Army Aviation Digest - Sep 1960

8/12/2019 Army Aviation Digest - Sep 1960

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EDITORIAL STAFFCAPT JOSEPH H PO OLEFRED M MONTG O ME RYRICHA RD K TI ERN EYDIANA G W ILL IAMSSY LV IA N DA Y

SEPTEMBER 196VOLUME 6NUMB ER 9

RTICLESMOHA WK AO-l-DO YOU K OW THE GLE?FALCO'S E T .TREASURE I THE AL AGE YARD, Lt Carl G Midget t, In f.MAINTEl A. CE TIME SAVER, J. R. Brackin.I ISIBLE INVADER, Richard K TierneyT\V

IR RAFT A AILABILITY AND THE HU-IA,CWO Richard N Cullen, TC17 ECOND K E hellis .CR TE 'EM OR FL EM? Lt Col John L Briggs, ArtyFI E PARM LTIPL PAR MA UAL, Lt William R Troy, TCLt Gene A. Truitt, Inf.RA H SE SE

TH R HOOD. BA K CO

m thln e o th D sign oardsA LIGHT ob ervation helicopter will replace three aircraftnow in the rmy viation inventory, according to arecent announcement by the Department of the Army. Indu try will be invited to submit design plans thi year.The new helicopter will eventually replace the L-19(Bird Dog) ob er ation plane, the H-13 (Sioux) and H-23(Raven) reconnaissance helicopters. The project i partof a long-range rmy A iation program drafted by a pecialrmy ircraft Requirement Review Board.Two different design for t he new helicopter will be elected from indu trial competition. Testing of the de igni lated for 1963, when one will be chosen for production.Production and procurement is expected in 1964 or 1965.The new helicopter will be powered by a turbine engine,weigh Ie and be mailer than the H-13, crui e at about126 mph, operate for minimum of 3 hour without landing,and have a 400-pound payload (plus pilot and 3 hour ' fuel)under hot weather conditions. The payload will be greaterunder good flying condition . Its missions will be ob ervation, target acquisition, reconnaissance, and commandcontrol.

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ER

U. S. ARMY AVIATION SCHOOMaj Gen Ernest F. EasterbrCommandantCol Delk M OdenA ssistant Commandant

SCHOOL STAFFCol Robert H. SchulzDirector of InstructionCol Allen M Bur dett, Jr .Com bat Development OfLt 01 Jack BlohmCO USA A VNS R egimenMaj Mark F. FowserA cting S ecretary

DEPARTME TLt Col Ritchie Garrison

Tact icsLt Col Oliver J . HelmuthR otary W ingLt Col John W. OswaltAdvanced F ixed W ingLt Col Har ry J . KernMaintenanceLt Col Thomas J . SabistonPublications and

Non Resident InstructionLt Col G Wilfred J aubertPrimar y F ixed Wi ng

The U. S. ARMY AVIATION DlGES1an off icial publication of the Departmentthe Army published month ly undersupervision of the Commandant, U. S. ArAviation School.The mission of the U. S. ARMY A VI1'ION DIGEST is to provide informationan operational or functional nature conceing safety and aircraft accident preventiotraining, maintenance, operations, researand development, aviation medicine aother related data.Manuscripts, photographs, and other illt rat ions pertaining to the above subjectsinterest to personnel concerned with ArAvia tion are invi ted. Direct commllnica tiis authorized to : Editor-in-Chief U.

ARMY AVIATION DIGEST, U. S. ArAviation School, Fort Rucker, Alabama.Unless otherwise indicated, materialthe U. S . ARMY AVIATION DIGES'l' mbe reprintt 'd provided credit is given toU. S. ARMY AVIA l'ION DIGEST andthe author.The printing of this publication has beapproved by the Director of the Bureauthe Budget, 22 December 1958.Views expressed in this magazine are nnecessarily those of the Department of tArmy or of the U. S. Army Aviation SchoUnless speeified otherwise, all photograpare U . S. Army .Distribution:

To he distrihuted in aecordan('e wrequirements stated in DA Form 12.


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ohawkAO l AFHE ARRIVAL of the AO-1-AF Mohawk for testingt the U. S Army Aviationmarks a significant milein Army Aviation.

The Army's new tactical obplane will be serviceby the United StatesAviation Board. U. S.Transportation Aircraftand Support Activity willfor logistests.

The side-by-side two-seaterisdifferent from curArmy observation craft.example, the Mohawk hasbrakes, twin Lyturboprop en

and a three-tail confiThe newcomer also boasts aspeed of 200 knots, a

top speed in straight and levelflight of over 281 knots, amaximum permissible of 350knots, a cruising altitude of25,000 feet, and a range of1,453 nautical miles with droptanks. The Mohawk weighs 11,-859 pounds loaded, but maintains an effective STOL capability - thanks to flaps, slats,speed brakes, and reversiblepitch props.

The primary mission expected of the Mohawk is visualobservation, with responsibilityfor the bulk of the Army'sAO operations. Secondary missions include utility, resupply,liaison, and day or night photography.A bubble canopy providesmaximum forward and downward visibility for the observers who must search out, de-

teet, identify, and locate targets for the combat zone commander.Coordinating these functionsis a difficult job and will remain so, even for specializedobservers the Army hopes tobe training soon (see story ofTask Observe, AVIATIONDIGEST, July 1959). The manyfeatures of the Mohawk shouldmake this job easier and boostthe capabilities and potential

of the Army A via ion-GroundForce fighting team.A quick look at the Mohawk'svital statistics may prove helpful. The wing span is 42 feetwith a wing area of 330 squarefeet. The plane's overall lengthis 41 feet and the tail stands12 feet, 8 inches high.The Mohawk weighs approximately 9,519 pounds empty


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Instrument panel s seen by pilot

and holds 1,950 pounds of fuel.Takeoff power is set at 1,005equivalent shaft horse powerfor each motor.

This plane underwent extensive tes t ing by Grumman.Landing and takeoff on shortfields and turns in an extremelysmall radius were stressed.Landings have been made inabout 300 feet with props atfull reverse pitch and employing vigorous braking. Thetouchdown speed was approximately 55 knots.

Seated side by side in thecockpit with bubble canopyeach crewman has unobstructedvision 22 0 down over the noseof the aircraft along the centerline of the seats. By movingthe line of vision outboard,visibility is expanded.The bubble side hatches in

crease downward visibility bythe extent that the lines ofsight of the aviator and observer converge at a point 36feet below the plane. A transparent, jettisonable hatch allows complete vision overhead.

Only 11 of rearward visibilityis obstructed by the wing.Efficiency and comfort havebeen obtained by maximumutilization of cockpit space. Theinstrument panel (consisting ofthe aviator s, observer s andcenter panels) slopes 15 forward to eliminate partial blocking of the instrument faces bytheir own bezels.

Flight instruments are duplicated for both crewmen; engine control instruments arelocated in a center panel, allowing both occupants to monitorthem with ease. Each man alsocan easily reach all trim controls and a central throttle, propeller quadrant - making soloopera ions possible if necessary. A newly designed stickgrip makes the left and rightcontrol sticks i n t e r c h a n g ~ a b l eEquipment for communications, navigation and photography is contained on a consolebetween the occupants. Threeoverhead consoles provide forall the engine, fuel, and electrical master panels. It also in-

cludes the engine fire extiguishing switches.Regulators for the oxygsystem are located on the ou

board side of the aviator s anobserver s instrument panelA first aid kit is mounted othe sloping bulkhead, alonwith pyrotechnic pistol, binoclars, a spotlight, and importacircuit breakers.The cockpit is heated by egine bleed air cooled in a heexchanger. Ventilation is prvided by diverting ram air useto cool engine bleed air. Thair conditioning system furthprovides air blast defoggingall transparent areas, camecompartment heating, and raair cooling of electronic equiment.

The Mohawk s crew can fea bit more secure observing thenemy than Army A via ocould when flying missions Korea and during World WII. Unlike its forerunners, thMohawk contains 246 pounof armor to protect its crewThis armor provides the cocpit with a 1-inch, bulletprowindshield, a l,4-inch thical uminum floor, a l,4 -incaluminum side panel, and rmovable flak curtains abovthe floor on the fore and abulkheads.

The Mohawk s basic configlration reduces vulnerabilitThe self-sealing 295-gallon fucell and the engines are mouned above the wings. Other prtection factors in cl u d e d u alongitudinal controls runseparated as much as possibthroughout the fuselage, ana cockpit area designed for 2g s vertically and 40 g s forand aft.If the Mohawk is hit an

rmy personnel who see this maneuver sh ke their he ds at the


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Crew can eject at allattainable speeds

has to be abandoned, the seatscan be easily ej ected to providethe crew a safe escape at allattainable speeds.

After ejection the parachuteopens automatically and liftsthe occupant from his seat.At high altitudes a barostaticcontrol on the seat delays theopening. The occupant remainsstrapped to his seat and issteadied by a duplex drogueparachute while he descends toa warmer altitude. At highejection speeds the opening isdelayed by a g switch. The seatis fitted with a face curtainfiring control that protects theoccupant as he is ejectedthrough the overhead hatch.An alternative firing handle ispositioned in the leading edgeof the seatpan. The overhead

maximum performance

hatch can be jettisoned only bya control located in the overhead console. The seats are notej ected by this control.The main parachute is stowedin a horseshoe roll shaped

pack behind the occupant'sshoulders and is combined witha back pad and harness systemcompatible with an integratedtorso suit. Bail-out oxygen isautomatically actuated on ejee-. tion.

Army Aviation is getting itsfirst turboprop aircraft in theMohawk. Each engine has atakeoff rating of 960 shafthorsepower and approximately100 pounds of jet thrust at agas prod ucer speed of 25 210rpm. The propeller shaft speedis approximately 1,678 rpm.Gear ratio between the powerturbine and propeller drive is12.46 : l

The three-bladed, variablepitch C.F.E. Hamilton StandardHydromatic propellers are 10feet in diameter, full feathering and have reverse pitch.The engine nacelle is easilyaccessible. Two side cowl panelshinge up and a lower panelhinges forward, providing 360 accessibili y.All fuel control adj ustmentsare easily reached. The powerplant, propeller, engine accessories and mount are movableas a unit and interchangeablebetween wings.

