By Guy Norris in Los Angeles
eneral Electric is investigating the cause of an apparent uncontained engine failure that caused extensive damage to an American Airlines Boeing 767-200ER at Los Angeles on 2 June.
The 19-year-old aircraft (N330AA) was undergoing a ground run-up of the No 1 (left) engine when the problem occurred. The CF6-80A was being tested after the crew bringing the aircraft in from the New York reported abnormal power response from the engine.
Reports say the engine was at more than 90% power when the failure occurred, either in the shaft or the high-pressure turbine (HPT) area. It appears an HPT disk ruptured, puncturing the fuel tank in the wing near the trailing edge, slicing partially through the aircraft’s belly and damaging the keel beam. The No 2 engine was also damaged by exploding debris and the fuel tank on the right wing punctured.
The wing puncture also caused fuel to be spilled on the tarmac, and that, along with a fuel line rupture, caused a major fire, which engulfed the wing and the rear fuselage. The damage to the wing trailing edge, flaps, aft fuselage, fuel tanks on both sides and the keel beam makes it likely the aircraft will be declared a write-off.
The CF6-80 has been hit by similar issues in the past, and as recently as January 2003 was the subject of a US Federal Aviation Administration airworthiness directive (AD) calling for inspections of the HPT disc. The AD was prompted by an incident on 8 December 2002, when a 767-200 equipped with CF6-80A series engines experienced an uncontained failure of a first-stage HPT rotor disk during climb.
The FAA said at the time the “results of the investigation indicated that the Stage 1 HPT rotor disk failure was the result of a crack that initiated in an aft corner edge of the bottom of a dovetail slot. The crack propagated in fatigue to critical crack size, and subsequently resulted in disk rupture and separation.” The FAA also notes that, in September 2000, a US operator experienced a similar uncontained failure of the Stage 1 HPT rotor disk during a ground maintenance run of a CF6-80C2 engine.
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| The No 1 engine is thought to have suffered an HPT disk rupture (top); fuselage damage was extensive |
Source: Flight International
