‘Precision’ and ‘Area’ Bombing: Who Did Which, and When?

Journal of Strategic Studies

Volumn 18, Issue 1, 1995, Pages 145-174

  Parks, W Hays ^a  

^a NONE

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EID: 40349088626     PISSN: 01402390     EISSN: 1743937X     Source Type: Journal    
DOI: 10.1080/01402399508437582     Document Type: Article

References (124)

1. Impact, April 1945 (Washington, DC: Asst. Chief of Air Staff, Intelligence), p.46.
2. Sir Charles Webster and Noble Frankland, The Strategic Air Offensive Against Germany 1939–1945 (London: HMSO, 1961), Vol.I, pp.13–14; II, pp.5, 213, 214.
3. Philip Babcock Gove (ed.), Webster’s Third International Dictionary, Unabridged (Springfield, MA: Merriam–Webster, 1976), pp.13–14, 1784–5;
4. J.A. Simpson and E.S.C. Weiner (eds.), The Oxford English Dictionary, 2nd ed. (Oxford: Clarendon Press, 1989), Vol.XII, p.321. Presciently, the minutes of the first meeting (6 April 1934) of the Bombing Committee of the British Air Ministry report that ‘The meeting was practically unanimous that the term precision was incorrect and misleading.’ AIR 2/1369.
5. Webster and Frankland, Strategic Air Offensive (note 2), Vol.I, pp.167–87, 190–257;
6. British Bombing Survey Unit (BBSU), The Strategic Air War Against Germany, 1939–1945 (London: Secretary of State for Air, 1946), pp.6–9;
7. Brereton Greenhous, Stephen J. Harris, William C. Johnson and William G.P. Rawling, The Official History of the Royal Canadian Air Force, Vol.III, The Crucible of War 1939–1945 (Toronto: Univ. of Toronto Press, 1994), pp.528–86.
8. Hugh Odishaw, ‘Radar Bombing in the Eighth Air Force’ (1946), Box 80, Spaatz Papers, Library of Congress, MS Div., pp. 106–9;
9. Wesley Frank Craven and James Lea Cate, The Army Air Forces in World War II (Chicago, IL: Univ. of Chicago Press, 1948), Vol.I, p.599;
10. US Strategic Bombing Survey (USSBS), Vol. 2 Over-All Report (European War), 2d ed. (Washington: GPO, 1947), pp.71–2;
11. James Phinney Baxter, Scientists Against Time (Cambridge, MA: MIT Press, 1946), p.294.
12. A recent assessment is Richard P. Hallion, Storm Over Iraq: Air Power and the Gulf War (Washington, DC: Smithsonian Instn. Press, 1992), pp.9–10.
13. AWPD-1, ‘Munitions Requirements of the Army Air Forces to Defeat Our Potential Enemies’, Film 145.82, AFHRC, Tab No.2B; James C. Gaston, Planning the American Air War (Washington, DC: National Defense UP, 1982), p.56;
14. Maj. Gen. Haywood S. Hansell, USAF (Ret.), The Air Plan That Defeated Hitler (Atlanta: Private Publication, 1972), p.86.
15. Using Eighth Air Force data for 1943–14, against a target 400 by 500 feet (200,000 sq. ft.), a Combat Wing bombing visually from 20,000 feet with 108 1,0001b. bombs had a 98.5 percent probability of achieving a single hit. Hansell, pp.118–21, 291–3. USSBS examination of 194 missions revealed that visual bombing performance was better then predicted in 73 missions, but worse than expected in 121. USSBS, Report 63, Bombing Accuracy – USAAF Heavy and Medium Bombers in the European Theater of Operations, 2nd. ed. (Washington, DC: GPO, 1947), p.6.
16. Maj. Gen. Ira C. Eaker, ‘The Case for Day Precision Bombing; Text of Presentation to Prime Minister Churchill at Casablanca Conference, January 1943’, pp.1–6, USAFHD 520.547C (emphasis supplied);
17. see also Craven and Cate The Army Air Forces (note 5), Vol. III, p.302. In a memo two months earlier Eaker declared that ‘I believe it is clearly demonstrated that the efficiency of daylight bombing over night bombardment is in the order of ten to one.’ Memo from Maj. Gen. Ira C. Eaker (Commander Eighth Bomber Command) to CG Eighth Air Force, 8 Oct. 1942, in Spaatz Papers, Diary, Box 10, File ‘Sept.–Oct. 1942’, Library of Congress, MS Division.