Engine anti-icing is providedby a flow of hot compressorbleed air through the engine

Takeoff distance over 50 ft

3 blade reversible propsinlet struts and inlet guidevanes, and by electrical heating for the propeller blades,spinner, and engine inlet cowling.The Mohawk is started bya starter-genera or used withthe plane's batteries or externalpower. The same system is usedfor air starts.

Photography promises, to beone of the Mohawk's most important secondary m i s sio ns.The plane can be equipped withone of three KA-30 cameraswith lens cones of either 3, 6,or 12 inches. The magazinecapacity in each case is 100 to250 feet of film. The KB-10acamera (3-inch lens with 50 to100 feet magazine capacity)also can be installed, but requires a special adaptor.The camera mount is locatedin the fuselage midsection. Itis remotely controlled by eithercrewman who can rotate, it tothe left or right, 15 or 30

obstacle is 793 ft


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SEPTEMBER 1960

STO characteristics are aided by speed brakes

oblique and vertical positions.The control system consists ofa cockpit console. During nightphoto missions flares may befired individually or salvodfrom pods attached above thewings between the engine andfuselage. Each pod holds 52flares.Items that may be carried

u n e ~ the wings are either twodrop tanks capable of carrying150 gallons of JP 4 each, re supply containers with a capacity of 1,000 pounds each,or wire dispensers.Other versions of the Mohawk will carry either infrared mapping equipment orside-looking airbO rne radar(SLAR). The radar antenna iscarried O n an 18-foot cylinderexternally mo un ted on thelower right side O f the fuselage. The mapping equipmentis carried internally. These surveillance sys tems are interchangeable between planes, butonly one can be carried at atime.A good STOL capability isprovided by hydraulically actuated slats (integral with wingflap contrO I) and speed brakes.4

The wing slats are arrangedin four mechanically intercO nnected sections along the wingspan. The slats operate in conjunctiO n with the flaps. Flapmovement can be cO ntinued independent O f the slats to 45degrees. A lock is provided forthe zero degree position. At theQutboard end O f each flap apushrO d is attached to O peratethe inboard aileron drQop inCQrporated with flap action.

The synchronized speedbrakes are located in the aftsectiO n O n the sides of thefuselage and swing on verticalhinges. Each is extended orretracted in three secO nds byits own hydraulic cylinder andmay be locked in any positiO n.The brakes add greatly to themaneuverabi l i ty of the Mohawk and are expected to playa maj or rO le evading enemyfighter planes. The gust locklever which locks all flight controls in neutral is located sothat the thrO ttles cannot beadvanced for takeoff when thecontrols are IQcked.The retractable, tricycle landing gear with pneudraulicshQck struts are equipped with

low pressure tires to facilitatQperation on unimproved aifields. The nO se wheel rotatethrough 360 0 Gear retractiQis accomplished hydraulicallwith mechanical up and dowlocks.

The Mohawk originally wadesigned with a single T-typtail. However, tests proved thasingle engine cQntrol was nopossible with this configuration. Three vertical fins anrudders solved this prQblem.

Fueling the MQhawk is simple. It is accomplished eithethrQugh 3-inch gravity filleunits or by single-point pressure fueling. Tiptank defuelinrequires a transfer of the fueto the main tank. This can bdone selectively at the fuelinstation by switching on Qne Qboth of the wing tank transfepumps. The flow of fuel fromthe wing tanks can be contrQlled from the cockpit.A dual fuel pump systemQperating from thel main tanis a fail safe factor since onpump can supply both engines

The Mohawk has a 28 voD C electrical system includina parallel 300 amp starter-gen


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panel nose and tail sectionsand wingtips are replaceableas units.

Special hoisting equipmentprovides an easy system forhandling propellers and enginesin remote areas. This mobilesystem consists of a hoistingdavit, slings and stands forthe engines and props.

The prop sling loops aroundtwo of the blades and secureswith snap hooks fastened intothe sling hoisting ring. Thedavit forward hoist attachest the same ring and lowersthe prop.

All major assemblies are interchangeableThe engine minus propeller)is handled by fastening the

sling t hoist fittings on topof the engine and attaching theerator driven by each engine; the Mohawk it becomes ap- davit hoist to the sling. Thetwo voltage regulators; two parent that the craft often may prop may be included if thereverse current cutouts and a have to undergo emergency hoist is moved further forward.24 volt 36 ampere-hour nickle- repairs under unfavorable con- The collapsible engine standcadmium battery. Either gen- ditions. Every effort has been contains bolts for securing theerator can carry the entire load made for maximum service- engine.and the battery adds another ability and maintenance. Quick Space provisions have beensafety measure by providing access is provided to all equip- made for the ASW-12 autoemergency power in event of a ment items. matic pilot television camera,double generator failure. Two All major assemblies are in- and recording equipment forinverters supply a 115/200 volt terchangeable. The entire wing forward looking radar.A C ~ e c t r i c l system. o r m a ~ly the instruments are suppliedby a 250 VA inverter. All otherA C is supplied by a 2 500 V Ainverter which can perform thefunctions of the 250 V A inverter.

The communications systemconsists of HF, VHF, and UHFtransceivers. An intercom system is included.

Navigation eq ui pm en t includes TACAN M receiverand LF/DF, and new Dopplerequipment. Transponder AN /APX-6B IFF) and CoderGroup AN-APA 89 identification are provided in the o ~hawk and mark their debuts inArmy Aviation.

Considering the missions of

The follo1wing chart handily sums up the performance ofthe Mohawk as determined by Grumman:Maximum speed 5 000 feet, military power level ftight __ 281 ktsStall speed sea level landing configuration 100/0 NRP__ 59 ktsTakeoff distance over 50-foot obstacle_________________793 ftLanding distance over 50-foot obstacle_________________847 ftService ceiling military power T.O. wt less 200/0 fuel1) __________________________________________ 25 000 ftRate of climb 2 engines, MRP sea level T.O. wt. less 200/0 fuel

2 950 fpm.Rate of climb 1 engine military power sea level T.O. wt. less200/0 1 050 fpm.Endurance at 200 kts, 5 000 ft. 2 hours without drop tanks.Ferry mission: 2)Range ______ _______ ______ ___________ ___ 1 453 NM

Time _____ ____________________ _________ 6.96 hrsCruise speed ____________________________ 200 ktsCruise altitude __________________________ 25 000 ft

Notes: 1) Engine data extrapolated over 25 000 ft.2) With two 150 gal. external tanks


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OYOU KNOW THANGLES


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BIRD DOG, turning baseinto tactical strip, stalledand spun in. Pilot fatally injured. Aircraft destroyed.B e a v e r developed enginetrouble, dived into canal duringattempted 180 0 turn. Pilot and5 passengers fatally injured.Aircraft destroyed.

These terse TWX crash factsseven (July 1960 victimsto a long and growing list.robably the most vicious killerall aviation is the low-levelstall.Ask any pilot you know whatto stall speed in a

banked turn. His replyIt goes up, natProbably he has imhis total knowledge of

subject in that one sen

Though all pilots know stallspeeds are higher in a turn,too few realize why or howmuch. Merely knowing that itincreases seems to satisfy somepilots. But ignorance of the relationship between angle ofbank and stall speed is the reason for the large number ofstall/ spin accidents. Do youknow the why and how much?

WHYFirst, why is stall speed

higher in a banked turn?Stall occurs when design lift

ing capability of the wing isexceeded. An g e of attack,speed, drag, weight, and angleof bank all contribute towardreaching this es i g n limit.Makes no difference if you're

flying a delta wing supersonics t 0 v e p ip e or a Bird Dog;they're sisters-under-the-skin.You know that lift varies directly with speed-low speed,low lift. You also know that

lift varies with the angle of attack - higher angle of attack,higher lift (up to the stallingangle) .

What happens when you bendyour wing into a s t e e p lybanked turn? To hold it, youhave to haul back on the stickand your airspeed drops some.You also get that sit-downh a r d e r feeling in the seat, .which indicates additional g-

This article was prepared by theUnited States rmy Board for1 viation Accident Res rch

1


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SEPTEMBER 1960

loading on the airplane fromthe centrifugal force generated.Now we have something to

work with that indicates stallspeeds are going to be higherin this turn: g-force, whichmakes the effective' weights ofthe airplane greater than theactual weight, and hence re quires more lift; the pull onthe stick, which increases theangle of attack; and the dropin airspeed during the turn.They're all tied together.

As you can see, the lift required in a 30 bank is onlyslightly g r e t e r than theweight. In the 60 bank, thelift is twice the actual weight,but e q u to the effectiveweight. The steeper the angleof bank, the greater the liftrequirement.

To get this extra lift whichwill overcome the g-effect ofcentrifugal force, we pull backon the stick and increase theangle of attack of the wing.This increased angle of attack

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causes a rise in induced drag(which incidentally, is alwayshigher at slower airspeeds) .Increasing the drag decreasesthe airspeed.See how this package all tiestogether? Low airspeeds andsteep bank angles are not compatible. In the turn, you tellthe wing it must produce morelift, and it does tha t -up to apoint. t stalls out trying toproduce beyond its capability.

Aviators seem to grasp therelationship between bank andstall faster and more completely when it is compared to astraight - ahead climbing stall.This probably results from amental image of automobilesor bicycles straining to climbsteeply graded hills. In effect,when you bank an aircraft, youare climbing Imagine t h teach time you enter a bank youare tilting the horizon andclimbing toward your desiredheading. N ow remember allthe stall series you have prac-

ticed and it becomes very easto understand this relationshipThere you have the why ohigher stall speeds in a banketurn. Now let's discuss thhow much.

