NTSB Identification: CHI98IA095.
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Nonscheduled 14 CFR NORTHWEST AIRLINES
Incident occurred Monday, February 16, 1998 in MEMPHIS, TN
Probable Cause Approval Date: 09/28/1999
Aircraft: Airbus Industrie A-320-212, registration: N341NW
Injuries: 117 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.
While en route from Detroit to Mexico City , the flightcrew received a warning message from the Engine Condition and Monitoring System (ECAS) that the No. 1 fuel filter was clogged. The flight was subsequently diverted to Memphis for a precautionary landing. Post-landing examination of the engine revealed a 4-inch long (circumferential) by 1-inch wide (axial) burn-through in the low pressure turbine case in the plane of the 2nd stage turbine stators at the 11 o'clock location. The examination of the fuel pump filter revealed the presence of a bronze-colored material. The fuel nozzles were reported to have bronze-colored material in the nozzle jets. Records show that the fuel pump had operated 17,208 hours time since new and 6,972 cycles since new. The disassembly of the pump revealed the pump housing had gear pocket milling. The fixed and driven bearings, which are made of bronze, were worn. The fuel pump's filter bypass valve was found to have bronze-colored particles on both sides of the valve. The fuel pump's four bearings were made of bronze and all four bearings exhibited wear and material loss.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: the inadequate (bronze) material used by the fuel pump's manufacturer, which wore and ultimately blocked the fuel filter bypass and partially blocked the fuel nozzles, causing the fuel spray to burn through the low pressure turbine case. Full narrative available
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