 The BOAC DC-3 "Ibis" had been operating on a scheduled Lisbon–Whitchurch route throughout 1942–43 that did not pass over what would commonly be referred to as a war zone.By 1942, however, the Germans considered the region an "extremely sensitive war zone".On two occasions, 15 November 1942 and 19 April 1943, the camouflaged airliner had been attacked by Messerschmitt Bf 110 fighters (a single aircraft and six Bf 110s, respectively) whilst "en route"; each time, the pilots escaped via evasive tactics.