What happened
On May 24, 1959, a Jodel D-117 aircraft, registration HB-SOO, attempted a takeoff from the Hasenstrick airfield. Seeking to avoid areas of tall grass, the pilot intentionally aligned the takeoff run at a 5-degree angle to the left of the runway centerline.
As the aircraft reached a speed of approximately 55–6 and0 km/h and a height of only 50 cm above the ground, the tail of the aircraft struck an iron barrel positioned just outside the runway edge. The impact was severe, tearing the tailwheel suspension and the rudder control linkage from the fuselage. Consequently, the pilot lost all rudder control. At an altitude of roughly 20 meters, the aircraft tilted onto its right wing and entered a steep, uncontrolled descent, crashing into a wooded area 600 meters southeast of the airfield. The two occupants, the pilot and his son, sustained two serious injuries involving multiple bone fractures.
The investigation
The investigation examined the operational conditions of the Hasenstrick airfield and the mechanical failure of the aircraft. Investigators found that the airfield's maintenance and layout did not meet established safety requirements. Specifically, the runway width was only 20 meters, failing to meet the mandatory 30-meter minimum. Furthermore, the grass had not been properly mowed, with significant portions of the runway covered in tall or semi-tall vegetation.
Regarding the obstacle, the investigation established that the iron barrel had been moved closer to the runway by a groundskeeper a few days prior to the accident. The airfield manager had noticed the barrel on the day of the accident but failed to move it back to its proper position, mistakenly viewing it as a marker for an uneven patch of ground.
Findings
- The primary cause of the accident was the loss of controllability resulting from the collision with the iron barrel.
- The pilot's decision to deviate from the runway centerline to avoid tall grass contributed to the collision.
- The presence of the obstacle at the edge of the runway, which was permitted by the airfield manager, was a significant contributing factor.
- Substandard airfield conditions, including insufficient runway width and unmaintained grass, created a hazardous operating environment.