It said that the crash was probably caused by a build up of ice in the fuel system. The ice is said to have formed within the fuel system from water that occurred naturally in the fuel when a particular temperature range would cause the ice crystals to stick.
The report states that “Certification requirements, with which the aircraft and engine fuel system had to comply, did not take account of this phenomenon as this risk was unrecognised at that time”
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.
Fortunately there were no fatalities as a result of the accident; however one passenger did suffer a broken leg. It may be difficult for them to make a successful claim for personal injury against the manufacturer however, as it seems clear from this report that the airplane conformed to the safety requirements at the time. It seems likely that a court would take in to account that the safety requirements imposed on the manufacturer at the time of the accident were met and would find it difficult to reach a verdict that the manufacturer was liable.
The AAIB has made 18 safety recommendations following the this incidents, and another involving a Delta Airlines Boeing 777 which suffered a similar problem, and Boeing and Rolls-Royce, which makes aircraft engines, say they have taken steps to prevent the ice problem from recurring.