What happened
On September 10, 2000, a DG-600/18 glider, registration HB-1954, crashed in the vicinity of Alp Fessis, Glarus. The flight began at Schänis airfield, where the pilot had prepared the aircraft with the assistance of his spouse. After a successful tow operation, the pilot released from the tow rope over the Schiltgruppe mountains.
During the subsequent glide toward Gufelstock, another pilot flying nearby observed the DG-600/18 traveling at very high speed on a straight course. The witness reported that the aircraft suddenly entered unusual flight attitudes, culminating in a steep left-hand turn with a bank angle between 60° and 90°. Ground witnesses also observed the aircraft in a high-speed descent, clipping treetops before striking a slope approximately 80 meters from their location. The impact was severe enough that the pilot was ejected from the cockpit, ultimately striking a rock 50 meters away. The pilot sustained fatal injuries.
The investigation
The investigation, conducted alongside the Glarus Cantonal Police, examined the wreckage and the pilot's medical history. Technical inspections of the control surfaces and flight controls revealed no evidence of pre-existing mechanical defects. The aircraft was destroyed upon impact, though the fuselage and wings remained relatively intact near the crash site.
Medical examinations performed by the University of Zurich Institute of Forensic Medicine provided critical insights. While toxicology reports were negative for drugs, alcohol, or medication, the autopsy revealed significant cardiovascular issues. The deceased suffered from severe coronary artery disease, including an 80% to 90% narrowing of several major coronary arteries, as well as a large aneurysm in the common iliac artery.
Findings
The investigation concluded that the primary cause of the accident was a loss of control of the glider. This loss of control was likely precipitated by a loss of consciousness in the pilot, brought on by a sudden lack of oxygen to the brain resulting from his underlying cardiac condition. The weather conditions at the time of the accident were favorable for gliding, and no external environmental factors contributed to the event.
Safety action
Following the findings, a safety recommendation was issued suggesting that the Federal Office of Civil Aviation (FOCA) should evaluate the necessity of reintroducing regular medical fitness examinations for glider pilots, similar to the requirements for powered aircraft pilots.