Pilots were forced to abort a takeoff and evacuate passengers from a burning American Airlines flight on a runway at Chicago O'Hare International Airport Friday after the airliner experienced what a federal official says was a rare and serious type of engine failure. American Airlines Flight 383 to Miami experienced an "uncontained engine failure," in which engine parts break off and are spewed outside the engine, the official tells the AP, speaking under condition of anonymity. The danger of such a failure is that engine pieces effectively become shrapnel and can cause extensive damage to the aircraft.
Uncontained engine failures are unusual thanks to improvements in designs and the metallurgy. There are many possible causes, including overheating, runway debris or large birds that get sucked into the engine, or parts that break when they wear out but aren't replaced during maintenance checks. The Boeing 767 involved in Friday's incident was built in 2003 and is among the airline's youngest planes of that model. Chicago Deputy Fire Commissioner Timothy Sampey says 20 passengers suffered minor injuries as they used the emergency chutes to evacuate. American, which had earlier said eight people were injured, later confirmed the 20 figure and added that one flight attendant was also injured. (Read more American Airlines stories.)