What happened
On June 7, 1964, a Karpf-Baby glider, registration HB-459, departed from Hausen am Albis for a local soaring flight. After initially climbing to approximately 950 meters, the pilot followed other aircraft southeast toward Baar. During the flight, the aircraft entered a sink zone, causing a rapid loss of altitude.
As the aircraft descended to roughly 250 meters above ground level, the pilot attempted to find suitable landing terrain. While avoiding a field where workers were haying, the pilot selected a valley floor area characterized by numerous obstacles, including houses, trees, and power lines. During the final approach, the pilot managed to clear a high-voltage line but lost significant airspeed. The aircraft subsequently struck a telephone pole, causing the right wing to snag on the structure while the left wingtip made contact with the ground.
The investigation
The investigation focused on the pilot's decision-making and the aircraft's flight path during the loss of altitude. Investigators examined the environmental conditions, noting clear weather with light westerly winds. The inquiry also reviewed the pilot's experience level, noting they had approximately 78 flight hours at the time of the accident.
Findings
- The primary cause of the accident was the pilot's excessive time spent searching for rising air, which resulted in a loss of altitude so significant that returning to the home airfield was no longer possible.
- The pilot's lack of experience contributed to a loss of situational awareness and difficulty maintaining control during the approach through obstacles.
- The pilot sustained one injury (a concussion) and experienced shock following the impact and subsequent jump from the aircraft.
- The aircraft sustained structural damage, including a broken right wing and deformed struts.