What happened
On June 1, 2016, an instructor and a student pilot were conducting a training flight in a 3X47 Navigator (registration SP-SBBA). The flight originated from Krasocin (EPKL) with an intended destination of Biała Podlaska (EPBP), including a planned stop at the Wiśniew airfield. Due to an approaching storm front, the crew landed at Wiśniew to wait for weather conditions to improve.
After approximately two hours, the instructor decided to continue the flight. Upon inspecting the Wiśniew airfield, the instructor noted numerous puddles on the grass runway but believed the eastern section was in acceptable condition. During the takeoff roll, the student pilot struggled to maintain directional control, prompting the instructor to take control of the aircraft at roughly the halfway point of the runway.
As the aircraft reached the end of the runway, it rotated; however, the insufficient remaining distance prevented a safe climb. The left side of the horizontal stabilizer struck a concrete fence post, approximately 180 cm above the ground. The impact caused severe damage to the tail section, including the left side of the stabilizer and the elevator. The aircraft subsequently struck the ground approximately 25 meters beyond the airfield boundary, coming to a halt 50 meters from the airfield perimeter. Both occupants exited the aircraft safely without injury.
The investigation
The PKBWL investigation focused on the aircraft's technical condition, the runway surface, and the takeoff parameters. Investigators examined the aircraft in a hangar and found no mechanical failures; the engine was operating at takeoff power, and all control linkages were intact. The investigation also analyzed the aircraft's weight and the environmental conditions at the time of the accident.
Findings
- The aircraft's takeoff mass exceeded the maximum allowable takeoff mass (MTOW) by approximately 19.71 kg (a 4.17% excess).
- The grass runway surface was soft and saturated with numerous puddles due to recent heavy rainfall, which increased rolling resistance and lengthened the takeoff roll.
- The pilot failed to make a decision to abort the takeoff when the aircraft failed to accelerate sufficiently or maintain direction.
- The primary cause was an improper assessment of the runway surface condition and the failure to abort the takeoff within a distance that would have allowed the aircraft to stop within the usable airfield area.
No safety recommendations were issued by the Commission in this report.