O'HARE — Investigators traced Oct. 28's pre-takeoff explosion of American Airlines flight 383 to a manufacturing defect in a 20-inch disk inside the plane's engine, according to officials from the National Transportation Safety Board.
The right engine of the Boeing 767 burst into flame as it was about to lift off the ground Friday afternoon, forcing an immediate evacuation of the flight's 161 passengers and nine crew members.
More than a dozen people were hospitalized after the explosion, all with "non life-threatening injuries" sustained during the mad rush to get off the plane, Fire Department officials said.
When the airliner was about halfway down the runway, a "high pressure turbine disk" inside the engine cracked, causing a "fuel leak" that led to an explosion, according to a report issued Friday.
The explosion shattered the disk into four pieces, one of which was launched so far that it ended up on top of a nearby building, investigators said.
While the full investigation will likely take months, it's "probably fair to say" that the cracked disk played a central role in the incident, NTSB spokesman Peter Knudson said.
The disk failed because of an "inclusion," the report read — an investigative term for "some foreign object that's not supposed to be there," Knudson said. In this case, it was more likely a manufacturing defect in the disk itself than an outside substance interfering with its function, he added.
The disk had already been used more than 10,000 times, according to the report, well shy of the instrument's typical "life limit" of 15,000 uses.
"If we find any issues that have systematic implications for the industry" during the course of the investigation, "we will provide recommendations for the future," Knudson said.
For more neighborhood news, listen to DNAinfo Radio here.