A preliminary report released last week included detail about the fuel, saying that the fuel to the plane's engines appeared to have been shut off.

Air India completed a fuel control switch inspection on Boeing 787 planes with no issues, amid scrutiny following a deadly crash. India and South Korea ordered airlines to investigate fuel switches, as a preliminary report found switches flipped causing a fatal incident,

The U.S. assessment is not contained in a formal document, said a source, who emphasized the cause of the deadly crash remains under investigation.