Army Aviation Digest - Mar 1967

8/12/2019 Army Aviation Digest - Mar 1967

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UNITED

DIRECTOR OF ARMY AVIATION , ACSFORDEPARTMENT OF THE ARM YBG Robert R. Williams

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COMMANDANT U. S. ARMY AVIATION SCHOOLMG Delk M. Oden

ASST COMDT, U. S. ARMY AVIATION SCHOOLCOL M. H. Parson

DIGEST ED ITORIAL STAFFMAJ l. J. Herman Jr . Editor-In-ChietRichard K. Tierney, EditorWilliam H. SmithDiana G. Williams

GRAPHIC ART SUPPORTHarold G. l innHarry A. PickelDorothy l. CrowleyAngela A. Akin

DIRECTOR, U. S. ARMY BOARD FOR AVIATIONACCIDENT RESEARCHCOL Warren R. Williams

USABAAR EDUCATION AND LITERATURE DIVPie rce l. WigginWilliam E. CarterTed KontosCharles Mabius

RMY VI TION1GESJMARCH 967 VOLUME 3 NUMBER ARMY HELICOPTER TRAINING. COL George W. PutnamTRAINING AN AIRMOBILE COMPANY.COL J Elmore SwensonSOMEONE HAD TRIED TO KILL ME.MAJ Charles W. Watkins.FLYING IN EUROPE. LTC Donald E. MulliganMEDITERRANEAN ADVENTURE. MAJ K. R. Jones

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NEVER AN AIRCRAFT DOWN FOR AVIONICS. LT Samuel 1C. Wilson and LT Norman E. ColtenAIRMOBILE FIREPOWER-. COL William F. Brand. Jr.. 1LTC Morris J. Brady and MAJ E. K. JohnsonADDITIONAL DISTRACTORS TO TAIL ROTOR FAILURE. 2CPT Earl WebbUHl ENGINE INLET AIR PROTECTION, 2MAJ William H. Edwards, Jr.HUNG OUT ON A LINE 3CRASH SENSE

THE CASE FOR BY -THE-BOOK MAINTENANCE, 3SUPERVISION, AND INSPECTIONSDELAYED DEC ISION 5PEARL S, R. T. Frothingham and M. Gilpartick 5MAINTENANCE PERSONNEL, William H. Barthel 5WINNERS PLAY BY THE RULES. Ted Kontos 5THE NEED FOR SELFDISCIPLINE

CAMP NUMBER TWO, PVT Mary Jo IzsakMEDIC AND GUNNER-TO THE RESCUEFOG DISPERSAL

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Inside BaBack Cov

T he m iss ion of th e U. S. AR MY AV I AT IO N DIGE S T is t o provide i n fo r ma t io n o f a n operatIOnfun cti ona l na tu re co nce rnin g sa fe t y and ai rcra ft a ciden t p reve nt i on tr ai nin g ma in tenance op e raresea rch and develop ment av ia tion medic ine . and ot her re la ted da ta.T he DIGE ST is an officia l Depar tmen t of the Army pe r iodi ca l pub l ished monthl y unde r the supe rvof th e Co mma ndant U . S. Ar my Avia\ion Schoo l. Views exp resse d he rei n a re not necessa rily th oD pa rtm e n t o f the Arm y or the U. . Army Avi a ti on Sc hool. Pho tos a re U. S. Arm y un less o thespec i fied. Mat e ria l may be r ep rinted pr ov id ed cr edi t is give n to th e DI GE ST a nd to th e a utho r uoth e rwise indicated.Articles p hotos a nd items o f int e res t on Arm y Avi a t io n a re invit ed . Direct communi t ion is aui=ed to: Ed it or .i llC hi e U .S. Arm y AviMion Diges t Fort Ru ck er, A laba ma.Use o f fund s for p rint i ng th is nub l ica ti on has bee n a p pr oved by H ea dquarte rs Depa r tme nt oArm y 29 Decem be r 1964.Ac ti ve Ar my units rece ive dis tr ibuti on un d e r th e p inp oi nt distributi on sys tem as ou tl in ed in AR 20 Ma rch 62 and DA Circ ul ar 310 -Si 14 March 63. Co mp le te DA Form 12.4 a nd se nd d ir ec tl y toAG Publi cations Ce nt er 280 0 E ast e rn Bou levard Baltimo re :\Id . 21 220 . F or an y change in distr i bre quire ments merely ini ti a te a revis ed DA Form 124.Nati onal Gua rd a nd Arm y Rese rve un its subm it requirem ent s throu gh th e ir sta te adju tan ts gene raU . S . Ar my Corps co mm ande rs respective ly.F or those no t eligible for offic ia l di s tributi o n or who des ire pe rsonal cop ies of th e DIGE ST paidscri p t ion S4 S0 domes ti c a nd SS .SO overseas ar e a vaila b le from th e Sup eri n te nd e nt of Doc um e nts

Governme nt P rin ting Ofuee W a s h i n ~ t o n D. C. 20402.


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Army Helicopter Trainingolonel George W Putnam

N 1964, THE United StatesArmy AviatiDn SChDDl develDped and submi t ted a Program

Df InstructiDn fDr an advancedflight training CDurse designed,amDng Dther things, tD qualifynewly graduated Army helicDpterpilO ts fDr assignment directly tDDperatiDnal Army aviatiO n unitsin Vietnam. This recDmmendatiDn triggered a thorDugh, thDughquick, I k at the Army s initialentry helicDpter training course.TWD related factDrs prDmpted theanalysis; first, rDtatiDn pDliciesand the ever- increasing cO mmitments Df Army aviatiDn in Vietnam wDuld SDDn require that allnewly graduated Army AviatDrsbe assigned directly tD Vietnamwi th as i tle in tervening timeafter graduatiDn as pDssible; and,secDnd, the new CDurse wO uld require additiDnal critical reSDurcesin aircraft, instructDr pilDts anddDllars, much in demand elsewhere.

Fr m the analysis came O nefundamental fact which dDminated cDmpletely all Df the thercDnsideratiDns. The Army s initial entry helicDpter flight training prDgram Df 32 weeks and 216flight hours aid nDt qualify thegraduate t fly any Df the DperatiDnal helicDpters in, r thenexpected t be in, Vietnam.

Fr m this fact came a clear-cutDbjective: t revise and reDrientMARCH 1967

esterday and odayThe views expressed in this article are those of the authorand do not necessarily represent the official position ofthe United States Army Aviation School or the Depart-ment of Army. Colonel Putnam is now commanding theDivision Artillery of the 1st Air Cavalry Division. He is aformer Deputy Director of Army Aviation and, more re-cently, Assistant Commandant United States Army Avia-tion School.

the initial entry training prDgramS that its graduate WDuld bequalified to perform DperatiDnalmissiDns in Vietnam (and lessclear cut, but essential) with anabsDlute minimum Df in-cDuntrytraining and indDctrinatiDn. Thechallenge was unique and aCCDm-plishment Df the task wDuld betime-cDnsuming. It was uniquebecause nD ther service sent newly rated pilDtS direct tD cDmbat(always there was an interveningperiDd Df advanced r unit training Df Dne s rt r anDther); timecDnsuming because different aircraft wDuld be required in theadvanced phases Df training andmuch new equipment, such ashelicDpter weapDnry and navigatiDn aids, was needed.

Fr m that beginning cameeventually the Army s 16 / 16 CDncept Df helicDpter flight traininginitiated with Class 66-1 at theUnited States Army Primary Helic pter School, F rt Wolters,Texas, in July 1965. TD highlightthe dDminant features Df the newCDurse the fDIIDwing table CDm-pares the old 12 / 20 cDncept (12weeks at Fort WDlters and 20weeks at Fort Rucker) with thenew 16/ 16 prDgram. (See chartp.2)

In addition, all performance b-jectives, lesson plans, and CDncurrent training were examined tDensure cDmpatibility with the mission at hand: training aviators fDr

Vietnam. When the review revealed otherwise, the item was revised r eliminated. Simply stated,if training cO uld nDt be utilizedduring the t ur in Vietnam, itwDuld most certainly be forgotten,and, therefDre, was cDnsidered notprDductive. CDld weather DperatiDns was Dne example.

Twelve classes, or lllore than2,700 aviatDrs, have now beeng.raduated from the new courseand eleven Df these classes, orabDut 2,400 aviatDrs, are currentlyserving in Vietnam. The twelfthclass, Df abDut 300, is due to arrive momentarily. Since practicallyall Df these are operational UH-1pilDtS or copilots, a safe cDnclusiDn would be that nearly all cDck-pit-seat UH-1 pilDts now in R VNare new graduates of the 16 / 16course.

The questiDn then becomes:How are these new graduatesmeasuring up t the course b-jectives?T 0 begin wi th , wha t are thestandards for graduation? In considering this questiDn one mustrecDgnize that flight grading Dn-sists Df a series Df subjective judgments with literally dDzens ofvariables affecting a particulargrade. The only really unquestiDned grade is the unsatisfactDrygiven when the student cDmmitsa dangerDus act - an act thatmight, in the opiniDn Df the InstructDr pilDt, have resulted In


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rmyHelicopter Trainins damage to the aircraft, its occupants, or both. And, even here,the timid or overly cautious instructor pilot can cloud the issueby taking control of the aircraftprematurely. An interesting observation on flight grading, givenmore in earnest than jest, wasmade by a high,ranking naval offi-cer with many years experiencein flight training during a conversation with me some monthsago. His view was that flight grading was more witchcraft than science, and far more influenced byvariables than even an academicsolution to a classroom tacticalproblem.But back to standards Duringthe primary phase of 11 0 flighthours at Fort Wolters the studentmust obtain passing grades fromhis instructor and, additionally,complete three check rides-presolo, primary and advanced-eachgiven by specially selected checkpilots. The last two of these areadministered by trained standardization check pilots who carryno students but administer checkrides to all. On each of these, thestudent must receive a passing

1. Preflight (for WOCs only)

2. Cross-country dual3. Cross-country solo .4. Low-level navigation .5. Night f lying. . .

grade. f not, he is evaluated, tdetermine whether he should receive more training or be eliminated. In the advanced phases atFort Rucker, the same principlesapply, but the student must passfour check rides-basic instruments, advanced instruments, contact (UR-l transition) and tactics.Now have the schools lowered

their standards because of thepressures of Vietnam and theshortage of pilots?Let's start by looking at attrition. Ten years ago flight traininginput far the average class exceeded those being graduated byfrom 25 to 35 percent. Invariably,about 2/ 3 of the losses resultedfrom flight deficiencies and theother third from other causes. Inone particular WOC class, whichI recall, the attrition was 65 percent of the input. Why, then, isattrition now averaging less thanhalf that experienced ten yearsago?

