NTSB Identification: CHI01IA211.
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Scheduled 14 CFR operation of Trans World Airlines, LLC (D.B.A. Trans World Airlines)
Incident occurred Thursday, July 12, 2001 in Whiteman AFB, MO
Probable Cause Approval Date: 05/30/2003
Aircraft: McDonnell Douglas MD-83, registration: N9413T
Injuries: 138 Uninjured.
NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.
The McDonnell Douglas MD-83, operated as a scheduled passenger flight, experienced a catastrophic failure of the left engine while flying at 31,000 feet. The flightcrew heard a thud and noticed that the left engine was surging. White smoke filled the cabin and cockpit. The flightcrew donned their oxygen masks, declared an emergency and initiated an emergency descent to Kansas City International Airport (MCI), Kansas City, Missouri. While descending towards MCI, the flight crew changed their emergency landing destination to Whiteman Air Force Base (SZL), Knob Noster, Missouri, when they were approximately 18 miles north of SZL. Flight crews are not issued approach charts for SZL by their operator. The flight crew requested the runway 19 instrument landing system (ILS) frequency from air traffic control (ATC) and were issued the incorrect frequency. The flight crew also requested and was given the inbound course for ILS 19. The flight crew never obtained the correct ILS frequency for the remainder of the flight and relied upon a radar approach to SZL. During the approach, ATC instructed the flight crew to maintain the a minimum vectoring altitude of 2,500 feet mean sea level. The flight crew descended below minimum vectoring altitudes of 2,500 feet mean sea level to 1,800 feet msl in order to descend below a cloud layer which was 1,400 feet above ground level during the radar approach to SZL. A metallurgical examination revealed a fatigue fracture of one fan blade. Examination of the left engine revealed that the fan exit case exhibited a 360 degree fan exit case fracture. Several service bulletins (SBs) applicable to the fan exit case introduce a newer engine case made of steel to replace the older aluminum case and to install stops to restrict the axial separation of the case in the event of case fracturing. The SBs state that there have been 5 instances of full 360 degree fan exit case fracture, all due to fan blade fracture. They further state that when the case fractures, the front of the engine with the cowl shifts forward. The incident engine had an aluminum fan exit case and did not have stops installed.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: The separation of a fan blade due to fatigue failure which led to case separation and loss of engine power in the left engine. Full narrative available
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