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 Air India airliner carrying 230 passengers and 12 crew members was on its way to the United Kingdom when it crashed into a building shortly after takeoff on June 12, killing all aboard, except for one survivor, and several people on the ground, according to authorities.

The preliminary report from investigators probing the Air India crash that killed 260 people showed that seconds after takeoff, the Boeing 787 plane's engine fuel control switches were switched off briefly,