The BBC's Jim Gilchrist reports on the "huge and costly implications"

The ruling by the US Federal Aviation Administration (FAA) means that extra refuelling stops may have to be made on long-haul flights.

But UK carriers British Airways and Virgin have told their passengers that their long-haul services will not be affected.

The FAA asked airlines operating Boeing 747 aircraft to maintain a mimimum level of fuel in the centre fuel tank.

It said there had been recent reports of pump failures due to premature wear.

More than 1,000 jumbo jets are in service

Normally, the pumps in both the horizontal stabiliser tank and centre tank are run until the tank is dry in order make efficient use of fuel.

A statement said new procedures should be established to prevent fuel pump parts rubbing against non-rotating parts.

"This metal-on-metal contact could cause hot spots and sparks, and a possible explosion," the statement said.

But Boeing spokesman Russ Young said tests had disputed the risk of an explosion.

Aviation Correspondent Christopher Wain: Journey times will increase

"We're convinced this problem would not ignite fuel vapour," he said.

The FAA said the problem was unrelated to the 1996 crash of a 747 off New York that killed all 230 people on board when its centre fuel tank exploded. The exact cause of the crash is still being investigated.