Casualties unknown

1971 Piper J3C Crash at Lämmerenhütte (HB-OIS)

Lämmerenhütte, VS, CH

On July 8, 1971, a PIPER AIRCRAFT CORPORATION J3C-65/L-4. (registration HB-OIS) was involved in an aviation accident near Lämmerenhütte, VS, CH. Investigators recorded the probable cause as: The pilot executed an approach for a potential load drop in difficult terrain with insufficient altitude and speed reserves, falling below minimum airspeed; the available altitude was inadequate to recover the aircraft in time. This summary draws on records from the Swiss Transportation Safety Investigation Board (STSB / SUST).

Sourcesthe Swiss Transportation Safety Investigation Board (STSB / SUST)Primary reportUpdated 2026-09-13Data APIEditorial standards

On July 9, 1971, a Piper J3C (HB-OIS) crashed into steep terrain near the Lämmerenhütte construction site in Switzerland. The pilot and passenger were killed while attempting a low-altitude maneuver to drop supplies.

Incident Overview

On Friday, July 9, 1971, shortly before 06:00 Central European Time, a Piper J3C with registration HB-OIS departed from the Reichenbach airfield. The aircraft was operated by a pilot accompanied by one passenger. Their objective was to fly over the construction site of the new Lämmerenhütte in the Valais canton to drop fresh bread for workers.

Flight Sequence and Crash

At 06:15, the aircraft flew westward at a low altitude over the construction site. Witnesses reported that the occupants waved to people on the ground. After executing a left turn back toward the Gemmi Pass, which involved some altitude loss, the pilot initiated a second approach in a slight climb. Approximately 50 meters before reaching the site, the aircraft suddenly rolled to the right from an altitude of about 50 meters and impacted the ground with the engine still running at full power.

Aircraft and Personnel Details

The Piper J3C was a two-seat high-wing monoplane manufactured in 1944. It had been rebuilt after a fire in 1956 and was owned by the Fluggruppe Reichenbach. At the time of the accident, the aircraft had accumulated 2,049 hours since its rebuild. The pilot, born in 1938, held a commercial pilot license and had over 300 hours of total flight experience, including 105 hours on this specific model. The passenger, born in 1947, had no prior flight experience. Both individuals were wearing seatbelts at the time of impact.

Investigation Findings

The investigation determined that the crash resulted from the pilot attempting a load drop in difficult terrain with insufficient altitude and speed reserves. The aircraft fell below its minimum safe speed during the second approach. Due to the low altitude, the pilot did not have enough vertical space to recover the aircraft's attitude. Contributing factors included the high elevation (2,480 m), an open cabin door which reduced climb performance, and a lack of visual references for judging position relative to the ground. Autopsy results confirmed that both fatalities were caused solely by traumatic injuries sustained in the crash, with no influence from alcohol or drugs.

Probable cause

The pilot executed an approach for a potential load drop in difficult terrain with insufficient altitude and speed reserves, falling below minimum airspeed; the available altitude was inadequate to recover the aircraft in time.

Investigation report by the Swiss Transportation Safety Investigation Board (STSB / SUST). Original record: https://www.sust.admin.ch/inhalte/AV-berichte/765.pdf. This page is a structured re-presentation; facts and quotes are in the Swiss Transportation Safety Investigation Board (STSB), Switzerland.