Air Fronts: Theaters of Operation - European Theater of Operation: Sunday Punch in Normandy - Aims And Commmitments
Wings at War Series, No. 2 ; Sunday Punch in Normandy. THE TACTICAL USE OF HEAVY BOMBARDMENT IN THE NORMANDY INVASION: An Interim Report; Published by Headquarters, Army Air Forces Washington, D. C., Office of Assistant Chief of Air Staff, Intelligence, From Reports Prepared by Eighth Air Force. CONFIDENTIAL. US GPO 1945. (declassified)
Eighth Air Force Aims and Commitments
Heavy Bombers
Before considering the tactical program involved, it is well to summarize briefly the strategic role previously enacted by the Eighth Air Force, together with RAF Bomber Command. This role, designed to provide indirectly for the ultimate success of the invasion, was incorporated in the Combined Bomber Offensive Program, its aim having been defined as "the progressive destruction and dislocation of the German military, industrial, and economic system and the undermining of the morale of the German people to a point where their capacity for armed resistance is fatally weakened."
Pertaining more directly to the success of the invasion was the corollary development of a specific bombing program against the German aircraft industry. This program was directed at the attainment of virtual air supremacy and as such was indispensable to operations by ground forces. It was not until the summer of 1943 that the Eighth Air Force could operate in sufficient strength to execute sustained large-scale attacks, but its efforts in those summer months were sufficient to keep the GAF from creating enough front-line strength to stop subsequent major operations. Adverse weather during November and December prevented the cumulative bombing necessary for complete success in such an undertaking, but production levels had been affected to the extent that the Luftwaffe had done little more than maintain its strength during 1943.
A more intensive campaign was possible during the early months of 1944, reaching a peak of sustained effort during the period 20—25 February and maintained, subject to tactical considerations, until the end of May. The substantial damage to factories and assembly plants, coupled with destruction in aerial battle of German first-line combat aircraft by both bombers and escorting fighters on a hitherto unprecedented scale, was unquestionably the decisive factor in reducing the GAF to the point where it had no more than a nuisance value during the critical invasion period. This was attested by the remarkably low number of sorties directed against the Allied beachheads and shipping lanes.
The following figures give some appreciation of the war of attrition by the Eighth Air Force against the GAF. During the first 6 months of 1944, 6,813 bombers dropped 16,522 tons on aircraft factories, and 8,257 bombers dropped 21,267.7 tons on airfields and air parks. In the same period 1,914 first-line enemy aircraft were destroyed by the bombers in aerial combat and 1,682 were destroyed or damaged on the ground as a result of bombing of air parks, air-fields, and factories. To these figures can he added the impressive total accounted for by escorting fighters-1,696 destroyed in combat and 761 in strafing attacks. Results obtained against other strategic targets were not so strikingly apparent in relation to D-day operations, but evident shortages in fuel, tanks, motor vehicles, radar equipment, and ammunition were traceable, at least in part, to the strategic bombing of the Eighth Air Force and the RAF Bomber Command.
During April and May 1944 continuation of attacks against strategic objectives was necessary to prevent reconstruction and as a means of holding the greater part of the GAF within Germany. At the same time the first commitments directly associated with the impending assault came into force. (There were also attacks against installations near the French coast when the weight of Eighth Air Force bombing was required in addition to the continual operations by tactical air forces.) These initial commitments consisted of attacks against 20 marshalling yards in occupied territory and neutralization of all active GAF operational bases within a 350-mile range of the invasion beaches.
TACTICAL TARGET. A good concentration of bombs on the Angoulême marshalling yard, scored by Eighth Air Force heavy bombers.
To avoid giving any clue as to the probable assault area, attacks on both target categories were widespread, the marshalling yards being key points throughout the rail network of western Germany, Belgium, and northern and eastern France, and the airfield targets including the more important bases in northern Germany. The purpose of the Transportation Plan was primarily the destruction of repair and maintenance facilities and only incidentally the tearing up of trackage and damage to locomotives and rolling stock. By these means it was hoped to prevent the enemy from effecting rapid concentration of men and materiel, cut the flow of supplies and reinforcements from Germany, and force increasing reliance upon road transport, thus promoting wastage of fuel and motor vehicles and offering targets most suitable for fighters and fighter-bombers. Pursuant to this plan, 3,469 bombers dropped 9,520 tons on marshalling yards in Germany, France, and the Low Countries during the month of May. These attacks were so successful that the Eighth Air Force was able to bomb additional targets not assigned in the original list.
