Accident Details
On 10 April 1969, at approximately 1330 MEZ, a Jodel D-11 aircraft, registration HB-SUV, was on a private training flight from Colombier/NE to Speck-Fehraltorf. The pilot, accompanied by his son as passenger, had departed Speck-Fehraltorf earlier at 1212 MEZ for a training flight to Colombier. The return flight proceeded without incident until the approach to Speck-Fehraltorf.
After a normal traffic pattern, the pilot initiated a landing approach to runway 30. According to the pilot, he intended to execute a low approach and a "power-on landing" due to grading work at the northern end of the field, which reduced the available runway length from the normal 700 x 30 meters to approximately 400 x 30 meters. A NOTAM (C 1006/69) had been issued on 23 January 1969 indicating that the airfield required prior permission (PPR).
During the final approach, the pilot reported that he was at an altitude of about 20 to 25 meters above ground level (AGL) while crossing a low wooded area, approximately 450 meters before the runway threshold. He then experienced increased sink, which he attributed to local turbulence, and compensated by adding power to maintain an approach speed of 100–105 km/h. The pilot intended to "power" the aircraft onto the runway at a height of 2–3 meters, about 150 meters before the threshold. At that moment, the aircraft sank abruptly; despite immediate application of power and aft control stick input, the pilot could not arrest the descent. The main wheels touched the soft field short of the runway, causing heavy braking and leading to the aircraft overturning after about 15 meters.
Aircraft and Crew
The aircraft was a Jodel D-11, a two-seat low-wing monoplane with a cranked wing, wooden construction, and fixed tailwheel landing gear. It was owned and operated by the Flugsportgruppe Zürcher Oberland, based at Speck-Fehraltorf. The aircraft had accumulated a total of 1640:21 flight hours. Its last 100-hour inspection was on 28 February 1969 (28:41 hours prior), and its last condition check on 31 October 1968 rated the condition as good. At the time of the accident, the takeoff weight was approximately 550 kg, within the maximum allowable weight of 620 kg, and the center of gravity was within limits.
The pilot, born in 1922, held a private pilot license issued on 12 March 1957, valid until 21 October 1970, with endorsements for towing and for Fairchild and Pelikan U4M aircraft. His total flight experience was 148 hours 18 minutes with 763 landings, including about 67 hours on the Jodel D-11 type. Since his last license renewal on 26 October 1968, he had flown 3 hours 46 minutes with 23 landings, about 2 hours in the last three months. There were no recorded incidents in his file.
The passenger, born in 1950, was the pilot's son and held a student pilot certificate for powered and glider aircraft.
Weather
The weather at 1330 MEZ at Zurich was reported as cloudless, visibility 20–25 km, temperature 19°C, relative humidity 32%, wind from WNW at 1 knot. The approach sector experienced light gusty conditions.
Investigation
The Swiss Aircraft Accident Investigation Commission conducted the investigation. The pre-investigation was completed on 13 May 1969, and the final report was issued on 3 July 1969.
The investigation determined that the pilot's chosen approach tactic was inappropriate. The pilot misjudged the approach height and trajectory. The available runway length of 400 meters was sufficient for a normal landing. The pilot's decision to conduct a low, power-on approach resulted in the aircraft touching down in the soft field before the runway, leading to the overturn.
Conclusion
The probable cause of the accident was an inappropriate approach tactic that resulted in the aircraft contacting the ground before the runway and overturning.