The heroic engine repair shown in the movie was based on an actual event. A Royal New Zealand Air Force pilot, Sergeant James Allen Ward, earned the Victoria Cross after he climbed onto the wing of his airplane on 7 July 1941 to smother the burning engine.
Filming of Royal Air Force Fortress Is (equivalent to USAAF B-17C Flying Fortresses) of 90 Squadron was done at RAF Polebrook, Northamptonshire, around September 1941. These early models were not really combat ready and had been provided by the U.S. for training purposes, but lacking anything else, the RAF pressed them into action with predictably poor results.
This film had its U. S. television premiere in Tucson Sunday 16 September 1956 on KDWI (Channel 9); it first aired in Cincinnati Saturday 13 October 1956 on WKRC (Channel 12), and in Portland OR Wednesday 16 January 1957 on KLOR (Channel 12); these telecasts were the severely shortened USA version; it finally found its way to cable TV when it was offered by Turner Classic Movies on 24 September 2007 during their festival of films made by Warner Brothers at Teddington Studios in the UK.