The CEO of Air India sought to draw a line under rife speculation around the cause of last month's air disaster in Ahmedebad, saying the preliminary investigation had ruled out a mechanical cause for the crash.

An official report on the world’s deadliest aviation accident in a decade, seen by CNN, has answered one key question – but raised others.

CEO Campbell Wilson said in an internal memo that the airline is open to further inquiries and warned against "premature conclusions."