HOW MUCHA simple thumb rule for angle of bank versus approximat

stall speed increase: 30 banis a 10 percent increase; 45bank is 20 percent increase60 b n k is 40 percent increase; 75 bank is 100 percenincrease.W h e n you're overshootinthe final turn for landing, wiyou wrap it up tighter or takit around? Just remember thaabove 60 banks, your staspeed goes out of sight inhurry. t is here that the stallspin accident occurs.Now what have you learnedWhat kind of answer can yogive the next generation aviator who asks you the questiowe began with: "What happento stall s p ee d in a steeplbanked turn?"

You know that stall occuwhen you exceed the desiglifting capability of your wingAn increase in gross weigh

raises the basic 1-g stall speeG in a turn acts as an effetive weight increase.In effect, you are climbind u r i n g banking turns. Thsteeper the bank, the steepthe climb.Stall speed rises rapidly asteep bank angles.In a 65 bank, your stallinspeed is half again as high awith wings level (an amazin150 percent of basic s t aspeed) .

These rules are applicabto any aircraft and at anweight, soIn a banked turn, it pays know all the angles


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DEPT OF PRI F WPOWER SSIST LANDING

AT THE TIME training ofPrimary students began atFort Rucker, it became apparent that directional problemsexisted due both to the runways not being into the prevailing winds and the characteristics of the t rainer, theTL-19 A and E. The trainerwas designed as a tactical airplane to be landed over barriers into short, rough strips,or perhaps on a narrow road.Such landings are made withpower to touchdown.

Why, then, should we use apower-off approach, round-out,and touchdown in the Primarystage of student training? tis very difficult to teach a beginning student to recognizeslight amounts of drift on thelanding approach, round - outnd touchdown. Experienceshows that we must fly an air

plane according to its characteristics and peculiarities.Experiments were initiated

to find an answer to this directional control problem. Theumber of directional controlthat a turn

ing or swerving of the airplaneook place after touchdown and200 feetthe after-landing roll. Thiswe r v e started during theby the pilot s failrecognize the airplane sor crabbing, coupledthe grounda three-point attitude.With power applied at theof the round-out

elevator and rudderis maintained throughround-out touchdown androll. The smallneeded alongthe thrust developed by..of power tend to

alleviate the swerve and causethe airplane to roll straight.Additional benefits are gainedthrough this technique. Withslower landing procedure, student reaction time keeps up

with the landing process. Positive three - point touchdownsare accomplished giving additional d i r e c t ion a I controlt h r 0 ugh the steerable tailwheel. The additional slipstream over the control surface makes for better reactionof the controls. Heavy braking c t i on is unnecessary.Overcontrolling with rudder isreduced as the airplane slowsdown.

EPT OF R/WHelicopter Instrument Train

ing has been a part of our program of instruction here atFort Rucker since 1958. Duringthis period many rotary wingaviators have earned their instrument ratings. The helicopters currently used for this

from th

training are the H-19 H-21 andH-34.Beginning in October or No

vember of this year, studentsattending the Helicopter In strument Flight Course can expect to train in the new turbinepowered HU-1A.

DEPT OF P NRIMany division staff aviationofficers are receiving the A via

tion School Catalog of Instructional Material, according toour mailing list. However theirdivision aviation companies areot aware of its existence. Thissituation could apply to all command levels in both active andreserve units.As long as Army Aviationcontinues to develop and refine

its procedures, organizations,equipment, and techniques, theAviation School will continue tomake available Master LessonPlans to organizations worldwide. These cover all residentinstruction, incorporating current procedures, organizations,equipment, and techniques.

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SEPTEMBER 1960If your organization wouldlike to be placed on regular distribution for the A v i a t i onSchool's Catalog of Instructional Material and its monthlychanges, write to the Com

mandant, U. S. Army AviationSchool, Fort Rucker, Ala.Work on the extension courseentitled Organizational Aircraft Maintenance Supervisor(Aviation) has been initiated.This will be Common Subcourse 57, administered by theArtillery School, For t Sill,Okla., upon completion and approval.

DEPT O T CTICSThe Department of Tacticshas submitted its final draftof Chapter 13, Medical AirAmbulance Company and Heli

copter Ambulance Medical Detachment, for FM 1-5, ArmyAviation Organizations andEmployment to the Department of P&NRI. This chapterpertains to Army Medical Service aviation units. It coversmission, capabilities, employment and organization in sufficient detail to provide unitand element commanders withnecessary guidelines for dayto-day operations.Recently, a Department ofTactics instructor was forcedto ditch an H-13G helicopter.Although the procedure as prescribed in the flight manualwas not followed, the ditchingwas successful. Since therewas a passenger aboard, heelected not to roll the helicopter. Had this been done, andthe person on top had been injured or trapped, the otherwould have had a difficult timeclearing the aircraft.By entering the water in atail-low attitude, the b a desstruck the water behind thecockpit and stoppetl after two1

or three revolutions. As thehelicopter settled in the water,the pilot exited through theleft door and the passengerthrough the right. By thistime the blades had stopped.Since there is not much of anexperience factor on this subject, the above is submitted forconsideration by other aviatorswho may find themselves in asimilar situation.

CDOAerial Combat and Reconnaissance Company has made

two simple modifications on itsH-13E armament system to enable aviators to arm or disarm, elevate or depress, charge,and fire t h e i r machinegunswithout releasing the flightcontrols. Only parts in the current military inventory areused.

The lower arm box from thecollective pitch stick of theH-13H model was placed on thecollective pitch stick of the Emodel. The starter and lightswitches on the box were replaced with two switches whichenable the aviator to arm, disarm, or place his weapons onsafe without releasing the collective pitch control stick. Itwas previously necessary to release the control to reach theswitches on the console.The H-13 cyclic stick gripwas replaced with the B-8(H-34) grip, which ACR modified to incorporate fingertipcontrol of firing, elevating ordepressing, and charging of themachineguns. This eliminatedanother problem of releasingthe control stick to reach for aswitch. (Provisions for a radioswitch also are included on theB-8 grip.)

Lights on the original master armament panel on the console were tearranged to indi-

cate condition of guns.The Role of Army Aircrafin CBR Warfare, is currentlybeing developed in study formThe study is to determine towhat extent Army Aviationcan assist in the conduct ochemical, biological and radiological warfare. It will recommend missions for Army aircraft in support of CBR operations and determine any speciarequirements for a i r c r a f ttraining, and associated equipment during the 1960 to 1970time frame. Recommendationas to modification of currenoperational Army aircraft andequipment will be considered aswell as levels of assignment fo

ew modified armament system


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specialized vehicles, if recommended.Army Aviation can providevaluable support within theframework of the field armyby providing rapid movementof personnel, supplies, ndequipment. However, the primary consideration of thisstudy is whether or not it isfeasible, economical and tactically practicable to dispensechemical, biological, and radiological sprays and agents fromArmy aircraft.At the request of the UnitedStates Army Aviation School,

the Army Aviation Branch,United States Army ChemicalCorps Training Command, FortMcClellan, Ala., recently demonstrated t h e smoke - layingcapabilities of the L-19 aircraft. The volume of smokeproduced by the L-19 equippedwith either two M-10, E-33, orE-37 tanks is great enough toscreen a company sized airmobile (ACR) operation for 5-10minutes during t h e criticallanding phase. I t is not greatenough to support a battlegroup size operation. However,this same equipment appears

capable of providing sufficientsmoke for screening the attackof a roadblock or strong-pointby a small unit (company orplatoon) -ground or airmobile- not having the immediatesupport of mortars or artillery.An improved tank and smokeagent can give Army aircraftan even greater coverage capability. Other possibilities include use of he i cop t e r sequipped with fog oil typesmoke genera ors as well asuse of fixed and rotary wingi r c r f t for dispensing ofchemical decontaminants.

A Letter from a Mechanic s ifeThree copies of your Mechanics Bulletin havecome into my hands and I want to tell you ofmy appreciation for this little magazine andthe purpose it is fulfilling. I feel that I canwrite with authority because my husband is anaircraft mechanic and I have heard little butaviation talk for nearly all my married l i fe -considerably more than a quarter of a century.For too long the aircraft mechanic has been

laboring under two misconceptions: (1) thegeneral concept that a mechanic is a workmanof lesser intelligence and ability, and (2) hisconcept of himself influenced by this generalverdict.I t wasn't always this way. In its earlier

days aviation was the great adventure. I t wasa new world of exploration and the lines between the explorers were not so sharply drawn.Mechanics, pilots, designers, financial backers,all were in it together, contributing equallytheir time, ingenuity, and patience, and sharingequally in accomplishment and in disappointment."Success brought bigness and with bignesscame the anomaly of expansion appearing asincreasing personal limitation. Everyone wasclassified, departmentalized, with sharply outlined fields of activity. Differences were emphasized. One heard the reference, 'only amechanic.' I t seemed that the mechanic wasto become an overspecialized automaton. ThenI found your Mechanics Bulletin and the assurance that this can never be

I am not technically minded and many ofthe articles in the Bulletin are beyond my comprehension. But the very articles that leaveme floundering indicate a readership with thebroadest possible understanding and mechanicalknow-how. The readers are men with a highorder of intelligence and a dedicated sense ofresponsibility. To them are entrusted equipment worth millions of dollars and lives thatare beyond price. They command our deeprespect. I glow with pride that my husbandis one of them.My thought turns gratefully to this wonderful country in which we live. Here the rightsof man are so safeguarded that a technicaleducation of the sort indicated in the MechanicsBulletin can be the experience of all who reallywant it. Here, to a greater extent than in anyother country, man has the freedom to partakeof and to develop all the qualities bestowed byan all-good God; the freedom to be the manhe wants to be.

We cannot be reminded too often of thesefacts, and your little publication must be ofcontinuing and expanding value as it adheresto the great purpose of appreciating and enhancing the work and the worth of the aviationmechanic." Sincerely yours,(Name withheld by request)

(This letter is a reprint from the AVIATIONMECHANICS BULLETIN published by theFlight Safety Foundation.)


