MIAMI, FL, USA
N8872Z
BOEING 727-225
FLT WAS UNABLE TO EXTEND NOSE GEAR AND A NOSE GEAR UP LANDING WAS MADE. INVESTIGATION REVEALED THE NOSE GEAR DRAG BRACE TO BE LOCKED IN THE UP POSITION. DISASSEMBLY OF THE DRAG BRACE REVEALED THE LINK ASSEMBLIES WHICH CONNECT THE LOCKING PAWLS TO THE LOCKING ACTUATOR HAD FAILED. METALLURGICAL EXAMINATION REVEALED THE LINK ASSEMBLIES FAILED DUE TO CORROSION CRACKING. CORROSION WAS CAUSED BY ELECTROLYTIC REACTION BETWEEN THE METAL IN THE BUSHING OF THE LINK AND THE METAL OF THE LINK. EXAMINATION OF THE BUSHINGS INSTALLED IN THE LINK REVEALED THE ABSENCE OF CADMIUM PLATING AND CHROMATE COATING. THE BUSHINGS WERE OBTAINED BY EASTERN AIRLINES FROM A VENDOR WHO WAS MANUFACTURING THE PART USING PLANS SUPPLIED BY EASTERN. THE EASTERN PLANS CALL FOR CADMIUM PLATING AND CHROMATE COATING.
Source: NTSB Aviation Accident Database
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