18. Craven and Cate, Army Air Forces (note 5), Vol. II, pp.270–2;
19. British Bombing Survey Unit (BBSU), pp.47–8;
20. Hansell, The Air Plan (note 6), pp.115–19;
21. USSBS, Bombing Accuracy (note 6), pp.2, 9, Exhibit G;
22. Roger Freeman, Mighty Eighth War Manual (London: Jane’s, 1984), pp.23, 45–6;
23. Charles W. MacArthur, Operations Analysis in the US Army Eighth Air Force in World War II (Providence, RI: American Mathematical Soc., 1990), pp.31–3;
24. Richard G. Davis, Carl A. Spaatz and the Air War in Europe (Washington, DC: Center AF History, 1993), p.477.
25. Craven and Cate (note 5), Vol. II, pp.217, 319–20;
26. Greenhous (note 4), pp.638–9.
27. Eighth Air Force subsequently adopted a similar policy forbidding H2X attacks in Nazi-occupied territory. Davis, Spaatz, pp.382,401, 564.
28. USSBS, Bombing Accuracy (note 6), pp.2, 3, 15;
29. Craven and Cate (note 5), Vol. II, pp.270–1. In a 27 May 1944 US Strategic Air Forces in Europe report on bombing accuracy to the CG, Army Air Forces reported that ‘about 30 per cent of our formation attacks fail to attack assigned targets and attack targets of opportunity instead.’ When attacking the assigned target, aircraft bombing from 20,000 ft resulted in a gross error rate of 30 per cent. ‘CEP for Heavy and Medium Bombardment Aircraft Operating from United Kingdom’, Spaatz Papers, Box 76, Library of Congress, MS Div.
30. ‘Air Historical Branch Narrative – Operational Research in Bomber Command’, Air Historical Branch [hereafter AHB], MoD, London, Ch.5 (hereinafter ‘BC Operational Research’); USSBS Report 64, Description of RAF Bombing, 2d ed. (Washington, DC: GPO, 1947), pp.7–9.
31. Memo, Eighth Bomber Command to HQ Eighth Air Force, 13 Sept. 1943, Subj: Bombing Accuracy (Spaatz Files, Box 76, Bombing Accuracy, Library of Congress, MS Div.).
32. HQ Eighth Air Force, AAF Bombing Accuracy Report No. 2 (1945), p.21 (RG 18, Box 550, Air Adjt. Gen. Files, 470, National Archives.)
33. Odishaw ‘Radar Bombing’ (note 5), pp.9–12, 17–18;
34. Hansell, Air Plan (note 6), p.86;
35. AWPD–1 (note 6), p.3; Harry C. Butcher, My Three Years with Eisenhower (NY: Simon & Schuster, 1946), p.136;
36. Craven and Cate (note 5), Vol.II, pp.232–3, 689–90.
37. For the Gorrell Plan discussion of weather, see Maurer Maurer (ed.), The US Air Service in World War I (Washington, DC: GPO, 1978), Vol.II, p.147.
38. Odishaw (note 5), pp.9–12 and Tables II and III; USSBS, Report 62, Weather Factors in Combat Bombardment Operations in the European Theater, 2d ed. (Washington, DC: GPO, 1945), pp.1, 3, 15–16, 19–20, Tables IX and X;
39. Craven and Cate (note 5), Vol.II, p.262.
40. The higher US abort rate was a result of its formation flying, which could be adversely affected by weather throughout the mission – at base, takeoff, rendezvous and assembly, enroute, at the target and on landing. Formation flying restricted the ability of a force to penetrate cloudy weather at flight levels. ‘Safe flying weather’ for US crews in Europe was defined by commanders after assessing equipment limitations, tactics, operational priority and state of crew training. USSBS, Weather Factors, pp.2, 9, and Table II.
41. USSBS, Bombing Accuracy (note 6), p.4; Minutes of conference held in Brig. Gen. F.L. Anderson’s office, 28 Oct. 1944 (Spaatz Papers, Diary, Box 19, File Oct.–Nov. 1944, Library of Congress, MS Div.).
42. Odishaw, ‘Radar Bombing’ (note 5), pp.31–9, 69–88;
43. Webster and Frankland (note 2), Vol.I, pp.178, 179; Vol.IV, Annex 1 (pp.3–17), Appendix 13 (pp.205–213);
44. BBSU (note 4), pp.44–5, 46–8;
45. A.C.B. Lovell, ‘Historical Note on H2S,’ T.R.E. Journal (Jan. 1945), pp.1–14;
46. Dudley Saward, The Bomber’s Eye (London: Cassell, 1959), p.223;
47. Henry E. Guerlac, Radar in World War II (NY: American Inst, of Physics, 1987), pp.737, 772, 784;
48. Bernard Lovell, Echoes of War: The Story of H2S Radar (Bristol: Adam Hilger, 1991). The latter (pp.275–6) summarises the various H2S systems, which underwent continuous improvement.
