The worst outcome from an air accident investigation is the conclusion that “we just don’t know”. Because, if we don’t know, there is no corrective action to be taken, and therefore the accident as investigated may happen again. So it is with the investigation – just published by the Air Accidents Investigations Branch (AAIB) - into the sudden loss of power aboard a British Airways Boeing 777 on approach to London’s Heathrow airport two years ago.
The flight, which had originated in Beijing, had been otherwise uneventful, until both engines failed to respond to an autothrottle command for power just over 700 feet above ground. Having lost power, the aircraft struck the ground 330 metres short of the paved surface of Runway 27 Left, with consequent damage to the aircraft and several minor injuries to passengers. Fortunately the aircraft cleared the airport’s perimeter fence, and, more significantly, the road just outside it.
It seems that the loss of power may have been due to a build up of ice in the fuel system. But that conclusion is not wholly certain, and in any case, thousands of aircraft fly routinely at similarly high altitude, without any apparent problem. Thus it comes down to the type of aircraft: there has been a similar problem affecting another 777, this one operated by US carrier Delta.
Boeing have taken steps to prevent a recurrence, and it is to be hoped that this will be the last we hear of the problem. And it would be reassuring to know that there would be no knock-on effect on the fuel systems of Boeing’s new hope, the 787 “Dreamliner”.