The head of the U.S. Federal Aviation Administration (FAA) said on Thursday the fatal crash last month of an Air India Boeing 787 jet does not appear to have been caused by a mechanical issue or inadvertent movement of the fuel control unit or switches.

Air India said on Tuesday it has completed precautionary inspections of the fuel control switch locking mechanism on all its Boeing 787 and 737 aircraft, with no issues detected. The probe into the Air India crash that killed 241 of the 242 people on board and 19 on the ground is focused on the fuel control switches of the Boeing 787 jetliner,

Says FAA teams have thoroughly examined the units, removed components for testing and conducted detailed inspections on other aircraft of the same type.