Engine explosion on Boeing 767 poses puzzle

The nearly catastrophic explosion of an engine that caused a fire on an American Airlines Boeing 767 just short of takeoff in Chicago on Oct. 28 occurred when a specific part that had never before failed broke into pieces.

The breakup of a heavy metal disk that rotates in the engine core reveals a new risk to airline passengers that, however rare, has already spurred a scramble by engine-maker General Electric and government safety agencies to find and fix the vulnerability.

'The risk will be eliminated,” said John Goglia, a former National Transportation Safety Board member with more than 40 years' experience in the aviation-safety industry. 'Will it be eliminated before the next one? That's the real question. Everything relies upon the timeliness of the system to correct itself.”

American Airlines Flight 383 to Miami was speeding down the runway at O'Hare International Airport in Chicago when the second-stage disk of the high-pressure turbine broke apart inside the right engine with a loud explosion that blew metal shrapnel out through the engine casing.

Hot metal ripped through the wing, igniting aviation fuel. Slamming on the brakes as the jet reached a speed of 154 miles per hour, the pilot brought the plane to a halt within 25 seconds and 900 yards further down the runway.

Moving quickly, the cabin staff evacuated all 161 passengers and nine crew using the escape slides on the undamaged left side of the aircraft. Twenty people suffered minor injuries.

GE spokesman Rick Kennedy stresses the reliability of the CF6 engine involved. The latest models, introduced in the 1980s, currently power about 4,000 widebody jets, including Boeing 767s, 747s and Airbus A330s, and have flown for more than 220 million hours.

'The CF6 is the workhorse engine of jumbo jets on a level never experienced before,” Kennedy said.

The NTSB said one piece of the broken disk went through the right wing, then arced high over the airplane and came crashing through the roof of a UPS warehouse almost 1,000 yards away.

'Any time a turbine disk fails, it's a big deal,” said Goglia.