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Tuesday, 13 November, 2001, 22:51 GMT
Q&A: Airbus engines

One of the engines from the A300 which crashed in New York was found several blocks away from the wreckage. Bill Read from Aerospace International looks at the plane's CF6-80 engines and why the crash might have happened.

Q: How much does one of the A300 engines weigh?

A: The basic CF6-80 engine (excluding pylon, nacelle, thrust reverser and fluids) weighs around 9,000lb.

Q: What strain is it under during takeoff?

A: The engine is producing between 52,000 and 63,500lb of thrust. The low-pressure spool will be rotating at speeds of around 6,700 rpm, while the high-pressure spool will be rotating in the opposite direction at speeds of around 21,000 rpm.

Q: How are the engines attached to the wings?

A: By pylons attached to the underside of the wings.

Q: Under what circumstances might one come off?

A: A sudden shock to the pylon, caused by either an external force or by the engine seizing up due to an internal failure or ingestion of external debris.

Q: Are they designed to come off in an emergency?

A: Yes. Each engine is fitted with two "sacrificial" pins which are deliberately designed to break off cleanly so that an aircraft can lose an engine without the wing being damaged.

Q: Can a plane fly if one engine falls off?

A: Yes. Twin-engined aircraft are designed to be able to fly on one engine. Simulating a takeoff with only one engine is part of a pilot's regular six-monthly flight training. However, there could be problems if the wing control surfaces, hydraulic systems or some other part of the aircraft was also damaged.

Q: How will the flight recorders establish what happened to the engine?

A: The flight data recorders will have monitored mechanical information on the engine's performance up to the point at which the engine was lost. The flight data recorder itself will only continue to record information as long as it has electrical power.

Q: If fuel was being dumped shortly before the crash, what would this tell us?

A: It could be that the pilot realised there was a problem and began to jettison fuel to reduce the aircraft's weight to bring it down to its maximum landing weight. However, fuel dumps should not be carried out over inhabited areas and there is no evidence yet that the pilot informed air traffic control that he was carrying out such an operation. An alternative theory is that the fuel was lost as a result of damage to the fuel tanks, but there is no firm evidence yet for this.

How common is it for a plane to lose its engine?

A: It does happen occasionally but most aircraft have survived such an accident.

Q: Have Airbuses had similar problems in the past?

A: The A300 has a very good safety record and has not had a fatal accident which was attributable to engine failure. However, there have been instances of A300s which have experienced engine problems in flight.


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12 Nov 01 | Americas
12 Nov 01 | Science/Nature
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