Status | |
Date | Monday 16 February 1998 |
Time | 14:40 LT |
Type |
![]() Airbus A320-212 |
Operator | Northwest Airlines |
Registration | N341NW |
MSN | 380 |
Year of manufature | 1992 |
Engines | CFMI CFM56-5A3 |
Crew | Fatalities: 0 / Occupants: |
Passengers | Fatalities: 0 / Occupants: |
Total occupants | Fatalities: 0 / Occupants: 117 |
Aircraft damage | Minor |
Location | Memphis, TN ![]() |
Phase | En route |
Nature | Unknown |
Departure Airport | Detroit, MI (KDTW) |
Destination Airport | (KMEX) |
Narrative | 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. Probable Cause: 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. |
sources
NTSB CHI98IA095ACCIDENT INVESTIGATION
Final report
Investigating agency: NTSB
Report nr: CHI98IA095
Duration: 1 year and 7 months
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