Aircraft and Location
The aircraft involved was a Piper PA-28-140, registration HB-PAP, built in 1976. It was owned and operated by Fluggruppe Seeland. The accident occurred on 17 April 2006 at approximately 17:45 local time at Biel-Kappelen airfield, a private grass airfield located 7 km southeast of Biel, Switzerland. The runway was oriented 047°/227° with a length of 570 m and a width of 30 m, and had a displaced threshold of 120 m on runway 23. Prior to the accident, the runway and taxiway were still somewhat soft from earlier rain, increasing rolling resistance.
Flight History
Earlier that day, a flight instructor had conducted two sightseeing flights with the same aircraft. In the afternoon, he met a prospective student for a familiarization flight. During the pre-flight briefing, it was agreed that the student's brother could also join as a passenger. At 17:20, the instructor taxied the aircraft to the holding position for runway 23. The aircraft had already been used for two other flights that day with a different pilot. After a delay due to explanations, the instructor initiated a rolling takeoff on runway 23 with flaps set to 25°.
Accident Sequence
Shortly after crossing a road that intersected the runway, the aircraft lifted off but then made several brief contacts with the ground. It came to a stop in a ploughed field approximately 200 meters beyond the end of the runway, slightly to the right of the runway centerline. The nose gear was broken off, the propeller blades were bent rearward, and the nose cowling was damaged.
Investigation Findings
The investigation included witness statements, a video recording, and examination of ground marks. The pilot reported that during the takeoff, the engine produced 2400 RPM. He noted that the aircraft rotated and lifted off at 45 mph almost by itself, and thereafter a continuous stall warning sounded. The video showed the elevator was held significantly nose-up from the start of the takeoff roll.
Weight and balance calculations indicated a takeoff mass of 2195 lbs, exceeding the maximum takeoff mass of 2150 lbs. With two occupants instead of three, the mass would have been 1919 lbs. The aircraft had no pre-existing technical defects; the engine and controls functioned normally. The fuel tanks contained 19 US gallons total.
Probable Cause
Inadequate takeoff procedure; factors included failure to abort the takeoff, high takeoff mass, and poor assessment of runway condition.