What happened
On June 18, 1968, a Piper PA-18-125 was conducting solo training maneuvers at the Beromünster airfield. After completing two successful circuit patterns, the student pilot attempted a third landing. During the touchdown, the aircraft experienced a sudden bounce, likely caused by the pilot not fully applying the elevator, combined with slight undulations in the grass runway.
The aircraft landed in a normal three-point attitude approximately 120 meters past the touchdown zone without additional power being applied. While the aircraft initially continued straight along the runway centerline for about 18 and a half meters, it began to drift progressively to the left. The aircraft eventually veered at an angle of 60 to 70 degrees, exiting the runway and entering the Wina stream, a small ditch bordering the western edge of the airfield.
The investigation
The investigation examined the pilot's actions, the aircraft's mechanical condition, and the airfield environment. The student pilot, who had recently resumed training after a four-week hiatus, noted that he did not apply the brakes during the rollout. He further stated that he failed to notice the narrow, grass-covered stream and mistakenly believed he could allow the aircraft to roll left across the level terrain and later steer it back toward the runway in a wide arc.
Technical inspections confirmed that the Piper PA-18-125, registration HB-OYB, was in airworthy condition and that the wheel brakes were fully functional. The investigation also noted that the aircraft sustained significant damage, including a bent propeller, a deformed engine mount, and a cracked crankshaft.
Findings
- The primary cause of the accident was the lack of pilot intervention during the landing rollout.
- The student pilot exhibited a passive response, failing to use the brakes to stop the aircraft before it reached the airfield boundary.
- The pilot's decision-making was flawed, as he underestimated the obstacle of the stream and attempted an unsafe taxi maneuver across the ditch.
- The recent resumption of flight training following a month-long break may have contributed to the pilot's psychological state or lack of situational awareness during the solo flight.