The investigation into last month’s Air India crash is focusing on the actions of the jet’s pilots and doesn’t so far point to a problem with the Boeing 787 Dreamliner, according to people familiar with U.

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.