On July 21, 1987, an Aeronca 7AC (registration N443WB) operated by 443 Flying Club was involved in an aviation accident near Columbus, OH. Investigators recorded the probable cause as: The loss of directional control was due to a broken tailwheel steering yoke, which had fractured at a retaining-bolt hole where an oversized bolt was installed. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During landing, a pilot experienced loss of directional control as the tailwheel touched down. A go-around was attempted, but on the second landing the airplane veered off the runway, crossed a grassy area, and struck a parked C-172. Post-crash inspection revealed a broken tailwheel steering yoke with oversized bolts.
Event Details
The pilot experienced a loss of directional control on landing as the tailwheel touched down, and executed a go-around. On the second landing attempt, the airplane veered off the runway, traveled across a grassy area, and impacted a parked C-172. The airplane was estimated to have traveled approximately 800 feet after touchdown prior to colliding with the parked aircraft.
Post-Crash Examination
A post-crash examination of the airplane revealed that the tailwheel steering yoke had broken. The yoke had fractured across one of two retaining-bolt holes in the yoke shaft. Oversized bolts were found installed in the holes.
Findings
The strength of a tailwheel steering yoke can be reduced by the installation of oversized bolts, leading to fracture. In this event, the broken yoke resulted in a loss of directional control during landing.
Probable cause
The loss of directional control was due to a broken tailwheel steering yoke, which had fractured at a retaining-bolt hole where an oversized bolt was installed.