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| Version 1 | Version 2 |
|---|---|
| Ice 'probable cause' of BA crash | Ice 'probable cause' of BA crash |
| (18 minutes later) | |
| The fault which caused a plane to crash land at Heathrow Airport was not covered by plane safety requirements at the time, an official report has said. | The fault which caused a plane to crash land at Heathrow Airport was not covered by plane safety requirements at the time, an official report has said. |
| The British Airways (BA) Boeing 777 lost power to both engines due to restricted fuel flow, the Air Accidents Investigation Branch (AAIB) said. | The British Airways (BA) Boeing 777 lost power to both engines due to restricted fuel flow, the Air Accidents Investigation Branch (AAIB) said. |
| It said the crash, on 18 January 2008, was probably caused by a build-up of ice in the fuel system. | It said the crash, on 18 January 2008, was probably caused by a build-up of ice in the fuel system. |
| None of the 152 people on board the aircraft was seriously injured. | None of the 152 people on board the aircraft was seriously injured. |
| The report said it was probable ice had formed within the fuel system from water that occurred naturally in the fuel. | The report said it was probable ice had formed within the fuel system from water that occurred naturally in the fuel. |
| 'Unrecognised risk' | 'Unrecognised risk' |
| It added that when fuel temperatures were at a "sticky range", ice crystals were most likely to stick to their surroundings. | It added that when fuel temperatures were at a "sticky range", ice crystals were most likely to stick to their surroundings. |
| The AAIB report said: "Certification requirements, with which the aircraft and engine fuel system had to comply, did not take account of this phenomenon as the risk was unrecognised at that time." | The AAIB report said: "Certification requirements, with which the aircraft and engine fuel system had to comply, did not take account of this phenomenon as the risk was unrecognised at that time." |
| Flight Captain Peter Burkill: "I thought I was going to die" | |
| The report added that research in the 1950s had identified the problem of ice formation in fuel systems from dissolved or trapped water, but it did not identify that it was possible for accumulated ice to restrict fuel flow. | The report added that research in the 1950s had identified the problem of ice formation in fuel systems from dissolved or trapped water, but it did not identify that it was possible for accumulated ice to restrict fuel flow. |
| The AAIB concluded that an engine component, called the fuel oil heat exchanger, on the crashed Boeing was likely to stop working in a combination of soft ice and with a fuel temperature below -10C (14F). | The AAIB concluded that an engine component, called the fuel oil heat exchanger, on the crashed Boeing was likely to stop working in a combination of soft ice and with a fuel temperature below -10C (14F). |
| The report added there were no published guidelines or tests on the susceptibility of a fuel system to ice. | The report added there were no published guidelines or tests on the susceptibility of a fuel system to ice. |
| Having lost power, the BA plane, arriving from Beijing, came down within the airfield boundary at Heathrow, but 330m (1,080ft) short of the paved runway, sliding 372m (1,220ft) before coming to rest. | |
| Everyone was safely evacuated from the aircraft, with one passenger breaking a leg. | Everyone was safely evacuated from the aircraft, with one passenger breaking a leg. |
| Mayday call | Mayday call |
| The report said the cabin crew, led by Captain Peter Burkill, had become aware of a possible engine thrust problem just 43 seconds from touchdown. | The report said the cabin crew, led by Captain Peter Burkill, had become aware of a possible engine thrust problem just 43 seconds from touchdown. |
| Losing speed, the crew tried to increase engine thrust but there was no response from the engines. | Losing speed, the crew tried to increase engine thrust but there was no response from the engines. |
| A mayday call put out three seconds before touchdown. | A mayday call put out three seconds before touchdown. |
| There was insufficient time for the flight crew to brief the cabin crew or issue a command for passengers to brace themselves, the report said. | There was insufficient time for the flight crew to brief the cabin crew or issue a command for passengers to brace themselves, the report said. |
| The AAIB said some passengers attempted to retrieve personal items during the evacuation. | The AAIB said some passengers attempted to retrieve personal items during the evacuation. |
| On 28 November 28 2008 a Delta Airlines Boeing 777 suffered a similar ice problem while flying over the USA, which prompted an investigation by America's National Transportation Safety Board, with the AAIB having an accredited representative. | On 28 November 28 2008 a Delta Airlines Boeing 777 suffered a similar ice problem while flying over the USA, which prompted an investigation by America's National Transportation Safety Board, with the AAIB having an accredited representative. |
| The AAIB has made 18 safety recommendations following the two incidents | The AAIB has made 18 safety recommendations following the two incidents |
| Boeing and Rolls-Royce, which makes aircraft engines, said they had taken steps to prevent the ice phenomenon from recurring. | Boeing and Rolls-Royce, which makes aircraft engines, said they had taken steps to prevent the ice phenomenon from recurring. |
| The AAIB has now made nine further safety recommendations, including some which address plane "crashworthiness", which test the ability of an aircraft to withstand an accident. | The AAIB has now made nine further safety recommendations, including some which address plane "crashworthiness", which test the ability of an aircraft to withstand an accident. |
| FUEL ICING PROBLEMS ON BOEING 777 FUEL ICING PROBLEM | FUEL ICING PROBLEMS ON BOEING 777 FUEL ICING PROBLEM |
| 117,340 litres of fuel carried in tanks in both wings and main fuselage Water occurring naturally in the fuel can freeze during "long-cold-high" flights Fuel/oil heat exchanger through which fuel passes on its way to engines failed to melt ice leading to build-up and blockage RECOMMENDED REMEDIES | 117,340 litres of fuel carried in tanks in both wings and main fuselage Water occurring naturally in the fuel can freeze during "long-cold-high" flights Fuel/oil heat exchanger through which fuel passes on its way to engines failed to melt ice leading to build-up and blockage RECOMMENDED REMEDIES |
| In flight where fuel temperature falls below -10C pilots should make periodic climbs to a higher altitude at full throttle | In flight where fuel temperature falls below -10C pilots should make periodic climbs to a higher altitude at full throttle |
| If aircraft has remained at the same altitude for more than two hours prior to descending to land, and fuel temperature is below -10C, the pilot must "advance the throttle to maximum for 10 seconds" to clear any ice in the fuel system Source: Boeing/National Transport Safety Board | If aircraft has remained at the same altitude for more than two hours prior to descending to land, and fuel temperature is below -10C, the pilot must "advance the throttle to maximum for 10 seconds" to clear any ice in the fuel system Source: Boeing/National Transport Safety Board |