Airlines around the world are examining about 3,000 Boeing planes after being told of a potentially dangerous fault in a batch of fuel pumps.

The US Federal Aviation Administration ordered mandatory checks on more than 1,400 Boeing planes operating in America, and advised other carriers flying the affected jets to do the same.

This is not an unsafe condition

Ron Wojnar, Federal Aviation Authority

The pumps under investigation were distributed this year and may have a wiring fault which, when fuel levels are low, could create a spark and ignite vapours leading to an explosion.

The FAA said no incidents had yet been reported and insisted the travelling public need not be alarmed.

The pumps are designed for use in centre-wing fuel tanks on Boeing aircraft, including many of the 737 series, as well as 747s and 757s designed for passenger or cargo use.

Ron Wojnar, the FAA's deputy director of aircraft, said any airlines with the pumps are being ordered to keep enough fuel in the tanks to cover the devices, even when the planes bank or encounter turbulence in flight.

Mr Wojnar said the submersion would prevent any sparks from igniting fuel vapours.

"This is not an unsafe condition," he said.

The FAA estimated that 1,250 of the pumps could have wiring problems, but it is not known how many of the 3,000 planes to be checked will have been fitted with them.

Worldwide action

Reuters news agency reported that Australia's national airline, Qantas, and domestic carrier Virgin Blue were telling all aircraft to fly with extra fuel to ensure pumps were submerged, until checks were completed.

It said Taiwan's China Airlines and Singapore Airlines were making the necessary investigations while Hong Kong-based Cathay Pacific's fleet was not affected.

US airlines have been given four days to check their planes.

The pumps may have been installed in fuel tanks but could also have been sent out in spare-part kits.

The alarm was raised by British carrier Easyjet which detected that pumps had stopped working, giving the crew an indication of low pressure in the tank, said FAA spokesman Les Dorr.

A fuel tank explosion was blamed for the crash of Flight 800

A week later, a Northwest Airlines 747-400 reported a low pressure indication and found a similar problem, he said.

A China Southern Airlines 747-400 experienced the same trouble.

The safety of fuel pumps came under new scrutiny after the US National Transportation Safety Board ruled that an explosion in the centre fuel tank of TWA Flight 800 caused it to crash off the coast of Long Island in 1996.

The agency said vapours in the tank were probably ignited by a spark in wiring.

The Paris-bound Boeing 747 exploded in a fireball at 13,700 feet (4,175 metres), minutes after leaving John F Kennedy International Airport. All 230 people on board were killed.