There are many reasons: Many of the officers now complete ROTC flight training during college. Those who can t flybecome airsick, or simply lose

12/204 weeks

2.5 hours3.5 hours1 hour6. Instrument qualification . . . .7. Tactical applications of instrument flight

12.5 hoursNo8. Low-level autorotations . . .9. Flight at maximum gross weights10. Formation flight-day .11. Formation flight-night .12. Helicopter gunnery training13. Survival, escape & evasion14. Unit type field exercise

15. Decca training16. Crew training . .17. Full UH-} qualification

NoNoNo3 hoursoNo24 hours3 daysNoNoNo

interest in flying, don t apply forflight training when called to active duty. The long-term noncommissioned officer used to be commonplace in Warran t Officer Candidate training; now he is the unusual exception. Not that the experienced NCO was an undesirable applicant; the exact oppositeapplies-he was and still is a highly desirable entry. But, the unadorned fact is that the motivation for many NCO applicationsat that time was either a desirefor transfer or to imp.rove statusrather than the fundamental requirements-a desire and a motivation for flying. The harsh, Prussian-type orientation of the woe course wasmodified. An obvious result waa reduction in self-initiated eliminations. Arbitrary standards were ignored. Training was shaped tothe individual, and now the Armyhas many, many fine pilots whodid exceed, for example, a formelimitation of 10 hours pre-solobefore they were able to fly alone Last, and the most overriding

16/16weeks - Concentrate academics more on map readingnavigation, weather, and otheraviation subjects.4.3 hours'*'18.5 hours'*'4.5 hours'*'30.7 hoursYes (50 hours)YesYesYes7.5 hours1 5 hoursYes26 hours8 days (in an RVN environ-ment)Yes (beginning March 67)YesYes

'*'Instructional flight hours only. They do not include the many hours of practice of these important flight maneuvers during flight to and from training areas, during practice airmobile operations, etc.

2 U. S. ARMY AVIATION DIGEST


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Tailored to fit the individuali:;1fluence of all, was the Army'sdecision to permit enlistment ofotherwise qualified high schoolgraduates specifically for flighttraining. One need only attenda WOC graduation party, or talkto the highly motivated WOCsons of business executives, farmers, bank presidents, Air Forcegenerals, plumbe.rs, and careerArmy men, to recognize the popularity and across-the-board appealof the Army's WOC flip:ht training program. I t is certainly one of,if not the most, popular militarytraining prog.rams ever initiated.

All of these factors have causeda dramatic reduction in attritionduring primary training at FortWolters. On the other hand, thelow attrition in helicopter training at Fort Rucker has been relatively constant for many years.N ever, in the past five fiscal years,have losses been more than 2.5percent or less than .6 percent ofinput. As of January 1967, attrition at Fort Rucker for FY 67stood at 1.5 percent. And hereeven the most persnickety nitpicker would have to agree thata variation from year to year ofless than 2 percent is insignificantas a factor in evaluating quality.

In fact, attrition at Fort Ruckerfrom class to class, while programmed at 3 percent, is not predictable. In one class, 100 percent of those en tering will beg.raduated; in another, ten ortwelve may be lost for a varietyof reasons, among them disciplinary, injury, self-initiated elimination, flight deficiency, etc.

One could conclude from theforegoing that quality has reallyimproved due to more demandingrequirements and higher standards for completion. But, theultimate question is: What ishappening in Vietnam? From theCONUS training point of view, aMARCH 1967

completely objective approachkeeping in mind time, dollars,length of tour, etc.- would be tograduate a new Army Aviatorqualified to be a copilot in Vietnam for his first six months withthe potential of becoming firstpilot, or aircraft commander, forthe last half of his tour. The factis, however, that the new graduatein RVN is becoming an aircraftcommander on an average of onlytwo to three months after arrival-some with as little as one month'sexperience. Is this a tribu te toprevious training, an indication ofoperational shortages, or an indictment of the commander inRVN?

The first really applies. It s atribute to training.

Another pertinent conclusionwas drawn rom an analysis ofnoncombat UH-l accidents inVietnam over a recent threemonth period. Then, althoughmost of the UH-I pilots in Vietnam were new graduates, theycaused less than half of these accidents. But, in mitigation, onereally cannot draw meaningfulconclusions from aircraft accidents tatis tics wi thou t detailed analysisof the cause factors for each accident. As a sidelight, however, theanalysis did indicate that if a newgraduate were to have a noncombat accident, it would probablyoccur during his first four monthsin-country.Last, with respect to quality, wehave the judgments of the usersthe commanders in Vietnam. I'llquote a few of many commen tsreceived, as well as one from anew pilot himself.

Brigadier General G. P. Seneff(CG, 1st Avn Bde): The productyou are sending us is superb.Colonel L. S. Browne (formerARVN Division Advisor): Ashort note to tell you about your

people over here. As you haveheard before, your guys are doing8.n outstanding job. Not only dothey transport my troops, theyfurnish fighter cover, medevac,R&R flights, close-air support.You name it, they will do it.

Colonel H. K. Joost (formerCO, 145th Avn Bn): I have thehighest praise for the enlisted,,.'arrant and officer product thatis being received in Vietnam. Hearrives there not only well-trainedand indoctrinated, he is also highly motivated-which can only beattributed to the m l attention he receives while at theSchool."

Colonel J. Marr (CO, 17thAvn Gp): There is no questionbut what we (the Army) are graduating the most highly qualifiedaviator in the history of the Aviation School. All he lacks is experience, and in the final analysisthere is no substitute for that andhe can't get it in school. He comeshere well qualified to become aproficient combat aviator in ashort time, but there is no wayhe can be one when he gets here:'

Warrant Officer W. L. Jackson(Army Aviator, 9th Cav Sqdn):In twelve years in the Army,

never have I seen training fit therequirement so well. We didthings during the tactics phase atFort Rucker exactly like we dothem here. The only differencesare that here you have rougherterrain, worse weather, more fly-ing and you get shot at.

And now for a really subjectivejudgment as Assistant Commandant, USAAVNS, I had directresponsibility for the advancedflight training of most Army Aviators now in Vietnam.I felt then that their trainingwas good; now that I'm servingwith them, I've found no reasonto change that view


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7/68

Colonel Elmore Swenson

anIRMOBILE COMP NY

T his article is pegged specifically at helpingthe UH 1 and CH 47 unit commanders and staffsin readying a CONUS aviation unit for deployment

UCH HAS BEEN saidabout the best means to

an Army aviation unitdeployment. But with the exof an article appearingthe September 1966 A VIA

DIGEST, much less haswritten on the subject. Theof the Army and Hq ,

have now decenthe activation and fill ofthroughout

The 10th Aviationwill therefore no longerthe sole tactical organizationraining base for these uni ts.

To facilitate spreading thetraining

deploying aviation uni ts, theAviation Group has a rush

underway to up-date docof the entire air

activation-through-deploycycle. Guide for Activation,

Training and Deployof Aviation Units was ap

for reproduction and dis1967. Pend-

crews of the 200th Avio m ~ a n y (Medium Helicopter) pracwith 'piggy-back loads of 105 mm

and tandem-rigged ammunitiont Fort Benning, Ga

1967

ing publication and distributionof the guide, however, this articleshould pass on a few time-saving

tips. t is pegged specifically athelping the UH-l and CH-47 unitcommanders and staffs in readyinga CONUS aviation unit for deployment.

Commanders interested in thesetips should be focused on training their units on a decentralizedhasis sans the aid of more than anominal number of skilled cadre.This system may appear to bethe new look in airmobile unitactivation, fill, training and deployment, but it is actually nothing more than a slow-down-tonormal process. The normal training process is thoroughly coveredin Army Training Program 1 77for airmobile It) companiesand a Third U. S. Army programof instruction for medium helicGpter companies. These references provide the best knowndeparture point since they arebased on the self-training processwherein a unit is filled with TOEequipment before or as it trains.

Certain characteristics or weaknesses in the ATP should be recognized as requiring modification

to meet the requirements ot specific programs. These follow: The ATP does not includearea orientation type subjects. The ATP is based on 18weeks of unit training time withTOE and personnel 70 percentnormally considered minimum fillnecessary). The ATP uni t training phases

team, section, and platoon) arebased on a certain minimum oflVIOS-qualified/ school-trained personnel in the hard skills such ashelicopter mechanic, radio mechanic, or technical inspector.

These points are stressed not tohighlight weaknesses at the ATPper se, but to indicate the needfor certain modifications modification authority for deviations tothe ATP is contained in paragraph 4 of the appropriate program in effect) .The most significant lessonslearned in the Group have beento expect: changing requirementsjn both POR and area orientationtype subject material; the variability of training periods allotted; and a critical shortage/COL Swenson s CO 10th Avi-ation Group Ft Benning Ga.

