XXI Bomber Command, Monthy Activity Report 1 March 1945

8/6/2019 XXI Bomber Command, Monthy Activity Report 1 March 1945

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MONTHLY

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XXI BOMBER COMMAND

A C T I V I T Y R E P O R T1 MARCH 1945


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F 0'R 1 ': .. / 0 P D---~.~.!.:..-~-This. is an attempt to sumcai-Lse some of the more

import~nt activities~of the. Command as disclosed by thes ta tis tic al da ta m.a int ain ed by this Unit, ard to i ndi cat ethe trends that may affect the future activity of theCommand.

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X X I B O M B E R C O M M A N D

M 0 NTH L Y . ACT I i T I T Y R E P_ .O R . T1 M a r c h 1 0 4 5

P a r t I.P a r t I I .P a r t III.P a r t I V .P a r t v .P a r t V I .P a r t V I I .

s t r e n g t h o f t h e C o m m a n dU s e o f A i r c r a f t a n d . C r e w sM a i n t e n a n c e A s It A f f e c t s U s e o f A i r c r a f tE f f e c t i v e n e s s o f A i r c r a f t O n M i f > s i o n sR e s v , J . t sC o s t of i \ ' l i s s i q l l So t h e r A c t i Y i ~ '

P r e p a . r e dBy~

3 3 r d . S t a t i s t i c a l C o n t r o l U n i t

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SCHEDtJLED FtpW OF VLR AIRCRAFT AND CREWS TO THEATERBased on Information Received Up To am Incllrling 1 March 1945

Before EnrouteJan 31 Feb 1 March March April M~y June JulyUnit At.C Cws A L c cws ALc, Cws A L c Cws ALc C 2 1 Z ! 3 . . A L e Cws ALc Cws ALc e~73rd Wing 180 240 I

313 Wg 504 Gp 20 20 10 10'505 Gp 30 306 Gp '27 27 3 39 Gp 27 21' 3 3Wg T/R :23 21 1 :28 5 2210 .4 137 6 .TOTAL 27 1 48 1 5 . 2 2.314 Wg 19 Gp 30 3029 Gp 29 29 . 11 l39 Gp 30 . ; - 3 9330 Gp 30 30 ,Wg T/R ? .4 6 JO :30 ":l0TOTAL ., ~ : .r ; __83 1 7 '60 90 _ . - _ . - - . - _ - 30' ..... 30.: :58 Wg 40 Gp 30 30444 Gp 30 30462 Gp 30 30468 Gp 30 30

W g T/R 25 55 22 2 2OTAL 85 115 ~5 115 I, .

315 Wg 16 Gp 30 30501 Gp 30 30331.Gp 30 30502 Gp 30 30Wg T/R- 30 30 30 30TOTAL 90 9 0 9 0 20:-.~' i.P hotoU/E & T/R 12 18Replacement 8 4 1 2 2 1 2 ..6 2 4 . 2 4- 2 4TOTAL 20 18 ,Ii 1 .2 , . . , 1'' - 2 '6 2 4 2 4. 2 4:XXI .BOMB QOMD ;REPLACEMENTS 62 21 ~2 20 1ft '2 7B_~ ' 60 149 '7 9 130 82 213 90 1~7GRAND TOTAL 369 416 124 161 17 13 223 348 150 270 219 239 226 307 122]31--Scheduled deliveries are based on i::1formationfrom 20 AF. H o we ve r, r ep la ce me nt sbeginning in May are based on rate of 16% U I E per month for aircraft and 15% for.crews during 1st five months of operations ,and 30% per month thereafter.Aircraft and crews of the 509th Composite Group are not included in the above

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P!~RTI. STRENGTH_F THECOrJlMAND

, -All Uriits assigned or attached t.o Headquar-ter-s X X I BomberCommand, and all units of the 73rd BombWing are now in place.3l3th BombWing units have: all arrived with the exceptions of the. 592nd AA:fBand and the 680th BombSquadron;" due t.o reach Tinianin .April and May, respecti vel.y, and the 509th ' Composite Group,which is scheduled to arrive during May and June. The last unitof the 3l4th BombWing is scheduled t o reach Guamin March. MOVie-mep.t of the 58th,BolIlbWing tnto this theater is scheduled to takeplace during ApJ:.l, 'May and June. Arrival of the 315th BombWing-, will be appr ox.ir.a'ce.Ly concurr-ent with ar-rLva.l, of the 58th BombWing, and will be cO~1?let,ed with arrival of the flight, and airechelons of the 331st and 502nd BombGroups in early July.'

