army aviation digest - oct 1957

8/12/2019 Army Aviation Digest - Oct 1957

1/36

LIBR RYi usAT R U K E r ~ . 1 ~ ~


2/36

U S RMY EDITOR-IN-CHIEFCaptain Theodore E. WaskoVI TION

ASSISTANT EDITOR-IN-CHIEFLieutenant John E. ArmstrongEDITORWilliam E. VanceDIGEST STAFF WRITERJohn S. Maltrotti

The U. S ARMY AVIATION DIGEST is an official publicationof the Department of the Army published monthly under thesupervision of the Commandant, U S Army Aviation School.COMMANDANTBrigadier General Bogardus S Cairns, USA

ASSISTANT COMMANDANTColonel John J. TolsonDIRECTOR OF INSTRUCTIONColonel William R. Tuck

The mission of the U. S. ARMY AVIATION DIGEST is to provide informationof an operational or functional natureconcerning safety and aircraft accidentprevention, training, maintenance, operations, research, and development,aviation medicine, and other related data.Manuscripts, photographs, and otherillustrations pertaining to the above subjects of interest to personnel concernedwith Army Aviation are invited. Directcommunication is authorized to: Editorin-Chief, U. S. ARMY AVIATION DIGEST, U. S. Army Aviation School,Fort Rucker, Alabama.Unless otherwise indicated, material in

the U. S. ARMY AVIATION DIGESTmay be reprinted provided credit isgiven to the U. S. ARMY AVIATIONDIGEST and t the author.The printing of this publication hasbeen approved by the Director of theBureau of the Budget, 15 March 1956.Unless specified all photographs usedare U. S. Army.

DISTRIBL TION:Active Army:OSD, SA, JCS, CofSA,DCSPER, ACSI, DCSOPS,DCSLOG. ACSRC, CMH,CINFO , Technical Svc (DA),USCONARC, USA Arty Rd,USA Armor Bd, USA InfBd, USA Air Def Bd, USAAbn & Elct Bd, USA AvnBd. USARADCOM, OS MajComd, OS Base Comd,MDW, Armies, Corps, Div,Brig,Ft Camps (CONUS),Svc Colleges, Br Svc Sch(CONUS), Specialist Sch(CONUS), AFSC, AFIS,NWC, Trans Cen, Arty Cen,Mil Dist.NG: State AG.USAR: None.

For explanation of abbreviations used, see AR 320-50.


3/36

UNITED ST TESRMY VI TION

DIGESTVolume 3 October 1957

RTICLESArmy GCA .Lieutenant Donald J Weigman Sig CHigh Flying Bird Dog .Lieutenant John R. Dome EMaster Army A viatorThe U. S. Army Aviation BoardAnalysis of an Aircraft Accident .

DEP RTMENTSNotes from the PentagonMajor General Hamilton H. Howze USPuzzlerBooks for the Army AviatorThe Gray Hair Department .

COVER

Number 10

5

10

41519

252628

Be it equipment like the GC unit on the cover or anew concept involving Army Aviation the United StatesArmy Aviation Board will test it sooner or later. Forother news of this lusty young infant see pages 15through 17 and back cover.


4/36

FROM THE PENT GON

Meditations n Hel

Maior General Hamilton H. Howze USDirector of Army Aviation OD SOPS

How vulnerable is the helicopter in combat operations? TheArmy is doing a bit of soulsearching on the matter, n -more practically-has instituteda comprehensive test at theCombat Developments Experimentation Center to find out.But in arriving at an ultimateanswer, we should recognizethat ll military materiel is subject to violent destruction by theenemy.Certainly a tank leading thepoint of an armored thrust isextremely vulnerable in spite ofits heavy armor. Faced with thisunhappy fact, the tanker followscertain techniques and maneuvers to reduce his periods of exposure to enemy action. If hecan reduce his vulnerability bymovement in a two-dimensionalplane, the aviator should be able

to reduce the vulnerability of hishelicopter by movement in threedimensions. True, the tank isheavily armed and armO red, butthe helicopter is extremely maneuverable, capable of rapidchanges in speed, direction, andaltitude-and perhaps most important, is not restricted to apredictable ground route.Before proceeding further, weshould consider the plannedmethods of employment of helicopters which may subject themto enemy fire. Essentially, thereare twO primary tactical missions in which helicopters maybe exposed to enemy fire, not including the important medicalevacuation job which helicoptersperformed so efficiently duringthe Korean War. These missionsare (1) reconnaissance to include seizure of critical points,


5/36

NOTES FROM THE PENTAGON 3

opter ulnerability

e.g., a bridge) in advance of rapidly moving ground units, and2) the transport of small combat units and their equipment inforward areas.Taking the second missionfirst, we should consider carefully the effect of the recent innovation of arming transporthelicopters with light machineguns to provide them with thecapability of suppressing enemyfires which may be encounteredin forward areas of the battlezone. Equipping helicopters withlight armament should materially increase their probability ofsurvival. If mallard ducks werearmed with BB guns, marksmanship from the blinds-already suffering from too muchrecourse to sour-mash CascadeMellow as Moonlight-adv. would presumably deterioratestill further. The principle ap-

plies equally to armed helicopters, which certainly should nottt ck a heavily defended enemyposition but which should beable to protect themselves andtheir cargoes by suppressivefires against light resistance.Helicopter-borne troop movements will be accomplished atlow levels, with flight followingvalleys and stream beds so thehelicopters may take advantageof defilade, concealment, andsurprise. Transport helicoptersmoving small ground units willoften follow routes already reconnoitered by reconnaissancehelicopters into areas where oursupporting ground fires haveneutralized enemy resistance.The reconnaissance helicopterwill survive through use of proper tactics. Basically, its bestchance is flight close to theground, taking maximum d v n ~


