British Airways is cannibalizing a mothballed jet engine on exhibition at a museum to keep its fleet of supersonic Concordes flying.

Twenty years after Concorde 001's maiden flight from Toulouse, spare engine parts have become so scarce that British Airways has begun dismantling an Olympus engine that has been on display at Bristol's Industrial Museum for several years.After technical tests, engineers from British Airways' engineering base in Treforest, Wales, decided it was safe and practical to use parts from the gleaming museum piece. It is an auxiliary gearbox slung under the turbine blades of the engine that has aroused BA's interest.

According to a company spokesman, "Owing to a particular shortage from the engine manufacturer, we have taken steps to insure a backup supply. One source is the Olympus at Bristol. It was given to the museum as surplus but on the understanding that it might be required at a later date."

Paul Elkin, curator of the museum, said, "The Olympus was originally given to the museum for display because the inner core of whirring rotor blades had sustained damage from bird ingestion tests. But the outer components, such as filters, pumps and piping, are in perfectly serviceable condition."

As bits are unbolted, BA replaces them with used ones, leaving the appearance unchanged.

The Olympus model, developed especially for Concorde, is the only civil jet engine equipped with military-style afterburners which ignite exhaust gases to yield a great surge of power. In service, a set of four Olympus engines pushes a Concorde effortlessly through the sound barrier.