Here's what is known about the air crash so far: One of the strongest pieces of evidence that investigators are reviewing is a 59-second CCTV video clip that clearly shows the takeoff and the crash of the plane from Sardar Vallabhbhai Patel International Airport in Ahmedabad city, western Gujarat state.

The deadly crash of an Air India flight carrying more than 240 people on Thursday arrives after years of efforts to turn around the country’s flag carrier — which had been plagued by tragedy and financial losses under prior state ownership.

Management installed by the Tata Group had spent three years struggling to undo a reputation for shoddy operations earned during decades of state ownership.