What happened
On the morning of June 2, 1968, a student pilot was performing training maneuvers at the Triengen airfield. Following a successful powered approach, the pilot attempted a signal landing, which required executing a landing within a specific 100-meter zone without the use of engine power.
During the glide, the approach became too low. As the aircraft passed over a patch of vegetation located just before the runway, the pilot attempted to round out the approach. In an effort to reach the target distance without applying throttle, the pilot misjudged the aircraft's altitude. The main landing gear struck one-meter-high grass approximately 28 meters before the start of the runway. The sudden deceleration caused the Piper J3 Cub, registration HB-OII, to capsize immediately.
The investigation
The investigation, initiated on June 3, 1968, examined the aircraft, the airfield conditions, and the pilot's actions. The aircraft, a single-engine high-wing monoplane, sustained damage to the propeller and vertical stabilizer, totaling approximately 30% of its value. The pilot remained uninjured.
Investigators noted that the airfield featured a 419-meter paved runway. On the day of the accident, a patch of grass one meter high was present 15 meters wide directly before the runway threshold. To assist students, the instructor had moved the start of the landing measurement zone to a point 50 meters past the runway start, marked by an orange flag, to account for such obstacles.
Findings
- The primary cause of the accident was the pilot's failure to take corrective action by applying power when the approach became too low.
- The pilot's stated intention to reach the target distance without using engine power led to a critical misjudgment of altitude.
- The presence of tall grass before the runway threshold acted as a significant obstacle that contributed to the sudden braking and subsequent capsize.