What happened
On August 19, 2006, a Piper Arrow IV PA-28RT-201, registration HB-PEO, was performing a training flight at Langenthal airfield in Switzerland. The flight was part of a pilot's transition training to this specific model, which features retractable landing gear and a constant-speed propeller. The aircraft was operating at a high takeoff weight on a grass runway, a condition that significantly increases the required takeoff distance.
During the takeoff roll, the pilot reached 50 knots near a local restaurant, meeting the pre-established criteria for continuing the takeoff. However, shortly after, the pilot began to doubt if the remaining runway length would be sufficient and partially reduced engine power. The instructor intervened by applying full power to maintain momentum. As the aircraft lifted off, the pilot pulled the nose up too sharply, prompting the instructor to take control of the pitch. At this critical juncture, the pilot reduced the engine power to idle, causing the aircraft to settle back onto the runway. The instructor applied full power once more in an attempt to clear an obstacle, but the aircraft overshot the end of the runway, crossed a stream, and came to rest in a field.
The investigation
The investigation examined the takeoff performance requirements, the crew's communication, and the instructor's interventions. Investigators found that while the pilot had calculated weight and balance, no specific takeoff distance calculation was performed for the actual grass runway conditions. Although the pilot had previously calculated distances for hard surfaces, the grass runway required an additional 20% to 25% distance due to increased rolling resistance.
Findings
- The primary cause of the accident was an improperly executed takeoff roll and a decision to abort the maneuver at a point where a safe stop was no longer possible.
- There was a significant breakdown in communication; the instructor used the command "stop!" to indicate the pilot should stop moving the throttle backward, but the pilot interpreted this as a command to abort the takeoff.
- The pilot's mental preparation for this time-critical maneuver was incomplete.
- The instructor's intervention was not sufficiently decisive to prevent the dangerous situation.
Safety action
No specific safety recommendations were recorded in the source material.