NTSB Identification: NYC00IA036.
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Scheduled 14 CFR UNITED AIRLINES
Incident occurred Saturday, November 20, 1999 in JAMAICA, NY
Probable Cause Approval Date: 12/04/2000
Aircraft: Boeing 767-200, registration: N610UA
Injuries: 179 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 on final, the first officer had trouble trimming the airplane. The captain attempted to trim the airplane via his yoke switch and the manual trim handle, with no success. A go-around was executed. The crew ran the checklist, but control of the stabilizer trim was not regained. The crew pulled circuit breakers H11 and H20, and then reset them. The stabilizer trim was still inoperative. The crew reset the trim cutout switches twice, and normal operation of the stabilizer trim was reestablished. The left stabilizer position transmitter, and the right stabilizer position transmitter were out of calibration. Also, the left stabilizer trim control module (STCM) was found to have a higher than normal leakage, and the connector for the corresponding shut-off valve was shorting across several of its pins due to skydrol incursion. No faults were identified for the right system except for the right-stabilizer-position transmitter. According to the operator, the system should have operated at half rate with the above discrepancy, but did not. There have been no reports of difficulties with the airplane's stabilizer trim system since the event.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: Total failure of the stabilizer control system for undetermined reasons. Full narrative available
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