6/36

4 U. S. ARMY AVIATION DIGESTtage of cover, and in good training and lots of practice in reconnaissance techniques. It will nomore fly into or over an enemyposition than a reconnoiteringjeep or light tank would driveinto enemy lines: there is no future in either maneuver. The observer-gunner in the helicopterwill use his single machine gunfor reconnaissance by fire. Weshould get the picture here ofthe zero ground pressure reconnaissance vehicle flying thefringes of the enemy, with themission only of discovering theenemy, not destroying him.Of interest of course is thevulnerability of helicopters interms of square feet of surfacepresented to an enemy bullet.Studies based on this criteriahave compared the vulnerabilityof helicopters with fixed-wingaircraft. However, in all knowncases the comparison was madeassuming the helicopter wouldfly in the normal environment ofthe fixed-wing aircraft, i.e., ataltitudes considerably abovetreetop level; none of the reports

took into consideration the capability of helicopters to operateat very low altitudes, often below treetop level. E stimates ofvulnerability stressed speed,with the vulnerability of the aircraft varying inversely to theairspeed. As could be expected,the helicopters came out thirdbest in comparison to the C-119and the C 123 because helicopters fly considerably slower.

However, the comparativelyslow speed of helicopters willpermit them to operate at owflight levels, enabling them toavoid detection by enemy radarand thus reduce their vulnerability to enemy antiaircraft orguided missiles.If we are clever enough to

make full use of the helicopter smobility, flexibility, agility, andlow.flying capability-and canteach the enemy that the helicopter is a long way from a helpless sitting duck-the helicoptershould be no more vulnerable onthe battlefield than any othercombat vehicle.


7/36


8/36

6 U. S. ARMY AVIATION DIGEST Octoberthis unit incorporates three major systems-search, precision,and communication.The function of the searchsystem is to locate aircraft within a 30-mile radius of the equipment. Constant surveillance ofthe area is maintained so thatapproaching aircraft can be located, identified, and vectoredinto position for the final approach.

The function of the precisionsystem is to track aircraft downthe optimum glide path duringthe final approach. The precisionsystem scans the final approachin both the vertical and horizontal planes, providing both courseand glide-path information tothe aviator.The communication systemperforms the vital function ofenabling the operator to relay tothe aviator the information presented on the search and precision scopes. The operator can select anyone of several HF, VHF,or UHF channels.EXTR FE TURES

Several extra features areincluded with the GCA set. Amoving-target indication (MTI)system functions with either orboth the search and precisionunits to cancel signals derivedfrom stationary targets, therebyreducing ground clutter. Cluttercaused by rain, sleet, or snow isreduced electronically.A VHF direction finding setincorporated into the search system permits rapid identificationof aircraft by projecting ontothe search scope an electronicstrobe, which identifies the target that is in radio contact withthe search controller at thatmoment.

One of the outstanding advantages of GCA is its capability toadapt procedures to meet anysituation. An aircraft within therange of the search scope can bevectored to the field, flown in arectangular pattern, guidedaround obstructions, or heldover a point without the use ofother navaids; it can begin finalapproach at five to ten miles, andeven make a controlled approachto a nearby airfield that has noGCA unit. The aviator needsonly the basic flight instrumentsand one radio receiver to utilizethis system.To begin an approach, the pilot normally reports over aknown fix. The search controlleris then able to rapidly identifythe aircraft, since he knows theposition of the fix on his scope(fig. 1).

After radio and radar contacts are established, the searchcontroller gives the aviator various headings and altitudes tofollow which will position theaircraft on the final approach,usually eight miles from touchdown and at an altitude of 1,000feet above any obstructions. Healso gives the aviator additionalinformation such as field weather, type of approach to bemade, length, width, and condition of runway, missed approachprocedures, and lost communications procedures. He reminds thepilot of cockpit checks andwheels down.As the search controllerbrings the aircraft into positionfor final approach, the aircraftappears on the precision scope(fig. 2). Since the precision scopecovers only 7 vertically and 20horizontally, the final controllercannot pick up the aircraft until


9/36

957 ARMY GCA 7

Figureit is almost in line with the runway. He depends upon the searchcontroller to bring the aircraftto him, and at a predeterminedpoint, the search controller re-linquishes control to him.Between the eight- and five-mile points, the final controllergets the feel of the aircraft asto speed, accuracy of directionalgyro, drift, and quality of pilottechnique. At approximatelyfour miles, he instructs the pilotto begin his descent.Directing the aviator tochange heading and rate of de-scent, he guides the aircraftdown the centerline of the pre-determined glide path, usually3 As the aircraft reaches theminimum altitude establishedfor the approach, he advises thepilot that he is passing throughGCA minimums. The pilotshould now have visual contactwith the airfield. If not, he mustexecute a missed approach.

The GCA approach officiallyterminates at the specified mini-mum altitude. However, the finalcontroller continues to advisethe pilot of the position of theaircraft in relation to centerlineand glide slope until the aircraftis over the touchdown point.

PAR APPROACHThere are many variations ofthe procedure described above,

and a GC approach does nothave to use both the search andprecision systems. If there is afix within the final approacharea over which the pilot can re-port, the final controller maypick up the aircraft and bring itdown the glide path without us-ing the search system.Any approach which utilizesthe precision system, either withor without the search system, iscalled a Precision Approach Ra-dar (PAR) approach.SR APPROACH

The search controller canmake approaches without theuse of the precision system, too.Although the search controllercannot provide any glide path in-formation and cannot match thecenterline accuracy of the preci-sion approaches, he can align theaircraft with any runway on thefield.An approach which uses onlythe search system is called anAircraft Surveillance Radar(ASR) approach, and weatherminimums are usually 100 feethigher than for the precisionsystem.

