The Bombardment of Mailly-le-Camp was an RAF raid against a German panzer training center located in northern France undertaken during the night of 3/4 May 1944. The mission was a part of the "softening up" campaign Bomber Command conducted prior to the D-Day invasion. The operation was assigned to No. 5 Group, which was joined by No. 1 Group. Estimated a lightly defended target, confusion in the mission plan and communication problems led to the force being held up at the assembly point, where German night fighters slipped in among the bombers. Though the bombers succeeded in destroying the training camp, the victory was achieved at a heavy price.
Planning.
Mailly chosen as target.
The military base at Mailly was just north of the community of Mailly-le-Camp, 80 miles east of Paris along the national road linking Châlons-sur-Marne to Troyes. It was built in 1902 as a barracks and training ground for the French army. In the 1930s it was used for their armoured formations, but since the fall of France it had been taken over by the Germans and used to train replacement crews for panzer units refitting from losses suffered in the east. In the autumn of 1943 requests to monitor the installation were sent to l'Armée Secrète. The organization's Brutus-Nord network was given the assignment of producing detailed plans of the panzer training grounds, and for providing a regularly updated inventory of the German units present.`In the spring of 1944 the group reported the arrival of elements of the 21st Panzer Division.
In April 1944 Bomber Command shifted its bombing campaign from German industrial centers to the destruction of the Wehrmacht's infrastructure in occupied Europe. The new directive was known as the Transport Plan, and was in preparation and support for the D-Day landings. On 2 May Intelligence sent the Mailly target to the Chiefs of Staff Committee, which in turn issued the request to destroy the camp at Mailly to Bomber Command. Bomber Command chief Arthur Harris assigned the mission to Ralph Cochrane and 5 Group.
5 Group Op.
5 Group had developed a low level marking technique that was very accurate. Since proving it to Harris a week earlier in a raid against the railyards at Munich, 5 Group had been given a measure of autonomy from the rest of Bomber Command. Harris had provided four Mosquitos to 617 Squadron to effect their low level marking. In addition, he transferred 627 Squadron (Mosquitos) from the Pathfinder Force, along with the Lancaster formations 83 Squadron and 97 Squadron. With the transfers, 5 Group had its own small marking force.
The mission was run the 5 Group way. Unlike a mission guided by the Pathfinder Force, there would be no Master Bomber. The 5 Group method used a Marker Leader who was in charge of marking the target, and a Main Force Controller in charge of the bombing force. In this case, Leonard Cheshire was the Marker Leader, who would make a low level marking of the target from his Mosquito. To support him were the three other Mosquitos of 617 Squadron, but the Lancasters of 617 Squadron were assigned a practice flight for a deception mission involving the delivery of Window at low level. In their place the aircraft backing up Cheshire's target markers were Lancasters from 83 and 97 squadrons, the PFF squadrons newly arrived to 5 Group. In addition, a number of Oboe equipped Mosquitos were assigned to the mission from the Pathfinder Force to drop shielded illumination flares over Mailly, and the yellow marker flares over the assembly point. The Main Force Controller was wing commander Laurence Deane, the CO of 83 Squadron. He was backed up by his Deputy Controller, squadron leader Neville "Ned" Sparks.
The planners hoped to catch the 21st Panzer Division in their barracks. As curfew for troops on the continent was midnight, Cheshire was to drop his target marking flares at 12:01, one minute after soldiers were required to return to barracks. Seeking to gain greater punch, Cochrane called upon Air Vice-Marshal Edward Rice, the CO of 1 Group, and asked him to join his force with Cochrane's for the mission. Like Cochrane, Rice wanted his group to operate independent of the Pathfinder Force, and was developing his own marker force. The unit of 6 Lancasters was called the Special Duty Flight. Cochrane stated that both groups would hit the depot buildings, but enticed Rice by noting the base had a tank repair facility that was a special target. The target could be destroyed by the aircraft of a couple squadrons, and could be marked by Rice's Special Duty Flight.
Cheshire had worked out his marking technique with 617 Squadron, with Cheshire or Martin marking, while the rest of the squadron waited to hear from him before coming over the target one at a time at altitude.
The seeds for disaster were sown with 5 Group's hasty preparation, the lack of a clear understanding of the mission in the minds of the various flight leaders, a lack of familiarity with Cheshire's method, and problems that developed in radio communication that were not apparent until the Main Force Controller was over the target.
Throughout the bombing campaign against Germany, Bomber Command aircraft had used HF for Radio Transmission on those occasions when radio silence was broken. The primary use was for the PFF Master Bomber to guide in the Main Force bombers during an attack. These were one-way conversations, and radio discipline was maintained. Cochrane had learned that Fighter Command had switched to VHF as it gave a clearer transmission of voice between aircraft. Never one to allow a technical advance to pass by him, Cochrane converted 5 Group to VHF as well. It was the belief of 5 Group planners that 1 Group was still using HF, so it was decided that Deane would transmit his orders to the bombing force by Wireless Transmission in Morse. Ironically, unbeknownst to Cochrane, Rice had followed his lead and converted 1 Group to VHF. Worse, a Wireless Operator was not a part of the crew in the Mosquito. Cheshire would not be able to communicate to the Main Force by wireless.
