Preliminary investigations into yesterday’s crash of a British Airways Boeing 777-200ER at London Heathrow have discovered that, on the final approach, the engines did not respond to demands for increased thrust.
An initial statement from the UK Air Accidents Investigation Branch says that the aircraft, arriving from Beijing, was 2nm from touchdown at a height of 600ft, with the autopilot and auto-throttle engaged, when the auto-throttle demanded higher thrust from the two Rolls-Royce Trent 800 engines.
But the AAIB says the powerplants “did not respond” to the auto-throttle request, adding: “Following further demands for increased thrust from the auto-throttle, and subsequently the flight crew moving the throttle levers, the engines similarly failed to respond.”
As a result the 777’s airspeed reduced and the aircraft lost height, touching down 1,000ft (300m) short of runway 27L, to which it had been conducting an instrument landing system approach.
“The investigation is now focussed on more detailed analysis of the flight recorder information, collecting further recorded information from various system modules and examining the range of aircraft systems that could influence engine operation,” says the AAIB.
Information on the final stages of the flight has been downloaded from both the cockpit-voice recorder and the flight-data recorder. The AAIB’s investigation is being assisted by the US National Transportation Safety Board, Boeing, the US FAA and engine manufacturer Rolls-Royce. It expects to release an interim report on the accident within a month.
Source: flightglobal.com's premium news site Air Transport Intelligence news