What happened
During a three-point landing demonstration, the left rudder pedal on the co-pilot's side of the cockpit collapsed. This mechanical failure caused the instructor pilot to lose control of the aircraft.
The investigation
An examination of the rudder pedal assembly did not reveal any specific component failure. According to a maintenance inspector, the locking assembly was re-engaged, after which the rudder assembly operated normally. The inspector concluded that the application of heavy braking caused the locking assembly to flex sufficiently to cause a release.
Additionally, the maintenance inspector noted that there had been several previous malfunctions involving this locking assembly. In those prior incidents reported by missionary pilots, the issue had been addressed by disabling the stow assembly and locking the pedals in the upright position.