American Airlines has announced that it discovered no defects with the tailfins on its fleet of 34 Airbus A300 aircraft during an investigation ordered in the wake of last week's deadly New York crash.

American Airlines today announced that an inspection of its entire fleet of A300s found no problems with the tail section of the aircraft

American Airlines statement

American aviation regulators demanded on Friday that checks be carried out in the hope of uncovering what caused the tailfin and rudder of Flight 587 to shear off shortly before the aircraft came down last Monday, killing all 260 people on board.

Flight data from the plane indicated that the flight was thrown off course by twice hitting turbulence from another jet. Investigators say the rudder of the plane shifted erratically and the aircraft careered sharply sideways seconds after the incident.

No evidence has yet been uncovered suggesting that the crash was the result of a terrorist attack or sabotage, investigators say.

"Wake encounter"

The National Transportation Safety Board (NTSB) has said that the final eight seconds of the plane's flight as captured in the plane's data recorder are proving essential in the investigation.

They say that after the plane hit turbulence, the rudder was no longer sending useable information to the recorder.

The plane then shook violently and went into a steep dive before crashing.

The pilot and first officer are heard to mention a problem of turbulence in the cockpit voice recorder which was recovered from the scene of the crash.

	Flight 587 timeline Departed: JFK Airport 0913 EST (1413 GMT) for Dominican Republic 107 seconds after take-off rattling noise heard by pilots 114 seconds: Captain reports "wake encounter" 121 seconds: Second airframe rattling sound 127 seconds: Control of the plane is lost 144 seconds: Recording ends as plane crashes

The Airbus A300 plane's flight data recorder indicated that it had two "wake encounters" during its three-minute flight, says the NTSB.

But officials are still unsure as to the role of the turbulence in bringing the flight down.

"Turbulence is significant," said NTSB's aviation safety director John Clark, quoted by the Associated Press news agency.

"It's a player. But we don't see a huge vortex that just came along and knocked the tail off."

One issue being investigated by the NTSB is whether the tail was weakened in 1994 when the plane hit an air pocket while flying to Puerto Rico. The turbulence in that incident was so severe that 47 people were injured.

Japan Air Lines Boeing 747 left from the same runway at Kennedy Airport less than two minutes before Flight 587 last Monday, closer than regulations allow.

It is thought the remaining 56 Airbus A300s in the country belong mostly to shipping companies such as Federal Express and the United Parcel Service.

A month ago the FAA issued a warning over the Airbus A300's engines, saying an "unsafe condition" had been found in the machinery.