An Air Accidents Investigation Branch (AAIB) report has found that an ice-related technical fault was behind the 2008 British Airways crash-landing on the border of Heathrow Airport.
The AAIB report said the fault was unrecognised by aircraft safety procedures at the time.
In January 2008, the pilot of the Boeing 777 jet was forced to crash-land the aircraft after it lost power due to an engine fuel-flow blockage.
The report said the fuel supply to both engines was restricted due to formation of ice crystals from water dissolved within the fuel.
The crash-landing caused minor injuries to 34 passengers and 12 cabin crew of the aircraft, which was carrying a total of 152 passengers.