1968 Piper Super-Cub accident at Bern-Belpmoos (HB-ORC)

Overview and aircraft details On 1 August 1968, a Piper PA-18 Super-Cub registered HB-ORC was involved in an accident at the Bern-Belpmoos aerodrome. The aircraft was a 1953-built, single-engine high-wing monoplane with fixed tailwheel landing gear, powered by a 150 hp Lycoming engine. It was owned and operated by the Segelfluggruppe Bern and was used in glider training operations. ## Approach and accident sequence The pilot, a private pilot with a valid licence and type experience on the accident aircraft, was acting as a glider tow pilot. After releasing the glider, he made a small circuit and entered the final approach. He reported an initial approach speed of 65 mph, later 60 mph, with flaps set to 50 degrees. At the start of the final approach, he stated the aircraft was about 40 metres above ground. He reduced the engine to idle while keeping his hand on the throttle. As the aircraft reached the beginning of a 20-metre-long strip of grain in front of the grass landing area, the pilot reduced speed to 55 mph. He reported that a sudden downdraft pushed the aircraft downward and the landing gear caught in the grain. He immediately advanced the throttle and pulled back on the control stick. Because the aircraft continued to sink, he reduced power again while keeping the stick fully back. At the end of the grain field, the aircraft pitched nose-down, slid a short distance, and came to rest on its nose 28 metres beyond the start of the landing area. ## Damage and injuries The pilot was not injured. The aircraft sustained damage to the engine, engine cowling, and fuselage skin, and the propeller was completely destroyed. Repair costs were estimated at about 20,000 Swiss francs. Ground damage to the grain was minor. ## Investigation findings The investigation noted that the approach was short and that the pilot had checked the windsock before landing and found calm conditions. The report questioned the pilot’s account of a downdraft, stating that in calm, sunny conditions over a flat grain field, updraft rather than downdraft would be more likely. It concluded that the aircraft likely lost altitude naturally when speed was reduced with the flaps fully extended. The pilot’s subsequent power application and immediate reduction were judged to be too late, leading to the collision with the grain and the resulting nose-over.