CHICAGO, IL, USA
N8048U
McDonnell Douglas DC-8-54
DURING THE LANDING ROLL, THE LEFT MAIN GEAR SWIVEL LINK PIN FAILED ALLOWING THE REAR SET OF TIRES TO BECOME DETACHED FROM THE MAIN STRUT AND DRAG ALONG THE RWY. THE LEFT MAIN GEAR BOGIE WAS LAST OVERHAULED IN 1981. AT THE TIME OF FAILURE, IT HAD 4459 HOURS SINCE OVERHAUL. METALLURGICAL STUDY OF THE SWIVEL PIN REVEALED, 1) INTERGRANULAR CRACKING THRU 40% OF PIN CROSS-SECTION, 2) EVIDENCE OF STRESS CORROSION FROM OVERTORQUING THE NUT ON THREADED END OF PIN, 3) TRACES OF COPPER, SOMETIMES USED BEFORE CHROMIUM PLATING DURING OVERHAUL, FOUND IN CRACK, 4) NO OVERLOAD EVIDENCE IN PREEXISTANT CRACK, AND 5) INDICATIONS THAT FINAL FRACTURE WAS DUE TO OVERLOAD.
Source: NTSB Aviation Accident Database
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