HUM N ELEMENTGCA has more human elementin its system than any othertype of instrument approach;


10/36

8 U. S. ARMY AVIATION DIGEST Octoberconsequently, the quality of aGCA approach depends on theproficiency and teamwork ofboth the aviator and operator.To minimize the possibility ofhuman error on the part of theoperator, careful attention isgiven to the selection, schooling,on-the-job training, and proficiency of personnel. Applicantsare screened for aptitude, intelligence, desire, voice, ability tokeep calm, teamwork, goodhealth, normal eyesight, andnormal hearing.At the present time, ArmyGCA operators receive approximately 20 weeks of trainingeither with the Naval Air Technical Training Unit, Olathe,Kansas, or the USAF TechnicalSchool, Keesler AFB, Miss. After completing either of thesecourses, the new operator beginsa period of extensive on-the-jobtraining in the GCA unit.He must memorize vital information concerning the airfield,such as runway numbers, runway lengths and widths, field obstructions, and traffic patterns.He must know the location of allnavigational aids and fixes, airways, control areas and zones,airfields, major obstructions,and populated areas within 50miles of the airfield.He must also learn the procedures and equipment in the typeof set used, the radio frequencies available in the unit and inthe control tower, and the communication lines available between GCA, tower, operations,and Air Route Traffic ControlCenter.The most important goal ofthis on-the-job training is togive the new operator experience, confidence, and a high de-

gree of proficiency by havinghim actually control a largenumber of approaches (approximately 200) under the supervision of experienced personnel.This training period normallylasts from four to six months,depending on the operator andthe number of approaches he isable to make. Not until he hasdemonstrated high proficiencyand knowledge is he qualified asan IFR Controller.

ELECTRONIC MARVELThe forgotten man of GCA,the electronics technician, keepsthe GCA unit functioning. Without this technician to maintainthe se t an electronic marvel ofthis day and age-all the profi

ciency and knowledge of theoperator would account fornought.The repairman must givecareful attention to the fine tolerances and alignment of the

Figureelectronic circuits, must alwaysbe alert to spot possible troublebefore it happens, and must per-


11/36


12/36

HIGH FLYING 811 0 OGLieutenant ohn R Dome CE

LTHOUGH THE ACTUAL TEST described in the following arti-cle was conducted in 1955, no similar experiment conducted atsuch a high altitude ,can be called to mind. Lt Dome, the author,and Lt Thomas Long, CE, assigned to the 937th Engr Co FortKobbe, Canal Zone, were given the mission by their Aviation Officerto determine if it were feasible to conduct a triangulation reconnaissance on the high plateau of the Andes Mountains. Successfulcompletion of the reconnaissance required extensive contour flying and the ability to land and take off with personnel and q u i p ~ment from landing strips higher than many aviators have ever flown.Many tests have been conducted in the United States at CampHale, Colo., where the elevation is over 9,000 feet, and helicoptershave recently conquered Pikes Peak, but the Army's fixed-wingaircraft are still virtually untried above the 10,000 foot level.-TheEditor.

W WERE ALERTED in September of 1955 to conduct ahigh altitude test in a B ird DogFi-r st L ieutenant John R. Dome sassigned to the Planning and ProjectsSection, G-J,., U. S. Army AviationCenter, Fort R ucker, Ala. He is fixedand rotary-wing qualified and hasove-r 2,500 hours in the air. Views expressed in this article m e the author sand are not necessarily those of theDepartment of the Army or of theU. S. Army Aviation School. - TheEdito1

in preparation for a low-level reconnaissance on the high plainregion ,of the Andes Mountainsof Bolivia. The average elevation of this plain is 13,500 feet.Despite its altitude, the highplateau is vast and flat. No major difficulties were anticipatedsince each of us had determined,through previous missions, thatthe Bird Dog responded well atthat height.We planned to test the control


13/36

HIGH FLYING BIRD DOGof the aircraft on the groundduring takeoffs and landings andto learn the flight characteristics of the B ird Dog while contour flying above the 2lj2-milehigh plain.Getting our equipment together, we took off from SantaCruz to fly to La Paz where therunways are long enough to letthe Bird Dog use a full groundroll.

The runway used in the testwas nearly 13,000 feet long andinclined so the east end is about400 feet higher than the west.Control tower personnel recommended that we make all takeoffs downhill and all landingsuphill, regardless of wind direction, which happened to be fromthe east northeast. The temperature was 1 C on the surface.We used a standard ird Dogcarrying two aviators and anARC-5 radio installation (approxima ely 85 pounds) . Alltests were conducted with twoand one-half hours of fuel in thetanks. Our only other equipmentincluded survival and oxygengear weighing in at about 20pounds.

TAKEOFFSAlthough we had originallyplanned to use three-point takeoffs for more positive directional control, we abandoned thisidea after noting the large

stones on the gravel runway anddetermined to get the tailwheeloff the ground as soon as possible. We also decided to hold ourird Dog on the ground until theair speed indicator showed 60mph, then to climb out at 70mph. Using the E6B, we sawthat an indicated 60 mph was

actually a true airspeed of 77mph, and with the tail wind, wereached a ground speed of over90 mph as the aircraft brokeground.We leaned the mixture for themaximum increase at 1,800 rpmprior to each takeoff, and a maximum of 2,000 static engine rpmwas developed. This increased toabout 2,250 as the aircraftreached 60 mph.Takeoffs were made with 0,30, and 45 flaps. Ground runstook about 3,000 feet, becausewe held the aircraft down untilreaching the desired airspeed.On each takeoff, we found thatthe tailwheel raised at 30 mph.Torque was slight, and gave usno real problem. Control on theground was another matter. We

got very little response from therudder in accelerating from 30to 50 mph.On our takeoff with 45 flaps,the aircraft lifted off at 60 mph.Though we held the nose downto gain airspeed, it remained at60 The aircraft climbed slowly,and all attempts to increase theairspeed above 60 mph with thisflap setting failed. The apparent speed was startlingly fast,while the aircraft itself seemedinsecurely airborne. We reliedon airspeed, rather than feel,to maintain the ird Dog inflight.On the 30-flap takeoff, theaircraft pulled off solidly at60 mph, and we were able to establish a climb at that airspeed.Flaps were retracted shortly after breaking ground, and theaircraft continued to accelerateto 70 mph, climbing steadily.The best control during theground run for takeoff was obtained with this flap setting.