Mission plan.
With only a day to prepare, 5 Group planners were very busy setting out all that needed to be accomplished before the aircraft took off for their targets. The plans for the mission were hurriedly put together. A route to target was picked, fuel requirements calculated, bombing heights set and bomb loads worked out.
The route took the bombers south from Lincolnshire, climbing as they crossed over England and turning southwest over Reading. Continuing on they would reach Beachy Head, where they would head out over the Channel. Continuing to climb, they would reach 12,000 feet before arriving over the French coast, crossing it north of Dieppe. Here they would turn slightly to the north, and make their 156-mile trek across northern France, losing altitude along the way, to reach the assembly point 15 miles north of Mailly-le-Camp. The location would be marked with yellow flares by Oboe equipped Mosquitos from the Pathfinder Force. From the assembly point the bombers would fly due south to the target, drop their bombs on the markers present and exit to the south. Continuing on for ten miles, they would reach Troyes. Here they would make a 90 degree turn to the west and head toward Fontainebleau. At Fontainebleau their course would bend slightly to the north, passing by Chartres on the way to a pinpoint near Flers. There they would make a second 90 degree turn, coming north to Bayeux 20 miles northwest of Caen, heading back across the Channel for Selsey Bill and England.
The bombing of the target could not be completed in the normal fashion for two main reasons. First, there was a French village nearby. Casualties among French civilians were to be kept to a minimum. It was decided to use a low bombing altitude to improve accuracy and avoid casualties among the French. Secondly, the marker aircraft would be using Cheshire's low level marking technique. For every thousand pounds of HE in a bomb, a heavy bomber had to have a thousand feet of clearance above the blast to avoid being knocked down by it. It was worse for a Mosquito. A Mosquito at 5,000 feet or less was unlikely to survive the bomb blast of a 4,000 pound cookie going off below it. The initial laying down of markers was not a problem, but if a second aiming point was needed mid-mission, the bombing would have to be halted while the new markers were being laid on if the marker crews were to survive their mission.
Bomb loads were set at one 4,000-pound "cookie", with 15 or 16 500 pound HE bombs, depending on the distance of the plane's field to the target. Though incendiaries usually made up 50% of the bomb load against a German city, no incendiaries were used on this raid. In addition, though a normal bombing mission over Germany would be flown at 18,000 to 21,000 feet, the raid to Mailly would be flown much lower. Bombing height would be from 6,000 to 8,000 feet to minimize scatter and improve accuracy. The low altitude of the bombers would place them in range of light flak, but the lowest aircraft would still be 2,000 feet above the height of the bomb blast shock delivered by the "cookies".
The mission was to unfold as follows: just before midnight Mosquitos from PFF were to drop shielded illumination flares over Mailly-le-Camp, using Oboe to confirm their location. Time on target was 12:01, when Cheshire would mark the east end of the camp. He had 6 minutes to check and reset these markers. If satisfied he would signal the Main Force Controller, Laurence Deane. Deane would call in the 173 Lancasters of 5 Group to bomb with the signal "Rat One, bomb". Over the next 6 minutes they would drop their loads upon the east end markers. After the first wave of bombers had passed over the target the bombing would be halted, while Cheshire used the next 9 minutes to return over Mailly and mark the west end of the camp. Now at 12:20, the marker aircraft would get out of the way and the second wave of 140 Lancasters from 1 Group would be called in with the signal "Rat Two, bomb". Over the next 6 minutes they would drop their bomb loads over the target. By 12:26 all aircraft would be out of the target area.
An assembly point was set up 15 miles north of Mailly near Germinon. Three 627 Squadron Mosquitos were assigned to keep the assembly point marked by yellow target indicator flares. As aircraft arrived they would make large left hand circles there until they received word that the target was accurately marked, so they could begin their bomb runs.
Being a target in France, little resistance was expected. The Met prediction was for clear skies and a 3/4 moon. One Commanding Officer said it would be like falling off a log. "Just go in, wipe it off the map and come home." The mission was expected to be the proverbial "piece of cake." Said wireless operator Ron Story of 166 Squadron "We were to bomb from 8,000 feet. On reaching the assembly point, we were to circle the avenue of flames, and await the instructions from the Master Bomber who would give the go ahead to head for the target and bomb precisely on the markers. It all sounded so simple, and we were in such good spirits."
Though the target itself would not be heavily defended by Flak placements, a problem lay in the fact that four German night fighter airbases were within easy reach of the assembly point: III/NJG-1 at Athies-sous-Laon, I/NJG-4 at Florennes, II/NJG-4 at Coulommiers, III/NJG-4 at Athies, plus III/NJG-5 and I/NJG-5 at St. Dizier. Of the 92 aircraft on inventory for these units, approximately 60 could be expected to be serviceable at any one time. In reviewing the mission, author and former RAF bomber pilot Jack Currie noted "That a planning staff could contemplate, or a commander countenance, any plan of action in which a possibility existed - even a remote one - of several hundred fully-laden Lancasters orbiting a marker, in bright moonlight, within striking range of at least four