What happened
On November 3, 2012, a Piper PA 19 Super Cub, registration F-BOMV, was performing circuit patterns at the Belvès-Saint-Pardous airfield. The aircraft was occupied by the pilot and a passenger, who was also a private pilot. Following the third takeoff, the engine experienced a loss of power at an altitude of approximately 15 meters.
Recognizing that the remaining runway length and the presence of a forest at the end of the runway made a runway landing unsafe, the pilot initiated an emergency landing in a field south of the runway. During the landing sequence, the aircraft struck the ground heavily. As the aircraft continued to roll, the right wing collided with a wooden post supporting a fence. The passenger noted that the aircraft entered a stall at an altitude of approximately five meters.
The investigation
The investigation focused on the engine's performance and the pilot's handling of the emergency. Investigators examined the engine components, noting that the spark plug electrodes were covered in black carbon deposits. The wreckage showed a deformed right wing leading edge and a broken main landing gear. Fuel was still present in the tanks.
Evidence was gathered regarding the engine's behavior during the flight. The pilot reported that during the first circuit, the engine had experienced a drop of 250 to 300 RPM accompanied by vibrations whenever the carburetor heat control was applied. Although the parameters returned to normal after several adjustments, the flight continued. Furthermore, reports emerged that other pilots had observed similar malfunctions when using the carburetor heat on this specific aircraft, though these incidents had not been recorded in the aircraft's logbook.
Findings
- The investigation could not definitively establish the exact cause of the engine power loss.
- Severe carburetor icing was a significant possibility, as meteorological conditions were conducive to such icing.
- The pilot's workload increased significantly while managing the engine failure, which likely led to insufficient airspeed monitoring.
- This lack of monitoring resulted in the failure to detect the onset of a stall at a low altitude.