http://news.bbc.co.uk/1/hi/uk/7941137.stm
Experts have warned there is a "high probability" that a fault which caused a British Airways jet to crash-land at Heathrow could hit other Boeing 777s.
US air accident investigators called for a component to be redesigned after a Delta Air Lines plane reportedly encountered a similar problem.
Manufacturers Rolls-Royce say the new part should be ready within the year.
It comes after tests proved a build-up of ice in the engine was the most likely cause of the Heathrow crash.
The Boeing 777, with 152 people on board, crashed in January 2008, causing one serious injury.
The captain and co-pilot were praised for averting a major disaster.
Power loss
On Thursday, a second interim report from the UK's Air Accidents Investigation Branch said that, during the flight from Beijing, ice may have developed in the fuel pipes.
Then shortly before landing, owing to factors such as turbulence or engine acceleration, a large amount of ice may have been dislodged and suddenly released into the fuel system, causing a fuel blockage.
Ten months later, it is understood a Delta Air Lines Boeing 777 was affected by a similar problem, known in the industry as an engine rollback or sudden power loss.
The plane experienced a single engine rollback while cruising over Montana while en route from Shanghai to Atlanta.
With two of these rollback events occurring within a year, we believe that there is a high probability of something happening again
US official Mark Rosenker
Tests support BA crash ice theory
The National Transportation Safety Board (NTSB) in the US said this was because there had been a build-up of ice, from water normally present in all jet fuel, on a component known as the fuel/oil heat exchanger (FOHE). This had restricted the flow of fuel to the engine.
It has now issued an "urgent safety recommendation", calling for a redesign of the FOHE to eliminate the potential for ice build-up.
Mark Rosenker, acting chairman of the NTSB, said: "With two of these rollback events occurring within a year, we believe that there is a high probability of something happening again."
Rolls-Royce has said a new version of the component was already being developed and it should be ready within 12 months.
A Rolls-Royce spokesperson said there had been no issues with its equipment, adding that ice build-up in commercial "long-cold-high" routes was an industry-wide issue.
New guidelines
There are currently 220 Boeing 777s, with Rolls-Royce Trent 800 engines, in operation. The planes are used by 11 airlines and British Airways owns 15.
Aviation expert David Gleave said he would have no concerns about flying on a Boeing 777 as new "operating procedures", such as boosting the engine on approach to landing to keep the heat up, had been implemented.
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"All the regulatory authorities are satisfied the new procedures which they will adopt or already have adopted will cure the problem as a temporary measure," he told BBC Radio 4's Today programme.
"Then new components will be fitted in time which will remove the need for the new operation procedure."
A Boeing spokeswoman said it had issued a set of guidelines for pilots to prevent long-term build-up of ice and these procedures had been approved by the regulatory bodies.
But the NTSB report said: "While the procedures may reduce the risk of a rollback in one or both engines due to ice blockage, they add complexity to flight crew operations, and the level of risk reduction is not well established."
An AAIB spokesman said it had not called for the planes to be grounded and neither had its US counterpart.
It joined the NTSB in recommending that Rolls-Royce should develop changes which prevent ice from causing restriction to the fuel flow.
"Operators have put in place procedures to prevent this causing another safety incident," the spokesman added.