance management informationsystem presentat ion in use atHunter Army Airfield by theAircraft Maintenance Brigade isone that is particularly usefullocally due to a unique organizational factor. At Hunter all turbine engine maintenance, exceptfor normal first-line troubleshooting, is performed by oneengine shop. This shop performsall hot end inspections and allengine changes for the entireHunter Cobra and Huey fleet.This centralization has greatlycontributed to quality standardsand it has streamlined and muchsimplified the management of thehigh value, supply critical engines and their components.

The data shown in figure 4 iss e Ie c ted, s 0 r ted .a n d p r i n tedFigure 4

ENGINE ENGINE NEW HOURSTYP SERIAL O/H H DUE

L ll LE10969 0 4482

L 13B LE21302 N 2291

L ll LE09499 0 3505

solely from data depicted in theScheduled Maintenance Projection (figure I). Figure 4 , HoursLeft Before Hot End In s pec tionis a printout listing every turbineengine at Hunter in relation toits next hot end inspection. Onthe day the report is printed theaircraft shown at the top of thelisting is the closest aircraft (andengine) to hot end inspection;the aircraft (and engine) farthestfrom hot end appears last. Thisreport enabled the centralizedengine shop to realistically , andwith an increased degree of ac curacy, project its requirementsfor engines and hot end components.All three of the maintenancemanagement information presentations developed thus far by theAircraft Maintenance Brigadeare in various stages of theirevolution. They are by no meansthe ultimate in management in-formation systems and eventhese still have bugs. Nevertheless, they represent an advancement in the state-of-the-artof maintenance management .Given the proper , skillful andaggressive use of these relativelysimple systems and intelligent,intensive and innovative thinkingby maintenance managers, ourar t will advance as it must to

meet the changing, growingdemand for Army aviation. . .e:;.

HOURS HOURS AV DAYSFLOWN REMAIN REMAIN

4481.1 0

2287.9 3 1.4

3498.9 6 3.0

11 .5

29


32/68

Q. Recently whi le planning an IFR f l ight Ifound the 8 model Huey dispatched to mehad no transponder. FLIP Sect ion states thatthe absence of a suffix in the aircraft designation box on a DO Form 175 indicates there isno Transponder/TACAN equipment onboard theaircraft. Should I have entered UH IB as theaircraft designation or should I have omittedthe 8 to avoid possible confusion?A. Aircraft model designations should not beused on DO Form 17 5 . In this case controllerscould have mistaken that B as indicating atra nsponder with 64 code capability and DMEequipment was onboard your a ircraft. Unnecessary radio transmissions which may arise tove ri fy your status could cause some confusion .Reference : FLIP Section II , dated 16 Sep 71 ,page II -53 , USAASO .

A'RCRAFT UN I T OF ASS I GNMENTMILITARY FL GHT PLAN 3 1 W \rLIGHTPLAN

?J L7; 9 AI R CR AFT OESIGNATION / ESI FR 0 DVFR TO CODEo VFR 0 FVFR f / -/-/IN IT IAL CRU I S I NG PO I NT OF DEPARTURE STANDAFALT 'T UD E P/ t l00 NAME AND NUM8E RI FR VFR ROUTE OF FL I GH T

Q. I am dual rated with a standard instrumentrating in both helicopter and fixed wing aircraft. I f I were to fail an annual instrumentcheckride in a fixed wing aircraft, could theexaminer revoke both my fixed wing and helicopter instrument ratings?A. Yes , the examiner reports the results of theexaminat ion with his recommendations as toth e award or revocat ion of instrument ratingsto the awarding author ity . AR 95-63 states: Int he case of an applicant who does not successfully complete the required exam ination, theawarding authority will invalidate ny instru ment rating currently held by the individual.The applicant must successfully complete areexamination within a 60 day period from thedate of initial failu re. Reference: AR 95-63 ,page 2-2 , paragraph 2-5c.(2) , dated 13 May1969 , and ACSFOR /AV.Q. At what point prior to departure should theanticollision l ight be turned on while operatinghelicopters?30

A AR 95 - 1, paragraph 4-5c, dated 12 Sep 69 ,states : Aircraft l ighting. (1) In fl ight the anti coll ision light (Grimes l ight) will be ON whenairborne , except while operating under actualinstrument conditions when the l ight may induce vertigo. During darkness the navigationl ights w ill be on STEADY unless the Grimesl ight is inoperative, in which case the navigation lights will be on FLASH . (2) Ground . TheGrimes l ight will be OFF during all ground operations , and ON when entering the active runway for takeoff .

The catch for helicopters is: Flying t imestarts when it l if ts off the ground. Therefore,the anticoll ision l ight should be turned ONprior to hovering flight. Changes to dash lOsand checklists are currently in the mill to reflect this. NOTE: The Study Guide and Reference Data Booklet for the 1972 annual writshould be arriving in your units soon. Thestudy guide is in programed text form and contains questions similar to those which will beused on the annual writ. Emphasis should beplaced on where in formation can be foundrather than on memorizing figures and rules .Q. Why does the Army use only 70 feet (.07) asallowable error in the Kollsman window of thealtimeter, and where does the K factor enterthe picture? The other uniformed services andthe FAA state that the allowable tolerance is75 feet (.075) in the Kollsman window.A The fact that we march to the beat of a different drummer is not so critical as you suppose. The difference between .07 and .075 ,expecially when you try to read i t (5 feet) on analtimeter , is minute. Consider i t as an extra 5-foot margin of safety.

The application of the K factor to altimetersettings is explained in TM 1-215. By continually adjusting the Kollsman window to the current altimeter setting the aviator compensatesfor the nonstandard surface pressure, and thealtimeter reads the field elevation when landingas well as displays the indicated altitude abovemean sea level in flight.

Concerning both your questions, stick to theguidel ines that TM 1-215 gives you. Theagency which has proponency for TM 1-215will be reviewing it shortly, and the proposal tostandardize altimeter error and K factor shouldbe on the agenda.

U S. ARMY AVIATION DIGEST


33/68

/ The rew Chiefaptain Edwin S arpenter

ANOTHER EARLY morningtakeoff for an all day ashand trash mission. Certainlydon t look forward to this mission.

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