An American Airlines engine failed and caused a fire that prevented a takeoff in Chicago because of a rare failure in a metal-alloy disk spinning in the engine, federal investigators said Tuesday.
The National Transportation Safety Board had discovered quickly after the incident Oct. 28, 2016, that a disk broke apart in the General Electric engine on the right side of the plane.
GE said within weeks of the incident there was a flaw in the common nickel-metal alloy used to manufacture the disk. But GE said the problem hadn’t been detected in 30 years and there was only one plane at that time still using a disk from the same batch of alloy.
The board ruled that the internal manufacturing flaw likely wasn’t possible to detect during manufacture or inspections between flights. The board urged the Federal Aviation Administration to develop new inspections for airliner engines to find internal disk cracks.
Robert Sumwalt, the board chairman and a former airline pilot, noted that nearly every airliner engine uses similar metal alloy and this was the only reported failure in this way.
“It’s going to scare people,” Sumwalt said. “The fact is this is a very, very rare failure.”
Nobody was killed in the incident at O’Hare International Airport, aboard a flight headed to Miami. But one passenger was seriously injured and 19 suffered minor injuries during the chaotic evacuation of the Boeing 767-300ER.
Investigators later found four pieces of the engine hurled up to a half-mile away on airport grounds. Holes were punctured in the right wing.
The pilots aborted the takeoff as passengers and crew members could see flames outside the window from rows 28 to 32. The pilots abandoned the takeoff at 147 mph, just before the limit of 154 mph to stop safely.
“They pulled this off spectacularly by having this rejected takeoff still stay on the runway,” said Christopher Hart, a safety-board member. “I want to give kudos to the flight crew.”
Passengers moved from the right to the left side of the plane before it stopped moving, witnesses told investigators. Then passengers rushed the exit doors before the plane came to a halt about 3,775 feet from the end of the runway, and the cabin filled with smoke, investigators said.
Flight attendants had reported a loud noise – like a blown tire – while rolling down the runway before the plane fishtailed.