Summary
On 12 November 1999, at approximately 14:54 local time, a Piper PA28-181 Archer III, registration HB-PNC, operated by the Segel- und Motorfluggruppe Grenchen, collided with terrain on the east side of the Galletgrat ridge near Kandersteg, Switzerland. The pilot, the sole occupant, sustained fatal injuries, and the aircraft was destroyed.
Flight History
The pilot, a Swiss citizen born in 1967, arrived at Grenchen Regional Airport in the early afternoon intending to conduct a training flight. He filed a flight plan for a route from Bulle to Thun with an estimated duration of two hours, planning to return by 16:30. He reported having checked weather, NOTAMs, and other relevant information.
At 14:02, the pilot requested taxi clearance for a VFR flight. The aircraft departed at 14:08, climbing to 2700 ft over waypoint ZULU. Subsequent radar data showed the aircraft tracking east of Thun at about 6600 ft at 14:41, then climbing to around 9500-10000 ft with course changes. The last radar echo was received at approximately 14:50, when the aircraft was about 6 km east of Reichenbach airfield at 9500 ft.
At 14:52:30, a Swiss Air Force PC-7 crew sighted a light aircraft matching HB-PNC over the southern Kiental, noting a slight oscillating roll motion. Based on radar data and estimated ground speed, the collision with the Galletgrat occurred between 14:53:30 and 14:54:00. The impact site was at coordinates 623 500/146 900, elevation 3040 m (9980 ft AMSL), with the wreckage coming to rest at 623 600/147 000, elevation 2840 m (9320 ft AMSL).
An ELT signal was received by two Swiss Air Force jets at 14:54:20 and 14:55:40, and later by the COSPAS/SARSAT system. A search was initiated after the aircraft was reported missing at 21:35, and the wreckage was located at 23:59.
Pilot Information
The pilot held a Swiss private pilot license valid until 5 April 2001, with ratings for single-engine piston aircraft with retractable gear, constant-speed propeller, and flaps. His total flight experience was 161:01 hours, including 21:00 hours in gliders and 140:01 hours in powered aircraft, of which 12:19 hours were on the accident type. In the last 90 days, he had flown 9:49 hours, with 2:29 hours on the accident type. His last medical examination was on 29 March 1999, with no restrictions.
He was described by acquaintances and instructors as conscientious, reliable, sociable, and calm, with good flying performance and no known incidents.
Aircraft Information
The aircraft was a 1995 Piper PA28-181 Archer III, serial number 2843004, with an FAA export airworthiness certificate issued 14 August 1995 and a Swiss certificate of airworthiness issued 1 December 1995. It was powered by a Textron Lycoming O-360-A4M engine and equipped with a Sensenich 76EM8S5-062 propeller. At the time of the accident, the aircraft had accumulated 1562:05 flight hours. The last 500-hour inspection was performed on 22 September 1999 at 1503:27 hours, and the next 50-hour inspection would have been due at 1560 hours.
Fuel capacity at departure was approximately 150 liters of AVGAS 100LL, providing about 2:50 hours of flight time. Weight and balance were within limits with one occupant and that fuel load.
Weather
The general weather was influenced by a high-pressure ridge over the British Isles. An inversion layer was present at about 3000 ft AMSL, with increasing high cloud from the southwest. At the accident site, visibility was over 10 km, with 3/8 stratocumulus at 3000-3500 ft and cirrus/altostratus above. Wind at 3500 m was from approximately 140° at 15-20 kt. Temperature was -2°C, dewpoint -14°C. Hazards included wind shear and possible downdrafts on the north side of the Fründenjoch ridge to the south of the accident site, as well as potentially diffuse lighting conditions. The sun azimuth was 210°, elevation 20°.
Investigation and Probable Cause
The Swiss Bureau of Aircraft Accident Investigation (BFU) concluded that the following factors probably contributed to the accident: inadequate mountain flying tactics, and loss of control following downdrafts or turbulence, resulting in collision with terrain.
The aircraft was equipped with a functioning emergency locator transmitter (ELT), which aided in the search. The transponder was not activated, preventing secondary radar tracking. No technical defects were reported.
The probable cause as stated in the report is: inadequate mountain flying tactics and loss of control due to downdrafts or turbulence, leading to collision with terrain.