Aviation experts say that the Gatwick-bound Boeing that crashed in India carrying 242 passengers, including 53 Britons, may have suddenly lost power 'at the most critical phase of flight' after takeoff.

The possible causes are believed to include a rapid change in wind, bird strike or weather, with an investigation yet to uncover what caused Flight 171 to crash shortly after departing Ahmedabad Airport in Gujarat this morning.

Video showed the plane rapidly descending into a residential area with a high nose angle and landing gear deployed before it crashed. The number of fatalities is not yet known but rescuers said at least 30 bodies have so far been recovered from a building.

Lt. Col. John R. Davidson (Ret.), former U.S. Air Force pilot and editor of Felons Assistance and commercial aviation safety consultant, said that, based on preliminary flight tracking data, the plane appeared to have reached takeoff speed but not altitude, suggesting 'either a very late rotation or a stall shortly after takeoff'.

'There are a number of possible scenarios: thrust or engine performance issues, excessive aircraft weight, poor trim or flap configuration, or a more critical failure that affected the aircraft's ability to climb,' he said.