Even as the initial report is eagerly awaited by the public and the aviation industry all over the world—considering the limited official information available about the probable causes of the tragic accident and the angles being pursued—it is not clear how detailed the report itself would be at this stage.

The Boeing 787-8 Dreamliner had crashed minutes after takeoff last month, killing all but one passenger and more than a dozen people on the ground.

A preliminary report into the deadly crash of an Air India jetliner in June is expected to be released by Friday, three sources with knowledge of the matter said, with one adding the probe had narrowed its focus to the movement of the plane's fuel control switches.