What happened
On June 18, 1999, a Piper PA 28-161, registration HB-PPA, crashed into the terrain near the Türlistock area of the Rossberg mountain in Switzerland. The flight originated in Kägiswil with the intended destination of St. Gallen-Altenrhein. After communicating with Alpnach and Buochs control towers and notifying Zurich FIC of the intended route via Zug and Pfäffikon, the pilot's radio contact ceased around 09:33 LT.
Witnesses observed the aircraft flying at a low altitude and an irregular path near the Morgarten mountain between 09:45 and 10:00 LT. The aircraft eventually struck trees on the northern flank of the Rossberg, causing the airframe to break apart. The right wing became lodged in the trees while the remainder of the aircraft struck the ground, resulting in a massive post-impact fire that consumed the cockpit and much of the fuselage. The pilot, who was the sole occupant, sustained fatal injuries.
The investigation
The investigation, conducted by the Swiss Transportation Safety Investigation Board (SUST) in collaboration with local police and forensic institutes, examined the aircraft wreckage, weather conditions, and the pilot's background. Investigators found no evidence of mechanical failure, as the engine and propeller were determined to have been functioning until impact. Toxicological analysis of the pilot showed no presence of drugs, alcohol, or carbon monoxide inhalation prior to the crash.
While the aircraft's Emergency Locator Transmitter (ELT) activated, the signal was only detectable in the immediate vicinity of the wreckage because the antenna cable was severed or burned during the impact. The investigation also noted that the pilot's license had expired on May 24, 1999.
Findings
- The primary cause of the accident was the continuation of VFR flight operations in deteriorating visibility and weather conditions, which led to the collision with trees and terrain.
- The pilot possessed limited flight experience and had very little recent training.
- The pilot's commitment to a scheduled business appointment in St. Gallen may have negatively influenced the decision-making process, potentially preventing an earlier flight cancellation or an alternative landing.
- Weather at the time of the accident included low clouds, fog, and light rain, significantly reducing visibility in the area of the impact.