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ATL90IA060

1990-01-31 · LOUISVILLE, Kentucky, United States · Minor · 1 aircraft · Status: Completed

Airport SDF

Aircraft involved

Probable cause & findings

THE DISABLING OF THE MAIN LANDING GEAR TORQUE LINK WHICH ALLOWED THE TRUCK TO ROTATE FREELY. THE TORQUE LINK WAS DISABLED WHEN EXCESSIVE VIBRATION WAS GENERATED BY EXCESSIVE PLAY OF THE TORQUE LINK PINS IN THEIR BUSHINGS.

Factual narrative

AFTER LANDING THE FLIGHT CREW NOTED A VIBRATION. LEFT MAIN GEAR TORQUE LINK APEX BOLT WAS FOUND TO HAVE VIBRATED OUT OF THE TORQUE LINK WHICH ALLOWED MAIN GEAR TRUCK TO ROTATE 360 DEGREES DURING LANDING ROLL. THE NUT HAD STRIPPED OFF OF THE BOLT. LABORATORY EXAMINATION REVEALED THAT THE TORQUE LINK ATTACHING PINS HAD EXCESSIVE PLAY. NEW & OLD APEX BOLTS WERE MEASURED. THEY FAILED TO PASS THE MOST STRINGENT QUALITY CONTROL CHECK FOR CORRECT THREAD SIZE. THE SAFETY BOARD BELIEVES THAT THE NUT STRIPPED OFF WHEN THE LOOSE TORQUE LINKS ALLOWED EXCESSIVE VIBRATION. THE UNDERSIZE APEX BOLT THREADS ALLOWED THE NUT TO SHEAR AWAY THE BOLT PIN DESIGNED TO RETAIN THE NUT. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1990_ATL90IA060.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

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