What happened
On June 4, 1966, a Mucha Standard SZD-22 C glider, registration HB-684, departed from Courtelary for a competitive flight. After being towed to the Montoz area, the pilot released from the tow rope and began a flight pattern. Around 11:30 AM, the aircraft was observed circling over Les Hauts-Geneveys and later over the hamlet of La Jonchdre.
During the flight, the aircraft began losing altitude. While flying southwest at approximately 80 meters above ground level, the pilot attempted to maneuver toward an open meadow for an outlanding. During this maneuver, the glider collided with a 16 kV high-voltage power line near the "La Rochette" farm. The impact caused the aircraft to catch fire, and although witnesses managed to extract the pilot from the wreckage, he succumbed to his injuries.
The investigation
Investigators examined the wreckage and the site of the collision, which occurred in the Val de Ruz region. The investigation focused on the visibility of the power lines and the flight path of the aircraft. The inspection of the aircraft's wreckage, including the control cables, revealed no evidence of mechanical failure or technical defects. Furthermore, the aircraft's weight and balance were found to be within permissible limits, and the pilot was reported to be in good physical and mental health prior to the flight.
Findings
- The high-voltage line was difficult to detect because a section of it ran along the edge of a forest, making it blend into the background.
- Several utility poles were treated with a greenish preservative, which further reduced their visibility.
- The pilot likely delayed the decision to land in order to search for additional updrafts or to reach a more accessible location near the main road.
- The pilot likely failed to notice the poorly visible power lines due to a late decision regarding the landing maneuver.
Safety action
While the report does not list specific regulatory changes, it notes that the collision resulted in the destruction of three power cables and the bending of five utility poles.