49. BBSU (note 4), pp.44–5;
50. Odishaw, ‘Radar Bombing’ (note 5), pp.15–19, 22–3, 31;
51. Webster & Frankland (note 2), Vol.IV, pp.11–15;
52. Guerlac, Radar, pp.776–8, 781, 783, 798–9.
53. British difficulties in getting H2S to operate at the higher altitudes desired by Eighth Air Force are described in Lovell, Echoes of War, pp.194–5.
54. Odishaw (note 5), p.31, fn.74.
55. Combined Chiefs of Staff Air Plan for the Defeat of Germany, Memorandum from the CG Army Air Forces (1 Nov. 1943), Papers of Henry H. Arnold, Box 39, Library of Congress, Mauscript Div.; USSBS, Report 61, Air Force Rate of Operation, 2d ed. (Washington, DC: GPO, 1947), pp.28–9, 35, 36, 38, 39–40, 41, Exhibits 24d, 25a;
56. Davis, Spaatz (note 8), p.297. USSBS Report 61 provides detailed analysis of 12 target categories, including industrial areas (to include urban areas). USSBS Report 63 (Bombing Accuracy) does not include industrial areas as a target category, apparently because of the Feb. 1945 recharacterisation of industrial areas as marshalling yards.
57. USSBS, Overall Report (European War), p.72.
58. Davis, Spaatz (note 8), pp.508, 568–70.
59. The British Air Ministry also played with words on occasion. ‘Industrial centres’ was substituted for ‘centres of population’ in summer 1942 because of the negative political-legal connotation of the latter. Greenhous (note 4), pp.620–1.
60. USSBS, Air Force Rate of Operation, Exhibit 24d.
61. Ibid., pp.38–9; Odishaw (note 5), p.122.
62. Craven and Cate (note 5), Vol. III, pp.13–22;
63. MacArthur, Operations Analysis (note 8), pp.68–71, 109;
64. Letter, HQ Eighth Air Force to CG, US Strategic Air Forces in Europe, 14 Feb. 1944, Subj: Comment on ‘Overlord’, Spaatz Papers, Diary, Box 17. In this letter from Maj. Gen. James H. Doolittle to Lt. Gen. Spaatz, Gen. Doolittle cautioned: There is often a tendency on the part of planners to measure destruction by tons of bombs dropped rather than by bombs on targets. This must be assiduously guarded against in connection with ‘through the overcast’ bombing. Our experience to date with this type of bombing technique indicates that it is closely allied with area bombing and does not lend itself to the precision bombing of pinpoint targets. We have not been able, with regularity, to take out precision targets using Oboe, GH or H2X. On those occasions when we have hit a precision target it has been largely luck. Ordinarily bombs are scattered over at least ten times as much area as with visual bombing … Odishaw (note 5), p.97, indicates that operational analysis revealed that to attain an equivalent concentration of bombs within a circular area having a radius of 1,000ft, an Eighth Air Force H2X force operating under 10/10 cloud conditions had to be approximately 150 times larger than a visual force bombing on a clear day.
65. Office of the Air Inspector, USSTAF Memorandum to Commanding General, USSTAF, 4 March 1944, Subj: Navigational Errors in Operations, Spaatz Papers, Diary, Box 17, Library of Congress, MS Div.; Memo from Eighth Air Force to CG, USSTAF, 22 March 1944, Subj: Utilisation of Improved BTO [Bombing through Overcast] Equipment by Eighth Air Force, Spaatz Papers, Diary, Box 17; Odishaw, ‘Radar Bombing’ (note 5), pp.97, 116;
