The National Transportation & Safety Board has determined that a disk in the engine turbine failed. NTSB investigators have been in Chicago all weekend trying to figure out why the plane experienced uncontained engine failure, which means parts of the engine exploded in different directions.
The NTSB said it will release a preliminary report later this week.
Today's briefing on #AA383 767 accident in Chicago: Examination of engine revealed that the stage 2 disk of high pressure turbine failed.— NTSB_Newsroom (@NTSB_Newsroom) October 29, 2016
NTSB briefing: a piece of the engine disk of #AA383 was found in a UPS warehouse about 2,920 feet away from the accident site.— NTSB_Newsroom (@NTSB_Newsroom) October 29, 2016
Nearly two dozen passengers sustained minor injuries, mostly related to the emergency evacuation. With a chaotic scene inside the plane, passengers used the slides to get out relatively safely.
With a charred right side, the American Airlines 767 was moved off the runway a day after it caught fire just before taking off for Miami. The jet skidded to a halt as passengers heard an explosion, a ball of flames and a cloud of smoke followed.
Illinois Institute of Technology mechanical engineering Prof. Francisco Ruiz has a theory.
"It was probably a methodological failure on the disk itself, those are subjected to high stress high temps and can develop cracks," Ruiz said.
Ruiz says engine failure is more likely to happen on take-off rather than in the air.
The point where the engine is mostly stressed is at take off because they are running maximum power
Years ago, uncontained engine failure was more common than it is today, Ruiz said.
However, it does happen.
A year ago, British Airways flight 2276 aborted take-off in Las Vegas after a GE engine caught on fire.
Aviation attorney Alexandra Wisner settled a lawsuit on behalf of the passengers. She called on the Federal Aviation Administration to take a more in-depth look.
"The FAA already requires inspecting and replacing, if necessary, engine parts, now it may need to require more frequent inspecting and potentially replacing," Wisner said.
The American Airlines engine that failed on Friday was also a GE engine.
So far, none of the passengers on the flight has filed a lawsuit.
WATCH: Sarah Ahmed describes her experience on the plane