US aircraft manufacturer Boeing has told the BBC that more than 3,000 of its aircraft may have faulty fuel pumps, which, in rare circumstances could cause a mid-air explosion.

Earlier estimates had put the number of planes affected at 116.

We are working with appropriate partners to resolve this as quickly as possible

Boeing statement

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

The revelation means airlines around the world will have to check their planes - but it is unlikely that any will have to be grounded.

The safety alert affects three Boeing aircraft: the 747, 757 and the 737, which are designed for passenger or cargo use.

Alarm raised

Last month Boeing said fuel pumps on 116 aircraft could be faulty.

The alarm was first raised by British carrier Easyjet which detected that pumps had stopped working.

The UK budget carrier replaced them on five of its planes.

Now, after further checks, Boeing says that 3,284 planes could be affected.

The fault could cause a mid-air explosion, but only if faulty wiring inside the fuel tanks was exposed to air which would only happen if the tank was nearly empty.

Airlines have been told to make sure that never happens until all faulty fuel pumps have been replaced.

Boeing issued a statement: "This issue is a concern to us, and that is why we have taken immediate steps to identify corrective action and inform our customers and operators.

"Boeing is committed to safe and efficient operation of all of its aircraft.

"We are working with appropriate partners to resolve this as quickly as possible."

Bill unknown

For some aircraft the problem pumps will take up to three years to repair and replace.

Boeing says it does not know how many UK aircraft will be affected or the total bill for the replacement programme.

It does not believe any serious aircraft accidents have been caused by the faulty parts.

In late August, the Federal Aviation Authority issued an emergency inspection order to all US airlines to inspect some 1400 aircraft for the potentially defective pumps.