"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. Third launch sequence (1): Flight Lieutenant J L Munro in Avro Lancaster ED921/G drops his bomb from below 60 feet.