Federal regulators propose requiring modifications to the engines of some Boeing 777 jets to prevent ice from forming in fuel lines during long flights, a problem blamed for the crash of a British Airways plane last year.
The work would have to be completed by January 2011.
The Federal Aviation Administration proposed the safety directive Thursday, following a similar move by European regulators. The FAA rule would call for redesigning a system that heats fuel and cools oil in the engines of some Trent engines made by Rolls Royce PLC and installed on some Boeing 777 jets.
Chicago-based Boeing Co. said there are about 50 such planes operating in the United States.
Boeing spokeswoman Sandy Angers said the company and Rolls Royce have been working with the FAA and European aviation regulators to certify a redesigned heat exchanger with greater ability to handle ice in the fuel system.
"The conditions that seem to have led to the British Airways accident are rare to start with, and we've got interim procedures in place to minimize the effects these conditions will have on airplanes in flight until the new (heat exchangers) are installed," Angers said.
Rolls Royce spokesman Ian Bustin said the company was confident of meeting the FAA requirements.
The proposed order would cover all of American Airlines' 777s.
Delta officials did not immediately respond to requests for comment.
The companies have until Aug. 24 to comment on the FAA proposal. The work on each plane would have to be completed before the jet flies another 6,000 hours after the rule takes effect, but no later than Jan. 1, 2011.