66. Craven and Cate (note 5), Vol.III, p.13;
67. BBSU (note 4), p.45;
68. Webster and Frankland (note 2), Vol.IV, pp.11–12;
69. Guerlac (note 17), pp.772, 790–2, 794–5;
70. MacArthur (note 8), pp.109. 111, 218;
71. Baxter (note 5), p.96.
72. See, e.g., Conrad C. Crane, Bombs, Cities, & Civilians (Lawrence: Univ. of Kansas Press, 1993), pp.76, 113.
73. In summer 1944 Eighth Air Force ran H2X tests in part to ‘determine the capabilities of the equipment under controlled conditions …’ The study concluded that H2X was an effective instrument against ‘appropriate targets, namely city areas or isolated industrial complexes. The experiment emphasises, however, that the chance of hitting a pre-assigned industrial target within the built-up areas of a city is extremely slight with any reasonable size force’ [emphasis supplied]. The Oxford Experiment in H2X Bombing, Spaatz Papers, Box 81, Bombing Overcast, Analytical Studies II, Library of Congress, MS Div.; see also Gordon Musgrove, Pathfinder Force (London: MacDonald and Jane’s, 1976), p.239;
74. Guerlac (note 17), pp.772, 787. USAF officers with radar bombing experience confirmed to the author that this capability did not exist until more than a quarter century after World War II.
75. MacArthur (note 8), p.154.
76. Saward, Bomber’s Eye (note 17), p.140;
77. Lovell, ‘Historical Note on H2S,’ (note 17), p.6;
78. Lovell, Echoes of War (note 17), pp.144–8.
79. Guerlac (note 17), p.736;
80. Craven and Cate III, p.18.
81. The pessimism was apparently that of Gen. Arnold and his staff. See Odishaw (note 5), pp.44–5.
82. Washington scepticism prevailed despite the urgings of Gen. Spaatz. In a letter dated 14 Jan. 1944 Spaatz stated that ‘The most critical need of the Strategic Air Forces is for more Pathfinder aircraft. A few H2X airplanes now will profit our cause more than several hundred in six months.’ Spaatz Papers, Eighth Air Force file, 1942–45, Library of Congress, MS Div. Blind bombing equipment (H2X) was essential to maintaining a low rate of complete abortives under the policy requiring a high rate of operations. USSBS, Report 62, Weather Factors (note 15), p.11.
83. Odishaw (note 5), p.48;
84. Guerlac (note 17), p.785.
85. Table VI. The Eighth Air Force practice of equipping Pathfinder aircraft only with H2X contrasts with RAF Bomber Command H2S use. Commencing 21 Feb. 1943, Bomber Command proceeded to equip its entire heavy bomber force with H2S, i.e., all Lancaster (Pathfinder and non-Pathfinder) aircraft other than those equipped to cany the 8,000-lb bomb, all Halifax aircraft, and Mosquito Pathfinder and target-marking aircraft. Lancasters carrying the 8,000-lb bomb could not utilize H2S because the rotating antenna could not be fitted due to the modified bomb bay and bomb doors. Saward, Bomber’s Eye (note 28), p.191;
86. C. Martin Sharp and Michael J.F. Bowyer, Mosquito (London: Faber, 1971), pp.354, 363. Comparing 12 H2X aircraft per US heavy bomber group (Guerlac, p.813) with RAF Bomber Command operational strength in Dec. 1944 (excluding No.100 Group and Oboe Mosquitoes) of 1,810 aircraft, and appreciating that all of the other 160 Mosquitoes were not H2S equipped, US H2X acquisition effort was roughly one-half that of Bomber Command (RAF Bomber Command strength from ‘Air Ministry War Room Monthly Summary of Bomber Command Operations, December 1944’, p.27, AHB, MoD, London). By the time Eighth and Fifteenth Air Forces had equipped their Pathfinder forces, however, RAF Bomber Command crews had more than a year’s operational experience in H2S use.
87. Odishaw (note 5), pp.48–54, 120–4;
88. Craven and Cate (note 5), Vol.III, pp.666–7;
89. Guerlac (note 17), pp.785–8, 805–7.
90. The Operational Research Section reported that while ‘the exact number of gross errors is not known, the evidence indicates it is not negligible.’ For example, on one mission 42 squadrons were dispatched to Ludwigshafen. One-half of the force misidentified check points and bombed Stuttgart; Odishaw (note 5), p.99.
91. Likewise, on the 3 Feb. 1945 Eighth Air Force raid on Berlin, some groups missed the 883 sq. miles of Berlin completely. Davis (note 8), p.553.
