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Fuel 'air bubbles' caused crash
Anna Davis, Evening Standard19 Feb 2008
Air bubbles in the fuel of a British Airways Boeing 777 could have caused it to crash land at Heathrow, according to investigators.
It comes as the evacuation procedure used after the plane crashed last month was criticised for causing a dangerous fuel leak that could have proved fatal.
The Air Accidents Investigation Branch has focussed on the plane's high-pressure fuel pumps, after a study found they were damaged. It has ruled out frozen or contaminated fuel, computer failure, or birds causing the flight from Beijing to lose power and land 1,000 ft short of the runway.
The report stated: "Detailed examination of ... fuel pumps revealed signs of abnormal cavitation (air bubbles) on the pressure-side bearings and the outlet ports. This could be indicative of either a restriction in the fuel supply to the pumps or excessive aeration of the fuel." Air in the fuel would have prevented the pumps from working properly. That could have led to inadequate fuel reaching the engines, which failed to provide the thrust needed to land.
The AAIB also stated that a large amount of fuel leaked from the plane as the 136 passengers and 16 crew were escaping. Investigators suggested the pilots failed to close the fuel supply valves before operating the switch that triggered fire extinguishers in the engines. Power to the system controlling the valves was cut off, which prevented them from closing. The AAIB has issued a reminder to BA pilots to follow the correct drill.
The AAIB has not pinpointed the exact cause of the crash, and cannot guarantee it will not happen again. The world fleet of 600 Boeing 777s has not been grounded because the risk of recurrence is so small.
Reader views (3)
It would seem sensible to link the fuel supply cut off and the fire extinguishers together on the same switch. Rather than leave it to aircrew under the extreme stress of a crashed plane.
- Rebeccah, London, 19/02/2008 15:48
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I blame gravity.
- Pat, The Hague , Netherlands, 19/02/2008 13:20
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Fizzy fuel , whatever next!
- Brian, Wiltshire, 19/02/2008 12:32
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