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Training an irmobile Company sion of mandatory POR subjecshould occur earlier in the fcycle if the company is beintrained as part of a battalion.consolidated input would justirecurring cycles of POR traininunder a battalion committee other critical maintenance anflight training functions arecontinue.

slow-down in school trained fillerpersonnel in the hard skills. The10th Aviation Group trainingsupervisors, including those in itssubordinate 37th and 44th Battalions, have thereby gained awealth of experience in trainingflexibility as shown by a localnew look in master training

plans (fig. 1) .This flexible training manage

ment device was developed withinthe Group for determination ofmilestones in an airmobile unit'straining cycle. It is adaptable teither light or medium helicoptercompanies. It is adjustable tovariations in either personnel onstation date (POSD), aircraftreadiness date (ARD), equipmentreadiness date (ERD), or personnel readiness date (PRD).

Note, however, that the t ~ i n i n gportion of the cycle may begin atany time after passing 50 percentpersonnel fill and when at leastFigure

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LEGENDGREEN PERSONNEL AND ADMINISTRATIVE ACTIONBLACK TRAINING BY THE GROUP CADREW ITE COMPANY SELF TRAININGGREY MAINTENANCE MOVEMENT

the equivalent of a compositeflight platoon in equipment hasbeen received. An intensive 0 Tprogram will not be profitableuntil a cross-section of TOE forboth service platoon and TC detachment is on station. Whileawaiting the POSD milestone,maximum emphasis is placed onindividual filler training qualifications and personnel actions;i.e., one-time training requirements as shown on DA Forms 20and 66, a review of medical qualifications (assigned or potentialcrews), and initiation of personalaffairs actions.

Aviator tranSI tIon traInIngshould begin at the earliest dateto provide the nucleus of an operational flight platoon. As thefirst aircraft is received, potentialcrewchiefs should begin immediate OJT up to 3 per aircraftunder the supervision of an experienced crewchief. The first ses-

M STER TR INING PL NIRMOBILE P CKET

Surely, the training most crical to the success of the unit mision is that which welds a teacapable of performing tacticairmobile assaults. For the slickthis teamwork is developethrough perfection of formationcontrol, and timing of assaulinto unimproved areas. For thmedium (Chinook) company, thperfect training vehicle for teamwork is practice of accuracythe placement of an artillery batery into its firing p0sitionwith ammunition and crews, usinthe piggy-back principle of eternal loads.

The most difficult portionthis team training for both Ch

U. S. ARMY AVIATION DIGES


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and Huey companies is theof gunnery training. An

company is not concombat ready when all its

are qualified in theirweapons. Likewise, inweaponry qualification

only a part of the necessaryin an airmobileDoor gunner training

not as difficult to accomplishtraining of the armed helicop

er pilot and crew training buttypes create almost insurproblems for a sepa

company i f the self-trainingrocess is used. It is in the solution to the gunnery training prob-

that 10th Aviation Grouphave developed theexpertise. During the activation fill, training and deploy

of approximately 20 airmoile companies from Fort Bening a wealth of gunnery inforation and experience has been

accumulated.First, it has been learned that

the problems result fromcombination of shortages, such

lack of adequate range facilities or existing range facili ties notinadequate ammuni-tion allowances; a shortage of

armament maintenanceand experienced gun-

ery instructors. In decentralizedtraining facilities, post range control personnel will not be familiar

ith aerial gunnery requirementsthe safety standpoint and

tend to overemphasize theafety fan. A summary of the mostgunnery procedures used

at Fort Benning are restated below, since they are not necessarilyincorporated in current regulations or training media.

Facilities. Range safety require-ents for initial firing of students

as shown in figure 2. On thisange the students must prove

their ability to keep all impactsithin 500 meters longitudinally

MARCH 1967

CFL

SFL NOT TO SCALE)READYLINE

Figure 2 is a reprint of a drawing appearing with Rotary Wing ArmamentTraining Jan 1965 DIGEST) with some marginal data eliminated for simplicityFigure 3 is a reduced fan for 2.75 rockets. I t was approved by the SafetyDivision, Headquarters, U. S. Army Materiel Command on 8 October 1966, providedthe specified safety control plan s rigidly adhered to.

CFL

SFL

RE DYLINEand 200 meters laterally of thetarget. When the instructor pilothas satisfied himself that the student s) can accomplish this (usually within one day s time), thenthe criteria shown in figure 3satisfies range safety requirementsfor subsequent periods of firing.

NOT TO SCALE)

Ammunition The followingammunition allowances are considered a minimum to accomplishthe desired degree of individualand fire team training:

7.62 mm (linked) 7,000 rdsper aviator; 4,000 rds per doorgunner.

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Training an Airmobile Company 2.75 Rocket, FFAR, 112 rds

per aviator. 40 mm cartridge, 450 rds peraviator.Safety ontrol Plan The fol

lowing procedures are used to implement and/or amplify localrange regulations:

The range control officerRCO) may control the rangesand range firing from an aircraft1 from the ground, but must

have radio contact with all aircraft conducting firing and be ina position to maintain visual contact. He will not be in one of thefiring aircraft.All firing will be conducted inthe firing lane between the Start

Fire Line (SFL) and the CeaseFire Line (CFL). Easily identifiable markers will be placed onthe ground to indicate the limitsof SFL and CFL. All firing will

be conducted under the directsupervision of an instructor pilotafter being cleared to fire by theRCO.The minimum slant range fromthe helicopter to ground burst forthe 2.75 rockets and 40 mm grenades will be 300 meters. No targetwill be overflown at less than 300feet absolute altitude.

When firing the modified range(fig. 3), targets will not be engaged beyond 1,250 meters withthe M-60 machineguns, or 3,000meters with 2.75 rockets.

During door gunner firing,there will be positive communication between the pilot andstudent gunner, a safety officerwill be aboard with access to allfiring systems in the cargo compartmen , and an P will beaboard to ensure that no firing isconducted when the aircraft isoff course or in an altitude/posi-

UH-l s of the 176th Aviation Company AMUparticipating in advanced unit training airmobileassault) at Fort Benning, Ga.

tion that could cause impacts ouside the impact area.The 10th Aviation Group hrecently received numerous visors involved in airmobile un

training from various CONUinstallations. They were warmwelcomed and wherever possibgiven training material and brieings in their areas of interest. Th44th Battalion, moreover, has prvided airmobile company suppoto alerted units of the CONUdivisions. The pattalion has alconducted a complete gunnetraining program for aviators andoor gunners from these divisionIt is hoped that in additionvisits to the 10th Aviation Grouthe soon to be published guilnd this article will provide ready reference for all. Mea'while, the 10th Aviation Groustands ready to share experien

and assist all others responsibfor future training of airmobiuni s. ------


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MARCH 1967

omeone ad Tried

T KILL MMaior harles W Watkins

HEN I WENT throughhelicopter transition back

in 1957 most of the flight maneuvers for the OH-13 called for3100 rpm. You could depend onthat instructor to roll his eyes tothe tachometer many times during the flight period and remonstrate, "3100, 3100." Another thingI did not forget was rotor in thegreen." Always keep your rotorin the green. f you have to redline a gauge, pick one of theolhers, but keep your rotor in thegreen.

Then why was that unfaithfulneedle dropping? Was there something wrong with the stupid instrument? The crewchief was going to hear about this. Inefficiencyon his part. But waitl Bothneedles, still joined, were fallingfrom 3100 rpmlAt this time my heart shouldhave been pounding in my chest.Adrenalin should have been racing through my blood and coldsweat popping out on my forehead. As the OH-13 stopped fly-ing, taking on the characteristicsof a rock, and began its rapid descent toward mother earth, mythoughts should have been of my

family. Did I leave my wifeenough insurance money? Whatwould she ever do without me?None of these things happenedto me. What did happen was thatthe OH-13 I attempted to hoversettled back down to the ground,not 600 feet but about 6 inches.l\ y forehead was not covered withperspiration but wrinkled as mymind puzzled what had happened.Since then the event has takenon a much clearer realization:SOMEONE HAD TRIED TOKILL ME

Let me tell you my story. I didnot hurry out to the airfield on ahot sumnler day. The scene wasGermany on a cold winter day.The reason I did not hurry tothe airfield was the falling snowand ground fog that filled thesky with zero-zero conditions. Myboss and I were to fly to the division headquarters airfield, pick upanother OH-13 helicopter, and flyout to the field to support a combat command for a week.

It was the middle of the after-M J Watkins s assigned to the205th viation Company FortSill Okla.

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I was shocked into action as yboss called IIYou re on fire '1noon before the weather lifted tohelicopter minimums. With aboutY hours of daylight left we hadjust enough time to pick up theother OH-13 and join the groundunit in the field. Arriving at theheadquarters airfield I completedadministrative arrangements forthe loan of the OH-13 and filed anew flight plan for the two 13s.Preflight and runup were norma]with no problems. We were onour way to the field.

We never made it. Within 20miles of the field location, theweather became worse. Faced withmaking a decision, we turned ouraircraft away from the badweather. Following the path ofgood weather we found ourselvesin a valley heading back to thehome station. We would spendthe night with our families andpursue our mili tary task in themorning. The decision seemedright as we arrived at the homeairfield after dark with snow andground fog closing in fast.

We congratulated ourselves onour astute judgment and decision-making ability. The helicopters were shut down on theramp and wheeled inside thehangar to protect them from thecold and to make starting easierin the morning. We could refuelin the morning. The hangar wasconstructed with a low ceiling forsmall airolanes; the main rotorblades o the helicopters couldnot be tied down inside withouthitting the rafters.

