The Air Accident Investigation Branch (AAIB) said in its report that the reduction in fuel flow, resulting from the ice formation, could have caused the engines to lose power less than a minute before touchdown.
The British Airways Boeing 777 flight BA038 crashed some 1000 feet short of the runway on Jan. 17 after it lost the power in both engines just before touch down.
The 136 passengers and 16 crewmembers on board were evacuated from the plane on emergency slides. Nineteen people suffered minor injuries in the accident.
The AAIB report said the incident was unique and added that the investigators have not yet been able to pin-point on how the ice could have formed inside the plane's fuel system. The report added that the investigation would continue.
"Extensive data analysis has revealed that not only has there never been a previous occurrence of this type on the Boeing 777, but also that this is the first known occurrence of this nature in any large modern transport aircraft," it said.
The report ruled out problems with the amount or quality of the fuel and cleared the crew of any wrong-doing in the incident.
