A preliminary report by Indian aviation accident investigators said on Saturday the fatal Air India crash that killed 260 people in Ahmedabad last month showed the plane engines fuel cutoff switches shifting from cutoff to run within seconds of each other.

A focus on the Boeing 787’s fuel switches in a preliminary assessment raised questions about the pilots’ actions, but much is still unknown about Flight 171.

The two engines on the Air India flight shut down within one second of each other before the Boeing 787 Dreamliner crashed last month in Ahmedabad, India, killing at least 260 people, according to a preliminary report released Friday.