Early the next morning theweather was flyable. The helicopters w ~ r rolled out onto theramp, refueled, and preflighted.Runup was normal and all instruments were in the green. My bosswas at a hover about 100 feet

away, waiting for me to pick upand follow him in flight. It lookedlike a good day for flying.

This brings us back to the startof my story. As I pulled pitch formy hover, the OH-13 rose about6 inches and settled back tothe ramp with both tachometerneedles falling. As I began to lookat the other gauges to determinethe cause, I was shocked into extremely fast action by my bosscalling over the radio, You're onFIRE. It is impossible to measure how many things can be donewith such speed when the occasion presents itself. All switcheswere shut off, safety belt released,door opened, and myself propelled around the comer of thehangar in less time than it takesto tell about it.I was unable to provide somepertinent information to the as-sistant division aviation officer.He wanted to know the transmission oil temperature at the exacttime my boss was informing methe aircraft was on fire. This wasalso the time I was making anexit from the helicopter. All Icould say was that all instrumentswere in the green when I attempted to hover. The fireturned out to be without flamesbut a great amount of smoke coming from the transmission housing when something inside, forsome reason or another, decidedto freeze the transmission.I needn't have worried aboutmy incomplete report to the as-sistant division aviation officer.In about two weeks a fellow aviator from the division headquar-ters airfield came to interview meand refresh my memory of theseevents in the form of an investigation. It seems the aircraft main-

tenance unit from higher headquarters, who were kind enougto replace the transmission on thiaircraft, were curious about thtransmission freezing. Their diagnosis indicated some foul play olack of professionalism on the parof the aviator in regards to preftight/runup. The investigatowanted to know if at any time diI start the engine with the mairotor blades tied down.Most insurance companies prescribe procedures to be followeafter an accident: assist the injured and take names of witnesseMany witnesses attested to the facthat at no time had I started thengine wi th the blades tied downIn fact, the blades of that helcopter had not been tied dowfrom the time I received the aircraft until after the accident. was exonera ted.Procedures and training wihelp eliminate an aviator's embarrassment of starting the enginwith the main rotor blades tiedown. One of the more effectivprocedures is to swing the blad90 0 when it is untied. But as lonas we have a main rotor systemwhere the blades are tied dowthis type of accident can happenJust one more reason for the usof a valid checklist.The aircraft maintenance unidiagnosed the primary cause fothe transmission freezing was thengine being started with thmain rotor blades tied down. believe them. A review of thmaintenance records for this helicopter revealed no writeup for start with the blades tied downThere is no doubt in my minthat someone had started this helicopter with the blades tied downThere is no doubt in my minthat by not writing this information in the book so appropriatmaintenance action could takplace, either by ignorance or embarrassment, SOMEONE HADTRIED TO KILL ME.

10 U. S ARMY AVIATION DIGEST


13/68

FLYING IN EUROPErmy Aviators assigned to USAREUR for afirst tour find flying rigidly controlled. Those

who were assigned to Europe in the 50s willfind many changes in flying rules and pro-cedures.

Lieutenant Colonel Donald E Mulligan

SSIGNMENT to Europe requires the aviator to learnflying rules and to develop

with differing weatherand terrain. For exam

recent changes in night flYIngfor West Germanynight VFR

except in local traffic patArmy Aviators assigned to

for their first tour willthat all flying is rigidly con

who were as-to Europe during the 50s

in flyingand procedures.

1967

For many years following theend of World War II, Allied military personnel were almost theexclusive users of European airspace. A few basic regulations governing Army aviation operationssufficed to ensure safe flying conditions. Gradually, as the variousnations of Europe recovered fromthe ravages of war, commercialaviation developed and increasedin tempo. Today the combinationof European military and civilianaircraft constitutes a significantportion of the world s total aviation fleet.

As a result of this aviation expansion those few basic post WWIIregulations gradually became inadequate. The most critical areaof European aviation operationsis in Western Germany where themajority of USAREUR s aircraftare based. This is a country, muchthe same in geographic size as theslate of Arizona, over which operate military aircraft of all theN ATO countries, commercial air-COL Mulligan is attending theArmed Forces Staff o l l e g e ~ Nor-folk Va


14/68

Flying In uropelines from all over the world, priva te aircraft, and local sports fly-ing clubs. Within 50 nauticalmiles of Heidelberg are 28 estabUshed airfields. Without adequateregulatory procedures aeronautical chaos would reign. Consequently, Army aviation regulations have become more complexin the past few years. This situation, coupled with the Communistdemonstrated intention of destroying any U. S. military aircraft fly-ing over Soviet bloc countries,places unusual demands on theaviator assigned to USAREUR.Department of the Army recognizes that it is impossible to design a regulation for worldwideapplication to Army aviation.Therefore, most Army regulationsin the 95-series contain a provision which permits major commanders to publish implementinginstructions or regulations. In thecase of USAREUR this was ac-complished with the publicationof USAREUR regulation 95-5,Regulations for U. S. Army Aircraft and Aviators.

This document is the basic fly-ing regulation governing Armyaircraft flights throughout Europe,the Middle East, and Africa. Itwas designed as a supplement toexisting Army regulations andprovides the greatest possiblelatitude for peacetime operationsthat the various European nations and existing treaties permit.USAREUR regulation 95-5 contains only those items which experience dictates must be regulated and does not repeat regulatory procedures of other publications. In spite of this concept, thedocument is lengthy and demandsdetailed study on the part of anyaviator who operates aircraft under its provisions.A significant portion of the2

publication is devoted to operations within the Central European Buffer Zone and Air DefenseIdentification Zone ADIZ). Toreduce the possibility of an inadvertent overflight of the EastGerman or Czechoslovakian borders, operations in the ADIZ arelimited to the minimum essentialmissions. An aviator who unfortunately finds he has flown into aSoviet bloc country is faced witha number of unpleasant possibilities. First is the very real possibility of being shot down by Sovietbloc air defense elements; nextfollows the embarrassing international publicity and complications for the United States government; and if he is fortunateenough to have survived, thereill be numerous boards of inquiries including a flight evaluation board.

Creation of the Central European Buffer Zone resulted fromthe loss of two USAF aircraft earlyin 1964. I t was designed to ensurethat military aircraft operatingnear sensitive borders remain under positive navigational controlat all times. The principal meansof identifying aircraft is throughthe use of transponders. Squawking the wrong mode and code orfailing to follow your flight planwill resul t in NATO air defenseelements intercepting your aircraft. Strict compliance with theprovisions of USAREUR regulation 95-5 ensures successful completion of assigned missions withno embarrassment to the aviatoror the U. S. government.

Operating an aircraft in thecontinental United States requiresthe aviator to adhere to rules inboth military publications andthose of the Federal AviationAgency. Operations in Europediffer because each nation pub-

lishes its own rules of the aIMost countries are members othe International Civil AviatioOrganization (ICAO) which atempts to standardize aviatiorules and regulations. Standardzation becomes difficult since eacnation reserves the right to publish additional rules for its owairspace. Consequently, the ArmAviator must be familiar witcurrent U. S. military regulationsICAO rules, and rules of the aiof the country over which heflying. Differences in rules anregulations can lead to potentially hazardous conditions. For example, one country issues altimeter settings measured abovmean sea level while another givea zero setting for the airfielelevation.

Fortunately, the English language has been adopted as standard for ICAO radio communications. However, difficulties stiexis t, since the ma ori ty of trafficontrollers speak English with aaccent. This complicates copyinof difficult ATC clearances oentering traffic patterns at strangairfields. Failure to understandclearance can lead to a dangerousituation. There is no ready solution to this problem and it taketime for the new aviator to adjust to the language problemsThe best solution is to pay closattention to instructions being issued by controllers.

To properly prepare newly assigned aviators for operations iEurope, USAREUR regulatio350-5, USAREUR Training Drective, requires a 10-hour flyinorientation for all aviators. Thit aining includes flying with experienced personnel and visits tvarious flight control agencies. Iaddition to this training eacnewly arrived aviator must atten

U. S. ARMY AVIATION DIGEST


15/68

USAREUR Regulation 955 governs U. S rmy flightsin Europe the Middle East and Africaa two-day classroom indoctrina-tion course. Both of these requirements must be met before theaviator is permitted to fly solo. Atthe conclusion of this training,aviators are prepared for bothlFR and VFR flying in Europe.

Army Aviators operating military aircraft crossing internationalboundaries must be familiar wi ththe provisions of the USAF Foreign Clearance Guide (FCG).This publication is composed oftwo versions; one is unclassified,the other classified. FCG containsessential information on suchitems as customs requirements ofall nations in the world as well asentry and departure requirementsfor U. S military aircraft.

Many countries require priornotification of military flights andsome other nations can be enteredonly after issuance of a diplomat-ic clearance from the des tination country. Awaiting receipt ofdiplomatic clearances can delaydeparture of a fligh t for as longas 21 days. To prevent an embarrassing situation, it is essentialthat all requirements of the FCGbe complied with before depar-ture on an international flight.Some NATO countries modifyentry requirements for militaryaircraft of member nations, butFCG requirements apply in themajority of cases.