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OFTEN INSTRUCTORS inon - the - job - training orschool classes need a trainingaid to make a point clear. Whileyou labor solely with words,that unavailable training aidmay be only a few blocks away.A trip to your nearest salvageyard might uncover a virtualtreasure of training aids.

The Department of Maintenance at Fort Rucker has salvaged many parts needed to2

Lieutenant Carl G MidgeH Inf

improve its classroom instruction. Some of the training aidsits instructors have devisedfrom salvaged materials are described.he Primary MaintenanceDivision teaches landing gearsystems, including hydraulic

systems, pressure type bleeding of the brakes and replacingbrake pucks in the wheels. Instructors f ro m the divisionwent to the salvage yard and

collected landing gears froma i r c r a f t that had crashed,ground - looped, or sustaineddamage due to hard landings.These and i n g gears weremounted on frames for the instructors to use in demonstra-

Lieutenant Midgett is assignedto the Aircraft Systems BranchPrimary Maintenance DivisionDepartment of Maintenance US-AAVNS He is fixed wing quali-fied and instrument rated.


15/40

tions and the students to workon during practical exercises(Photo No.1).The Aircraft Structural Repair Section also a part of thePrimary Maintenance Division

obtained an empennage sectioncomplete with tailwheel assembly. This is used to teach themechanics to m a k e aircraftskin patches in the sheet metal(Photo No.2). They also havean L-I9 fuselage and a wingsection both found in the salvage yard.

The Rotary Wing Sec cion ofthe Intermediate MaintenanceDivision made a partial cutaway model from a salvaged H-13. Different parts of the rotorhead assembly were c o l o rcoded (Photo No.3). Now thestudents c n follow controlmovements by watching thecolors.

One of the most up-to-datetraining aids in the Department of Maintenance is a largemagneto mockup built here atthe Aviation Center to illustrate the internal parts of amagneto mechanism. Of coursethis wasn t found in the salvage yard, but you may findthe magnetos that would bejust the thing you need toteach bench timing.Another new training aid wehave here at the school didn tcome from the salvage yardeither, but was built by theEngineers f r o m an originalidea of Major General Easterbrook Commandant of the Aviation School. The Generalthought it would assist the Department instructors to have aturntable large enough to holdan L-I9 or H-I3, thereby allowing one instructor to conduct the class without the useof assistant instructors. Thisis another step forward in theincreased utilization of instruc- Photo No.1 top Photo No.2 centerPhoto No.3 bottom

3


16/40

SEPTEMBER 1960tor personnel.

Many other training aidshere at the Army AviationSchool have ee n developedthrough imagination and initia-tive. We certainly do not recommend crashing aircraft toobtain training aids, but thechances are you ll find anythingfrom engines to instruments inthe salvage yard. So go takea look.

Now probably the questionpops into your mind, How do Igo about getting these treas-ures? Paragraph 13, AR 755-7deals specifically with this typeof issue and spells out in detailthe course of action to be takento obtain property in possession of the Property DisposalOfficer. Procedures probablydiffer in some areas, but hereat the Aviation School and in

the Third Army area it is nottoo difficult to obtain these salvaged parts.First, fill out Form DD 1149

(Third Army Area DA 1546)and submit it to the PropertyDisposal Officer, who is underCenter Quartermaster. On thisform you write a certificatestating, I certify that aboveitem (s) will be used (as) tomake) ___________, a purposeother than for which they wereoriginally intended. This procedure is for parts that areclassified as scrap. Normally awing, fuselage, etc., would beconsidered scrap.

The unserviceable items haveto be issued to the Tech Serv-ices Officer and, if accountable,picked up on their propertybook and reissued out to theus.ing organization.

Top: A valuable teaching aid H 13 or H 19 on a turntable.Bottom: Compass swinging taught the easy way

14

Empennage used toteach internal structure


17/40

TREASURE IN THE SALVAGE YARDI know many of you makeCR flights that take you intoAir Force or Navy bases. They

mi g h t have something youcould use. Why not look aroundthe next time you fly into oneof them? From strictly hearsay, I understand that it's nottoo difficult to get an item fromthe Air Force. Normally their

salvage is not accountable, sothere are no funds involved.Can a person from Fort Benning or any other post come toFort Rucker and get salvagedparts? Certainly; all he has todo is to have the Training AidsOfficer at his post fill out theDA 1546 or DD 1149 and sendit to the Property Disposal Of-

aintenanceTime averJ R rackinA ROVING PARTS bin forcommon usage items has

reduced the maintenance timeon L-19s undergoing periodicinspections at Lowe AAF, FortRucker, Ala. Such a bin can beinexpensively made at mostmaintenance shops.

Supervisors at the Lowe inspection hangar observed thateach mechanic was losing up to30 minutes a day by having tointerrupt his job to obtainneeded parts. Free stockhardware bins we relocated

within the hangar, but theworker had to walk a considerable distance to pick up abolt, nut, washer, gasket, orsimilar item. Each trek tookonly three or four minutes perman, but the total time consumed amounted to many manhours each shift.A plan was devised to allowmechanics to stay on the joband obtain bits and piecesand general supplies at theirwork stations. A discardedcafeteria cart was adapted to

ficer here at Fort Rucker. Ifit's available in the salvageyard, he will issue it to you.We want the best aviators

and the best maintained aircraft available. Good trainingaids often mean good training.Perhaps you can find a treasured training aid in your salvage yard.make a portab1e base for afree stock bin. A wooden stockbin was cut in half and mounted back-to-back to provide 84storage spaces (each bo u t4112 inches square) for nuts,washers, screws, bolts, and thelike.A rod across the top of thebin suspends assorted sizes ofcolor coding, masking, and upholstery tapes, and safety wire.One end of the bin is devotedto a display of the variousclamps required for L-19 aircraft maintenance. The opposite end has an arrangement ofgaskets, 0 rings, and relatedparts.

Identification t g s for removed parts also are includedon the bin. Package goods, suchas tailwheel main leaf, eyeboltand thru-bolt, that are knownchargeout requirements foreach aircraft are prepacked andimmediately available.

The roving parts bin ismoved from crew to crew atleast once a day by a supplyproduction parts expeditor andenables the crew chief and / ormechanics to resupply theirtoolbox rollaways as needed.This permits the mechanic tostay at his job station continuously, and an optimum outputcan be maintained.

Mr. Brackin, who devised th eroving parts bin, is th e supervisorof supply for the l-Iayes A1rcraftJorporation at Lowe AAF FortR/(,c cer, Ala.

5


18/40

HE SERGEANT AWOKEwith a throbbing headacheand a thick feeling of nauseachurning in his stomach. Hedismissed it as airsickness andglanced at his watch. They hadbeen flying an hour and a half.

Suddenly the sergeant noticed a bluish-red coloring under his fingernails. Carbonmonoxide " he said aloud. Hestood up and immediately experienced a sensatio.n of dizziness and a feeling of confusion.He stumbled fo.rward to thecockpit and informed the captain, who instantly turned offthe heater and opened the windows.

The H-34 was landed at thefirst opportunity and a checkof the cockpit and cargo. compartment with a carbon monoxide detector kit revealed asaturation of the deadly gas in16

icha rd K Tierney

both areas. t was estimatedthat after an hour and a halfin flight the air in the cargocompartment had been .045percent carbon mono.xide andthe percentage in the cockpitwas about .028 (see chart 1).

This story is fiction, buteasily could be fact. The PDS-sibility of carbo.n monoxideendangering personnel in anytype of Army aircraft is always present, especially in coldmonths when windows areclosed and heaters are on.Carbon monoxide is difficultto detect without pro.per equipment. t is an odorless, colDrlessgas formed by combustiDn ofany carbon-containing materiala s in gas engines and various

t y p ~ of heaters. There arenumerous ways carbon mDn-oxide can invade cockpits orcabins when you consider the

many combinations of defectthat might occur in heatingand exhaust systems and otheopenings to the cockpit (seeCRASH SENSE, Aug. 1960issue of DIGEST).Currently the Army requiresdetector kit checks fo r carbonmonoxide only in L-19s, L-20and UI-As (see respective -6)However, some autho.rities feethat all Army aircraft shouldbe checked perio.dically withappropriate detector kits, suchas pictured in figures 1 and 2The A viatio.n Medical Adviso r of the U. S. Army AviationSchool recommends tha alArmy aircraft be checked periodically fDr CO with detectokits.I t is a simple matter to ordeand use carbon monDxide detector kits. Those pictured infigures 1 and 2 carry a FederaStock Number of 6665-283-0654


19/40

wa::wI

.100

In .080o~


20/40

THEI . S. RMY

O ~ R QF oRVI TION.

