Event Description
During the takeoff roll, at a speed between 90 and 100 knots, the No. 2 engine experienced an uncontained failure. The flight crew promptly aborted the takeoff. Upon being informed that smoke was emanating from the No. 2 engine, the crew brought the aircraft to a stop on a taxiway. The pilot then commanded a passenger emergency evacuation.
Engine Examination
Post-incident examination of the engine revealed that one of twelve low pressure compressor (LPC) rear tiebolts had fractured at its 4th stage disk land and separated into the plenum ahead of the LPC. The separated tierod subsequently impacted the other eleven tierods, causing them to eventually fracture. This resulted in a catastrophic separation of the LPC assembly between the 3rd and 4th stage rotors.
Metallurgical examination of the failed tierods determined that the first tierod failed due to fatigue, while the other eleven failed due to stress. It was further revealed that an anti-gallant treatment, which is applied to the lands of the tierods at manufacture as specified in Pratt & Whitney Service Bulletin No. 5407, was not present on these tierods.