It becomes apparent that theaverage aviator does not have timenor access to all published material to become intimately familiar with the various rules andregulations devised for operationsil.. Europe. One of the tasks of theclearance officer at Army FlightOperations Facility (AFOF) is tobecome an expert in Europeanfiying regulations. It pays to poseany questions to AFOF before departing on a flight because thatMARCH 1967

organization has the resources toprovide you an answer.A good example of a differencebetween flying in CONUS andEurope is the military flight plan.To assist the various ICAO member nations in transmitting U. Smili tary aircraft flight plans itbecame necessary to replace theDD Form 175 with a flight planin a format compatible withICAO transmissions systems. Thisresulted in the three U. S militaryservices designing a flight planwhich differs in form and contentfrom the DD Form 175. All U. Smilitary aircraft flying in Europeuse USAFE Form 249 which hasprovisions for entering the standard flight plan information butcontains additional requirementsover those required in CONUSflight plans. The different formatand additional items make it compatible with lCAO systems.Adverse weather is a major factor which should be taken intoaccount by the aviator while fly-ing in continental Europe. Germany and France lie on roughly

the same latitude as the northernborder of the USA. This, coupledwith its geographic location nearlarge expanses of water, results ingenerally poor flying conditions.Winter weather in Europe is charo.cterized by prolonged periods oflow ceilings and reduced visibilities coupled with freezing levels

or near ground level. An aviator's first year of flying in Europewill expose him to weather conditions which require careful studybefore he departs on a flight.

f you are a seasoned veteran ofEuropean flying and are return-ing for another tour, this articlewill probably provide a certainamount of nostalgia for the goodold days. f you are an aviatorcoming to Europe for your firsttour there is probably a certainamount of anticipation for whatthe future holds. In either case,this article will serve as a briefindoctrination. Flying in Europedemands a completely professional approach to the executionof responsibilities as an ArmyAvia tor. . ~ a . . . J

CH 3.4s land tr ps during maneuvers in Europe

13


16/68

MEDITERR NE N DVENTUREWAS ASSIGNED to an ArmyMap Service project in Libya

and it was a pleasure to be spending 30 carefree days touring Europe with my family. s the endof my leave was fast approachingI began to make plans for thereturn trip to Tripoli. A telegramfrom my unit arrived directingme to pick up a TO-ID at Coleman Barracks Mannheim Germany and deliver it to my unitin Libya. Free transportation forme. That sure was a welcome tomy shattered budget.

Two days after receiving thetelegram I was at Coleman Bar-

ajorK R onesracks having my first look at aTO-ID. Of course I had flown theO-IA and did not anticipate anytrouble with the D model. A fastcheck with pilots who had flownthe D produced some recommended power settings. I signedfor the aircraft filed a flight planand departed on an uneventfulflight to Lyons France where Isent the required RON messageand spent the night.

The next day I departed Lyonsearly flew to Nice refueled andflew on to Rome. I refueled atRome and departed on the first

overwater leg of the flight toPalermo Sicily. Here I refueledsent the RON message and headedfor the hotel.

Early the following morningprepared a flight plan for a direcflight to Wheelus Air Base Tripoli Libya. I checked the weatheand started to file the flight planThe man at the counter upondiscovering who I was presentedme with a message that instructedme not to go beyond Malta withou t an escort. I changed the destmation and ETE on the flighplan and sent a message to

The one hour flight to Malta was a breeze but problems loomed ahead


17/68

Wheelus requesting that the escortmeet me at Halfar, Malta.The one hour flight to Maltawas a breeze. After landing I wentto the operations office to checkon the ETA of my escort. Evidently my message had not arrived at Wheelus. An escort wasnot on the way.I obtained permission to usethe hot line to communicate withWheelus. I made arrangemen s tomeet the escort at Point Beta, theapproximate mid-point betweenTripoli and Malta.A request for fuel revealed thatthe lowest octane available atHalfar was 115/145. WeHler s see,I had flown for one hour, twohours to go and that left an hourand a half reserve I thought). Irapidly filed a flight plan and departed south along the airway. Afew miles south there were scattered clouds at my flight altitude.I began to climb to the requireddistance above the clouds. Thecloud cover below me turned solidand rose at the same rate the aircraft was climbing. When Ireached 14,500 feet, the cloud layer leveled below me. I elected tocontinue south along the airwayand let down at the first opportunity.

An hour after departure I tunedthe predetermined frequency onthe radio and called the escort. Igot an immediate reply, and aftera few minutes I sighted the AirSea Rescue amphibian directly tomy front. I told him that all waswell with me and that he might aswell return to Wheelus. He circled around me and headed southalong the airway.As the amphibian was fast disappearing in the distance, thepilot started to tell me somethingM J Jones was project officerOperations Division Dept ofMaintenance Training Ft Ruck-er Ala. when he wrote this r-ticle. He is now serving in Viet-nam.MARCH 1967

about an unreliable bird dog theADF, not the 0-1 due to thunderstorms. I heard only the firstpart of his sentence. The enginehad quit. In much less time thanit takes to tell about it, I switchedfuel tanks, turned on the boostpump, pushed the mixture rich,put on full carb heat, and checkedto see that the mags were onBOTH.I reached for the door with onehand and the mike button withthe other. As a 3 3 aviator I hadno intention of staying with theplane in the clouds below. Thatparachute and the attached rubber raft looked better to me thanriding the 0-1 through the cloudsto the Mediterranean below. As Istarted to talk to the pilot of theamphibian, the engine caught andran smoothly. I explained my circumstances to the pilot and askedhim to say again about the thunderstorms and unreliable bird dog.

The remainder of the flightwas uneventful, although I spentan hour anticipating how it wouldfeel to be floating in a rubber raftor being a meal for the sharks. As1 neared the African continent,the clouds ended like a cliff.When I knew that I could not

fail to make the runway with adead engine, I pulled the throttleback and started a descent from14,500 feet.

Upon landing, I confirmed mysuspicion that I had allowed atank to run dry, though the fuelgauge indicated several degreesfrom the empty mark. Approximately 4 gallons remained in theother fuel tank.

Why didn t I discover that thefuel gauge was inaccurate? Whydidn t I fly to another airport onMalta to obtain the 80 octane fuelthat was used in the 0-1 at thattime? Why had I failed to properly recheck the weather beforedeparting Malta?

Most important of all, why hadI failed to get a proper checkoutwi th an P in the D model beforetaking the flight? Then I wouldhave known, among other things,that the aircraft didn t have thefuel endurance of the O-IA.I have asked myself these questions many times since that day,and I often remember the incident when I file a flight plan.That incident taught me an unforgettable lesson about properpreflight preparation and flightplanning.

Near the African continent the louds ended like a liff


18/68

Students and graduates of theBasic Avionics Maintenance OfficerCourse at Fort Gordon Ga. areproud of their motto.

Never An Aircraft Down For AvionicsLieutenant Samuel C. Wilson and Lieutenant orman E. Colten

Saigon Tower, this is Fang One.Over.Saigon Tower, this is FangOne. Over.Several more attempts to contact the tower failed, so CPT FlipHazzard switched to his emergency radio, contacted Saigon,and landed. After closing out hisflight plan, the captain walkedover to a large van, marked 007thSignal Detachment (Avionics)above the door. Stepping inside,he walked to Lieutenant Cancel'sdesk and collapsed into a chair.

Alfred B Cancel, 007 th SignalDetachment commander, peekedaround a 2-foot stack of paper andgreeted his visitor, How did itgo today, Captain?AI, the captain began, a bereaved look upon his face, todaywas the third time this week thatmy UHF went out.

Lieutenant Cancel took notesas his visitor expounded upon themany afflictions of his unit's aircraft. After the captain left, Lieutenant Cancel called over hisNCOIC, Sergeant Goodwood, andasked, Sergeant, please explainwhat the captain was talking16

abou t. When it comes to thesenames and nomenclatures, I'mlostlAs Army aVIatIOn grows, thecomplexity of the electronic com

munications and navigation equipment aboard each aircraft expandsto meet the new demands. Tomeet its field needs, the UnitedStates Army Southeastern SignalSchool, at Fort Gordon, Ga., hasincreased the capabilities of itsenlisted avionics courses-both inscope and training.

Many of these enlisted personnel are forming the nucleus ofnew units. With the formationof these avionics signal detachments and their deployment toSoutheas t Asia, one weak link became apparent: detachment commanders assigned to these newlyformed units, or sent to fill vacancies in the field, were out in thecold with respect to aviation andavionics.

In April of 1966, the Southeastern Signal School saw the beginning of BAMCO. The BasicA vionics Maintenance OfficerCourse is specifically designed totrain selected officers to assume

command of avionics detachments. This unique four weekcourse covers five main areas inits program of instruction. Lighobservation and light transporaircraft, phases I and II, occupymost of the first week, with theemphasis on the individual comm u n i c a t i o n s ~ na viga tion, andflight control systems. Then aircraft configurations are examinedand finally, an equipment servicability criteria evaluation is performed on each aircraft by thestudents.

Next, the students move intophase III, command surveillanceaircraft. The same system of teaching applies in this annex, with individual system and aircraft configurations discussed, and, finallyESCs performed. Throughouthese phases of training, constanstress is placed upon the maintenance responsibilities of direcsupport and general support avionics units, as applicable to present configurations and also thoseT Wilson and T Colten are

i n s t r u c t o r s ~ Avionics e p a r t m e n t ~U S A rmy Southeastern Signa

c h o o l ~ Ft G o r d o n ~ GaU. S ARMY AVIATION DIGEST


19/68

configurations planned for futureprocurement.By the middle of the thirdweek, the students have movedinto phase IV, a variety of groundand tower communications andnavigation equipment. Groundcontrol radar and the newest family of landing contr-JI centralscomplete this week. The fourthweek is devoted entirely to thevast area of administration andsupply. An attempt is made inphase V to present all problemsnormally facing the incoming offi-cer of a typical avionics detachment. The property book, TOEequipment, and the personnelstructure of various avionics detachmen s are examined. The commander's responsibilities, mission,

organizational maintenance procedures, and 1 1 helpful tips fromex-commanders, now instructors,take each student through the as-sumption of command. Finishingout the instruction is MILSTRIPand the repair parts supply system.

After seeing our first threeclasses of ten through, and witha few minor changes to the program of instruction, it is felt bythe BAMOC faculty that eachgraduate officer will be able toimmediately function as a detachment commander.

