An interim report by the UK's Air Accidents Investigation Branch (AAIB) said turbulance or engine acceleration could cause the ice to be dislodged and released into the fuel system.
A blockage could then cause the engines to suddenly lose power.
The report said the reduction in thrust from both engines, called "rollback", in the flight from Beijing to London, was the result of a "reduced fuel flow".
The US National Transportation Safety Board said: "With two of these rollback events occurring within a year, we believe that there is a high probability of something similar happening again."
But some experts believe the situation is not as dangerous as it may appear.
David Gleave, an aviation expert, told Al Jazeera: "They've identified this problem, they've come up with a procedure which says to effectively rev the engines.
"Every time you climb, climb at full power to put more heat into the system, and when you descend, just before you descend, warm the engines through so that the oil is warm in the engine, which means that the ice doesn't form into solid lumps," he said.
The AAIB report has recommended the Federal Aviation Administration and the European Aviation Safety Agency introduce redesigns that would prevent ice from causing a restriction to the fuel flow, and conduct research into ice formation in fuel-feed pipes.