The National Transportation Safety Board determines that the probable cause of fire onboard a American Airlines Flight 383 in October 20...
The National Transportation Safety Board determines that the probable cause of fire onboard a American Airlines Flight 383 in October 2016 was due to failure of a engine turbine.
The internal defect in the engine caused an uncontained engine failure resulting in a fire and the emergency evacuation of all aboard.
On October 28, 2016, the Flight 383, operated by a Boeing 767-323, N345AN, had started its takeoff ground roll at Chicago O’Hare International Airport, Chicago, Illinois, when an uncontained engine failure in the right engine and subsequent fire occurred.
The flight crew aborted the takeoff and stopped the airplane on the runway, and the flight attendants initiated an emergency evacuation.
The failed high-pressure turbine (HPT) stage 2 disk, severed the main engine fuel feed line and breached the right main wing fuel tank, releasing fuel that resulted in a fire on the right side of the airplane during the takeoff roll.
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| The failed HPT Stage 2 |
The failed turbine disk was recovered in four pieces, one of which weighed 57 pounds and was found more than a half mile from the airplane.
Investigators further determined the defect had been propagating microscopic cracks in the disk for as many as 5,700 flight cycles – one takeoff and one landing – prior to the accident. Although the disk had been inspected in January 2011, the NTSB said the internal cracks were also most likely undetectable at that time because the current required inspection methods are unable to identify all subsurface defects.
Of the 2 flight crew members, 7 flight attendants, and 161 passengers on board, 1 passenger received a serious injury and 1 flight attendant and 19 passengers received minor injuries during the evacuation. The airplane was substantially damaged from the fire.
Contributing to the serious passenger injury was:
(1) the delay in shutting down the left engine and
(2) a flight attendant’s deviation from company procedures, which resulted in passengers evacuating from the left overwing exit while the left engine was still operating.
Contributing to the delay in shutting down the left engine was:
(1) the lack of a separate checklist procedure for Boeing 767 airplanes that specifically addressed engine fires on the ground and
(2) the lack of communication between the flight and cabin crews after the airplane came to a stop.