As the graduates departed FortGordon for their field assignments, the roar of automobileengines could not drown ou t theBAMOC motto: Never An Aircraft Down for Avionics.

Right: Students learn operational check procedures andconfigurations on a table before going to the aircraftLower left: B MOC students performing equipmentserviceability criter ia evaluation on Army aircraftLower right: n instructor discusses the ChinookS S and speed tr m systems

MARCH 1967 17


20/68

18

Airmobile Firepowets\

In July 1965, an article in AVIATION DIGEST reflected early enthusiasmand hope for air assault artillery. Jhe findings and evaluations were basedon the 11 th A i t ~ a l J l ~ D i v i s i o n mobility tests during the Carolina maneuvers.Naw the test of time and evidence of combat experience can be added. Thearftcle which folLPws d 9 ~ S t h i ~ in a professional way.~ e n .the 1,.,OOOth round was fired by the 1st Air Cavalry Divis Ar .tillery on 11 November 1966, it represented 14 months of reliable combatsupport for the s ~ troopers in Yietnam. It also represented remarkab' . operational r e a d i n e ~ s across the 250 kilometer depth and 2 kilometer widthof the division's area of commitments in the II Corps tactical zone, a readinessdemonstrated repeatedly by rapid deployments, in all directions.

E x & e r i e n c ~ to' dAte has shown that the sky trooper do , , I I n d i n g thenemYi: can be assaulted to any terrain of the varied geography found inVietnam; their supporting firepOWer can be placed wherever n e e ~ e d andthe logistical support can back them all up with responsive facility. This comPosite package of reconnaissance, assault, combat support, and responsivelogistics gives the 1st Air Cavalry Division's maneuver commanders heretofore@n,matched p&tential for creating and exploiting tactical advantage on theJ a t t l e f i e l d . 'The Ufirst el" f the air assdult division has performed b e y o n ~ e x p e cions. ,.he pential of follow-on .or retrofit de,igns of air cavalry organi aions is beyond measure, but un';oubtedly below conscious expectation, att ,js time. Conr ed imaginative attention and progressive effort wi\' yieldfurther signific rewards in terms of b a t t l ~ f i e l d fuperiority.

hWILLIAM A. BECKER,rigadiltt, General, USAA'\sistant Division Comma r1st Air Cavalry,Division

u, s. ARMY AVIATION DIGEST


21/68

H ~ l l m a r k of th lst evalry i v i s i o nCOL William F Brand, Jr.

T HE HISTORY of the Army smost unique experience infirepower, the 1st Cavalry Division Artillery, is brief but bold.Born as a concept, the divisionunderwent exhaustive tests as theSouthern United States witnessedthe spawning of an airmobile unitthat early in 1965 became the 1stCavalry Division (Airmobile).The newly formed division proud-ly accepted the dashing traditionsof the 1st Cavalry, translatingthese into modern airmobile versatility. In July 1965, the divisionbegan a movement to contact thatcarried its colors halfway aroundthe world.

In anticipation of the job athand, and realization that hardhi tting cavalry tactics would bethe key to success, the First Team sartillery punch was tailored tomeet the challenge. Normal general support firepower, includingthe Little John Battalion, wasleft behind and the burden ofproviding responsive reinforcingfires fell squarely on the AerialArtillery Battalion.

The First Team, a lean butlethal package, stripped of impedimenta to meet the demandsof c o u n t e r i n s u r g ~ n c y warfare,came to stay. Gone was the fat-prime movers stayed behind; vanswere deleted; equipment wasespecially designed to be compati-ble with Army and Air Force aircraft. New generations of combatequipment waited to be unleashed by the division s airmobile agility. The division was collapsible, prepackaged and readyA CH 54A Flying rane airlifts a 155 mmhowitzer into combatMARCH 1967

LTC Morris J. Brady

to meet the call for widely diverseoperations over a far-flung area.The Army s new family of radios,compact, light, and long ranged,became key items. Missing werethe luxuries of living; personnelincluded only those needed. Thevoids thus created were filled withthe satisfaction of being lightningswift and deadly effective.

On arrival in Vietnam, the division was faced with the task ofestablishing a base of operationsthat would enable its combat elements to move quickly into anyzone within its area of tactical operations. The historic village of

MAJ E K Johnson

An Khe, astride highway 19, inthe central highlands, was selected. In addition to its central location, An Khe was selected becausethe area is not scourged by thefull brunt of Vietnam s biannualmonsoons, thereby allowing thedivision to capitalize on everyhour of flyable weather.

From An Khe, _ he CavaLry s influence spreads eastward throughthe Deo Mang Pass from the median plateau of the central highlands t the coastal plains of QuiNhon, and westward over the

~ a n g Yang Pass to the upperhighlands of Pleiku, Darlac, and

19


22/68

uxuriesof living w r missing enemy forces were pounded fromdistant, mutually supporting positions and from within the surrounded perimeter. A highlightill airmobile artillery displacement came when four 155 howitzers were airlifted into combatoperations for the first time inVietnam. During the division

~ I a s h e r W h i t e Wing Operations,giant CH-54 Flying Cranes movedthe general support firepower, infour sorties, using improvisedslings.

Northern Kontum Provinces.Sandy coastal plains, tropical forests, impenetrable jungle withIOO-foot canopies, and precipitousmountains typify the terrain inthe division's area of operations.This was Charlie's back yarda Viet Cong stronghold that hadshehered an elusive, highly mobile, native enemy since beforethe signing of the 1954 GenevaAccords.

The enemy was a highly organized, well trained force dedicated to a master plan designedto tear South Vietnam from eastto west along highway 19 In concert with this plan, the Viet Congand the Army of North Vietnamhad massed large forces for strikesagainst the Plei Me and Duc CoSpecial Forces camps-the firstphase of his planned sweep to theeast. The arrival of the HorseSoldiers" upset Hanoi's timetableand at D plus one year haschangeo. the face of the war inthe highlands from a grand strategy involving large massed enemyforces to a small, fluid, piecemealcommitment of enemy manpower.

The division's early combat operations in the Chu Pong Massif,along the Ia Drang Valley andthe Cambodian border, announced in bold type the presence and effectiveness of airmobile firepower. Typical of theenigma attached to counterinsurgency warfare is the fact that thedivision's firepower was most effective when the combat elementsof the division were on the defensive. This paradox was best de-COL Brand was c o m m a n d e r ~ 1stCavalry Division Artillery; LTCBrady was c o m m a n d e r ~ nd Bat-

t a l i o n ~ 20th r t i l l e r y ~ 1st CavalryDivision; and MAl Johnson wasliaison o f f i c e r ~ nd Battalion 20thr t i l l e r y ~ 1st Cavalry D i v i s i o n ~when this article was written.20

scribed by a beleaguered paratrooper who happily reported:The poor bastards have us surI'ounded again "Regardless of where the Horse

Soldiers rode their helicopters tofind the enemy, division artillery's Chinook-transported howitzers were emplaced to fix and des troy him. Ba tteries of the new,lightweight M-I02 howitzers, nowbeing used by the three directsupport artillery battalions, wereemplaced on mountain peaks andin positions blasted and hackedout of trackless jungle. Encircling

The ever-changing situation inspired the "Redlegs" of the FirstCavalry to devise and employ newand unique tactics. Fires were de-

atterieswere pl ced in positions bl sted nd h cked out of tr ckless jungle

U. S ARMY AVIATION DIGEST


23/68

livered over all quadrants of thecompass, requiring the use of6,400 mil firing charts. Artilleryposition areas were dispe.rsed toensure support for widely separated units. These same positionshad to allow for massing of allavailable fires over the entire areaof operations.Use of interdiction fires was ofsignificant value against an enemy that capitalized on hit-andrun tactics. Planning for thesefires presented a major challengeto the artilleryman since hard,timely intelligence informationwas rarely available. The fireplanners had to search for information, analyze terrain and enemy tactics in planning fires to destroy his supplies and demoralizehis forces. Conventional artillery,unexpended T AC Air, and aerialartillery were used in the interdiction role.

The value of well planned,timely interdiction fires was attested to by prisoner of war reports. On one occasion, a prisonerstated that a battalion commander of the Quyet Thang Regimentand a force of 20 personnel werekilled by heavy interdiction fires.The wily Cong soon learned tofear the Cavalry's massive firepower and quickly countered bymoving as close to the friendlyforces as possible, in bear-hugfa.shion, to evade heavy volumeso indirect artillery fire. To copewith this, extensive use was madeo direct fire and close-in defensive concentrations.

High density of aircraft overthe division's area of operationsrequired the cannoneers to deviseyet another special techniquethat allowed for smooth and coordinated fire support while aircraft operated within and aroundthe area. This system, called FireFly, gave priority to artilleryfires and required aircraft to coordinate their flights with the direct support artillery battalion.MARCH 1967

his w s II harlie s b cky rdAdditionally, every howitzer crewchecked the sky forward of themuzzle before pulling the lanyard.

Countermortar fires, needed toensure base ~ c u r i t y presented stillanother special problem to thedivision artillery planners. In thiscase, heavy reliance had to beplaced on detailed terrain studiesand intimate knowledge of theenemy's mortar tactics. Whencombined, these elements formedthe basis of Quick Fire - a sys-tem that provided instant reaction to place large volumes ofcounterfires on likely or suspectenemy mortar positions. As information on the active mortarpositions is received the countermortar fires are refined to destroythe actual mortar location. Theimmediate reaction of all available artillery is known to havecurtailed several mortar attacks.Conventional countermortar firesare habitually reinforced by thedirect fire aerial artille.ry and atthe appropriate time the enemyis pursued by fire - as well as byassaulting air cavalry troops - byduecting all fires against his likely escape routes.