, During February the t.ot.e.L strength in the theater ofunits assigned or attached to. the XXI Bomber CommarrlLncreased~0.6% over January to a total of )4.003 officers and enlisted men.The ultimate strength of the COIDnlandn a five-wing basis is over6),000.

I -, It should be noted that the lower loss rates (see Part VI)coupled with the flow of replacement ai:r;craft at, a rate greater. '.'. than losses has Imade possible a epeedd.er build-up to authorized.strength than was antd.c ipa ted, Replacements in Febr uaz-y were 17aircraft. over losses, ai.. to date are 25 aircraft over Los'se s ,, Crew r-ep.l.acements to date, however, are )0 crews less than losses ..suffered. The 9::. aircraft and 145 crews 'scheduled to arrive.' inMarch as replacements are further indication that the Co~~and mayaccelerate the builu-up to present authorized strength.I

The estimat.ed 'growth of the strength of this Commandinthe thetLter is shown below: I : , r "Tentative Est~tes \28 FEB (ONH A N D ) 31 'MAR ;30APR31 MA.Y0 JUNE . : 3 1 JUL

OFF EM TOTAL TOTAL TOTAL TOTAL TOTAL'TOTALHq XXI Be & Hq Units 487 2054 2541 2550 2650 2750 ' 2800 2800'73rd BombWing 1887 10028 11915 '11915 11915 11915 11915 11915313th BombWing 1/+48 9232 10680 10900 11400 13000 13400 13'400314th BombWing 1(;00 7867 8867 111{)0 11700 11700 11700 11700315th BombWing 30/00 7300 9500 1170058th BombWing 6900 8500" 11600 11900,

TOTAL 4822 29181 34003 ,36465 48265 55165 60915, 6311'5

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, '. .'--.. :." ~.PART II. U SE O F B -29 ,,;cIRCRAFT AND CREW S

~n average of 60 hour's per aircraft and 4,7 h ours per crew~was flow~ by ,the Command during February, the best record to date;As shown in the following table, the 73rd Wing attained 6 5 hours'\ l' , ' .. . per aircraft for, t he '2~lm:':1despite a .subst.ant.Laf increase in thenutnber'of aircraft assigned 'and fewer days in the month. Inaddition, with this increase of,ai~craft on ham, the Command wasstill able to fly over 6 0% of as s i.gned aircraft on combat missions.

-65 % V iere re: _adyfor combat on mission da,ys during ,February, theadditional:aircraft being utilized chief11 'for training flightsal~ weather strike missions.

Both the 73rd and 3l3th Wings showed Lncreases in combathoUrs" and the 7 Jrd wing also 'tripled its flying training time~The 4~208 hours used for training time, or 1 3.4 training hoursper aircraft was the chief factor in the slight decrease of totalsorties per aircrar't. (See table on preceding page)

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These factors for February highlight two things: Fir,st, theL nc re as f. ng ' t ra in in g t im e" and second, the ability of the Commandto absorb more aircraft and still flar e ach aircraft n greater

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number of hours.

