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DEN92IA005

1991-10-24 · DENVER, Colorado, United States · None · 1 aircraft · Status: Completed

Aircraft involved

Probable cause & findings

A MALFUNCTION IN THE STABILIZER TRIM CONTROL MODULE.

Factual narrative

DURING LEVEL OFF AT FLIGHT LEVEL 290, WHILE ON A SCHEDULED INTERNATIONAL PASSENGER FLIGHT FROM SAN FRANCISCO, CALIFORNIA, TO LONDON, ENGLAND, ELEVATOR PITCH CONTROL BECAME ERRATIC AND OSCILLATIONS OF UP TO 1,000 FEET EITHER SIDE OF THE BASE ALTITUDE OCCURRED. THE AUTO PILOT WAS DISCONNECTED, COMMUNICATIONS WITH MAINTENANCE CONTROL WAS HELD, AND THE FLIGHT PROCEEDED TO THE NEAREST AIRPORT WITH RUNWAYS EXCEEDING 10,000 FEET IN LENGTH. AN UNEVENTFUL PRECAUTIONARY LANDING WAS CONDUCTED IN DENVER, COLORADO. STABILIZER TRIM COMPONENTS WERE EXAMINED REVEALING DISCREPENCIES IN THE TRIM MODULE AND ELEVATOR FEEL COMPUTER, DUE TO NORMAL WEAR. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1991_DEN92IA005.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

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