Relative freedom of the AnKhe base from enemy mortar attack seems to be creditable testimony to the effectiveness of theCavalry Division's defensive fireplans. This deterrence is undoubtedly reinforced by groundpatrols and by the nightly presence of a mortar patrol aircraftfrom the Aerial Artillery Battalion. This aircraft continuouslysurveys the surrounding countryside, alert for flashes from enemymortar tubes. The aerial artillerymen are always ready to answersuch audacity with rocket firewhile alerting their ground comrades of the threat and possiblerequirement for Quick Fire.

The key to successful employment of firepower in the FirstCavalry Division to date has bdirectly attributable to the artilleryman's aggressive ingenuity.His unique use of airmot>ility ledthe Viet Cong to christen theFirst Team's artillery The FrogArtillery. Selection of widelyseparated and isolated positionareas compounded the problemsof providing position area security and clearing and coordinatingfires. At times artillery units were

Divarty s mobilit y made the forward observer s job tougher

2


24/68

The M 22 provides th 1st Cavwith a bunker busting punchrequired to provide their own se-curity and did so with great success over short periods. Ideally,artillery units were collocatedwith infantry reserve elements.In addition, airmobile artillerybatteries conducted leap-frogmoves from one position to another, never occupying a singleposition long enough to present alucrative target.

The familiar term FEBA wasmissing from the combat jargonof the division, and heavy emphash had to be placed on no firelines that took the form of boxesand circles. Because of this situation, the role of the forward observer and artillery liaison officerbecame tougher, more challenging, and more exacting than inany other war. The liaison officerhad to feel the pulse of the operation and make constant revisions as the fire support needs ofthe ground commander changed.The forward observer was facedwith problems of orientation andcoordination: Where am I? -Where are the friendlies? Oncethese questions were answered,the observer learned to adjust artillery by sound or in conjunctionwith an aerial observer. The forward observer quickly became theArmy's counterpart of the forward air controller, guiding andadjusting the most versatile andeffective weapon in the divisionartillery's arsenal: aerial artillery.

On numerous occasions, MajorGeneral Harry W. O. Kinnard,speaking of concepts developedduring Air Assault II, indicatedthat his gravest concern centeredon the aerial artillery. On his departure f,rom the First CavalryDivision in June 1966, GeneralKinnard said that of all the innovations of the Airmobile Division, the Aerial Artillery Bat-

talion had proved to be the mostgratifying. Aerial artillery s demonstrated ability to support dive.rse operations and simultaneously undertake independent operations within and outside thedivision s area of operations supported General Kinnard's remarks.

Capitalizing on airmobility, theAerial Artillery Battalion operated with virtual disdain of terrain, weather, and the cumbersome logistical problems that areassociated with the movement ofconventional artillery. The constant threat of road ambush hadi tle significance to the rocketfiring helicopters. The entire bat

talion could be instantly displaced with minimum concernfor intricate movement plans,route reconnaissance , or the detailed coordination normally attached to such moves. Of specialinterest to the ground commander was the speed and freedom ofmovement characteristic of aerialartillery. Rapid reaction and demonstrated first round accuracyformed the basis for a deep andlas ting camaraderie between theaerial artillerymen and their supported ground elements.

The Aerial Artillery Battalionwas found to be best employed inthe reinforcing role with eachaerial artillery battery enjoying ahabitual association with one ofthe three direct support artillerybattalions organic to the division.Committed brigades have learnedto ,rely on the highly responsivefires of the Armed Falcon. Thisreliance is typified by the actionat landing zone X-ray during thefirst Chu Pong - Ia Drang campaign. In this historic action thecavalrymen found themselves surrounded by a regimental size enemy force employing bear hug

tactics that initially ruled out theuse of conventional artillery support.

Aerial artillerymen respondedto the situation and provided airborne control for the groundforces, enabling them to establisha well defined and cohesive perimeter. Once this was accomplished, the airborne Redlegsset to work placing the aerialrockets within 50 meters of friendly elements throughout the dayand seemingly endless night. Asa result of this fierce 24-hourclash and in mute testimony ofthe effects of coordinated fire support the enemy was forced towithdraw, leaving 634 dead onthe battlefield. It was estimatedthat 581 additional enemy deadwere carried off by the retreatingenemy.

Again at landing zone Eagle,the far-reaching aerial rocketships answered the call when reconnaissance elemen ts of the division, operating well beyond therange of conventional artillerysupport, were surrounded by anumerically superior force. As theonly fire support available, aerialartillery remained constantly onstation, delivering over 1,400rockets into the jungle sanctuaryof the Congo These decisive, closein fires turned the encirclementinto a grave tactical mistake forthe Viet Cong force. Not only didthe enemy fail to destroy the outnumbered Americans but thewake of the enemy retreat left 122bodies around the perimeter.

The Flying Falcons learned tolavish special attention on thelife blood of their operation,aircraft fuel and the 2.75 ae.rialrockets. The flow of these essential items is maintained by divisional lift elements, who haveearned the admiration and respect of the Aerial Artillery Battalion.

The bunker-busting punch ofthe aerial artillery is in their

22 U. S ARMY AVIATION DIGEST


25/68

M 22 SS-ll) wire-guided missiles.This weapon has been employedwith deadly accuracy on many oc-casions as in the instance when aU. S. Special Forces sponsoredunit called for the M 22 againstthe heavily fortified ga tes of aViet Cong controlled village. Theflying cannoneers destroyed theheavy gates with two missiles andgained access to the village without causing needless injury ordeath to the inhabitants.

The deadly roar of aerial rockets over the First Team's battlefield has become a common andcomforting sound to the skytroopers. The call sign ArmedFalcon is a byword in the central highlands, synonymous withhighly responsive, accurate andlethal firepower.

Any discussion of airmobilitymust consider the effects of weather. No one can dispute thatweather has long been the baneof those who travel the skyways,or that it is a major considerationin the planning and execution ofairmobile operations. The admission that weather is a limiting factor is no more surprising thanthe fact that jungle expanses areformidable barriers to the footsoldier or that rivers form imposing barriers to armor units.

Weather has occasionally causedthe postponement of an operation, but rarely has it caused acancellation. The balance between airmobility and weather isfound in improvisation. Operations to date in the central highlands have sustained the value ofthe helicopter and the professional attributes of the aviator whohas learned to operate under adverse weather conditions.

In the final analysis, at D PlusOne Year, it can be stated thatairmobility has been a decisive instrument in the hands of aggressive, visionary commanders.

erial artillery breaches the walls ofa iet ong vjllageMARCH 1967

Ground elements, moving to battle through the skies, need nevertravel without decisive firepower.The conventional and aerial artillery organic to the First Cavalry Division has conclusivelyproved that it can match themovement of its supported groundforces in speed and efficiencywith little regard to the limitations of terrain and weather. TheFirst Team's artillery has writtena proud record as the forerunner

of future division artillery concepts.One year ago, the central high

lands represented a serious threatto the Republic of Vietnam. To-day, the Cav stands poised todestroy the Cong anywhere, anytime. The mettle of the enemyhas been tested in the centralhighlands and, by his choice, confrontation has all but disappeared. The Horse Soldiers mustnow search to destroy.


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dditionalDistractorsTo Tail Rotor Failure

UST A TAIL ROTOR failurealone is a bone-chilling thoughtto any single-rotor helicopter pilot, even under the most ideal cii'cumstances. * Add a few addition

al dis tractors, such as being overunfriendly territory, surroundedby unfriendly people, and havingall the crewmembers slightlywounded, then the chill factoris lowered almost to the freezingpoint. I had the misfortune to experience two antitorque failureswhile flying the UH-IB in Vietnam. Addi ional dis tractorscaused me to deviate considerablyfrom the procedures outlined inthe operator's handbook. See Inflight Tail Rotor Failure in theIroquois, January 1967 DIGEST.4

aptain arl Webb

The UH-IB operator's handbook states that in event of tailrotor failure you should reducethe airspeed to 50-60 knots (lAS)and ente.r autorotation. My experiences should not cause you todeviate from the standard emergency procedures. I share themwith you only in case you findyourself with a tail rotor failureand no place to land immediately.

Let us first examine some of thepossible tail rotor failures beforewe look at mine. First, and mostserious, you could lose some ofthe hardware (tail boom, pylon,etc.). This would cause a seriouscenter of gravity problem in addition to loss of directional control.The decision to continue flight

or enter autorotation would depend on the amount of controyou have over the ship. Anotherpossible failure is the loss opower to the tail rotor. An example would be a loss of the 90gear box or some of the tail rotorshaft. Another failure would beloss of directional control only.An example is loss of the tail rotor cable.My first tail rotor failure wascaused when a bullet severed thetail rotor cable, and on the second instance a bullet entered the90 gear box, causing a partialCPT Webb s assigned to theMultiengine Branch InstrumentDivision Dept of Rotary WingTraining Ft Rucker Ala.



27/68

loss of power to the tail rotor. nboth instances I was ove ' hostileterrain and about 20 minutes toa secure airfield. I might add thatI had previously considered thesepossible failures and had donesome practice landings wi thou tusing the pedals. I learned fromthis practice that the UH-IBstarts to yaw to the right underpower at approximately 50 knots.

The first failure occurred during a rocket pass at an altitude of200 feet. We had two other aircraft down in the landing zoneand a real hot fight on our hands.All of the crew aboard my aircrafthad been wounded, although notseriously. We recognized the lossof directional control while firingour rockets. The rockets firingcaused the nose to yaw 30 eachside of our flight path. An immediate turn was made at 80 knotsand the crewchief sighted the bullet holes and the loose cable flaoping. He could also see that ~had lost no hardware and stillhad power to the tail rotor.

