With flames clearly visible, the Airbus A-300 with 251 people aboard turned back for an emergency landing.
Engine fires are rare, but federal investigators are particularly concerned about this one -- because of what did not happen when the jet was still in the air.
American Airlines says the pilots -- following emergency procedures -- immediately shut off the fuel to the burning engine and triggered the engine's fire extinguishers.
However, while the extinguishers appeared at first to do their job, the fire quickly re-ignited and continued to burn just beneath the wing, which was filled with thousands of gallons of fuel.
Veteran investigators say that if the engine fire had erupted just a few minutes later -- with the jet farther from the airport -- it could have been catastrophic.
The engine involved in the incident is made by General Electric and is used on 750 planes around the world.
While the engine has a reputation as a reliable workhorse, NTSB investigators want to know why, in this case, the critical fire suppression system apparently failed.
Reported by Bob Orr
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