The pilot of the plane that crashed at Essendon Airport killing himself and four passengers on Tuesday was the subject of an ongoing investigation by the Australian Transport Safety Bureau that had been deferred on three separate occasions.

Max Quartermain, the 63-year-old owner and pilot for charter company Corporate and Leisure Aviation faced referral to the Civil Aviation Safety Authority and possible suspension of his aviation licence over a "near collision" with another plane on Mount Hotham in September 2015.

Read more here.