14/36

12 U. S. ARMY AVIATION DIGEST OctoberOn the no-flap takeoff, the aircraft broke ground at 60 mph

and continued to accelerate to70; our climb was steady, butshallow. t was hard to maintainproper ground control withoutflaps. Wheel bounce vibration,common to spring steel landinggear, was severe on all takeoffs.This lack of positive control ontakeoffs was partially due to thedownwind conditions; however,the recommended flap setting of30 was still considered the mostappropriate.

L NDINGSOf our total of five landings,we made two in the three-pointattitude from a power approachwith 45 and 60 flaps. The otherthree were wheel landings with30, 45, and 60 flaps. The approach airspeed on all landingswas 80 mph.The aircraft had a tendencyto fall through four or fivefeet during the two three-pointlandings but the three wheellandings were normal.We decided beforehand to relyon the brakes for directionalcontrol after touchdown on alllandings and noted that thewheel landing with 45 flaps afforded the best overall control.At 14,500 feet, maximum engine rpm at full throttle was2,300 and could be maintainedwith a 25 per cent throttle reduction. The attitude of the ird

Dog with no flaps in level flightat this altitude, was slightlymore tail low than the normalthree-point position, and the airspeed indicator showed 70 mphat 2,200 rpm.We obtained a more favorableattitude, and possibly more airspeed for cruising, by blocking

the flap handle up until the flapswere lowered about four inchesat the trailing edge. Thisbrought the tail up almost tolevel flight and increased the indicated airspeed to 72 mph.

ST LLSUsing different flap and powersettings, we conducted stalls at14,500 feet and found that theindicated airspeed of the stalls

was the same as at sea level. Wenoted two differences, however.The normal whistling of theird Dog approaching a stallwas not audible, and the rate offall after the stall was alarmingly rapid. A normal power increase and release of back pressure on the stick broke the stallbut did not arrest the fall. We

had to fly out of the stall andquickly retract the flaps to regain airspeed.CONTOUR LYING

To check the contour flyingcharacteristics of the ird Dogat this altitude, we flew it downa straight, level road with theflaps completely retracted. Whileholding an indicated airspeed of100 mph, we tried a slight pullup to simulate an obstacle in theflight path. The airspeed immediately fell to 8 mph, and fullpower was added. Since the airspeed continued falling to 60mph, the contour flying phase ofthis test was considered to betoo dangerous to continue. Vertical currents of air made thesuccessful completion of thisportion of the experience doubtful.At one point, after we hadclimbed from the road, a strongdowndraft caught us and thevertical speed indicator showed


15/36

1957 HIGH FLYING BIRD DOG 13a loss of 800 fpm with full throt-tle at 60 mph.

SUMM RYShould it ever become neces-sary to fly under these condi-tions in a Bird Dog, the follow-ing suggestions will prove help-ful:1 Takeoffs should be madewith 30 flaps.2. Airspeed should be flownthroughout.3. Take advantage of risingair currents.4. All landings should bewheel landings with 45 flaps.5. Fuel the aircraft for eachmission, plus a good reserve.From the results of the tests

Superintendent of DocumentsU. S. Government Printing OfficeWashington 25, D. C

we suggest the following modi-fications when a Bird Dog mustbe flown under these conditions:1. A supercharged engine.2. A controllable pitch propel-ler.3. Electric flaps (now beinginstalled on all Bird Dog aircraftthrough the SCAMP* program).

4 Elimination of all excessweight within the aircraft.Though this series of landingsshould not be used as the solemeasure for future operations,we believe normal operations atthis altitude are entirely prac-tical for the Bird Dog.*The new Standard Configura-tion and Modification Programreplaces the old IRAN program.

Please enter my subscription for one year (twelve issues) for ARMYAVIATION DIGEST.Please check which)o 2.25 for mailing to domestic or APO address.I enclose payment of 3.00 for mailing to foreign address.

Name _ _Please print)

Address __Make check, postal or money order payable t Superintendent of Documents.)


16/36

M STER rmy viator

Colonel Robert R. Williams, President of the United States ArmyAviation Board, has been awarded the Master Army Aviator Badgeeffective 10 September 1957. This is the first Army one-one ratinggiven to an officer on active duty. There have been many otherfirsts in Colonel Williams' career since he started flying in 1935at Baton Rouge, La. See inside back cover.


17/36

Ourbusiness is aircraft andallied equipment-our interest extends from its birth toits death COL R R WILLIAMS

Col Williams; Gen Wyman, CG USCONARC;Gen Taylor, Chief of Staff

The U S Army Aviation Board

Service testing is one of the most importantresponsibilities of the Board. Service tests aredistinguished from engineering tests in thatthey evaluate the combination of equipmentand military personnel in their normal operational environment. The service test will beconducted, insofar as practical, under simu-lated combat conditions in order to allow thefactors of weather and terrain full play inthe test. All conclusions are oriented to theprime purpose of the service test-to determine the degree to which an item of equipment meets the military requirement as expressed in military characteristics.

