LONDON (Reuters) - An ice-related technical fault which caused a Boeing 777 to crash-land on the perimeter of Heathrow Airport two years ago was "unrecognised" by aircraft safety procedures at the time, an accident report said on Tuesday.
The Air Accidents Investigation Branch (AAIB) said the British Airways jet was forced to ditch after it lost power because of an engine fuel-flow blockage.
The pilots managed to bring the arriving plane carrying 152 passengers down safely just short of the runway.
Captain Peter Burkill and co-pilot John Coward were hailed as heroes for narrowly averting a catastrophe. Just 34 passengers and 12 cabin crew suffered minor injuries in the January 2008 crash.
The AAIB said it was probable the fuel restriction to both engines was caused by a build-up of ice in the fuel system. The problem, described as unique, occurred after "sticky" ice crystals formed from water dissolved within the fuel.
"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 official report concluded.
It said that research in the 1950s had identified the problem of ice formation in fuel systems from trapped water molecules but did not identify the dangers of ice release.
The AIB has made 18 safety recommendations as a result.
Burkill, who believed everyone would die when the plane hit the ground, is still traumatised by the event.
"I always think about it -- as well as my wife -- it will probably never leave me," he told BBC television.
"We were in an aircraft on the ground that was sliding uncontrollably and at that point I thought I was going to die, so I said goodbye to my wife."
(Reporting by Stefano Ambrogi; Editing by Steve Addison)
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