Preliminary investigation revealed there was a cur in the fuel supply to the engines of the ill-fated Air India Flight 171 that crashed, killing 260 people on board in June.

India’s Aircraft Accident Investigation Bureau, in a 15-page preliminary report released on Saturday, said the engines of the 12-year-old Boeing 787 Dreamliner suffered total power loss after its fuel-control switches moved to the “cut-off” position.

The Air India fuel-control switches “transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec,” the report said.

Fuel-control switches are usually moved to the “cut-off” position when a plane is landing. However, in the case of the ill-fated Air India Flight, the fuel control switches flipped to the “cut-off” position while the aircraft was airborne.

The report also revealed that the cockpit recorder captured the moment a pilot asked why his colleague “did the cut-off,” and another voice replied that he hadn’t cut off.

“In the cockpit voice recording, one of the pilots is heard asking the other why he cut off. The other pilot responded that he did not do so,” the report said.

The voices in the cockpit recorder have not been identified, while investigations into the plane crash continue.