By David Shepardson
WASHINGTON (Reuters) - A fire on an American Airlines passenger plane as it was taking off from Chicago's O'Hare International Airport last week was sparked by the uncontained failure of the right engine, the U.S. National Transportation Safety Board said on Friday.
Pilots applied the brakes to the Boeing 767 bound for Miami and did not complete the takeoff of Flight 383 on Oct. 28. The engine failure prompted a fuel leak that resulted in a fire under the right wing. The incident led to the emergency evacuation of 161 passengers and nine crew members, but no serious injuries.
The plane experienced the failure about 6,550 feet (2,000 meters) after beginning the takeoff and came to a full stop around 9,225 feet (2,800 meters), about 27 seconds after the engine failure, the NTSB said in an interim report on the incident.
Investigators looking for what caused the General Electric CF6-80 engine to fail are focusing on an engine high pressure turbine disk that broke into at least four pieces.
One bit hit a UPS warehouse facility, about 3,000 feet (900 meters) from the runway, after slicing through a portion of the wing and traveling over the fuselage. The majority of the disk was recovered ,and during laboratory inspection showed features consistent with fatigue cracking, the NTSB said.
The disk had gone through 10,984 cycles, or takeoffs and landings, and had a life limit of 15,000 cycles. Review of the engine maintenance and manufacturing records and processes were continuing, the NTSB said, adding that additional examinations of the disk would focus on the cracking.
GE said the rotating disk "operates in one of the most harsh environments of a jet engine, especially at aircraft takeoff."
The NTSB was looking at the metallurgical properties of the failed disk, and checking documentation about its manufacture, GE said.
Uncontained aircraft engine failures are rare. GE said it had not suffered an engine failure caused by a problem with the alloy used in the disk for more than 30 years.
American Airlines declined to comment.
The fire last week prompted 130 delays of departing flights and 170 inbound flights within two hours of the incident, according to flight-tracking website FlightAware.com.
(Additional reporting by Alwyn Scott in Seattle and Jeffrey Dastin in New York; Editing by Frances Kerry)