CCIDENT RESE RCH

H 23C FUEL EXHAUSTED during flight. Aircraft made autorotation into railroad yard andright skid caught on track causing main rotorto strike boxcar . Major damage. No injuries .L-19E STALLED, struck tree and crashed duringattempted go-around. Aircraft destroyed . Minorinjuries to pilot and observer.L 19A ENCOU NTERED DOWNDRAFT andcrashed into mountain during search and rescuemission. Major damage . Pilot suffered bruises .Injuries to observer undetermined .L-19A ENGINE LOST POWER during flight.Forced landing completed with no damage .Power loss caused by fouled plugs.H 19D MAIN ROTOR BLADE damaged whenlanding area marking panel was blown into rotorsystem by downwash.H-13E ROTOR STRUCK TREES during practicefor demonstration in confined area. Resultanthard landing caused bounce and loss of di rectional control. Tail rotor blades tail boom, leading edge of both main rotor blades dented; skidsand cross tubes bent. No injuries.U 1A PROPELLER STRUCK RUNWAY duringtouch-and-go landing . Incident damage to propeller tips. Caused by excessive forward pressureprior to lift off.H 21C TAIL CONE scraped during tail-lowlanding.H 21C LANDING GEAR DRAGGED through treesduring low-level flight . Brake line broken atwheel cylinder.s

L-20A TAKEOFF ABORTED from field stripAircraft crossed ditch and ground - looped. Lelanding gear collapsed; propeller bent; and leelevator damaged .H 13H FELL THROUGH during practice autorotation. i rcraft destroyed . Pi lot suffered bacinjury. Crew chief suffered minor injuries tleft side.L-23D LEFT MAIN LANDING GEAR lock hooassembly failed during takeoff . Tips of left propeller struck concrete runway. Takeoff completeand wheels-up landing performed at another airbase. Propeller tips bent; exposed antennabroken ; and rivets in nose compartment radibracket severed.L 20A ENGINE FAILED during flight . Attempteroad landing aborted due to vehicle traffic . Aircraft crashed and destroyed . No injuries. Causof engine failure : split in No . 1 cylinder wallH-13E LANDED HARD during practice autorotation. Major damage to main rotor bladestail rotor section and right skid . Tail boomsevered. No injuries .H 21C ROLLED DOWN HILL during attemptemountain slope landing. Front rotor blades structree and aircraft was purposely rolled on side tprevent further rolling. Major damage to fuselage, power train fl ight controls and rotor bladsystems . No injuries .H 13G FELL THROUGH during attempted powerecovery from practice autorotation . Suspect partial engine failure. Cause undetermined pendininvestigation. Damage to cross tubes main rotocable assQmbly and main rotor hub . No injuries


21/40

iuly and augustTWO H 21 s DRAGGED tai I cones during slopelandings . Incident damages . No injuries.L 19E STRUCK TREES during road landing.Major damage to wings; right fuel tank rup-tured ; fuselage dented; plexiglass broken. Noinjuries.H 19D CENTERI NG MECHAN ISM of right nosegear failed to align nose gear during runninglanding. Bulkhead bent at landing gear mount-ing bracket .H 34 ENGINE FAILED during service f l ight .Forced landing completed with no damage .Cause of engine failure undetermined pendinganalysis.L 20A LANDED SHORT during night approach .Skin damage to tail cone . No injuries.L 20A STABILIZER STRUCK BUSH during nightlanding . Aircraft veered into rough terrain . Tailsection buckled; right stabilizer and elevator tornoff; stringer and left landing gear damaged .No injuries.H 23D STRUCK GROUND in tail low attitudeduring practice 180 0 autorotation . Main rotorflexed down and severed tail boom . No injuries .L 23D LANDED on wet grass and rolled intobarbed wire fence at end of runway . Minordamage. No injuries .H 13G LANDED on road with 7 foot embank -ments following loss of power after takeoff .Major damage to tail rotor and main rotor sys-tems . Cause of loss of power undeterminedpending investigation . No injuries .

H 13E ENGINE FAILED during landing approach.Main rotor flexed down and severed tai I boom .Major damage . No injuries . Suspect faulty fuelsystem .L 19A ENGINE FAILED during formation f l ightover water. Pilot bailed out and aircraft sankin ocean . No injuries .L 19A ENGINE FAILED during f l ight over beach.Beach was heavily populated and aircraft waslanded in lake water. Pilot suffered minor bruisesand scratches. Major damage to right wing flapsengine cowling windshield engine mountingengine firewall; and water damage to all instru -ments. Cause of engine failure: oil pump failure.TWO H 13Gs STRUCK PINE TREES during low-level reconnaissance fl ights . Canopies broken .No injuries.L 19A VEERED TO LEFT and crashed duringroad takeoff around curve . Major damage toall components. No injuries.H 13H TAIL ROTOR STRUCK foreign objectduring flight. Directional control lost due toantitorque failure . Aircraft destroyed . No in -juries .L 19E LANDED SHORT and struck embankmentshearing left gear . Major damage to le t wingand aileron left landing gear propeller elevatorand horizontal stabilizer. No injuries .H 13G BOUNCED during touchdown from prac -tice autorotation. Main rotor flexed into tailboom . Major damage . No injuries.L 19A TAXIED into open manhole . Major dam -age. No injuries.

9


22/40

A RCRAFT AVAILABILITYhas been a primary concern of the commander sinceaviation began. The problemof programming aircraft formissions is compounded by thepercentage of total aircraftcapable of safe flight. UsingPHst performance and maintenance records as a guide manyyears of research and development have gone into the fixedwing program to reach thepresent point of reliability inpredicting aircraft availability.The Army s F / W and R/W2

CWO Richard N Cullen TC

programs have yet to reach thepoint where exact availabilitycan be determined in advancebut these goals are nearer attainment with the developmentof new aircraft, powerplantsand more modern maintenancetechniques.Maintenance will be great lyimproved with the Army s newHU-IA gas turbine poweredhelicopter. It was specificallydesigned to incorporate manynew ideas and simplified maintenance techniques. rm yspecifications required an air-

craft that would permit operations under combat conditionswith as little maintenance aspracticable. Such provisions asthese were made for ease ofmaintenance in the field: rapidunit replacement of major components; a minimum requirement for special tools; rapidassembly and disassembly;ready transportability by air

Mr . Cullen is an instructor withthe H U-1A section Department oMaintenance US VNS . H e isrotary wing qualif ied.


23/40


24/40

Special hoist is used

to.r transmission and engine.Remo.val replacement andrigging of the tail rotor assembly can be accomplished in avery short time. The tail rotordrive shafting is easily removed and replaced. All fivesections of tail rotor driveshafting are interchangeable-Special tools required for o r-ganizational maintenance arethe mast retaining nut wrenchcyclic stick centering fixturehoist and slings. The hoist isa lightweight portable typewhich will easily fit inside thecargo compartment o f the helicopter for transportation. twill lift the main rotor assembly transmission o r engineand swing it into. Po.sition forIo.wering onto a special stand;it may also be used for installing the same.

Smaller items such as timing the stabilizer bar damperson the aircraft are accomplished in a very short time.Too I s required are commonwrench screwdriver and awatch with a sweep secondhand.22

All gear boxes have been designed so that the oil need notbe drained from the box whenthe magnetic plug is removedfor checking. Nor will the oildrain through the magneticplug opening.The HU-IA trim system incorporated in the cyclic and antito.rque control consists ofthree magnetic b r k e s ndthree tube assemblies. Themagnetic b r k e s are interchangeable by repositioning theactua or arm.

Let us take a closer look tosee why some components require less maintenance thanitems used in recips. Due torelatively few moving partsvery little can go wrong withthe engine. It has no magnetostiming points cylinders orrings air filters to be cleanedo r spark plugs to foul out.

The main rotor hub savesconsiderable time not only inremoval and replacement of thehub but also in removal and replacement of a single blade. Ono.ther type helicopters considerable time is required daily tolubricate with g r e s e themain motor assembly. All lubrication on this hub is accom-

plished by turbine oil containein reservoirs mounted on thhub.

Time - saving adaptions othe transmission include thmounting of accessories. Amounting pads are semi-permnently shimmed; thereforenew unit may be installed othe original shim wi t h uchecking gear pattern or backlash.In the tail rotor system asections o f drive shafting arm s t e r balanced and intechangeable. The sections arheld together by the use ofcurvic-co.upling a radial beaing and marmon clamp. Thcouplings and bearings arlubricated on assembly and a300 hour intervals. Tail rotoblades may be changed indvidually.You can now see that thnew co.ncept of design has increased the available flighhours and decreased the manhours required to maintain thhelicopter. It is a definite stein the right directio.n. We caexpect further refinements ithe years ahead. Perhaps theaircraft availability will ceasto be a problem the commandemust consider.

. to exch nge main rotor transmission and engine


25/40


26/40

SEPTEMBER 1960utes," the Institute said in itsreport of the experiment. K. E.Chellis of Tall ahass ee, Fla.,forcefully tells what those 178seconds mean to the pilot.Author Chellis is a flight instructor and a certificated 180 0Rating instructor.-The AOPAPilot.

The sky is overcast and thevisibility poor. In fact, thatfive-mile reported v isi b iIi tylooks more like two now. Youare no longer able to judge theheight of the overcast. Youraltimeter says you are at 1 500feet and your map tells youthat there is terrain up to 1 200feet beneath you. There mighteven be a tower around heresome place for you are notexactly sure just how far offcourse you are. But you'veflown in worse weather thanthis, so you go on.You unconsciously ease backon the wheel just a bit, to clearthose not too imaginary towers.Then with no warning you arein it. You stare so hard intothe milky white mist that youreyes hurt, but you see nothing.You fight the feeling that isin your stomach, and swallowonly to find your mouth dry.Now you know you should havewaited for better weather. Theappointment was important butnot that important. Somewherea voice is saying, "You've hadit--you've had it "

24

You Now Have One HundredSeventy-eight Seconds ToLive

Your airplane is still on aneven keel but your compassis turning slowly. You push alittle rudder and add a littlepressure on the wheel to stopthe turn, but this feels unnatural and you return the controls to their original position.This feels better, but now yourcompass is turning a little faster and your airspeed is increasing slightly. You scan yourinstrument panel for help butnow it looks almost unfamiliar.You are sure you will breakthrough in several minutes.This is just a bad spot. Butyou don't have several minutesleft.

You Have One HundredSeconds To LiveYou glance at your altimeter

and are shocked to see it unwinding. You already are downto 1 200 feet and instinctivelyyou pull back on the wheel.But the altimeter still unwinds,the engine is revving too fastand the airspeed is almost tothe red line.

You Have Forty-five SecondsTo Live

N ow you are sweating anshaking. There must be something wrong with the controlfor pulling back on the wheeonly moves the airspeed indcator a little farther into thred. You can hear the wintearing at the airplane.

You Have Ten Seconds ToLiveSuddenly you break out othe overcast. There is th

ground. You can see the treerushing up at you and you casee the horizon if you turn youheard far enough. It's at an unusual angle you are almost inverted. You open your moutto scream-but you are too late

YouHave

NoSeconds

ToLive

It's all over son.