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P ART III. MAINT ENANC E AS I T AFFECTi3 US E . QF A IRCR AFT

The mere' fact of gr.eater hours flown per aircraft despitean increased number of aircraft on hand is some indication ofincreased mad.nt t.nance efficiency as w ~_l as gr er.t. erutili zatio nof operation'1 1aircrcJt. In add.i.t.Lo n, only 12% of airborneaircraft failed to bomb th~ primary target because of mechanicalreasons in Febr-uar-y compared to 2 2% in Janua.ry and 2.3% i n D ec em be r.This F ebruary r~: ,.:Ol. dompares favorably with the D ecember-Januaryfig ure of 1 4 % and November figure of 20% for the XX B om be r C om ma nd .It m u st b e pointed out, how ever, that these trends took placeduring a period when battle damage substantially decreased (SeePart VI) and bombing altitude w as Lower-edvA ircraft g rounded for parts durin g F ebruary were 4.5%of assigned aircraft compared to 4.6 % in'January. Although thefigure for the 73rd Win g was 2.4 % ' for F ebr~ry, the 3 13th Win ghad 6.9 % and the 3l4th Wing, 5.6%. The n~lber of aircraft readyfor combat on' mission day varied from 7 3 % o f assigned for the73 rd Win g to 5 8 % for the 313 th.P erformance of R-33 50 engines still remained the largestmaintenance problem, 53% of mechanical failures to bomb the primarytar get caused by this reason. As of 28 Feb these engines averaged16 2 hours before removal was required. The number- of hours

required before removal has riseL,steadily am the ultimate fi gurecan not ,yet be determined.Engines w ere also the chief cause for Unsatisfactory Reports,

270 of the 49 1 submitted to date being for tl:.li;.'eason. Cylindersand valve mechanisms w ere the largest categpries' in this classof URs.In connection with Avo.luating the effect of ma.Lnt.eance on 'use of aircraft, it shoui.d be noted that production control report-in g now being establisheu will enable a more complete am.lysison this factor, especially as concerns hO UTS used in varioUs classes

of maintenance, cack. Logs , and effect of battle damage.

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, PART IV. EFF~CTIVENESS QF AIHCRAFT O~UlISr.nONS

During Febr-uary 4 9 % of aircI',;:.:..ft airborne on Honshu miss l onsbombed the pr-imary target, weather being- the clicf' cause offailure s to bomb' the. primary. Only 19% .of the [;.irborne aircraftbombed t.he primary target visually. Fli&:ht:;rfor th0 f'ourLh sue-cesaave morrth, in FdJl'UIJ.l7 87,;!; of' af.rbor-ne aircrdft bombed alItargets.

Thus it lS seen that: while the Command is st.ead.i Ly Lncreas-.ing both the number and percentage of (';,ircraft bombing bhe Japan-

, ,I _ 'ese ma'l.nl.and , , bad weather has permi t.t.ed ?nly a' sma.l.L per-cent 'to'bomb v.isuakl.y , ThE;!following tnbles show -the effectiv\messof .ttircraft sf.nee November.'

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NOV DEC . JAN73PJ) rl)illJ : 7 JHD ' 7 , ' ~ ;~-lJ l% Id.rborne Bombing Primnry 21.3 G7~7 ,!;.3.7 \47.0

FEBRUJ .RY313TH Jl/t-TH TOTAL51.0' SL8' .4 .9.418./."., o 18.9Airborne Bombing Primary,Visually"10.9 45.3 38.4 20.18J.7 95.5 87.3Airborne Bombing All TargGts 79.2 82.9. 81.9' 8 5 . 8

I ' % lk1rborne Failing to Bomb Pr-Imar-y TI).rget-Bacause Of:ME;chanica1'Fr.ilure 29.5 22.7 21.7 13.8' 10.2 0 12.2Pcrsonpe1 Error ';1.4 2.9 6 ..2 5.9 5 ! 7 I~.5 5 . 8Weather 56'.1 0.7 23.7 29.3 2 9 . 8 9.0 28.9Other and UnknOTm i . 8 6.,0 4 .7 3.9 3.3 1;..5' 3.7J "

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fART V, RES U L T S1. ~ombi!l.6Accurall

Bombing accuracy information was available on only one of the fiveJapanese mainland mrae ic..e conducted during the morrth, No figures were avail-able on the first two mf.asi.one in' which 89 aircraft, bombed the primary targetvisually, nor on the last two n,tissions in which none of the aircraft bombedthe prllnary target visually" On 15 February, however, 17%of the bombs re1easedon the Mitsubishi Engine Plant in Nagoya fell within 3000 feet of the aiming_'point, and 18 hits were identified in the target area. Photo coverage was alsoincomplete for this mission~ It should be noted that these figures are basedon photo coverage dl~ing the mission and do not reflect later damage assessmentstudies, which are not available in this office. In vieu of the fact, as statedin a recent Operations Analysis report on bo@bing, that probably less :than fourdays a month vdll be suitable for visual bombing during the, next eight months,it seems evident that even less 'bombing accuracy inforn:ation ,\7ill ,be ava.ilableinthe fu tur e., especially as to wing and group comparisons.

