Basic definitions,
Sortie: A sortie is an aircraft airborne on a mission against
the enemy (synonymous with terms 'aircraft dispatched",
"aircraft airborne", and "aircraft taking off", previously used.
Aircraft Credit Sortie: An aircraft credit sortie is deemed to
have taken place when an airplane, ordered on an operational
mission and In the performance of that mission, has entered
an area where enemy anti-aircraft fire may be effective, or
where usual enemy fighter patrols occur, or when the airplane
is in any way subjected to enemy attack. (Definition previously
used for sortie to the ETO)
Non-Effective Sortie: A non-effective sortie is a sortie which
for any reason fails to carry out the purpose of the mission.
(Synonymous with the term "abortive".)
It is assumed operational flying hours are for credit sorties.
The USAAF compiled quite detailed statistics about its
activities which makes analysis much simpler. So for
the 9th Air Force in the European Theatre, October 1943
to April 1945.
The A-20 averaged 13.1 credit sorties per aircraft per month
in sorties lasting an average of 3.31 hours (about 3 hours 20
minutes). A total of 67,917 hours of operational flying,
37,351 hours of non operational flying. So on average
of 43.46 hours of operational flying per month. All up
22,999 sorties, 20,522 credit and 15,855 effective sorties.
90 A-20 MIA, 79 write offs, 0.82% losses per credit sortie.
Note in November 1944 two of the three A-20 groups
officially converted to A-26.
The A-26 averaged 12.4 credit sorties per aircraft per month
in sorties lasting an average of 3.55 hours (about 3 hours 33
minutes). A total of 35,513 hours of operational flying,
40,796 hours of non operational flying. So on average
of 44.02 hours of operational flying per month. All up
10,441 sorties, 10,009 credit and 9,201 effective sorties.
35 A-26 MIA, 28 write offs, 0.63% losses per credit sortie.
The B-26 averaged 11.0 credit sorties per aircraft per month
in sorties lasting an average of 3.44 hours (about 3 hours 26
minutes). A total of 267,941 hours of operational flying,
113,975 hours of non operational flying. So on average
of 37.8 hours of operational flying per month. All up
85,706 sorties, 77,785 credit and 62,686 effective sorties.
Four of the B-26 groups were operational with the 8th Air Force
before being transferred to the 9th while in February and again
in April 1945 a B-26 group was converted to A-26. 320 B-26
MIA, 253 write offs, 0.74% losses per credit sortie.
Unfortunately crew and aircraft status is only given for
bombers as a group, so A-20, A-26 and B-26.
The 9th Air Force reported its average authorised bomber
strength was 764.2 aircraft, with 827.1 on hand in the air force
of which 611.6 were in the tactical units of which 497.7 were
operational, there was an average total of 851.6 crews
authorised, 917 assigned.and 681.3 available in the tactical
units giving an average strength of 471.6 operational aircraft
with crews.
The bomber units had about the same number of aircraft and
crews from October 1943 to February 1944, the 10 to 20%
more aircraft than crews until July 1944, then parity again in
August and September, then 25% more crews in October and
November peaking at 50% more crews in March 1945.
There were effectively 4 bomb groups operational from
October to January 1944, 4.5 in February, 7 in March,
9 in April and 11 in May 1944.
Bomber groups were authorised to have 85 aircraft and
96 crews until October 1944 when the number of aircraft
was raised to 88.
The P-38 averaged 17.3 credit sorties per aircraft per month
in sorties lasting an average of 2.51 hours (about 2 hours 30
minutes). A total of 82,581 hours of operational flying,
18,905 hours of non operational flying. So on average
of 43.4 hours of operational flying per month. All up
34,038 sorties, 32,928 credit and 31,868 effective sorties.
317 P-38 MIA, 77 write offs, 1.2% losses per credit sortie.
On 20 February 1945 the 367th Fighter Group officially
converted from P-38 to P-47, on 9 March 1945 the 370th
Fighter Group officially converted from P-38 to P-51.
The P-47 averaged 18.9 credit sorties per aircraft per month
in sorties lasting an average of 2.41 hours (about 2 hours 25
minutes). A total of 475,052 hours of operational flying,
134,029 hours of non operational flying. So on average
of 47.4 hours of operational flying per month. All up
201,546 sorties, 197,191 credit and 190,450 effective sorties.
1,208 P-47 MIA, 249 write offs, 0.74% losses per credit sortie.
Due to a shortage of P-51 and changes in designations the
9th air force fighter units peaked at 2,944 P-51 credit sorties
in July 1944, was down to 826 in September, 506 in October,
555 in November, 38 in December, 0 in January 1945, 474 in
February then 3,359 in March.