We had good control over theaircraft so we continued ourrocket passes. The area was realhot and our ordnance was sorelyneeded. After expending our ordnance (four passes) we depa:tedfor home base. Several practiceapproaches were made at altitudeto verify when the nose started toyaw under power. Our aircraftstreamlined nicely at 70 to 80knots and the aircraft started toyaw between 40 and 50 knots at85 percent Nl. Nearing the airfield, a decision was made to execute a running landing at approximately 50 knots. The copilotread off the airspeed on final untiltouchdown was made. Touchdown power was maintained andthe aircraft started a gradual leftturn of 20 The aircraft wasbrought to a smooth halt by slowly reducing the collective pitch.Other than 39 bullet holes andMARCH 1967

he nose st rted a y w to the leftworn out skid shoes there was nodamage to the aircraft.

The second failure was causedby a bullet going through the 90gear box. This failure was moreviolent because of the intermittent operation of the gear box.The tail rotor would work properly at times, and then bind andthen surge again. Rememberinghow well the first emergency hadworked out, I decided to try thesame technique again. We headedfor home base, practicing altitudeapproaches on the way. The nosestarted to yaw to the right underpower at approximately 50 knotsas the first aircraft had. An approach was started at 70 knotswith a gradual deceleration to thetouchdown speed of 50 knots.Again the nose started a yaw tothe left. I applied some additionalpitch and the aircraft yawed backto the right. A gradual decreasein pitch and gentle closing ofthrottle brought the aircraft to asmooth stop in the center of therunway.

I would like to offer the following points for you to rememberif you find yourself with a tailrotor failure and no place to landimmediately.

The UH-I flies well at 70-80knots (lAS) without tail rotorcontrol.

The UH-l starts to yaw tothe right under power at speedsbelow 50 knots (lAS).

A power running type landing can be controlled by a combination of cyclic, pitch andthrottle.

A go-around can be madefrom this type approach. Once youhave entered autorotation with atail rotor failure, you are prettywell commited to a landing.

I would like to add that theonly reason for my deviation fromthe operator's handbook was theadditional dis tractors I have

mentioned. In any emergency youwill probably be better off following the established (and practiced) procedures.

e had good control so we continued our rocket passes

5


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UH l ENGINE INLET AIR PROTECTION

E XPERIENCE gathered fromair assault exercises and tactical airmobile operations in Vietnam has identified a problem offoreign material being ingestedby engines on UR-I helicopters.Engine failures and engine surges(compressor stalls) have occurred

on aircraft operated in sandy ordusty terrain or over freshly cutgrass.

To solve this problem the Annyis cur.rently installing a device26

Major William H Edwards Jr

known as a barrier fil ter on allUR-ID helicopters. In the nearfuture however, all UR-I ( )helicopters will be equipped withan inertial-inlet type separator(particle separator) as soon asthese devices are produced. Bothdevices have been tested in thesevere environments of sand, dust,and cut grass. Results of tests areof interest to Ruey pilots andthose commanders responsible forplanning and conducting tacticalopera tions.

When design specifications fothe T53 gas turbine engine werdeveloped in the mid-1950s, thdevelopers did not envision modern airmobile operations involving the use of large formations ohelicopters operating from unimproved areas. During airmobiloperations rotor wash from thhelicopters at times creates densMAJ Edwards s attending thCommand and General Staff College Ft Leavenworth Kan.



29/68

clouds of dust. Relatively largesize sand particles are picked up inthese clouds and then ingested bythe engines. The nature of theparticular operation often forcesthe helicopters to remain in thisadverse atmosphere longer thanduring routine helicopter operations, thereby increasing ingestionof these foreign particles. Erosionof engines from such ingestion isresponsible for subsequent enginesurges.

Even though the T53 enginehas proved its reliability in overa million hours of operationalemployment, one may questionwhy the engine does not appearto be able to withstand these tactical envitonments. The answeri5 that sand and dust requirements during engine developmentare far below those encounteredin the field today.

Original specifications for sandand dust ingestion called for theengine to operate successfully inan environment with sand particles up to 200 microns in diameter, with concentrations of 0.0015gram per cubic foot, for 10 hours.In recent tests, sand samples takenin tactical formations showedaverage concentrations varyingfrom 0.003 to 0.005 gram percubic foot, with an average of 60percent by weight of the sandparticles larger than 200 microns.Operational environments can befar more severe than design specifications anticipated.

The T53 engine has also experienced some catastrophic failures after operation over freshlycut grass. Ingested grass lodgedon the inlet guide vanes. Thisgrass blockage restricted the airflow and resulted in rapid pressure oscillations within the compressor. These oscillations induceharmonic vibrations in the secondstage compressor blades which, inthe presence of any minor imperfections, result in a stress levelsufficient to produce a fatigue frac-MARCH 1967

The U S Army Aviation Test Boardtested filter and separator devicesture. The separation of onesecond-stage blade will producean engine failure.To protect the T53 engine fromthese hazardous environments,the barrier filter was installed onUH-ID helicopters. (The problem appeared initially to be moresevere in UH-ID helicopters thanin UH-l Bs.) At a later date, aninertial particle separator, whichin laboratory investigations. appeared to be more efficient thanthe barrier filter, was developedto solve the ingestion problems ofthe T53 engine.

estingThe United States Army Avia

tion Test Board was assigned thetask of conducting comparativetesting of the engine inlet air barrier filter and particle separatorto determine which device wasmore suitable to provide protection for the T53 engines ofUH-l ) helicopters. During thesetests three helicopte.rs equippedwith new calibrated engines werehovered in formation over a loosesandy soil until engine surge wasencountered. One aircraft was astandard configuration UH-I Dwith no engine inlet protection.The other two aircraft were eachequipped wi th engine protectivedevices.

The engine with no protectivedevice surged first. The UH-IDequipped with the barrier filterexperienced engine surge after a60 percent longer time than thestandard configuration UH-ID,while the helicopter equippedwith the particle separator survived 234 percent longer in thesand environment. After the engines surged, they were returnedto the manufactu.rer for analysis.For additional comparative infor-

mation, a factory calibration andcompressor inspection was alsoperformed on the engine equippedwith the particle separator at thesame sand-exposure time that hadcaused engine surge to the bar,rier fil ter protected engine.

Inspection of the unprotectedengine showed massive damagethroughout the compressor section. In particular, the first-stagecompressor blades had severe impact damage from large particlesof sand. The entire engine waseroded by the ingested sand andexhibited a substantial loss inperformance.The engine protected with thebarrier filt r had much less damage in its compressor section. Condition of the compressor bladesshowed that the barrier filter hadeffectively diminished the amountof contaminant ingested by theengine and, in particular, hadprevented the passage of largeparticles of sand. The engine sperformance deterioration was indicative of one that had surged,but it had survived in an adverseenvironment for a 60 percentlonger period of time than theunprotected engine.

Intermediate engine calibrationand inspection of the particleseparator engine (performed atthe same sand-exposure time thatthe barrier fil ter engine experienced surge) revealed that thisengine could still meet new engine specifications for engine pe r-formance and compressor bladetip clearances. Although there wassome er?sion within the engine,it was insufficient to affect materially the engine s operation.

Final inspection and calibrationof the particle separator engineshowed engine operating characteristics and erosion damage simi-

27


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U l ngine Inlet ir Protectionlar to the barrier filter engine.Some erosion damage was slightlymore severe than the barrier filterengine, but it was attributed tothe much greater time the particleseparator engine was exposed tothe sandy environment.Engine-survival times during thecomparative test were extremelyshort (a maximum of 7.67 hoursof sand exposure for the particleseparator engine). However, thiswas an accelerated test in whichthe aircraft were flown at maximum gross weight, on days with adensity altitude of 2,200 feet, inthe worst possible sand by mineral content and size distributionthat could be iocated at FortRucker. The time accumulated onsand-exposure flights could be related statistically to operationalexperience with field engines exposed to sand and dust environments throughout the world. Onth.e basis of the erosion observedin these engines, valid test resultswere obtained.

The barrier filter and particieseparator also demonstrated a so-lution to the grass ingestion problem in this test. Two UH-IDhelicopters, each equipped with abarrier filter and a particle separator, hovered over a cut-grass fieldfor over two hours. The externalscreen assembly of the particleseparator and the barrier filterscreens were completely coveredwith grass, but no engine failureoccurred. Al though the enginesoperated with less efficiency, thereappeared to be no danger of aflame-out. Practically no grass wasingested during this flight period.

Engine SurgeMuch has been written about

engine surge since gas turbineoperation has become commonplace in Army aviation. Enginesurges have proved particularly

troublesome ih UH-I helicopters,on occasion resulting in seriousdamage to the airframe. In general, engine surges which occurwith Nl speeds below 85 percentare not particularly dangerous.However, engine surges at N 1speeds above 85 percent can bedisastrous.

Engine surges in sand-erodedgas turbines result from a combination of variables. Sand ingestion will seriously damage thecompressor section of the engineas well as wear the turbine portions of the engine. Thus, compressor efficiency deteriorates atthe same time as the turbine'sability to convert the energy ofcombustion into useful work diminishes. Since this damage decreases the horsepower output ofthe engine for a given gas-producer speed, the pilot increases thefuel flow to the engine to demandsufficient horsepower to accomplish whatever maneaver is desired. The increased fuel ra te fora gas-producer speed increases thepossibility of an engine surge.Gas turbine fuel flow is programmed to the engine by thefuel control. In uneroded enginesthe fuel control meters the fuelpassed to the engine to ensurethat the engine accelerates or operates in a surge-free regime. Aserosion occurs in an engine, themaximum fuel rate that an engine can maintain wi thou

Army Aviation Digest - Mar 1967

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