The Airfield Plan was designed to deprive the Luftwaffe of bases within effective striking range of the assault beaches by destruction of permanent installations for repair, maintenance, and servicing, and by cratering runways and landing grounds to an extent that fields would be unusable. Parked aircraft destroyed in these attacks would constitute a further blow against the enemy's dwindling front-line strength. It did not prove feasible to conduct operations against all such targets, but the most important were hit and a good percentage was effectively neutralized. From D minus 30 and D minus 21, respectively, the scope of the attacks against rail and airfield targets was considerably narrowed, but special care was taken in the selection of targets so as not to reveal the actual invasion area. Airfields attacked were confined to those within a 130-mile radius of Caen and in the Brest-Nantes region, to compel German fighters to operate from bases at least as far distant from the beachhead as those of the Allied tactical forces.
In addition, it was agreed with the Naval Chief of Staff that the Eighth Air Force would undertake to attack bases for submarines and light naval vessels if diversion of effort from other commitments was feasible. Only one such attack was undertaken, and adverse weather prevented its successful completion.
Throughout this preliminary period, wherein the original commitment against strategic objectives was modified by the Transportation and Airfield plans as well as by the occasional attacks required against coastal installations, the Eighth Air Force, nominally under the control of SHAEF from 14 April 1944, was allowed to retain freedom of decision in fulfilling its varied assignments. This greatly facilitated operations, as priorities could be carefully balanced against weather factors and other operational considerations by those best qualified to cope with the problems of heavy-bomber operations. Not until 1 June 1944 did control under the fixed schedule provided for in the over-all air plan for the invasion pass to Headquarters, AEAF.
Immediately prior to D-day (D minus 3 through D minus 1) Eighth Air Force operations were to be twofold in nature, consisting of final attacks against rail junctions and airfields as well as missions against coastal installations. The postponement of D-day brought into effect a previously prepared schedule of targets in the same categories. Their size and the identification problems which they presented made the probability of direct hits very small, and, even if hit, the concrete emplacements were of such thickness that little harm was likely to result. During this short period prior to D-day, bomber forces were to be carefully husbanded to ensure that the necessary strength for the comprehensive D-day program was maintained. Therefore, the operations for each day were to employ only 50 percent of the available strength with one important exception: if visual conditions prevailed over Germany on either D minus 3 or D minus 2, 100 percent of the effort was to be expended, 40 percent against the usual tactical targets and 60 percent against strategic objectives within Germany. The latter mission was designed as a final attempt to contain enemy fighter strength for defense of Germany until the last moment before the actual landings.
The most important and by far the most elaborate D-day plans concerned the first mission of the day, involving attacks immediately prior to H-hour against 45 coastal installations between the Orne and the Vire estuaries on the Normandy coast of France. The 6 mile coastal strip included all assault beaches except an adjacent American beach, designated as Utah, which was the responsibility of the U. S. Ninth Air Force.
Some 1,200 heavy bombers were to participate, flying in squadrons of six aircraft. Following a carefully devised system of predawn assembly aided by searchlights, navigation lights, Aldis lamps, buncher and splasher beacons, and Gee equipment, the aircraft were to fly predesignated courses to the target area, bombing in successive waves until H-hour (or thereafter attacking secondary targets well inland). Assault craft were to remain 1,000 yards offshore until H-hour, and a 5-minute interval was to elapse between the releases by the last wave of bombers and the initial touchdown by the assault troops. These safety factors represented the final compromise between the desire of the ground forces to exploit immediately the demoralization resulting from the bombing at the risk of casualties and the inclination of the air forces to impose considerably greater intervals to minimize the dangers from possible bombing errors.
Demoralization of enemy front-line defenders and disruption of communication lines for reserve forces were the sole aims of the pre-assault bombing. It was understood that only a small percentage of the actual targets would suffer direct hits and smaller still would be the number seriously affected. Bomb loadings were established of 100-lb. GP, 120-lb. fragmentation, 500-lb. GP, and 1,000-lb. GP, the last for installations well clear of the beaches. Fuzing was to be instantaneous to avoid cratering the beaches except for targets away from the landing areas, where 1/10 nose-1/100 tail was permissible.
Alternative plans were provided for bombing through overcast, since it had been agreed that, other factors being favorable, the ground assault would be initiated whether or not visual bombing was possible and, if necessary, entirely without bomber cooperation, in which event the Eighth Air Force was to be in constant readiness. Minimum requirements for visual attacks by heavy bombers were an 8,000-foot ceiling, 3-mile visibility, and sufficient breaks in any low cloud to permit ready target identification. Less favorable conditions would demand the substitution of the plan involving overcast technique. Pinpointing of targets would be impossible, but since demoralization and immobilization of enemy forces were the principal aim, it was considered that area bombing of the sectors wherein lay the specific visual targets would provide virtually the same effect.
