The United States Federal Aviation Administration (FAA) has asked airlines operating long-haul Boeing 747-400 aircraft to stop immediately running fuel pumps until tanks are dry.
The FAA issued the order after learning that a piece in the tank's fuel pump could throw off sparks if it is working when the tank is dry.
Although the order legally only affects US airlines, the Civil Aviation Authority (CAA) in Britain said yesterday it was adopting the directive. Other countries are likely to follow suit.
Normally, the pumps in both the horizontal stabiliser tank and centre tank are run until the tank is dry to use up fuel efficiently. Fuel in excess of that needed for the journey cuts into profits. Airlines operating very long-distance flights will either have to make refuelling stops, take fewer passengers or carry less freight, experts said.
Kieran Daly, editor of Air Transport Intelligence, an Internet service, said the main impact would be on airlines flying from Asia to Europe and the US.
He said refuelling stops would lead to longer flight time and "more potential for aggravation as airlines never change their schedules to allow for it".
Mr Daly said carrying fewer passengers would be a last resort. "It is all about preserving market share and they won't want to push people away because they may not come back."
A third option is to carry less "belly cargo" - freight in excess of luggage - which represents pure profit for the airline.
"Everything that contributes to an increase in costs ultimately gets paid for by passengers. But equally every time they make an efficiency saving that also gets passed on," he said, adding that he was confident the historically low price of fuel would keep fares low.
The order applies to all 246 US-registered 747s. Worldwide there are 1,087 such jumbo jets. British Airways operate 50 of the 747-400s, and Virgin six.
A BA spokesman said: "Our longest continual flight is one of 6,748 miles between London and Singapore. We have looked at this flight and other long-haul services and we are happy to say that we are able to implement the FAA directive without having to reroute for fuelling and without having to make any extra stops."
A Virgin spokesman said: "All our really long flights, to the Far East, are on Airbus planes. Our longest 747-400 flight is between London and Los Angeles and the public need not worry about our having to make any extra stops."
Northwest Airlines said weight restrictions or a refuelling stop might have to be used on its Detroit-Peking route. United Airlines will include some fuel stops on its longest trans-Pacific flights. All Nippon Airways, the Taiwanese carriers, and Japan Airlines warn of cuts in passenger numbers and extra refuelling stops. Cathay Pacific has put a crew at Anchorage, Alaska, in case its Los Angeles service has to refuel.Reuse content