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.

Both 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.

Errors made by two Air India pilots before the plane’s fatal crash will reportedly be the focus of an investigation into the tragedy. All but one of 242 people board the Boeing 787 Dreamliner died when the aircraft plunged into a medical student hostel in a built-up suburb last month, less than a minute after take-off from Ahmedabad airport.