2. Bomb,Weight and FU~l DataAs or- 28 February, 6793 tons of "bombshave been dropped by "the comnand

on J'alJancae targot~)' 3 0 % of these tons were mcendaar tes , 1494 tons have beenreleased on five ,major aircraft and engine fac toies. Of the ur-ban areas ,: Tokyoreceived the ,greatest tonnage, 1016 tons being dropped 'on this city to date.

Greater tonnagG has been made possible by measures increasing the bombload. I n February the 73rd Uing carried an averag of 6739 pounds campareuto 5646 L~January. At the same time average gross '~~ht decreased to 133,600pounds from 135,700 in January, and the average, fuel returned decr-eased to923 gallons from 987. Even the february averages rrere not indica ti ve of theactual progress' in substan tieLly mcr-eas ing the bombload on missions to the ;Japanese mainland. Individual aircraft carried about 7500 pounds of bombs ll1 ,~some cases and returned 13SS fuel. Increased experience and the emphasis onthis problem point to a steady upward trend in bombtonnage carried during March.

3. llpane.?~eAircraft DestroyedDuring the month, 71 Japanese aircraft uere destroyed, 59 probably des-

troyed, aUQ126 damaged. T O date, 267 enemy aircraft have been destroyedoThis is equivalent to a ratio of 6i Japanese aircraft destroyed per each B-29lost to enemy action in combat missions~ or an average of 14 Japanese aircraftdestroyed per 100 B-29 sorties. Based on information from 20th Air Force, thisrate of fig~ter destruction is by far the greatest averago achieved by eitherf;i.ghters or bombers in the U.S .ArmyAir Force.

The number of enm~ attacks per B-29 over the target dropped in Februaryto 2.1 fram the January figure of 7.6 and December figure of 4.4. Ho~muchof this decline is due to bad target and Japanese base ueather and to Navystrikes is not yot doterminable~ ..._......~

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.' PARTVI': OOSTOFMISSIONS

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.-. B-29 aircraft losses in February ''Were"oril.y 12%of .uni t equip-. ". ment compared 'to 22%in December'arid January , At 1;.hesame ..ime .. 'B-29 crew 'losses in February wene ..onlyll%-of unit 'equi.pmerrt ccompar=-.-"~do 15% in December am 23%in January ... On bombing missions,3;2% 'of 'airborne aircraft -and B ,.O % of airborne crews were lost'dUring the' -month. 3.8% of a.i.r-bor'ne aircraft were lost in December'and 5.5% in January. 'It should:.Y5estat.ed that February figures .do not. yet form .scund basf.s for predf.ct.Lon of trends because ofthe. TtJkyo mission of' 2 5 ,Fob~uD.ry when 229 {lircre.ftw~reu..J...1''Oor.neith:only, two .16$68S.. 7urther stilly must be made to 'deter-'. mine the effect of radar bombing'days as- relates to enemy fighterreaction and aircraft lasses. It' may.be that the bad weather for"Japanese missions will substantially decr-ease previous sor td,e loss. rates. '

As shown Ln vthe table below;. enemy'act.Lon continues to be"the major cause of losses a m . epemyfighters have been the' biggestsingle factor. ',It must be noted .heze that ~lhileact~l cost.,o:(, "missions can effectively. be a&Sessed in re+ationto number of lossesper bomb tonnage dr-opped ,,-lTithinthe. target area" this type of .assessment awaits more detailed bombing accuracy figures ..... ",-,1

CAUSESFORB-29 &F-13 AIRCRAFT,LOSSES '".' , . t , tN O V " , D~C . 'JAN. , .,FEB TODA;. " ; . 1 : . '; . . , . . _ ; _ 1 _ #,., % .# % Ii % I{ .%