27/40

.. .1. .... o

F ,', @ , m 1 ' 1 1 4 V U & ; ' ; J $ > ' W ' d ~ ' : ' r ' ' \ ;.1'h,,,.' ,7>'%'::' < : : < \ ' > . + P : ~ @ : ; : ; ~ : : : : ; : > ' : ~ : : ' d, ; ' : ' , , " ;

' + , : .> :

Lieutenant Colonel John L Briggs rty

WHEN AN ARMY A VIATION unit has to move alarge number of aircraft fromhere to there, it brings up thequestion of whether it's betterto crate 'em or fly 'em. Ex-perience at the U. S. Army Pri-mary Helicopter School, CampWolters, Texas, has proved conclusively that flyaway deliveries payoff in almost everycase and for any type of air-craft.Camp Wolters personnel re-cently ferried 130 H-23D helicopters from the Hiller factory

at Palo Alto, Calif., to Wolters.They saved $222,718 and 1,560aircraft days by flying insteadof shipping them in. Otherbenefits res ul t ing from theflyaway delivery included thetraining acquired by the crewferrying the aircraft and thecondition and almost immediateavailability of the helicoptersupon arrival at Wolters.A carefully documented studyof all experience data on theactual flight delivery of theseH-23s was made. Aircraft dayslost were computed from the

date of final acceptance testflights at the factory to thedate that the aircraft wereready for training use atWolters. Every gallon of POL,every penny of the taxpayer'smoney, every minute of time,and even trade stamps wereincluded. Against this data,

Colonel Briggs is AssistantCommandant United States rmyPrimary H elicopt er School CampWolters Texas.25


28/40

SEPTEMBER 1960actual time and CDSt figures ncrating and shipping by railor van were Dbtained from thefactory and government transportation experts. Estimateduncrating and test flight timesalso were included. (See box forcomparative figures.)

Once a plan for an en masseflyaway is decided upon, anSOP should be established. Ina flight delivery program TMCwill nDtify the gaining unitwhen to pick up the aircraftand will give fund citations forcosting the trip. During thePalo Alto-Wolters operation,TMC sent a canned messagefor each trip. These TWXs contain cost accounting and shipping number informatiDn andare cited as authority in unittravel orders.

The kit TMC provided forthe flyaway contained SOP f rferry pilots, SF 44 (five copies),a list f POL credit cards, andan addressed envelope to bereturned to TMC. t was augmented by a letter of instructions and maps with route distances and heading markingsannotated. A briefing of all invDlved in the Dperation includedissuance of orders, advance per

diem (whose wife ever allDwshim enough extra m ney fora six-to-seven-day trip that isgoing to touch Dn such pointsas San FranciscO , Palm Springs,Los Angeles, Phoenix, and EIPaso?) and a TR for thDsegDing by commercial air.The Wolters plan involvedtwo trips a month to meet themission delivery requirementof 10 helicopters per mDnth.A ferry crew cons,isted f nepilot f r each aircraft to bepicked up, a mechanic and anescort pilDt. The mechanic isprovided in event somethingbeCDmes unglued en route. Actually, other than rDutine maintenance, the mechanic had toreplace parts Dnly twice duringthe entire operation.

TH S HEDULEThe following schedule was

prepared for the ferry crew:Monday morning: An L-20with pilot, mechanic, twO ferrypilots, spare parts, tools, andall flight kits to depart CampWolters, arriving at Palo Altoshortly after nODn on Tuesday.(Monday night RON at thecrew's discretion.)

Tuesday morning: The re -

Map, of inl nd nd co st l route of fly w y

26

mainder of the ferry crew todepart Fort W Drth by commercial air f r San Francisco, arriving at PalO Alto in the evening.

Wednesday mDrning: Checkaircraft, test fly, and move toPalo AltO airport for earlyThursday m 0 r n i n g takeofprior to plant opening time.

Th ursday morning: DeparPalo Alto for Palm Springs oLos Angeles, depending on theweather, utilizing the coastaroute via Paso Robles, SantMaria and LDS Angeles, or Dnthe inland route via Bakersfield. There are advanta.ges anddisadvantages bDth ways. LoAngeles is always loaded withVFR traffic flying IFR conditions; the Bakersfield-San oaquin Valley rDute in volvesmountain flying. The first legof the flight should be shDrand a shakedown in natureDuring this leg the crew should


29/40

CRATE EM OR FLY EM?moke Qut any mechanical de- wQrk fQr a day s pay Qn Mon- flight, checks navigation, re-

defects (clear out day morning. lays weather information, andthe San Francisco. fog), and LESSONS LE RNED arrives at the next fuel stopfuel consumption on in advance of the helicoptersll aircraft to provide a pace- Here are a few lessons to make POL arrangements.setter fQr the remainder of the learned from the Palo Alto- This is a big time saver.light. Wolters flyaway. Organization of flight per-

Friday morning: Depart Los Make sure your escort air- sonnel with assignment of tripAngeles or Palm Springs for craft has radio equipment com- duties is suggested as follows:hoenix Qr Tucson (depending patible with the helicopter s POL officer: Handles all ren who in the flight has rela- radios. This may require the fueling, signs gas tickets, andtives where), with fuel stOoP at installation of auxiliary equip- keeps the record of all transBlythe, Calif. Use the field west ment in the escort aircraft. actions. The POL officer shQuldf Blythe, not the cropduster Avoid fixed. gas pits when- be the pilot of the escort plane.strip east which is too crowded ever possible on fuel stops. Flight planning and weather

refueling space. They are too time-consuming. officer: Files and closes allSaturday morning: Depart None have hoses long enough flight plans, keeps current runPhoenix or Tucson for EI Paso to accommodate five aircraft, ning account of weather situawith fuel stops at Cochise and the pilots are required to tion, briefs pilots of the flightCounty or Deming. jockey the aircraft about. This prior to each leg and duringSunday morning: Depart EI cuts into rest and coffee time. the fly-through. The escortPaso fQr Camp Wolters. This is The helicopters should take plane pilot also should assumethe longest single day s flight, off first on each leg, while the these duties.with fuel stops at Van Horn L-20 pilot brings fuel consump- Transportation officer: Arr Carlsbad, Midland and Abi- tion statistics up to date and ranges transportation for thelene. Upon arrival at Wolters, pays for the gas. The L-20 entire flight when required,shut down, greet the family, pilot then departs and flies usually upon arrival at theand get ready to put in a day s by or through the helicopter RON point. The transportation

Camp Wolters the end of 1 335 mile flyaway from the factory

27


30/40

SEPTEMBER 1966officer should be one of thehelicopter pilots. On most ofthe Wolters flights the individual with the most rat holemQney was picked for this jQb.He paid all the bills and claimedreimbursement O n his vQucher(underscO'ring impor tan t forstaying out of Leavenworth).NO'te: With large groups, usinga shuttle system and depending on the distances, it canprove more economical to thegovernment and convenient tothe crews to use U-drive-itautO'mobiles (not convertiblesfor dO ing the town).

Billeting officer: Arrangesovernight accommodations forthe entire crew, less individualists. He should be one of thehelicopter pilO'ts.

your post P&C officer with thgas tickets. P&C officers arauthO'rized to' turn t radingstamps over to special servicofficers whO can use them tprocure troop welfare items(Don't let the wife hear yohave th e, stamps.)

Maximum effort should bemade to allow the helicopterpilots as much rest as possibleat fuel stops. The escort planepilot should see to' this. In summary, single aircrafpickup is expensive and shoul

be avo-ided if possible. In addition to expense, it might binadvisable if the trip is ovedesolate O r dangerous terrainespecially since escort aircrafwould not normally accompanQne helicopter

f some alert gasoline vendorgives trading stamps with thesale, try to' make a deal withhim to reduce the cost ofthe fuel in lieu of taking thestamps. Failing this, take thestamps and turn them in to

. COMPARATIVE ST TISTICS ~ ~The fO'llowing chart shows the results of thestudy in a nutshell and should dispel any doubtas to the best method to use:

Crate & Ship FlyawayAcft days lost: 2,600 1,040Total cost: 261,895.40 39,881.74Savings n time: 1,560 Acft days

Savings in cost: 222,718.26(The total cost under Crate & Ship above

is for rail. Van costs were 260,029.90. Complete breakdO'wn listed in chart of comparativestatistics.)Crating ShippingDisassy, crate, factory ______________ 2 DaysShipping time __________15 DaysUncrate, assy, destination___________ 3 DaysTotal per acft______________________20 DaysTotal 130 acft___________________2,600 DaysDistance (rail) __________________ 1,922 MiDistance (130 acft (rail) _________249,860 MiDistance (van) __________________ 1,750 MiDistance 130 acft (van) __ ________227,500 MiShipping CO st per H-23 (rail) ______ __ 701.22Shipping cost per H-23 (van) ___ _____ 686.87Shipping cost total (rail) (per H-23D) 2,014.58Shipping cost total (van) (per H-23D) 2,000.23Crating cost per acft__ ____________ 1,250.00Crating cost total 130 acft__ ______ 162,500.00Uncrate assy, destination, per acft __ 63.36Uncrate assy, destination, 130 acft__ 8,236.80Total cost, 130 acft (van) _________ 260,029.90Total cost, 130 acft (rail) _________ 261,895.40

8

FlyawayPilot travel ________________________ 2 DayReceive, test fly, factory ____________ 1 DaFlight ______________________________ 4 DayInspect, destination ________________ 1 DayTotal per acft______________________ 8 DayTotal 130 acft____________ _________1,040 DayDistance H-23D ___________________ 1,335 MDistance 130 acft________________ 173,550 MDistance L-20, one trip _____________2,691 MDistance L-20, all trips ____________67,275 MDistance total flight ______________240,825 l\,fFlight time, H-23D, av trip__________21.1 HFlight time, total 130 acft __________2,743 HFlight time L-20 av trip_____________30.1 HFlight time, all trips, L-20___________752 HFlight time totaL _________________ 3,495 HPOL Av H-23D___________________ 16.8 GPHPOL total H-23D _________________ 46,082 GaPOL Av L-20_____________________22.2 GPHPOL total L-20 __________________16,694 GaPOL total ______________________62,776 GaPOL cost H-23D ___________________ 306.77POL CO st, total H-23D acft_________ 14,335.17POL cost L-20, per trip _____________ 239.63POL cost, total L-20 trips __________ 5,541.98POL cost, totaL __________________ 19,877.1585 cQmmercial air t i c k e t s _________ 8,383.24Per diem 157 persons, 7 days average 11,621.35Total cost, flyaway, 130 aircraft ____ 39,881.74Average CQst, per flt of 5 acft______ 1,533.91


31/40

ive art Manualultiple artCROSS THE COUNTRY, inmaintenance shops everywhere, this question is fairly

common: What's the deal onthis Five Part Manual? Nearlyeveryone has heard about it,but few have seen or used ityet.To begin with, the term fivepart manual is actually a misnomer derived from the fiveechelons of maintenance covered in a basic set of publications for the Army Aviationfield.

Designed to replace the oldTM 1 series, the new manualsystem includes a family ofpublications to provide all ofthe information necessary forany given echelon of maintenance to carry out its mission.Because instructions for thirdand fourth echelon maintenance have been combined intoone manual, there are only fourmanuals to cover the five echelons of maintenance. So, theterm Multiple Part Manualwould be more accurate for thisnew system.The multiple part manualsystem will become effectivefor all Army aircraft as soonas conversion is comp I eted.Many individuals accustomedto the old system will naturallyview a new system with misgiving; however, most peopleagree that this new system isa change for the better. Oneof the biggest and most obviousimprovements is the combiningof material previously found in

Lieutenant William R Troy TCLieutenant Gene A Truitt Inf

a variety of TMs and ARs.A new numbering systemwill also be used. The letterdesignation TM for technical manual will be retained.The first number will be thatof the preparing technical service, (in the case of Army Aviation 55, designating Tranportation Corps) followed by a dashand the four-digit numeral representing the Federal SupplyClassification (FSC) assignedto the equipment covered. Thenfollows three numerals whichindicate the particular equipment in the FSC group or class.This begins with 200, and successive TMs in the same classwill be 201, 202, etc. The lasttwo numbers will represent theechelon of maintenance.As an example, let's use thenumbering system for the HUlA: TM 55-1520-207-20.

55- Preparing technical service (in this case TransportationCorps) .1520- FSC class of equipment

(aircraft, rotary wing).207- Num erical seq uen ce

(eighth TM for TM 55 serieswithin class 1520).

20- Echelon of maintenance(organizational) .Repair parts lists, when published separately from maintenance instructions, will carrythe suffix letter P. Otherthan this letter, these manualswill have the same basic number as the TM with which theyare used.

FIRSTECHELON MAINTENANCEPart 1, -10, contains instruc

tions for operators and crewmembers. This manual replacesthe -1 and -5 Handbooks ofInstruction. t contains the Aircraft Inventory Master Guidewhich gives specific information relative to maintaining thecurrent DD Form 780 Series.The Pilot's Flight Information(formerly in -1 handbooks) describes the aircraft and givesoperating procedures and flightcharacteristics. The old Weightand Balance Handbook has beenincorporated into the new -10also. t includes such information as the definition of termsand instructions for use in completing the standard balancecontrol forms. The -10 also includes instructions on how toload, unload, and secure cargo.

SECONDECHELON MAINTENANCEPart II, -20, incorpora tes

organizational maintenance instructions. This manual obviously replaces the -2 handbookand, in addition, includes in-

Lieutenant Troy is assigned toForms and R ecords Branch Pri-mary Mainternance Division D partment of Maintenance USA-AVNS

Lieutenant Truitt is assigned tothe Special Subjects Branch In-termediate Division Departmentof Maintenance USAAVNS

9


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SEPTEMBER 1960spections requirements. T hiswill take the place of the -6handbook.A chapter is included on thestorage of aircraft. The Maintenance Allocation Chart (formerly the -18) is also availableto define the maintenance functions to be performed at eachechelon of maintenance. TheRepair Parts and Special ToolsList (-20P) appears in thismanual as Appendix III. Containing maintenance suppor tdata, it replaces -4 and -4-20P.

THIRD ND FOURTHE HELON M INTEN NCEPart III, -34, contains the

essential information for thefield maintenance level. However, material in the -10 and-20 is not repeated in this manual; therefore, they must beused in conjunction with thisone. It replaces the -2 and -3at this level. Both third andfourth echelon information hasbeen incorporated into this onemanual. A chapter is devoted

to structural repair, a list ofrepair materials by stock description gauge, commercial design and specification of all repair material required for repairs outlined in the StructuralRepair chapter.

The -34P is shown as appendix III to this manual and isused to order items with For H maintenance level code.FIFTH

E HELON M INTEN NCEPart VI, -50, coupled withthe preceding manuals will pro

vide complete maintenance instructions for depot maintenance activities. This TM hasadditional structural repair information not authorized atfield level. It gives the procedure for preservation andpackaging of aircraft for shipment to any climate. It alsocontains complete overhaul instructions for components,along with two lists of overhaul instructions; one for government-furnished p r ts and

T FLON

one for contractor-furn is h eequipment.The -50 also has an AppendiIII devoted to Repair Parts anSpecial Tools List (-50P). Iincludes all breakdowns and information listed in the -20P an

-34P, making only the -50necessary at Depot M a in t enance Level.

This briefly is a look at thmultiple part manual systemWhen these pUblications arrivat your organization, stop antake a good look at them. You'lprobably like what you see.You can requisition thesnew manuals through normaAG publication channels asoon as each is listed in thDA pamphlet 310-4. Some aravailable now: -20P, -34P, and-50P for the HU-IA. In ordeto maintain these handbookin current status, requirementmay be entered on DA Form12-5 in the column headed Operators and Crew Members Instruction for the RespectivAircraft.

SE OF TEFLON hose in Army aircraft isincreasing rapidly. While this durableproduct has many advantages, it also containssome pitfalls that should be pointed out to Armymechanics.

compound into the desired tube-shaped sizeSteel wire then is braided on the outside for protection and strength.Teflon easily withstands pressures and temperatures ranging from _65 0 F. to +500 0 FThis makes it desirable for use in modern aircraft systems where intense heat and pressureoccur.Many are not familiar with teflon hose,despite authority for its installation in Armyaircraft by Supply Bulletin 1-15-13 in Octoberof 1957. General usage evolved slowly while the

regular inventory of rubber hose was available.However, this stock is diminishing rapidly andteflon hose will be encountered much more frequently. A look at its characteristics may provehelpful.Teflon is a durable fluorocarbon plastic discovered about 22 years ago. It is compoundedfrom a tetrafluoroethylene resin and is excellentas a protective coating on almost everythingfrom greenhouses to aircraft parts.

The hose is made by molding the plastic30

But, teflon hose has some bad points. Itakes on a semi-permanent set when exposedto high fluid pressures and temperatures. Ifit is bent or twisted in this manner, kinks maydevelop in the tubing and be hidden by thebraiding. The hose could then easily fail inflight.Teflon hose is strong, but the mechanicshould remember not to bend or twist it beyondits limits. A bent and. set hose should never bestraightened; bending opposite to the set planeshould be avoided. Hanging or supporting objects from teflon hose also causes failures.


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PREP RED BY THE UNITED ST TES RMY BO RD FOR VI TION CCIDENT RESE RCH

UTUMN

ONE DAY she's in a bikiniyour eyes glued to herfigure assplashes in surf or poolbrunette or auburn pony-bouncing behind. Tear afrom the calendar and youher dashing across the cam-

in wool skirt and

sweater, bobby socks and sad-dle oxfords. This change is thesignal to retune your weatherthinking.

Whether you're stationed inthe short days of the northernhemisphere, or the longer daysof the southern, one thing issure: it's time for a changeHot equatorial air, enjoyed or

cursed during the s u m m rmonths, shoots skyward, driftstoward the north polar regionand sinks into the icy coldnessof the long Arctic night. tspreads across the globe in aseries of fast moving coldfronts into the Gulf of Mexicothe Mediterranean and ChinaSea bringing a winter brandof woes to Army Aviators.

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SEPTEMBER 1960

hite trapS OWSnow started to fall at 1130

hours continued steadily untilafter 1600 hours and began togradually subside. A thickblanket of white covered theterrain and blended into heavylow-hanging clouds at the hori-

zon. The Army Aviator wasflying a Sioux in support of abattalion field training exercise.A decision was made to movethe aircraft to another areawhere a gun cover was availableto protect it from the fallingsnow. The aviator picked the

Visibility zero

Sioux up to a hover and moveforward. Suddenly he spottean unmarked communicatiowire between the trees directin his path. He flared the aicraft and started a right turin an attempt to miss the wirThe Siuox went into a noshigh attitude and the tail rotoguard struck the ground. Thtail section bounced upwarcausing a main rotor bladeflex down and break a dynamstop cable. One tail rotor bladwas lost and the other crumpled. The aircraft was landewith no further damage.Un m r ked communicatiowires are difficult t spot under the best conditions of visbility. Blanket them with snowstring them through trees anan effective trap is set for evethe most sharp-eyed pilot. Investigation revealed that thwire which caused this accidehad been strung three days before with no consideration foany type of marking.One of a flight of five thShawnee pilot taxied out behind the others for takeoff. Hwatched the other aircraft takoff picked his Shawnee up t


35/40

nowbank

The aircraft was taxied outand the runup completed. Thepilot opened his window andwiped the snow from the windshield. He decided against theuse of flaps and applied takeoff power, using the snowbankon his left as a guide for an at tempted visual takeoff. The aircraft rolled straight down therunway and the nosewheellifted off at approximately 740feet. Some 1,000 feet fartherdown the runway the left mainwheel struck a 15-20 inch snowbank and pulled the aircraft tothe left. The aircraft skiddedfrom the runway and came torest at the bottom of a steepshoulder approximately 1 3 0feet from the runway.

a 10-foot hover and preparedto make a 90 turn to line upith the runway. A Beaverwas parked on the right side ofthe runway making i t necessary for the Shawnee to turnaround it. During this turn the

lost forward speed andpproximately 4-5 feet of altiude. Swirling snow, picked upthe downwash, engulfed the

and caused the piloto los,e visual contact with theround. He applied power for

when he estimated thewas over the center ofhe runway. The i r c r f t

and lurched to thepilot immediatelyright pedal, maximumand left cyclic. He deto land and let the swirl

snow settle before attemptanother takeoff. But it wasThe aircraft touchedlurched to the rightrolled to its side.

The L-26 pilot arrived at theat 0500 hours for an0600 hours departure.had fallen most of theand the runway was covby 4 inches of snow and

inch drifts. I t was stillDetermined to make thethe pilot obtained a truck

equipped with a snowplow fromnearby post engineers. He instructed the driver to clear thetaxiway and make 4 trips upthe runway stating that thesnowplow s l2-foot blade wouldclear his takeoff path.

While the snowplow was atwork, the pilot and copilot wentto the weather station andoperations to obtain their flightclearance. At approximately0630 hours the truck driverreported that he had cleared astrip approximately 35-40 feetwide down the length of therunway. Neither pilot nor copilot made an attempt to physically examine the runway condition.

Moral: Takeoff and landingsurfaces demand an equal shareof preflight.

The ground was covered withsnow. W e t he r conditionswere: ceiling, 700 feet overcast;visibility, 5 miles, with fog. TheRaven pilot departed on a training flight, flew to a parade fieldand began a practice autorotation. During the flare, the tailrotor struck the ground anddirectional control was lost.The pilot, not knowing thatthe tail rotor was lost, appliedpower and pitch. This caused

How far is down


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SEPTEMBER 196

the aircraft to turn violently tothe right, and he took off powerand pitch. Maximum pitch wasapplied as the aircraft approached the ground for thesecond time. However therewas not enough rotor rpm tocushion the landing. The air-craft struck hard, bounced andturned 180 t the right, coming to rest in an upright position.Low ceilings fog and snow

often blend into an indistinguishable white mass; autoro-tations require an exacting degree of depth perception. Moral:Put off until tomorrow whatyou can't practice with accuracy todayTwo Seminole aviators departed their station at 1130hours for a long cross-countryflight. ly i n g IFR, t h e yreached their first fuel stop andlanded some 3 hours and 20minutes after takeoff. Weatherforecasters advised that theirdestination was below minimums and recommended theyfile to overfly the original destination in hopes the weatherwould improve and permit alanding.A new flight plan was filed34

and the aircraft departed at1507 hours flying IFR at analtitude of 10 000 feet. Weatherforecast for the new destinationwas 3 000 feet scattered; 8 000feet scattered; visibility 5miles in haze. The aviators contacted their original destination en route and learned thatit was still below instrumentmInImums. However t h e ywere advised that a nearby air-base was reporting clear skies

Below m n mumsand 15 miles visibility. The aviators decided to change theirflight plan and make the air-base their destination. Whenthey landed at the airbase at1908 hours they were advisedof a NOTAM which declaredthat no aircraft could entertheir original destination air-space after 2400 hours. Discussion with weather personnelat the airbase revealed thattheir 0 r i g i na I destinationweather had improved to a500- foot ceiling with 2 milesvisibility in ground fog. It wasforecast to improve.The aviators filed anotherflight plan for their originaldestination and departed theairbase at 2008 hours WITHOUT REFUELING. En route

the aviators found headwinmuch stronger than forecaand it was necessary to revitheir ETA. They arrived ovthe destination beacon cotacted GCA and reported 4minutes of fuel remaining. Thradar controller notified thaviators that the airfield wbelow minimums and advisethat the GCA pattern would ba box type close t the aifield. During the approac

the controller also advised thatheir alternate airport was aminimums.The aviators elected to makan approach to their origindestination planning to proceed to their alternate if thecould not land. The GCA ap

proach was begun at an altitudof 3 200 feet. As the aircrawas vectored around to finathere was confusion about instructions received from thcontroller. The aviators undestood him to say "Maintai2 300 feet." They immediatebegan a descent and a turn tthe final heading. The aircracrashed and burned approxmately 5 miles from the end othe runway. Both aviators sufered compound skull fracture


37/40

and numerous lacerations. Onealso had a broken ankle. Theflight surgeon estimated thatone aviator would not be ableto fly again for a year and theother for more than 6 months.These were highly experienced aviators. One had morethan 8,000 hours flying timeand the other more than 4,000hours flying time. Both heldspecial instrument tickets.What could have induced aviators of this type into the conditions which caused this accident? First, there was the urgency of a high priority mission,probably the dominating factorwhich caused this gamble inthe face of high odds. t mayexplain why the aviators failedto refuel at the second stop,despite IFR en route flight conditions; why they failed to eatat either stop though facing 7-8 hours total flight time; whythe decision was made to at tempt an approach with theairfield below minimums whenthe alternate was already atminimums; why they decided todescend to 100 feet above theground and face a flight violation.Other possible contributingfactors, according to the flightsurgeon were: A possible combination of borderline hypoxia(the aviators were flying at10,000 feet after dark, without using available oxygen),mild hypoglycemia, and fatiguecould have contributed greatlyto this accident by reducing thepilots' physical and mentalefficiency.

I INGA Raven pilot took off in thefollowing weather conditionsfor a service flight: ceiling, 800feet, obscure; visibility, 3t milein light snow and fog; temperature 29 F.; dewpoint 27 F.

Because of the indefinite ceiling and low visibility, the aviator flew at an altitude of approximately 140 feet. Fifteenminutes after takeoff he hearda thump which appeared tocome from the main rotor head,and the nose of the helicopterpitched up. There was a loss ofpower and he went into immediate autorotation.

The aviator pulled pitchabout 10 feet above the groundand the power surged. The aircraft skipped twice and bouncedback into the air. At this time,engine power dropped abruptlyagain. The aviator kept a levelattitude and headed generallyinto the wind. He was unableto regain enough rotor rpm fora gentle touchdown and the aircraft landed hard, bounced, andslid to a stop.

The aft and forward springassembly and tail boom weredamaged beyond repair.

Engine failure was caused bythe formation of ice on the carburetor intake screen. Thiscondition results in an over-richmixture. The aviator, thoughmonitoring carburetor he tclosely, flew into snow andfreezing weather with the carburetor air intake by p s sclosed. Moral: The 1 makesfor excellent and informed reading.

These are a few examples ofwhat can happen during coldweather flying conditions. tshould be evident that an understanding of winter weather,a knowledge of 1 cold weatheroperating procedures, and strictadherence to regulations couldhave prevented each of theseaccidents.If this issue of CRASHSENSE is successful in its purpose, you will now find yourselfclosely reviewing all availableweather references and -l 's

CRASH SENSEfor the aircraft in which youare qualified. When you havefinished, here are some AirForce suggestions which mayhelp you to avoid common pitfalls:

For VFR f i g h tu d e rcloud ceilings, calculate clearance over obstructions from sealevel heights and not just reported ceiling heights. Mostweather reporting stations areat airports built on level areasconsiderably below surroundingterrain and obstruction crests.Be certain that sufficient fuelis aboard for flight and alternate, considering winds and allowing for 25 percent strongerwinds than forecast. The 25percent leeway is to allow forforecast error and for the zigzag course that results fromwind variations en route.Choose alternate airports onthe lee side of nearby terrain(where practical). Downslopewinds warm adiabatically, causing evaporation of clouds andreduced precipitation, resultingin favorable ceilings and visibility.Where dewpoints en routeare reported below 32 F. atsurface stations under cloudswhere rain and/ or sleet is occurring or forecast to occur,do not file VFR to avoid IFRin icing conditionsabove. Whenrain strikes metal aircraft surfaces in cold dry air, evaporation causes rapid cooling andsevere clear icing may occurquickly.Where snow . s forecast orlisted as a possibility at destination, select an alternatewhere snow is definitely not expected and proceed to it without delay if destination goesbelow mInImUmS in snow.When snow reduces visibility tobelow minimums, it also reduces the radar capabilities of

35


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SEPTEMBER 1960GCA (especially wet snow) byblurring the scopes. Snow intensity is difficult to forecastand heavy snow often persistsfor a long period of time.

Where IFR flight altitude isto be below the height of ter-rain within 100 miles of course,check flight altitude windsclosely and cancel flight ifwinds are excessive (over onethird of the airspeed). Strongwinds over high terrain andthrough mountain passes produce turbulence, ICIng andgreat variations in velocity.Large drift corrections addedto these hazards make navigation a very difficult task. Lostaircraft may quickly drift intothe higher terrain.C h e c k runway conditionsclosely and cancel flight wheredestination has ice-coated run-ways and temperatures are nearfreezing and/ or rain or freezing rain is falling. AlsOi cancelflight plan if fresh wet snow

is on the runway or forecast tobe on the runway. Ice and snowon runways are dangerous forlandings and takeoffs. Snow isparticularly s 1 i p p r y whentemperatures are near freezing; wet snow on the runwaysoffers little friction. Ice is always slick; and when wet withrain, it offers practically nofriction.

When first suspecting thatyou may be lost, attempt orientation in such a way that winddrift will not carry the aircraftinto terrain or other obstruction that extends above youraltitude. Strong upper windsare usually a factor in causingaircraft to become lost. Thefirst precaution upon becominglost must be to avoid obstructions.

Where weather at destinationis reported

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Army Aviation Digest - Sep 1960

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