Part of rudder falls off Concorde on flight to New York

British Airways and air accident investigators have begun an urgent inquiry into why a piece of the rudder 2ft square fell off a Concorde travelling from London to New York.

The incident was the fifth time since 1989 that a BA Concorde has lost part of a rudder, and the second time since all were replaced in 1992 because of a series of problems.

The piece detached from the lower quarter of the four-piece rudder, which is made of an aluminium skin and glued to the aircraft. Unofficial sources suggest that the glue failed in the extreme conditions that Concorde has to endure.

When Concorde reaches supersonic speed, the heat generated in the metal skin by friction with the air makes the 62-metre aircraft lengthen by 20cm. Yet the external air temperature is minus 76F.

"The trouble is that it's impossible to check that it is the glue, because the relevant piece of the aircraft is at the bottom of the Atlantic," said one aviation source.

The incident happened last month, one hour into the three-and-a-half-hour flight, when the plane was flying at 45,000ft, 850 miles west of Ireland. It had broken the sound barrier roughly 40 minutes earlier, while travelling over the Bristol Channel.

The pilots noticed a slight "pop" at the time, and more sounds when the plane decelerated towards New York, but had no trouble controlling the flight.

There are at present no plans to ground the seven BA aircraft – unlike the action eventually taken after the crash in July 2000 that killed 113 people, caused by a leak from a punctured fuel tank. The Air Accidents Investigation Branch could call for safety modifications if it decides they are needed.

A BA spokeswoman said yesterday: "A small part of one of the lower rudders became detached during the flight. The aircraft flew safely throughout the flight and landed safely. The missing part did not affect the safety of the aircraft and at no stage during the flight were the passengers or aircraft in any danger."

The plane was carrying 96 passengers and nine crew.

Experts said that the plane was completely controllable, despite the loss of the part. Jock Lowe, a former Concorde pilot, said the plane could fly "very successfully" with just one of the four rudder pieces, and that in normal circumstances they were not needed at all.

"It only comes into use for steering during take-off, and if there is an engine failure or if there is a cross-wind, so for most flights it is not needed at all," he said.

But the failure raises fresh questions over the airworthiness of the ageing supersonic aircraft, which came into service in 1972. It remains the world's only supersonic passenger aircraft, with seven owned by British Airways and six by Air France.

David Learmount, operations and safety editor of Flight International magazine, said: "The rudders are made at Toulouse and now everyone will have to look at ways of strengthening them."