92. USSBS, Description of RAF Bombing (note 11), Exhibit H, and BBSU (note 4), Fig. 8.
93. BC Operational Research (note 11), pp.14–16, 19;
94. BBSU (note 4), pp.46–8;
95. Webster and Frankland (note 2) Vol.II, 179, 186–8, 214, 283, 288.
96. Webster and Frankland (note 2), Vol.III, pp.27–8, 39, 41, 125, 130, 151–3, 165–7, 182;
97. ACM Sir Arthur Harris, Bomber Command (London: Collins, 1946), pp.197–214, 266;
98. Greenhous, Crucible (note 4), pp.803, 805, 808.
99. Richard P. Hallion, Strike from the Sky (Washington, DC: Smithsonian Press, 1989), pp.206–14;
100. Ian Gooderson, ‘Heavy and Medium Bombers: How Successful Were They in the Tactical Close Air Support Role During World War II?’, Journal of Strategic Studies 15/3 (Sept. 1992), p.367;
101. Harris, Bomber Command, pp.191, 209, 211–14.
102. BBSU (note 4), p.44;
103. Webster and Frankland (note 2), Vol.III, 183–4, 187, fn.2;
104. F.H. Hinsley, E.E. Thomas, C.A.G. Simkins, and C.F.G. Ransom, British Intelligence in the Second World War, Vol.3, Pt.2 (London: HMSO, 1988), pp.517–18;
105. ‘The Development of Gee-H,’ Bomber Command Quarterly Review, October–December 1944, pp.27–9.
106. AHB, MoD, London. Sept.–Dee. 1944 was also selected for comparison due to other shifts in bombing policy occurring thereafter that would affect any accuracy comparison. See, e.g., Richard G. Davis, ‘Operation “Thunderclap”: The US Army Air Forces and the Bombing of Berlin’, JSS 15/1 (March 1991), p.90.
107. BC Operational Research (note 11), Ch.5; BBSU (note 4), pp.23–4.
108. AAF Bombing Accuracy Report No.2 (note 13), Table 3.
109. Ibid., Chart II, Table 9; USSBS, Bombing Accuracy (note 6), p.13.
110. Odishaw (note 5), p.93, provides the following Eighth Air Force figures: In contrast, 50 per cent of RAF Bomber Command bombs dropped using H2S fell within 1,2 miles of the aiming point. Odishaw, p.123.
111. AAF Bombing Accuracy Report No.2, Table 9; MacArthur (Note 8), pp.71, 290–4, 296, 297;
112. Davis, Spaatz (note 8), pp.508, 550, 551, 568, 570.
113. USSBS, Vol.61, Air Force Rate of Operation (note 19), pp.61–73.
114. Arguably the USAAF differed from the British in that the former intended to hit the target listed in their records, while the British engaged in a general area offensive against industrial cities. Certainly intent counts where there is some degree of accuracy. But when the USAAF leadership directed blind-bombing attacks against a selected target in an urban area knowing that accuracy was five per cent or less, and as low as 0.2 per cent, their claimed intent is subject to challenge.
115. Craven and Cate (note 5), Vol. III, pp.281, 640–2, 644–5;
116. USSBS, Air Force Rate of Operation (note 19), Exhibit 24h;
117. USSBS, Report 109, Oil Division, Final Report, 2d ed. (Washington, DC: GPO, 1947), pp.1–2, 122;
118. USSBS, Report 110, Oil Division, Final Report, Appendix, 2d ed. (Washington, US: Dept. of War, 1947), Table G14.
119. BBSU (note 4), Figure 9. See also USSBS, Bombing Accuracy (note 6), Exhibit O.
120. USSBS Bombing Accuracy (note 6), pp.10–11.
121. HQ Eighth Air Force Operational Research Section Memorandum, Subject: Report on H2X Operations During September [1944] Against Targets in Ludwigshafen and Mannheim (25 Oct. 1944), Table 2, Spaatz Papers, File 82, Bombing Overcast Operations. H2X discrimination was not fine enough to detect canals and rivers (such as that adjacent to the Ludwisghafen-Mannheim target) unless they were exceptionally large. Odishaw (note 5), p.116.
122. Webster and Frankland (note 2), Vol. III, pp.234–5;
123. IV, pp.338. Maj. Gen. Gerlach of the Staff of the Luftwaffe Flak Defence of Leuna stated in Nov. 1944 that ‘The management considers the guided English night attacks with heavy calibre bombs to be more dangerous than the American day attacks, especially when the flak is handicapped by low visibility.’ USSBS, Oil Division, Final Report (note 44), p.137. That volume reports that German oil plant employees and defence personnel were ‘almost unanimous’ that ‘RAF attacks … were more damaging,’ attributing RAF success to each bombardier sighting his bombs independently (as opposed to USAAF formation bombing on the leader) p.7, and RAF Bomber Command using a single aiming point (as opposed to USAAF use of multiple aiming points) p.124.
124. Oil Division, Final Report (note 44), pp.4, 122. USSBS analysis of airstrikes against the I.G. Farbenindustrie at Ludwigshafen revealed the following ratios: