Further training continued, while 617s long term future was discussed in high places. At the end of August the Dambusters left Scampton for their new home at RAF Coningsby, this was a more suitable bomber base having concrete runways as opposed to Scamptons grass. At this time their standard Lancasters were given a new code, KC while the remaining Type 464 (P) aircraft retained their AJ code. The Dortmund-Ems canal was a vitally important waterway which despite being subjected to repeated attacks since mid 1940 was still in constant use. A plan to use the ‘Upkeep’mine, bouncing over land and dropping into the canal had been shelved, so when No617 Squadron was detailed to attack this target they received another new weapon. Each aircraft would carry a single 12,000 lb High Capacity bomb, codenamed ‘Blockbuster’. On September 14th, eight Lancaster led by Holden, accompanied by six Mosquitos of 605 and 418 squadron as fighter cover set off. However at 00:38 hrs No 5 Group sent a recall message, as weather conditions had severely deteriorated over the target. As they turned for home, dams veteran Dave Maltby’s Lancaster was seen to hit the water and explode, there were no survivors. The following night they tried again, with the six Mosquitos as cover and the same aircraft, but with dams veteran Mick Martin taking Maltby’s place. After crossing into Germany they were cloaked in thick fog. Near the target they were engaged by flak, Holden was hit and his fuel tanks exploded. The plane crashed onto a farm, a few minutes later the bomb ‘cooked off’ flattening the farmhouse and killing an occupant. Among the dead on Holden’s plane were 4 of Gibson’s dams crew and one of Bill Townsend’s, it was also George Holden’s 30th birthday. Mick Martin assumed command and he along with Plt Off Wilson, and dams veteran Les Knight began flying box circuits looking for a break in the fog and a view of the target. Wilson’s aircraft took heavy flak and crashed killing all on board. Minutes later Knight was hit, having jettisoned his bomb he tried to make it home. Despite the crew jettisoning everything not fixed down, Knight realised they would not make it, he ordered his crew to bail out, as the last one jumped the aircraft rolled over and crashed, Knight still at the controls died instantly. Martin meanwhile having been over the target for 84 minutes finally caught a break in the murk and dropped his bomb, but the canal was not damaged. The second group now arrived led by Allsebrook, he dropped his bomb some way from the aim point after running into heavy flak, his port wing disintegrated and the bomber clipped a house and a canal side crane before crashing into the canal. When dropped, his ‘Blockbuster’ failed to explode, for the second time the Germans had a new weapon to exam after only it’s first use. Geoff Rice and Bill Dival jettisoned their bombs and headed for home, but Divall’s aircraft was hit and the fuel tanks exploded, the aircraft crashed with no survivors. This left only Dave Shannon, after circling for 45 minutes he caught a quick sight of the target and released his bomb which exploded on the towpath A few feet to one side and the canal would have been breached. While the escorting Mosquitos all returned safe, having encountered no fighter defence, 617 squadron had paid a high price with only three of the eight aircraft that set out returning to Coningsby. The first Dortmund-Ems operation was a disaster, the target was largely undamaged and, including Maltby the night before, two thirds of the crews had been lost. After only a handful of operations No 617 Squadron had lost it’s new C/O, four Flight Leaders and eight more crews. It was no surprise, therefore, when word started to spread that No617 was a ‘suicide squadron’.