What happened
On June 20, 2015, a private flight was departing from Thun Airport (LSZW) bound for Freiburg im Breisgau. The pilot, who was preparing for a long-distance trip to Norway, had recently completed several check flights under light load conditions. For this specific departure, however, the Cessna 172P, registration HB-CIE, was fully fueled and carrying a passenger.
During the takeoff roll on the dry runway, the pilot noted that the engine RPM remained steady at just over 2300. Despite the aircraft being heavier than during previous training flights, the pilot became concerned because the aircraft's performance did not match his expectations. Disturbed by the recent maintenance work performed on the aircraft and sensing insufficient power, the pilot decided to abort the takeoff before reaching the midpoint of the runway.
As the pilot retarded the throttle, the aircraft was approximately one meter above the ground. In an attempt to re-apply power, the aircraft's stall warning activated. Convinced that a safe takeoff was no longer possible, the pilot continued the abort. The aircraft touched down again and could not be stopped within the remaining runway length. The aircraft crossed the taxiway and came to a halt in tall grass after narrowly avoiding a metal barrier.
The investigation
The investigation focused on the aircraft's performance and the pilot's decision-making process. Investigators examined the mechanical state of the Cessna 172P and found no technical malfunctions or engine limitations. The investigation also considered environmental factors, noting that a slight tailwind cannot be ruled out given the prevailing weather conditions at the time of the incident.
Findings
- The aircraft was operating at a higher weight than during the pilot's recent check flights due to full fuel tanks and an additional passenger.
- The pilot experienced a perceived lack of performance, which was compounded by anxiety regarding recent maintenance work.
- The decision to abort the takeoff while the aircraft was airborne led to a secondary touchdown and subsequent runway excursion.