US AAC/AAF Doctrine: Normandy - Tactical Air War
The following text is a reproduction of: Invasion of France; IMPACT, Vol. 2 No. 7, July 1944, Assitant Chief of the Air Staff, Intelligence, Washington, D.C.
WE STRIKE, AND HARD
The same strip of low coast from which the last invasion of England was launched 878 years ago by William the Bastard, witnessed the return of a good many of that same William's descendants on the morning of 6 June, 1944.
The part played by air in this operation was a dominant one. It started over a year ago with the task of photographing enemy defenses along the entire coast. When the Allied commanders decided last August on a provisional landing spot, it was still the task of the aerial photographer to keep them informed of changes in these defenses. During the rest of that year and through the spring just past, the American strategic bombing forces and RAF have hammered Germany relentlessly to sap her industrial strength and make sure that when D-Day came the GAF would be the puny thing it turned out to be. The tactical preparation (IMPACT, Vol. II, No. 6) began in April. It had four purposes: (1) to weaken the enemy's transportation system by slamming 99 rail centers in France, Germany and the Lowlands, (2) to push her fighters back from the invasion area by bombing and strafing all airfields within 130 miles of Caen, (3) to soften up the coastal defenses, (4) to delude the enemy regarding the direction of our initial thrust. This preparation lasted two months, during which time 166,940 tons of bombs were dropped.
On D-21 the bombing focus was narrowed to include only 16 key rail centers, 25 airfields and 24 emergency strips. The tempo of blows on the coast defenses was increased. Highways and rail bridges across the Seine were attacked daily.
On D-1, the focus was further narrowed. The shore from Isigny to Caen was saturated. That night the RAF made the heaviest single lift on record, 5,197 tons. At the same time three divisions of airborne troops were dropped, and the largest invasion fleet in history was proceeding across the Channel under a continuous umbrella of fighters.
Seine Bridges Hit., Also GAF Airfields
While blasts at airfields, shown by the picture at right, went relentlessly on, the placid loops of the Seine river, along which barges drift and Frenchmen fish, felt throughout May the shock of bombs from Abbeville to Paris. Targets were the 24 rail and highway bridges which connect the invasion area to the rest of Hitler's fortress. By D-Day all but three were out. Six days later the last link was severed. German troops to the east of the Seine, if they are to reinforce their embattled brethren in Normandy, will now have to cross by night, on rickety pontoon bridges. Movement of the heavier field pieces and tanks must be by barge or not at all.
Preliminary Air Hoax Aids First Landings
The maps on these two pages, showing Allied tactical air activity during the four days immediately preceding D-Day, make very clear the plan of the invasion commanders: to soften up one part of the coast, then at the last minute to hit another hoping for surprise. The speed with which our beachheads 'were consolidated on D-Day indicates that this strategy was eminently successful.
The best spot for a landing, from the geographical point of view, is the Pas de Calais area. It is the nearest point to England, has desirable beach characteristics and more than one excellent deep-water port, without which no invasion effort can be expected to prosper for very long. Accordingly, it was rocked by bombs daily to make the enemy think our first attack would be made there, although the actual landing was scheduled for the Cherbourg-Le Havre section 150 miles to the west. This was chosen because it offers the next best beaches, is also close to Britain, is less heavily defended than the Calais area, and is near enough to Cherbourg and Le Havre to offer possibilities for the capture of either or both of those ports. Also, the German armies behind the beaches were believed to be inferior to those defending Calais.
The problem in building up a gigantic hoax of this kind is to weaken the intended target without concentrating too hard on it, and yet not to leave it too suspiciously alone. Accordingly, only a few critical spots were pounded in the landing area until the emphasis suddenly shifted on D - 1. Even then, the deception was kept up with blows at Le Havre and Calais. Much of our Calais tonnage was directed at the rocket installations near that city-in anticipation of the robot planes which materialized on 14 June.
THE D-DAY AIR SMASH
Wrecking of some 200 coastal radar stations by D-Day contributed strongly to the enemy failure to realize that the invasion was upon him. He apparently failed to pick up the invasion fleet massing across the Channel, and made little air effort to interrupt the airborne operation which started during the night. He may have been well prepared up the line at Calais. He wasn't around Isigny. Some of the strongest opposition encountered there by Americans was from German troops surprised in the midst of beach maneuvers. Landings proceeded on schedule, due not only to the long aerial preparation and to Allied naval and ground efforts, but also to the way Air handled its three main D-Day tasks.
The convoy, first, was well protected. RAF fighters covered it continuously by night, USAAF fighters by day. Sub attacks were warded off by constant patrol by the RAF Coastal Command, which also laid a fence of mines from England to France on either side of the convoy lane.
Result: no sub or air losses. (By D + 12 two small escort vessels had been sunk by subs-at a cost of six subs.)
The second task was to drop three divisions of airborne troops, the Sixth British on the Orne river north of Caen, the American 82nd and 101st on the Cotentin peninsula, one on the main rail line to Cherbourg, the other in the flooded area to the south and west, both playing a critical role in the plan to cut off Cherbourg.
The final task was to implement the landing itself. The RAF 5,000-ton night run was followed at 0630 hours by 1,350 USAAF heavies dropping 3,096 tons through partial clouds while the convoy waited just off the beach. When it moved in, 1,347 fighters took over, covering each beach at all times with either two or three squadrons of low, three squadrons of medium, and two squadrons of high cover. Later in the morning, 424 B-26s dropped 634 tons, followed in the afternoon by 594 heavies dropping 1,636 tons on airfields and rail yards, then by more mediums and fighters with 516 tons, and in the evening by 184 mediums and 400 fighters which got in some late licks at truck convoys, highway bridges and the town of Caen. All together 7,106 AAF sorties were flown on D-Day and 6,408 tons of bombs dropped.
THE DAYS AFTER D-DAY
Even though weather made many of the critical days following D-Day generally unfavorable for air operations, the tempo of USAAF activity continued unabated. Swarms of fighters and light and medium bombers covered the invasion area like a blanket, attacking roads, bridges, troop concentrations, ammunition dumps, enemy headquarters, and defended points which were giving the ground forces trouble. Wherever the German moved, he was hit. The beachhead spread inexorably, crossing the Cherbourg peninsula and killing the great port at its head. Emergency landing strips were rushed to completion, shortening by over a hundred miles the distance our fighters had to fly to get into combat, and making possible the evacuation of wounded by air, direct from battlefield to London hospital.
Meanwhile the campaign to knock out airfields (mostly USAAF effort) and railroads (mostly RAF effort) continued at a scale to jar the senses. And everybody swatted bridges. German passage across the Orne is interdicted. It continues interdicted across the Seine. It should soon be interdicted across the Loire, separating the German armies in northern and southern France. And, thanks to the strategic battles of the past, we are still waiting for the GAF to answer the bell for the first round
