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MIA91LA167

1991-06-23 · TUPELO, Mississippi, United States · None · 1 aircraft · Status: Completed

Airport TUP

Aircraft involved

Probable cause & findings

THE IMPROPER INSTALLATION OF THE NOSE STEERING ACTUATOR ARMING VALVE BY A MECHANIC WHICH RESULTED IN FAILURE OF THE ACTUATOR AND ON GROUND LOSS OF DIRECTIONAL CONTROL BY THE PILOT DURING LANDING ROLLOUT.

Factual narrative

ACFT MADE SHARP RIGHT TURN AND DEPARTED RUNWAY WHEN NOSE STEERING WAS ACTIVATED DURING LANDING ROLLOUT. POST ACCIDENT INVESTIGATION REVEALED THE NOSE STEERING ACTUATOR HAD MALFUNCTIONED. THE UNIT'S ARMING VALVE WAS BACKED OUT AND NOT SECURED BY A REQUIRED SET SCREW. THE SEATS FOR THE VALVE WERE THE INCORRECT SEATS. THESE TWO FINDINGS CAUSED THE ACTUATOR TO HAVE INTERNAL LEAKAGE WHICH RESULTED IN FAILURE OF THE ACTUATOR. LOGBOOK RECORDS INDICATED THE ARMING VALVE WAS CHANGED BY A MECHANIC IN THE FIELD IN SEPTEMBER 1988, 401 FLT HOURS BEFORE THE ACCIDENT. IN APRIL 1989, FAIRCHILD AIRCRAFT ISSUED A SERVICE BULLETIN THAT REQUIRED THE ACTUATOR BE RETURNED TO THE MANUFACTURER FOR REPLACEMENT OF THE ARMING VALVE. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1991_MIA91LA167.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

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