What happened
On April 17, 2006, a Piper PA-28-140, registration HB-PAP, was performing a VFR instructional flight at Biel-Kappelen airfield. The flight, intended as a discovery flight for a prospective student, included a second passenger in the rear seat. During the takeoff roll on runway 23, the pilot attempted a rolling takeoff using 25° flaps.
Shortly after passing a road crossing the runway, the aircraft lifted off but failed to maintain a stable climb. The aircraft experienced several bounces, with the tail skid making contact with the ground, leaving visible tracks in the turf. The aircraft eventually came to a stop in a plowed field approximately 200 meters beyond the runway end. The passenger in the front seat sustained bruises from the seatbelts, while the pilot and the second passenger remained uninjured. The aircraft sustained damage to the nose gear, propeller, and cowling.
The investigation
Investigators examined the aircraft's technical condition, the airfield environment, and the flight parameters. The investigation utilized witness statements, video footage, and physical evidence from the terrain.
Technical inspections of the engine and control surfaces revealed no mechanical failures. The investigation noted that the airfield's grass runway was soft due to recent rainfall, increasing rolling resistance. Furthermore, the aircraft's weight and balance were analyzed. The presence of a heavy passenger in the rear seat shifted the center of gravity significantly aft compared to the pilot's usual experience with lighter loads. The pilot had also applied significant back pressure on the elevator from the start of the takeoff roll to relieve pressure on the nose gear.
Findings
- The aircraft's takeoff mass was above the maximum allowable takeoff weight.
- The center of gravity was shifted aft due to the heavy rear passenger, creating a highly tail-heavy moment that caused an unexpected and premature rotation.
- The pilot's inadequate takeoff procedure was the primary cause, characterized by an attempt to force an early rotation.
- The pilot failed to abort the takeoff after the initial loss of stability and ground contact.
- There was a misjudgment regarding the soft condition of the runway surface.