What happened
On May 23, 1965, a Piper Cub J3C, registration HB-OUO, was engaged in a training flight at a military airfield. During the course of a simulated emergency landing exercise, the flight instructor attempted to increase engine power. However, the engine failed to respond immediately, likely due to being too cold. As the pilot attempted to maneuver the aircraft back onto the runway centerline, the loss of power caused the aircraft to stall and drop over its right wing at a very low altitude.
The investigation
The investigation focused on the mechanical performance of the engine during the maneuver and the subsequent flight path of the aircraft. Investigators examined the engine's behavior during the application of throttle and the environmental conditions affecting the engine's responsiveness. The inquiry established that the engine's failure to react promptly to the pilot's input was the primary factor in the loss of control.
Findings
- The primary cause of the incident was the engine's failure to respond to throttle input, which was likely caused by engine undercooling.
- The aircraft's flight path became unstable during the attempt to realign with the runway axis.
- The aircraft sustained significant damage, estimated at approximately 15 percent of its total value.
- There were no injuries to the occupants of the aircraft.