"Royal Air Force Bomber Command, 1942-1945." Operation CHASTISE: the attack on the Moehne, Eder and Sorpe Dams by No. 617 Squadron RAF on the night of 16/17 May 1943. No. 617 Squadron practice dropping the 'Upkeep' weapon at Reculver bombing range, Kent. Wing Commander Guy Gibson flies at low level along the shore in Avro Lancaster, ED932/G 'AJ-G', at the end of the practice.