US National Transportation Safety Board (NTSB) investigators are examining the manufacturing and maintenance records of the General Electric (GE) CF34-3B1 involved in the 25 January uncontained engine failure of a Mesa Airlines Bombardier CRJ200LR to determine if existing fan disk inspections are appropriate and effective and whether further corrective action is warranted.
The engine history probe comes after a 31 January search for engine parts over mountainous terrain in Colorado uncovered about half of the fan disk, fan blades, parts of the engine cowling and thrust reverser, the engine spinner, and pieces of the fan containment case lost in the incident.
The wreckage arrived 2 February at the NTSB’s materials laboratory, where specialists identified the fracture’s point of origin, reveals the NTSB in a preliminary update of its investigation.
A safety board spokesman adds that investigators are using their knowledge of the fracture surface “in their examination of the history of that [fan disk] piece”, but adds: “I can’t get anymore specific than that.”
He says that while investigators would “like to find the mating piece to the fan disk”, they are “very satisfied with the results of the search”, a sentiment supported by its finding of the fracture surface “within days of the incident”.
The aircraft, operating as US Airways Express flight 2985 from Denver to Phoenix, was climbing through 24,000ft (7,300m) when the left engine failed, shedding components over the mountainous terrain. It returned uneventfully to Denver and none of the 55 people onboard was injured.
Preliminary examination of the Number 1 engine revealed that the inlet, fan rotor assembly, fan containment case, and thrust reverser were missing.
Inspection of the aircraft revealed impact damage to the fuselage, in-line with the plane of rotation of the engine fan rotor, as well as impact marks on the vertical and horizontal stabilizers.
The NTSB says investigators have ended their active search of engine parts, but notes that “everyone in the area has been apprised of what’s out there, and I wouldn’t be surprised if, over time, people find” other pieces.
GE is not commenting on the investigation.
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Source: FlightGlobal.com
