What happened
On March 4, 2004, a Piper PA-28-140, registration HB-PAP, was performing a VFR training flight at Biel-Kappelen airfield. The flight, involving a student pilot and an instructor, included several maneuvers, including simulated approaches and touch-and-go landings. During a touch-and-go attempt on runway 05, the aircraft touched down approximately 143 meters past the runway threshold. Due to the soft condition of the runway surface, the aircraft experienced more deceleration than anticipated.
Following the touchdown, the instructor ordered a go-around. The student pilot briefly hesitated before advancing the throttle. However, the engine failed to build power effectively. Realizing the takeoff was not proceeding correctly, the instructor took control and ordered an immediate aborted takeoff. Despite applying brakes and attempting to lift the nose, the aircraft could not be stopped before exiting the runway. The aircraft crossed a main road and a cycle path, eventually coming to rest in a field after the nose gear struck an embankment. The crew escaped without injury, though the aircraft sustained damage to the nose gear, propeller, and engine cowling.
The investigation
Investigators examined the aircraft's technical condition, the engine, and the environmental factors. While initial inspections of the airframe and controls showed no pre-existing defects, subsequent engine testing revealed significant vibrations and an uneven running pattern at approximately 1600 RPM. Further analysis of the spark plugs indicated that five of the eight plugs failed under high pressure.
Additionally, the investigation noted that a required cockpit placard—warning pilots not to open the throttle rapidly—was missing from the aircraft. The investigation also looked into the runway conditions, noting that while the instructor believed the runway was frozen based on earlier temperature reports, the surface had actually begun to thaw, making it soft.
Findings
- The primary cause of the accident was the overrun of the runway threshold because the takeoff attempt was aborted too late following a long landing.
- The engine's failure to provide sufficient or timely power contributed to the inability to complete the go-around.
- An inaccurate assessment of the runway surface conditions led the crew to believe the runway was frozen when it was actually soft.
- The student pilot's hesitation and the subsequent rapid application of the throttle may have contributed to the engine disturbance, especially as the required warning placard was not present in the cockpit.