Squadrons were to fly six abreast and bomb on the release of a Pathfinder aircraft in one of the center squadrons. By such an arrangement deflection errors were largely neutralized, but further safeguards against errors in range were deemed necessary. Accordingly, the interval between the final bombing and the initial touch-down was to be increased to 10 minutes. One other necessary change was the instantaneous fuzing of all bombs, since the entire attack was to be directed against the assault beaches, which must not be cratered. Since the Ninth Air Force aircraft were not equipped for overcast bombing, provision was needed to cover Utah beach in their stead, should it prove impossible for even the medium bombers to operate beneath the cloud base.
Subsequent to the assault phase, additional missions were laid on in cooperation with the landing operations. Targets outlined in the over-all air plan consisted mainly of transportation choke-points, including several Normandy towns through which ran important lines of communication. Leaflet warnings were to be dropped to the populace of these towns before bombing.
Weather, photographic, and visual reconnaissance missions, special supply operations to the French Forces of the Interior, leaflet-dropping sorties, and radio countermeasure flights were to be undertaken in conjunction with the over-all ground and air activities.
No exact schedule of operations subsequent to D-day could be prepared in advance, since the progress of the ground forces and the nature of the enemy's reaction would be the determinants, but certain general features of the program were decided upon. Detailed target material, covering virtually all known potential tactical objectives in northern France, received the required distribution well in advance of D-day. Attacks were to be continued against road and rail transport facilities, including bridges on the Brest peninsula and across the Loire River; enemy airfields; concentrations of enemy reinforcements and supplies; and coastal defenses in the Pas de Calais sector. Blasting of robot-bomb launching sites was also contemplated if the security of the British Isles called for such action.
Requests for specific attacks were to be forwarded from Headquarters, AEAF, when the Eighth Air Force representative was in regular attendance. It was anticipated that a number of these missions would have to be undertaken on very short notice. The interval prior to a return to strategic bombing was dependent upon the degree of success attained by the ground forces, and it was recognized that even after the need of continual cooperation by heavy bombers had passed there would be periodic demands for tactical operations.
Fighters
No marked deviation from the normal escort tasks of Eighth Air Force fighters was required until D-day. Early in 1944, following substantial increases in fighter strength, the policy had been inaugurated of executing strafing attacks upon completion of escort duties. Such attacks became an accepted adjunct to high-altitude escort and, due to the tremendous scale of activity, provided the best possible training for ground-cooperation missions. On days when no heavy-bomber operations were scheduled, it was often possible to dispatch the fighters on independent bombing and strafing missions, some in the nature of experimental attacks against airfields and bridges. To a large degree, experience gleaned from these missions equipped fighter pilots for the job ahead.
The first fighter commitment to become effective on D-day was the protection of Allied shipping during daylight hours. P-38's were detailed to this task because of their readily identifiable lines and also because this fighter, relatively less effective than the P-47 and the P-51 at high altitudes, can operate without handicap at 3,000/5,000 feet, the altitude designated for these patrols. The four P-38 groups operating under the direction of the Combined Control Center at Uxbridge and in conjunction with Ninth Air Force P-38 groups were to work under the Type 16 ground control station at Ventnor; there-after, Fighter Direction Tender No. 13 would be stationed in mid-Channel and would assume control. Each of four sectors was to he covered by one P-38 squadron, flying in 90-minute patrols according to a predetermined schedule.
On D-day the other Eighth Air Force fighters, four P–47 and seven P–51 groups, were to support all American and British bombers operating during daylight hours in the vicinity of the assault area by means of continuous area patrols east, south, and west of the beachhead, patrols which would also serve to form a protective screen around the ground forces. The cover area was bounded approximately by the Seine on the east and the Loire on the south and, to avoid identification difficulties, excluded the actual assault locality where Ninth Air Force and Second Tactical Air Force fighters would be operating.
These operations were to be conducted in accordance with three well-formulated plans, two for the two peak periods of bomber effort, dawn and late afternoon, and one for the intervening period of less activity. To avoid continuous patrols the fighter groups were divided into two units, an "A" group of two squadrons to fly during the peak hours and a "B" group of one squadron for the in-between period.
An important secondary function, subordinate to bomber support, was the execution of strafing and bombing attacks at the end of area patrols or on independently scheduled missions when the bombers were not operating. It was expected that more emphasis would be given to this type of operation subsequent to D-day. The principal aim of such activities was the destruction of enemy road and rail transport and the interdiction of all types of enemy movement toward the assault area. Target priorities were established as follows:
1. Enemy rail transportation
2. Enemy road transportation
3. Ammunition dumps
4. Troop concentrations
5. Airfields
Although direct control of the P-38's was to pass to the tactical fighter forces' Combined Control Center, the operational and executive control of the Eighth Air Force groups was to remain the responsibility of Eighth Air Force and VIII Fighter Command, which also had the task of preparing the detailed plans for implementing the over-all assignments.