The United States Army Aviation Board,Fort Rucker, Alabama, was established as aseparate CONARC Board on 1 August 1955.Its mission: to conduct service tests, preparemilitary characteristics, maintain a review ofaeronautical equipment developed by otherservices and civilian companies for Army application, and to observe aad review per-formance of standard items.

The Board's field of responsibility includesArmy aircraft, communication and navigational aids used in controlling aerial flights,and allied equipment.

Ma jor General Ralph M Osborne, AssistantChief of Staff for Materiel Developments, HqUSCONARC.


18/36

Test report on lightweight GCA radar held by project officer represents peof the Board the technical and maintenance support of SATSD as well a


19/36

nel and maior items of equipment as shown This includes every divisionsupport of T TS and the civilian contractor for the aircraft involved


20/36

18 U. S. ARMY AVIATION DIGESTThe Board s interest in equipment

starts with the conception of the ideafor an item and ends when the last ofits type is phased out of the Armysystem. The cycle starts with a requirement for which the Board preparesmilitary characteristics. Technical specifications are followed by manufacturers proposals. Once a specific design is chosen the manufacturer constructs a mock-up. The Grumman Mohawk, pictured at the left is at thisstage now.) Following the mock-up, aprototype is constructed. The Iroquoisis an example of an aircraft in thisstage.) On completion of engineeringtests, the first of the prototypes forservice test is delivered to this Board.

The Board s decisions and the characteristics they develop must be realistic and reflect thebest state of the art. To accumulate a backlog of technical knowledge and flight experience inall types of aircraft, every opportunity is taken to check out in something new or different.

From a one-man rocket helicopter to a convertiplane, from a Piper cub to a jet fightersomeone at the Board has flown it.

One of the major current projects of the Board is its instrumentprogram. Its goal is to arrive tthe best interim solution to zeroz ero weather flying for both fixedand rotary-wing aircraft. One facetof this complicated problem is thesolution of the best instrumentpresentation possible. Capt MerrillE Jameson and Major Willie W. J.Barrios of the Test Division of theBoard are shown discussing one ofthe many possible presentations.

A wide variety of items are being tested in conjunction with the instrument program. Included are automatic stabilization equipment, various autopilots, integratedflight systems, instrument landing systems, GCA, doppler radar, radar altimeters,and TACAN.


21/36

TH ARMY TODAY is facedwith an injury problem in flying. This problem demands closecooperation between designers,accident investigators, researchscientists, and engineers.One agency providing designengineers with valuable information in this field is the Aviation Crash Inj ury Research ofCornell University. It is concerned primarily with what is termedsurvivable accidents.A survivable accident is onein which major portions of thecabin or cockpit structure re

main reasonably intact duringimpact. When the magnitude ofcrash forces is insufficient to totally demolish an aircraft struc-Views expressed in this article arenot necessarily those of the Devartment of the Army or of the U. S.Army Aviation School.-The Editm

. . .u.tD. . . . . .V s ...... C L-l9, C-.s . .a lCN'-. MI . . . . .bu29, 1 5

- S - - - __r

ture, it is not enough in itself todirectly cause dangerous injuryor death. Such an accidentshould be survived.In the April 1956 issue of theU. S. ARMY AVIATION DIGEST, A Howard Hasbrook described the objective of AviationCrash Injury Research (AvCIR) as follows: To improvethe 'State of the Art' of crashsurvival design.A v-CIR, a function of CornellUniversity, is sponsored jointlyby the U. S Army, Navy, andAir Force under the direction ofMr. Hasbrook. Other supportinggroups include industrial leadersin aviation safety.This research department obtains comprehensive medicaldata and related accident detailsfrom survivable crashes.These relaterl data are then n ~alyzed and the results given to


22/36


23/36

1957 ANALYSIS OF AN AIRCRAFT ACCIDENT 21forward, striking the front seat.His left foot apparently jammedunder the flap handle, causingthe complete fracture of all fivemetatarsal bones.In this accident, extensivelydetailed investigation was madeof damage to floor structure,seats, and seat anchorages. General damage to the aircraft wasthoroughly investigated. At thesame time, thorough and detailed medical examinations wereconducted on the injured aviators.

RECOMMENDATIONS ANDCOMMENTS

Searching analysis of thesedetailed findings resulted in thefollowing recommendations byAv-CIR. The answers to eachspecific recommendation weremade by engineers of Cessna,manufacturers of the ird Dogwith the exception of recommendation four, which was answer-ed by the Chief; Flight SafetyDivision, ODCSOPS, Departmentof Army.1. Increase the strength ofthe rear safety belt tie-down.Revision of a Civil Aeronautics Administration Regulationrequires a stronger safety beltattachment for the observer'sposition in the instrument train-er. This 'beefed-up' attachmentcould be incorporated on allird Dog aircraft by installationof a retrofit kit, consisting of

reinforcement angle whichwould run from the rear doorpost bulkhead to the cantedbulkhead. A reinforcement angleat the attachment fitting couldalso be included. An ECP [Engi-neering Change Proposed couldbe easily prepared for this installa ion.

2 Design seats and seat at-tachments to deform, but notfail completely, under dynamicloads equivalent to requiredsafety belt load factors.We feel that the seat designfor the pilot and seat floor at-tachments are equivalent to thesafety belt strength. In reviewing the report, it is believed thatthe force of the observer's bodyagainst the rear of the seat backresulted in the complete failureof the pilot's seat legs. We believe the pilot is more protected

Six Inch Displacement of Poleif the seat fails progressively atthe time of impact, since this re-sults in a much lower load factoron the pilot's body. Therefore,we do not recommend any


24/36

22 U. S. ARMY AVIATION DIGEST Octoberchange in seat structure on thebasis of this single report.

3. Utilize a type of shoulder

Approach Path to Touchdownharness that is less restrictive(opera ionally ) and more comfortable in order to promotemore routine use.The installed shoulder har-ness is a standard Air Force approved inertia reel. f the har-ness had been properly used, in

Shoulder Harness in Stowed Positionlieu of being in a stowed position, it is believed that both thepilot and observer would have

sustained only minor injuries. Inreviewing other Army accidentreports, we have found that theshoulder harness, if worn properly, has worked in all cases.Present accident statistics showthat the harness which has beenprovided in all ird Dogs is sat-isfactory.4. Require use of lightweightcrash helmets by all occupantsof liaison aircraft during all missions.The Quartermaster Corp isin process of developing a suit-able helmet for Army flight personnel. Meanwhile, to provide

_ ~ l e 1 a 1 . 1 _. back r b M

Observerimmediate protection pendingcompletion and approval of theprototype helmet, QM has pur-chased 300 APH-5 helmets fromthe Navy, which will be modified to accommodate Army communications equipment. This isa new type affording excellentcrash protection. These helmetsbecame available in August,1957. QM is considering an additional procurement of theAPH-5 helmet in sufficientquantity for issue to all flightcrews of helicopter and reconnaissance aircraft.5. Increase the strength of


25/36

1957 ANALYSIS OF AN AIRCRAFT ACCIDENT 23the upper cabin structure and/or design the wing butt attachments to fail during a crashwithout causing complete collapse of the overhead structure.We do not believe that theaircraft warrants structural'beef-up' for the upper cabin. Inreviewing past Department ofArmy accident reports, we cannot find reason to warrant thisheavy, expensive, and impractical rework. We also reviewed theNavy-Marine background for theOE-l aircraft and have foundthat 'beef-up' to its structure is

Pilotunnecessary.6. Utilize a lightweight, protective (delethalized) shield onthe instrument panel, similar tothat installed on the SeminoleA protective instrument panel shield would be a considerableweight increase item. Such ashield would be completely unnecessary if the pilot and observer would wear the shoulderharness and safety belt as provided in the airplane. For thisreason we do not recommendsuch a device on a military airplane.

7 Install a lightweight shieldover the rear and top of the horizontal (flap) control tuhe to

Left Outer Wing Panelprevent jamming of the observer's left foot under the tube.Department of the Army haspurchased some 1,800 electricflap kits. The flap control tube is

Safety Belt End Still Attached to Fragmentremoved from the aircraft whenthis electric flap system is in-stalled, eliminating this hazard.

CESSNA CONCLUSIONSI t is noted in the report that


26/36

24 U. S. ARMY AVIATION DIGESTthe aircraft stopped within sixfeet after contact with theground. Since the airplane speedwas approximately 70 mph, deceleration of the airplane wasof such magnitude that any typestructural 'beef-up' to take careof this type of accident wouldrequire a complete redesign ofthe fuselage which could not beincorpora ed in existing aircraftby kit form.

If Army accident statisticsindicate a real need for reinforcing the rear safety fitting, it isrecommended that the rear seatsafety belt attachment rein-

forcement be incorporated inexisting planes.COOPER TION COUNTS

This is the kind of crash-injury and crash-survival datathat is needed on military accidents. Quick action by aircraftengineers resulted from qualitative and quantitative information furnished by Av-CIR, usingclassifications and terms thatthe engineers understand. Thisis the type of Army-Manufacturer-Research Team cooperationthat will payoff in safer equipment.

Reference to Library PublishedSpecial Bibliography No. 1 onArmy Aviation has been issuedas the first publication of theU. S Army Aviation School Library. This list of referencesidentifies all the unclassified ma

terial at the Library on the general subject of Army Aviationand includes detailed referencesto 500 magazine and newspaperarticles from April 1952 to April1957.

Distribution has been made todepartments of the U. S ArmyA via tion School and to otherArmy schools nd librariesthroughout the United States.Additional copies may be obtained by writing to:CommandantU. S Army Aviation SchoolFort Rucker, AlabamaATTN: Librarian


27/36

PUZZL RN ARMY AVIATOR departedOzark AAF, Ala., IFR toSpartanburg SPA) S. C. withKnoxville TYS), Tenn., as analternate. He received a weatherbriefing prior to departure andwas informed the ceiling wouldpossibly be lower at Spartan-

burg, but should remain abovethe minimum. The aviator wascleared to Spartanburg airportvia R-67 and G-6 airways. Hisaircraft was equipped with LF,Omni, and ADF. He received aweather broadcast over Royston.Ga., indicating the ceiling atSpartanburg had reached theminimum. Ten minutes from his

D Return to the SPA LF R andattempt another approach,provided he does not go abovethe minimum altitude andcan complete the second approach within 30 minutesfrom his last estimated timeof arrival.D Transition to the SPA VORand immediately execute anOmni approach, provided hedoes not go above the minimum altitude.

D Switch to Omni and proceedto Asheville AVL) via V-53,provided he does not go abovethe minimum en route altitude, and execute an Omni approach on arrival.D Switch over to Omni and proceed to Knoxville TYS) VORvia V-185 at minimum enroute altitude and immediate-

destination the pilot attemptedto contact Spartanburg Approach Control for an approachclearance, but was unable tomake contact. After holdingover the SPA low frequencyrange until five minutes past hisestimated time of arrival withno contact established, the pilotstarted a standard approach. Hearrived at the minimum approach altitude without breaking out, and immediately executed a missed approach. AirTraffic Control would expect thepilot to:Indicate by a V the proper procedures to follow.)

ly execute an Omni approachon arrival.D Proceed to Knoxville TYS)LF range via B-28 and G-5 atminimum en route altitude orthe altitude last assigned enroute to SPA, whichever ishigher, and immediately execute an LF approach on ar-rival.D Proceed to Knoxville TYS)LF range via B-28 and G-5 atminimum en route altitude,maintaining true airspeedfiled in flight plan and immediately execute a standard LFapproach.

D Proceed direct to KnoxvilleLF Range by ADF to arriveas soon as possible, and execute any type approach thepilot chooses.Reference: Charts 17 and 18of TM 2557.The correct solution to the PUZZLER may be found on page 32.


28/36

MEN IN ARMS: A History of War-fare and Its InterrelationshipsWith Western Society - R A.Preston, S F Wise, and H. oWerner Frederick A. Praeger,Inc., 150 East 52d Street, NewYork 22, N. Y. 6.50)

Reviewed byBrigadier General Carl I. Hutton,USCommanding General8th Infantry Division Artillery

This book is military historywhich describes no battles. t isan enquiry into the social andtechnical changes which haveaffected war. The field for suchan enquiry is extremely broad,and the accomplishment of theauthors in presenting the sub ect in 340 pages of text is oneof masterly compression. Chapters of standard military history have been reduced to singlesentences, and whole volumeshave been reduced to paragraphs.The factors of nationalism,popular governmental forms,technological development, ideological conflicts, and mass communication media have coincidedin history with the growth ofair power, resulting in the complications of the problem of survival of civilization. The nation

Book reviews appearing in this de-partment o not necessarily reflect theopinions of the Department of theArmy or of the U S. Army AviationSchool. The Editor

in a m is maintained not onlyin war but in peace. The greatproblem for the military planners, as far as we can see, is toreconcile the two needs, militaryforces for local wars and preparedness for the dreaded recurrence of total war.This book, then, ends with theassumption that the force requirements for atomic and nonatomic wars are necessarily contradictory, and that a nationmust have forces of both kinds.Had the authors included, eitherin the excellent bibliography orthe text, reference to AirborneWarfare by Lieutenant GeneralJames M Gavin, the possibilityof a different conclusion mighthave arisen. There is a famousstatement from this latter bookto the effect that the future ofthe armed forces lies in the air.With proper development of doctrine and material we may findthat the atomic and non-atomicmilitary requirements are not asopposite as they first appear.THE COMPACT HISTORY OF THEUNITED STATES ARMY - ColonelR Ernest Dupuy (HawthornBooks, Inc., 70 Fifth Ave., NewYork 11, N. Y., 1956. 4.95)

Reviewed byLt Col Raymond S Pratt, Jr., rtyThis book is an easy-to-read,thought-provoking account ofAmerican fighting men and their


29/36

OOKS 27women from the American Revolution through Korea. It is afactual story of people that willprove interesting to the youngsoldier as well as the old and tothe Army wife.The author has skillfullywoven into his theme historicalfactors which have determinedthe character and efficiency ofour Army and its membersthroughout its history. He presents a clear and sympatheticexplanation of the occasionaldisgraceful episodes suffered bythe Army as well as of its heroicaccomplishments. Readers ofthis book will be enriched by theunderstanding gained and atthe same time entertained bythe very human presentation.SHIPS IN THE SKY-John Toland(Henry Holt and Company, 383Madison Ave., New York 17, N.Y., 1957. 4.95)

Reviewed byMaior R J Sweezey, Jr., rtyThis book is a highly stimulating popular history of thegreat dirigibles and the men whodeveloped and flew them. It concentrates upon the climaxes andhuman drama inherent in thestory of the silver ships in thesky.The book begins with the triumphal approach of the Hinden-burg to Lakehurst Naval Air

Station in 1936 which heraldeda new age in flight and endswith its destruction a year later.The book tells of such people asDr. Solomon Andrews the stubborn Yankee inventor whothrilled New York with the first

airship that could move againstthe wind; Santos Dumont thecelebrated Brazilian millionairewho became the rage of Parisand then of all Europe as hepursued an elusive speed record;and Count Von Zepplin who firstdeveloped the dirigible as apractical commercial and military weapon and bequeathed hisname to the ships of the sky.But the heart of the book liesin the contemporary period. Mr.Toland has obviously performedprodigies of research in investigating the triumphs and tragedies of the dirigibles in theUnited States during the twenties and thirties. He has talkedto hundreds of people-passengers, crew members groundcrewmen and eye witnesses-intimately connected with the dirigible story.As a result we seem to be inthe ship with the crew feelingseeing and hearing what theyexperienced when for examplethe Shenandoah groaned andbuckled caught between twomurderous line squalls or theHindenburg collapsed a fiery incandescent coffin that sealed thefate of the dirigible. The bookhas the same kind of stunningveri-similitude as Walter Lord'sNight to RememberShips in the Sky is not a technical Ischolarly history of thedirigible. Mr. Toland is interested in the human drama, theemotional force that bound crewand general public alike to theill-fated craft in spite of calamity after calamity. Ships in theSky is a joy to read, both for thedirigible enthusiast and the general reader.


30/36

TWO AIR WEATHER stations50 miles to either side of theArmy Aviator s home base reported VFR conditions as hetook off in a Bird Dog on an ad-ministrative cross-country flightwith a ceiling of 3 500 feet andvisibility five to ten miles for thefirst leg.The route included a narrowdefile through high mountains.As he entered the pass the aviator encountered a light turbulence but there was no perceptible change in the weather.About 15 minutes later, as he

The Gray Hair Department is pre-pared by the U. S ARMY AVIATIONDIGEST staff with information -tained from the files of the U SArmy Board for Aviation AccidentResearch The views expressed in thisdepartment are not necessarily thoseof the Department of the A rmy or ofthe U S Army Aviation School -The Editor

rounded a turn, a wall of snowappeared. It was impossible togo farther, so he elected tomake a 1800 turn and returnover his previous route. As hestarted the turn (altitude 1 000feet above the river bed), he no-ticed a continuing loss of altitude at 1 000 fpm. He increasedpower but the plane continuedto settle. Thirty-degree flapswere applied decreasing the rateof descent to 500 fpm and fullthrottle was applied. Airspeedwas maintained at 8 mph.Upon completion of the turn,the aircraft touched down on theriver bed and bounced. As it ap-proached the ground again, theaviator cut power and executedan emergency landing. Afterbraking to a stop and. turning offall switches, he left the aircraftto survey the damage. He foundthe main gear sprung and the


31/36


32/36

30 U S. ARMY AVIATION DIGEST October

The Bird Dog Turned to the RightThe subsequent investigationrevealed that the split conewasher assembly had slippedfrom place during landing. Thispermitted the main rotor assem-bly to move downward when itsweight exceeded lift and centrif-ugal force.A series of small marksaround the top of the washer as-

sembly indicated that this important part had been installedUPSIDE DOWN.The installation of the mainrotor assembly had been per-formed by organizational mechanics and supervised by theline chief. Although normally afield maintenance function per-mission had been granted bythat supporting activity to per-form the work locally. In theabsence of the unit rotary wingmaintenance officer the linechief approved the job andsigned off the entry.Usually when a field mainte-nance installation is authorized

to be done at organizational level a mechanic specificallytrained to perform that type installation is furnished by thehigher activity to supervise thejob. This was not done.The line chief exceeded his au-thority in approving and signingoff the completed installationand it is doubtful that the rotarywing maintenance officer wouldhave caught the error. t takesyears of experience or a similaroccurrence to develop an abilityto catch these partially hiddenerrors. Lack of supervision byqualified unit and field mainte-nance personnel is vividly appar-ent.

PERFE T L NDINGTwo Army Aviators took offin ird ogs to practice land-ings at a well-used road strip.The first aviator landed and tax-ied to an intersection wherethere was enough room for bothaircraft to turn around.


33/36


34/36

3 U. S. ARMY AVIATION DIGESTsenger debarked to unload luggage from the cargo racks.While the aviator was unloading the left cargo rack he hearda loud banging noise. He walkedto the other side of the helicopter and saw his passenger lyingface down on the ground justoutside the rotor diameter. Thepassenger was bleeding profusely from the back of the head. Aquick examination showed thathe was dead.A reconstruction of the accident indicated that the passenger unloaded the right cargorack and walked upslope awayfrom the Sioux in a stooped position. He apparently raised upand was struck on the rightshoulder and back of the headby the rotor blade tip.

The aviator had little choicebut to land in the center of thefield; however had there been

the opportunity to land the iouxto one side the passenger sideof the helicopter should beplaced downslope. The aviatorshould then remain at the controls and tip the rotor arc awayfrom the passenger until he hascompletely cleared its path.If there is any doubt concerning freedom of movement beneath the rotor arc the engineshould be shut down and the passenger remain in the aircraftuntil the rotor ceases to turn.Since it is general practicethroughout the Army to debarkpassengers with the rotor stillengaged and moving aviatorsshould place particular emphasisupon instructions to passengersabout the dangers involved. Thisshould be done before each flightregardless of frequency of utilization by a passenger.Death is final.

g o u i ~ PUZZL ROn the basis of the factual information contained in thePUZZLER on page 25 the recommended solution is as follows:

v Return to the SPA LF R andattempt another approachprovided he does not go abovethe minimum altitude and cancomplete the second approachwithin 30 minutes from hislast estimated time of arrival.

v Proceed to Knoxville TYSLF range via B-28 and G-5at minimum en route altitudemaintaining true airspeedfiled in flight plan and immediately execute a standard LFapproach.


35/36

Colonel Williams fffirstsHe was the first ground forc.e Liaison Pilot to hold an Army Air Corps Instrument Rating 1942).He was the first Army Aviator to hold an Air Force Green Instrument Cardand has held one continuously since 1950.He was the first Air Officer of the first Army Aviation operational unit, theUnited States Constabulary Flight Detachment. This same unit was the firstArmy Aviation unit to operate multiengine aircraft C-45s).He was the first chief of the Army Aviation Branch, G-3, Department of theArmy. This was the first identifiable agency on the Army General Staff established for the purpose of coordinating and supporting Army Aviation.He is the first President of the Fnited States Army Aviation Board.

The following requirements are necessary to qualify for the aeronautical designation of Master Army Aviator:

a. Be assigned or detailed In a branch of service authorized ArmyAviation.

b. Hold the aeronautical designation of Senior Army Aviator andbe currently on flying status.

c Have been designated as an Army Aviator, Senior Army Aviator,or liaison Pilot in the United States Army on flying status for a minimum of 5 years; have officially logged a minimum of 3,000 hoursflying time as a student pilot, first pilot, copilot, an d or instructor pilotin civilian an d or military aircraft.

d. Commissioned aviators must have held a valid Army, Navy, orAir Force standard or higher instrument certificate for a minimum offive years prior to the date of application and must hold a currentlyeffective special instrument certificate.

e. Be currently qualified in rotary wing aircraft.


36/36

.r ~

, : ~ . .....In the field of jet experience the U S Army Aviation Board recently completed an extensive

program through the cooperation of the Naval Air Training program Eight Army Aviatorswent through the standard Navy jet training program at Olathe Kansas and Memphis Tenne e. These aviators included Colonel Williams Lt Colonel Rankin Lt Colonel Byrd MaioMahone Capt Cranford Capt Lefter Capt Jameson and Capt Irockmyer