Preliminary Reports Focus On Turbine Disk Fatigue Cracks

The National Transportation Safety Board announced Tuesday it will investigate an uncontained engine failure on an American Airlines Boeing 767 that was undergoing testing June 2 at Los Angeles International Airport.

As Aero-News reported, at 12:27 PST, during a ground maintenance test run, the high-pressure turbine stage one disk on the number one engine, a GE CF6-80A2, broke into several pieces that were later found embedded in the fuselage, the number two engine, and scattered as far as 3,000 feet from the airplane.

Numerous holes punched in the wings by pieces of the engine caused fuel leaks, that led to a ground fire that was extinguished by airport fire department personnel.

There were no reported injuries to the three maintenance technicians aboard the airplane at the time of the accident. Runway 25-right and several taxiways were closed for several hours as crews removed blast debris, and mopped up the spilled fuel.

NTSB investigators were at the accident scene from June 3 to 7. Pieces of the high-pressure turbine disk were recovered and brought to the NTSB Materials Laboratory in Washington DC, for analysis. Initial examination of the disk pieces found indications of fatigue cracking.

The failed engine has also been brought to the American Airlines facility in Tulsa OK, for teardown this week under NTSB supervision.

FMI: www.ntsb.gov, www.aa.com