NTSB Advisory
National Transportation Safety Board
Washington, DC 20594
February 9, 2007

UPDATE ON NTSB INVESTIGATION INTO UNCONTAINED ENGINE FAILURE IN COLORADO

On January 25, 2007, at approximately 4:50 MST, a US Airways Express Bombardier CL-600-2B19 (N17337), operated by Mesa Airlines as flight 2985 from Denver to Phoenix, sustained an uncontained failure and separation of components of the number 1 engine. The airplane was approximately 70 miles west-southwest of Denver, climbing through 24,000 feet when the event occurred. The aircraft returned uneventfully to Denver and none of the 55 persons aboard was injured.

The engine was a General Electric CF34-3B1. Preliminary examination of the number 1 engine revealed that the inlet, fan rotor assembly, fan containment case, and thrust reverser were missing. Examination of the airplane 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.

Using a combination of information from the plane's flight data recorder, and radar data from the Federal Aviation Administration and the military, NTSB investigators were able to determine when and where the event occurred. Vehicle performance engineers in the NTSB's laboratory in Washington, D.C. received the FDR and radar data on Monday, January 29. Within 24 hours, after identifying primary targets presumably from the aircraft, they were able to produce trajectory calculations and identify a 1-square-mile search area for the engine components.

With the cooperation of the Teller County Sheriff's Department and local residents, a search was conducted on Wednesday, January 31. In addition to five NTSB investigators, the team consisted of representatives from the FAA, General Electric Engines, an aircraft recovery company and officials from the county. The team searched the mountainous terrain all day in blowing snow and found 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.

The wreckage arrived at the NTSB's materials laboratory on Friday, February 2 and was immediately examined by materials specialists. The point of origin of the fracture was identified. Investigators are currently examining the manufacturing and maintenance records of the engine to determine if existing fan disk inspections are appropriate and effective and whether further corrective action is warranted.

Jennifer Kaiser of the NTSB's Central Mountain Region is the Investigator-in-Charge of this incident. The NTSB case number is DEN07IA055.

NTSB Public Affairs: Ted Lopatkiewicz
(202) 314-6100
lopatt@ntsb.gov

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