Cause
The causes of the crash have always been a mystery, although there has never been any suggestion of enemy action or sabotage. The crash took place at 10:15 in the morning in fine weather, in what the Melbourne Herald called "ideal flying conditions".
James Fairbairn had served in the Royal Flying Corps during World War I and still enjoyed flying. It has always been suspected that he may have persuaded the RAAF crew to allow him to fly the plane into Canberra.
More recently the RAAF Historian C. D. Coulthard-Clark, in his book The Third Brother, called into question the flying ability of the pilot-in-command, FLTLT Hitchcock. An account of his comments appears in the book Air Crash vol. 2 by noted Australian aviation writer Macarthur Job (Aerospace Publications, Canberra 1992).
Read more about this topic: 1940 Canberra Air Disaster