On July 6, 2000, a Bellanca 7GCBC (registration N10989) was involved in an aviation accident near Wildwood, NJ. Investigators recorded the probable cause as: Overload failure of the landing gear bolts exacerbated by corrosion pitting. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During the landing roll, the left main landing gear separated from the fuselage after bolts failed due to corrosion and overload. The bolts, in service for 20 years and 580 hours, exceeded the manufacturer's 500-hour replacement recommendation.
Accident Details
During the landing roll, the airplane's left main landing gear began to wobble and ultimately separated from the fuselage. The failed landing gear section was held in place by a through bolt near the center of the fuselage and a u-bolt at the point where the landing gear exited the fuselage.
Bolts Examination
Examination of the failed bolts revealed corrosion pitting and that the bolts had failed by overload. The corrosion pitting likely weakened the bolts, making them susceptible to overload under normal landing loads.
Maintenance History
According to the airplane owner, the bolts had been in place for 20 years and had accumulated 580 hours of service. The manufacturer recommended replacement of the bolts when they had accumulated 500 hours of service, but did not specify a calendar time for replacement. Additionally, there was no regulatory requirement for the owner to follow the manufacturer's recommendations.
Probable cause
Overload failure of the landing gear bolts exacerbated by corrosion pitting.