Lost To'EnemyAct~on 1 '7 % 10 )6% 16 ,60% 11 37~ 38: 38%. EnemyA lc (I) (7) (7)'(25} 14)(52) (9)(30 (.1) (31)Flak (I.) ( 4 ) (1) (1)A lc &Flak (2) (7) (2) (8) (2) (7) (6) (6)Lost on Ground to E / A 9 60 5 18 14 14MechFailure ~ 7 5 18 5 18 6 ,?O . 1'l 114 Ace., Wea.,'Pers. Error 1 7 5 18 7 23 13 13Unknown 3 19 3 10 6 22 6, 20. 18 18~ TOTAL 15 100 28 100 27 ~OO 30 .100 100 100eAUSESFORCREWLOSSES

EnemyAction 1 0 % 7 3'7$' ,15 ' 52% 7 23% 30 35%Operational Loss 1 20"':~ ." 6 . ~l 4 14 8 .,26 19 23Reorg. &Rec1ass. 3 16" 3 10 10 32 16 19Unknown 3 60, 3 ;L6 7 24 619 19 23TOTAL 5 100 19 100 29 100 31 100' 84 100


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- .. - ,~ .., .2. Battle Damage

21% of aircraft airborne on Japanese mainland missions incurred battledamage during February.. Thjs decrease fr'om the 31 % figure of January was ingreat part due to the last mission of the pe~iod and h~nce is not yet soundevadence of a reversal of the previously increasing trend. The effect ofradar bombi.ngdays must; be studied in this c'onnec tacn, too. The percent ofbattle-damaged aircraft uhi.ch required over 6 days to repair has slightlydecreased each'month. the Feb~uary figure being 1~%as' compared to l~ forJanuary and 21% for December. The causes and effect of battle da~~ge uillbe the-subject of more detailed analysis when the new reporting and analysisprocedures nou in process of being formula~ed. became effective. A briefsummar-y' of the general causes of aircraft. Los t- and battle damagedfollous: .

CAUSESF A JRC ftAFT LO ST j~ BATTlE-DLlY1 l .GED, .\ l'e~cent- of ~Total ,LoatandDamagedDecember' J81mary Febr\lary

Enenzy- Aircraft 27 .6% 51 .6% 34.6%EneIzy Flak 40.1% 12.7% '42..6%. Ene I zy A le and Flak 15 .2% 15..9% .8.1%Accidents &!Aalfunct~ons 7 . ( : J f , . I. 2. .5% 4.8%Self Inflicted '5~ 7 . . 1% 4.3%other and UnknoilD.i 3. ~ 10.2% 5Q6%

Only 22% of thoso failing to return fram combat missions or 5 0 % ' ofthose knoon to have ditchod TIere reacued during,Februnry. Thi"s representsa substantial increase over January figures of 7 1 % and 9%, and \o-datefigures of 19% and 33%. ' 258 crow members failed to return from missionsduring the month. Of these. 113 uere known to have ditched and 56 wer eroscue~. '

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PART VII. OTHER ACTIVITY1. Weather Strike Mis:sions

Dur'Lng February, I 83 aircraft were airborne on weather strikemissions comparedto 7 4 in January. 9 0 % of the Februa~Tmissionswere effect-i ve as against ocly 93 % in January? and two aircraft,were lo~t during the month comparegto none in Janlmry. 184 tonsof bombswere dropped' in r:,:}bru.e.ryo' makea total of 5 1 4 tons todate. In addition, the 655th BombSquadron (WeatherReconnaissance)began flying at the 1ast~of the m0nth.

2 . :r:notoReconnaissance MissionsA total of 42 aircraft, 33 from the 3rd Photo Reconnai~sanc~

Squadr-on and 9 from the 73rd Wing, were airborne (on photo' recon- ,naissance missions during the month. 7 1 % of these sorties vvere,eff;'ecti ve as comparedwith 61%in January. H owever ;: only .3'8% ofairborne aircraft obtained good to excellent photo results.' F-13aircraft averaged only 2 8 hours per aircraft during the month, or2 . 2 sorties per aircraft

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XXI Bomber Command, Monthy Activity Report 1 March 1945

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Transcript of XXI Bomber Command, Monthy Activity Report 1 March 1945