Primary finding
Probable cause
The failure of maintenance personnel to comply with a service bulletin, which allowed a cracked landing gear housing to go undetected, resulting in failure of the landing gear.
Investigator assessment
Analysis narrative
Flight experienced collapse of the left main landing gear during landing rollout. The pilot/mechanic reported the strut housing had cracked and failed just below the point the trunion web ends. PIPER aircraft corporation service bulletin 787a, dated august 15, 1985, requires inspection of the landing gear housing just below the trunion web for cracks each 100 hours. If a new landing gear strut housing is installed in which the trunion web extends the length of the housing the inspection is not required. No record of compliance with service bulletin 787a was found in the logbooks for n975da. On june 22, 1990, the NTSB issued safety recommendation a-90-92 to the federal aviation administration, recommending that PIPER service bulletin 787a be made mandatory by issuance of an airworthiness directive.
Source record
Factual narrative
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