A year after Air India crash killed 260: Do we know what happened?

Friday marks one year since a deadly Air India Boeing crash , which killed 260 people in a densely populated suburb of the city of Ahmedabad in India’s western state of Gujarat.

Families of those killed gathered at the site on Friday to mark the anniversary of the disaster, but they are still waiting for answers about what caused the plane to come down shortly after takeoff from the nearby airport.

Indian authorities are expected to issue an interim report in the coming days, another source of frustration for the victims’ relatives, who had been hoping for a definitive finding and a final disclosure. Media reports, citing unnamed sources, suggest that Indian investigators will delay issuing a final report into the crash, citing the need to complete an analysis of the plane’s engines.

Under international aviation rules, a final report is due “if possible” within a year of an accident. If an investigation goes on for longer, an interim statement should be issued on each anniversary.

Flight AI171, an Air India Boeing 787 Dreamliner plane which had taken off only moments before, en route to London Gatwick, crashed into a medical college hostel in the residential area of Meghani Nagar, close to the international airport on the edge of India’s western city of Ahmedabad.

According to flight tracking website Flightradar24, the plane’s final signal was received seconds after takeoff at 1:38pm local time (08:08 GMT). It had reached an altitude of 625 feet (190 metres) before crashing back to the ground outside the airport.

The plane had issued a mayday alert to air traffic control just before all communications from the aircraft ceased.

Of the 242 people on board, all except one passenger were killed. These included 169 Indian nationals and 52 British nationals. A total of 260 people died, as 19 people on the ground close to the crash site were also killed. Another 67 people near the site were injured.