On 10 September 1944 the 363rd Fighter Group with P-51
officially became the 363rd Tactical Reconnaissance Group,
after which its activities were recorded under reconnaissance.
On 22 November 1944 the other 9th AF P-51 unit, the 354th
Fighter Group officially converted to P-47, it officially converted
back to P-51 on 15 February 1945.
The P-51 averaged 16.8 credit sorties per aircraft per month
in sorties lasting an average of 2.96 hours (about 2 hours 58
minutes). A total of 72,609 hours of operational flying,
21,933 hours of non operational flying. So on average
of 49.7 hours of operational flying per month. All up
25,546 sorties, 24,505 credit and 23,932 effective sorties.
253 P-51 MIA, 19 write offs, 1.1% losses per credit sortie.
As with bombers crew and aircraft status is only given for
fighters as a group, so P-38, P-47 and P-51.
Fighter groups were authorised to have 96 aircraft and 108
crews until November 1944 when it became 100 aircraft
and 126 crews. It means there was an average of 1,224.6
authorised aircraft strength of which 1,180 were on hand in
the 9th Air Force of which 885.8 were in the tactical units of
which 718.8 were operational. Average authorised crew
strength was 1,486, 1,654 were assigned, 1,164.6 available
in the tactical units, giving an average effective strength of
696.8 aircraft with crews.
The fighter units had 10 to 20% more aircraft than crews to
May 1944, by July 1944 there were 30% more crews and
growing, peaking at 70% more crews in January 1945.
There were an average of 0.4 fighter groups operational in
December 1943, 1 in January 1944, 3.2 in February, 6.2 in
March, 8.9 in April, 17 in May, 18 in June, 18 in July 1944.
Some 9th Air Force Fighter Groups were transferred to the
1st Tactical Air Force dropping average Fighter Group
strength to 15.17 in November 1944, it then stayed between
14.67 and 15,67 to end April 1945.
Operational flying hours per aircraft per month were
more uniform, A-20 43.46, A-25 44.02, B-26 37.8, P-38
43.4, P-47 47.4, P-51 49.7, which would indicate overall
the allocation of crew and maintenance personnel was
well matched to the aircraft type. The light twin engined
bombers and the P-38 are in one group, the single
engined fighters did better, the heavier bomber with the
larger crew did worse, am indication of crew sizes is the
average number of men posted missing in 1944 was 2.25
for each A-20 listed as MIA, for the B-26 is was 5.41.
For the P-38 0.84, P-47 0.75 and P-51 0.87 men MIA per
aircraft MIA, the final figure fitting with the 30 minute longer
average flight time compared to the P-38 and P-47.
The bomber and P-47 loss rates were 0.6 to 0.8%
the P-51 1.1% and the P-38 1.2%. around 45% of all
bomber losses were write offs, versus 7% for the P-51,
17% for the P-47 and 19% for the P-38. This probably
initially relates to the amount of air combat the types saw,
the bombers claimed a total of 65 kills, the P-38 266 kills,
the P-47 1,130 kills and the P-51 748 kills. Then comes
the radial engine in the P-47 and the twin engines of the
P-38 in terms of making it back when heavily damaged.
As fighters the P-38 claimed a kill every 124 sorties, the
P-47 one every 174 sorties and the P-51 one every 33
sorties which again should mean a lower write off rate
for the P-51, fighters were more lethal than flak.
Table is month \ average operational hours flown by by
available bomber crews \ average operational hours
flown by by available bomber aircraft \\ average
operational hours flown by by available fighter crews \
average operational hours flown by by available fighter
aircraft.
Oct-43 \ 7.14 \ 6.29 \ \ \
Nov-43 \ 15.52 \ 14.49 \\ \
Dec-43 \ 20.54 \ 22.85 \\ 9.24 \ 14.56
Jan-44 \ 17.69 \ 19.00 \\ 15.50 \ 14.49
Feb-44 \ 32.88 \ 35.30 \\ 23.47 \ 22.57
Mar-44 \ 29.92 \ 28.96 \\ 34.46 \ 25.98
Apr-44 \ 39.98 \ 33.43 \\ 40.13 \ 33.12
May-44 \ 48.86 \ 39.66 \\ 48.15 \ 43.29
Jun-44 \ 45.56 \ 39.00 \\ 46.00 \ 52.97
Jul-44 \ 34.59 \ 28.06 \\ 32.38 \ 43.68
Aug-44 \ 40.72 \ 42.15 \\ 37.08 \ 49.43
Sep-44 \ 22.58 \ 22.63 \\ 31.18 \ 44.05
Oct-44 \ 12.43 \ 15.31 \\ 22.62 \ 32.61
Nov-44 \ 16.84 \ 21.16 \\ 16.99 \ 27.19
Dec-44 \ 20.44 \ 26.58 \\ 21.80 \ 34.84
Jan-45 \ 12.23 \ 16.50 \\ 15.31 \ 26.20
Feb-45 \ 26.48 \ 36.96 \\ 23.65 \ 35.68
Mar-45 \ 47.31 \ 72.21 \\ 47.59 \ 65.21
Apr-45 \ 30.88 \ 45.23 \\ 42.31 \ 58.61
So peaking in the mid 40 hours per crew per month.
