On April 28, 1987, an Aeronca 11AC (registration N3167E) was involved in an aviation accident near Daytona Beach, FL. Investigators recorded the probable cause as: The collapse of the left main landing gear due to a support brace that had rusted through from the inside, which was previously repaired and normally covered by fabric. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A hard landing caused the left main gear to collapse, leading to a ground loop and runway excursion. Investigation revealed internal rust had weakened a support brace that was previously repaired.
What happened
The pilot executed a hard landing on the runway. During the impact, the left main landing gear collapsed. The aircraft subsequently ground looped and ran off the runway.
The investigation
A post-crash examination of the left main gear revealed that a support brace had rusted through from the inside of the tube. This structural failure caused the collapse during the hard landing. The brace had undergone a previous repair and was normally covered by the aircraft's fabric, which likely concealed the corrosion.
Findings
The primary factor in this accident was the structural failure of the left main gear support brace due to internal rust. The presence of a previous repair on the brace may have contributed to the corrosion process. The hard landing initiated the sequence of events that led to the ground loop and runway excursion.
Probable cause
The collapse of the left main landing gear due to a support brace that had rusted through from the inside, which was previously repaired and normally covered by fabric.