LancasterED915 AJ-Q during Chastise op. preparations over Derwent Reservoir. Pilot F/L J.C. McCarthy; Flight Engineer Sgt W.G. Radcliffe; Navigator P/O D.A. MacLean; Wireless Operator F/S L. Eaton; Bomb Aimer Sgt G.L. Johnson; Front Gunner Sgt R. Batson;