Summary
On Saturday, 13 April 1963, at 1020 hours, a student pilot departed La Côte aerodrome in a Piper Cub J3C (registration HB-OUU) for a 300 km navigation flight. The planned route was La Côte–Granges–Sion–La Côte. After refueling at Granges, the pilot departed at 1210 hours. At 1314 hours, the aircraft struck a slope in the Selibüel area at an elevation of 1660 meters, about 45 km from Granges and off the intended route. The pilot was ejected and killed instantly. The aircraft was totally destroyed.
Aircraft and Pilot Information
The aircraft was a Piper J3C (L-4), serial number 47581-0-8, powered by a Continental C-90-8F engine rated at 90 horsepower. It had a certificate of airworthiness valid from 30 March 1963 to 22 April 1964. At the time of the accident, the aircraft weighed approximately 504 kg, within the maximum of 580 kg, and the center of gravity was within limits. Total time in service was 1013 hours 50 minutes, with 7 hours 50 minutes since the last 33-hour inspection. No preaccident mechanical issues were identified.
The pilot, born in 1916, held a student pilot certificate valid until 24 April 1964, with authorization for cross-country flights. He began flight training in April 1962 and had logged 43 hours 16 minutes total (23 hours 13 minutes solo) on the Piper Cub. He was described as very athletic. No evidence suggested impairment at the time of the accident.
Flight History
The student pilot had previously attempted the required 300 km navigation flight on 19 October 1962 but encountered adverse weather, losing his way and landing at Interlaken. On 13 April 1963, he obtained permission from his instructor after the instructor checked weather reports from Granges, Sion, and Geneva. The reports indicated good visibility at Granges, good conditions in the Sion valley (though Alpine passes were closed), and generally improving weather. The student pilot departed La Côte at 1020 hours and landed at Granges at 1130 hours. After refueling, he stated his intention to continue to Sion via Fribourg, Montreux, and Martigny, and was advised against attempting Alpine passes. He departed Granges at 1210 hours.
Accident Sequence
No information is available about the aircraft's movements in the hour following departure from Granges. Around 1315 hours, witnesses in the Selibüel area heard an aircraft engine, noting normal sounds and turns near the Schwefelberg. One witness briefly saw the aircraft flying very low in thick fog. At 1314 hours, the aircraft, approaching from the north, struck a group of small fir trees and impacted the ground between the Selibüel summit and the col at 1660 meters.
Meteorological Conditions
The general weather situation was dominated by high pressure over France and low pressure over the Po Valley, creating a blocking situation north of the Alps with local showers and scattered to broken clouds over Valais and the northern Alps. At the time and location of the accident: evolving cloud cover, 2–5/8 stratocumulus at 1200 meters, 7–8/8 stratus at 1500 meters with tops at 3500 meters; visibility below 1200 meters was 15–20 km, near cloud base 4–8 km; wind from the northwest at 5–10 kt up to 2000 meters, no turbulence, light icing above 2000 meters. In the Bulle area, morning cumulus varied from 3–4/8 to 4–5/8, base 300–600 meters above ground; Moléson was in clouds halfway up; around noon, Oron had a ceiling of 400–500 meters, and the valley between Rossens and Bulle had 300–400 meters. Lake Geneva was clear.
Investigation Findings
The investigation revealed that the student pilot, caught in unfavorable weather over unfamiliar terrain, lost all ability to navigate and continue safely. It could not be determined when, where, or why he deviated from the prescribed route or whether the earlier failed navigation attempt influenced his decisions. The distance from Granges to the accident site is 45 km, corresponding to about 25 minutes of flight, but the accident occurred 65 minutes after departure, indicating the aircraft did not fly directly from Granges. The weather forecasts, while not optimal, did not constitute a definitive reason to prohibit the flight given the student's training level.
Probable Cause
For unknown reasons, the student pilot entered an area where meteorological and topographical conditions no longer allowed him to continue his flight safely.