The A-20 flew 1.82 operational hours for every 1 hour of
non operational flight, the A-26 0.87 (reflecting the need to
retrain crews and its late arrival), the B-26 2.35, P-38 4.34,
P-47 3.54, P-51 3.31, P-61 1.01 (Night fighter), F-3 0.41
(Presumably mostly used for training), F-5 1.74, F-6 3.22.
I would not stretch this too far but in weight terms,
A-20K 17,000 pounds empty, 10,000 pounds load
A-26B 22,400 pounds empty 12,600 pounds load
B-26G 23,800 pounds empty, 14,400 pounds load.
P-38J 12,800 pounds empty, 8,800 pounds load
P-47D-25 10,000 pounds empty, 9,400 pounds load.
P-51D 7,125 pounds empty, 4,500 pounds load
A sort of match to flying hours in terms of empty weights
(basic equipment needing care) and loads (the time and
effort to crew, arm and fuel) with the note engines tended
to require plenty of maintenance. Then add the extra crew
for a B-26.
Comparing these figures to others has the hazard October
1943 to April 1945 is not two full years and includes two
winters, plus the surge in activity in June 1944, the 9th Air
Force flew 110,966 hours that month, only exceeded in
March and April 1945. Add the inevitable disruptions in
moving from England to France and then into Germany.
Even using May 1944 to April 1945 has problems given
the effect weather had on operations, for bombers the
average for the above year was 12.75 operational days,
6.1 part operational and 11.6 non operational due to
weather. Operational days ranged from 24 in March 1945
to 5 in October 1944, part operational from 9 in November
1944 and February 1945 to 1 in June 1944. However even
this needs qualification as the bomber units received radar
bombing equipment towards the end of 1944 and so could
operate in worse weather.
For fighters the averages were 14.75 operational days, 8.4
part operational days, ranging from 24 operational days in
August 1944 to 6 in November 1944 and January 1945, part
operational ranged from 16 days in November and December
1944 to 2 in June 1944 and March 1945.
Missions were still run on declared weather non operational
days, 10.7% of total bomber, 7.1% of total fighter and 6.9% of
total reconnaissance sorties.
Some better figures for the 8th Air force versus some earlier
estimates.
From the Statistical Summary of Eighth Air Force Operations,
Figures include 24 credit sorties by light bombers in September
and 12 in October 1942 versus 106 and 157 by heavy bombers
for those months. Also 23 credit sorties in May, 245 in July, 996
in August, 2,344 in September and 485 in October 1943 by
medium bombers versus 1,340, 2,334, 2,058, 2,561 and 2,159 by
heavy bombers for those months, hence the drop in average sortie
length in August and September.
Table is month \ operational hours per sortie \ sorties per crew
assigned \ sorties per aircraft on hand tactical units \ operational
hours per crew \ operational hours per aircraft. For bomber aircraft.
Aug-42 \ \ 2.4 \ 2.9 \
Sep-42 \ \ 1.4 \ 1.6 \
Oct-42 \ \ 2 \ 2.2 \
Nov-42 \ 4.8 \ 2.5 \ 2.5 \ 12.0 \ 12.0
Dec-42 \ 4.3 \ 2.4 \ 2.1 \ 10.3 \ 9.0
Jan-43 \ 4.7 \ 2.4 \ 2.3 \ 11.3 \ 10.8
Feb-43 \ 4.3 \ 3.7 \ 3.6 \ 15.9 \ 15.5
Mar-43 \ 4.1 \ 6.3 \ 5 \ 25.8 \ 20.5
Apr-43 \ 4.4 \ 2.4 \ 1.9 \ 10.6 \ 8.4
May-43 \ 3.7 \ 5.2 \ 4.8 \ 19.2 \ 17.8
Jun-43 \ 4.1 \ 5.1 \ 4.7 \ 20.9 \ 19.3
Jul-43 \ 5 \ 6.1 \ 4.8 \ 30.5 \ 24.0
Aug-43 \ 3.5 \ 4.5 \ 3.9 \ 15.8 \ 13.7
Sep-43 \ 3.9 \ 5.2 \ 5.2 \ 20.3 \ 20.3
Oct-43 \ 5.6 \ 3.3 \ 3.6 \ 18.5 \ 20.2
Nov-43 \ 5.2 \ 4.2 \ 5.1 \ 21.8 \ 26.5
Dec-43 \ 5.9 \ 4.1 \ 6.1 \ 24.2 \ 36.0
Jan-44 \ 5.2 \ 4.2 \ 6.4 \ 21.8 \ 33.3
Feb-44 \ 6.2 \ 6.2 \ 7 \ 38.4 \ 43.4
Mar-44 \ 6.5 \ 7.4 \ 8.1 \ 48.1 \ 52.7
Apr-44 \ 5.8 \ 8.3 \ 8.9 \ 48.1 \ 51.6
May-44 \ 6.2 \ 9.2 \ 9.7 \ 57.0 \ 60.1
Jun-44 \ 5.6 \ 10.2 \ 11.5 \ 57.1 \ 64.4
Jul-44 \ 6.4 \ 7.7 \ 10.2 \ 49.3 \ 65.3
Aug-44 \ 6.3 \ 7.1 \ 9.7 \ 44.7 \ 61.1
Sep-44 \ 6.7 \ 6 \ 8.8 \ 40.2 \ 59.0
Oct-44 \ 6.3 \ 5.5 \ 7.6 \ 34.7 \ 47.9
Nov-44 \ 6.5 \ 4.9 \ 6.9 \ 31.9 \ 44.9
Dec-44 \ 6.6 \ 5.1 \ 8 \ 33.7 \ 52.8
Jan-45 \ 6.6 \ 4.7 \ 7.7 \ 31.0 \ 50.8
Feb-45 \ 7.4 \ 6 \ 10.5 \ 44.4 \ 77.7
Mar-45 \ 6.9 \ 8 \ 13.8 \ 55.2 \ 95.2
Apr-45 \ 7.9 \ 5.4 \ 8.7 \ 42.7 \ 68.7
Averages November 1942 to April 1945, sortie length 5.55
hours, 5.44 sorties per crew per month, 6.64 per aircraft,
31.18 hours per crew, 39.42 hours per aircraft.
The figures indicate if there is a limit of around mid 40's hours
of operational flying per month it is more the limits on crew
strength that determined this, from July 1944 onwards the
average aircraft in the tactical units flew at least 30% more
hours on operations than the average crew, for 1945 it was
57 to 75% more.
For the 8th Air Force's heavy bomber units the number of crews
assigned to the combat units was around the same as the number
of aircraft August 1942 to February 1943, for March to August
1943 the units generally had 10 to 20% more aircraft than crews,
then the ratio rapidly shifted so crews outnumbered aircraft by
nearly 1.5 to 1 in January 1944 which seems to be a surge of
crews arriving before aircraft, by May there were about 5% more
crews than aircraft, in June the 8th hit peak average aircraft
strength in the units, 2,547, while average crew strength went from
2,180 in May to 3,213 in July, stabilised at around 3,400 to 3,500
for most of 1944, then jumped to 3,835 in February 1945 for
2,230 aircraft.
For another contrast, long duration flights,
Coastal Command Sorties per month per aircraft, 1941, 1942, 1943
Catalina 2.87, 2.19, 3.95
Hudson 3.83, 4.56, 7.35
Liberator 1.13, 1.90, 2.597
Sunderland 3.90, 2.81, 3.35
Wellington 3.67, 3.22, 3.77
Hours per sortie
Catalina 13.7, 13.5, 15.44
Hudson 4.8, 5.28, 5.96
Liberator 10.88, 10.92, 12.27
Sunderland 8.42, 10.78, 11.56
Wellington 6.68, 8.14, 8.35
Hours per month
Catalina 39.32, 29.57, 60.99
Hudson 18.38, 24.08, 43.81
Liberator 12.29, 20.75, 31.87
Sunderland 32.84, 30.29, 38.73
Wellington 24.52, 26.21, 31.48
For those who want to consider an earlier operation Overlord, the
8th Air Force went from 37 operational groups at the end of
December 1943, to 44 end March 1944 to 57 end June.
The 9th Air Force had 4 bomb and 1 fighter groups operational
at the end of December 1943, 5 bomb and 5 fighter groups by
end March 1944 and 11 bomb and 18 fighter groups by end
May 1944, the final 8 groups being made operational between
1 and 9 May.
And it needs to be pointed out the number of aircraft per group
was going up. The 8th air force on average had 723 operational
heavy bombers with crews in December 1943, and 1,855 in June,
fighter effective strength grew from 565 to 885 over the same time.
The 9th Air Force had an effective strength, aircraft with crews, of
224 bombers and 50 fighters in December 1943, versus 620 and
1,009 respectively in June.
Geoffrey Sinclair
Remove the nb for email.
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