What happened
On April 24, 2023, a Reims F 172P, registration D-EIRX, was attempting a private VFR departure from the Fur (EKFU) airstrip toward Endelave (EKEL). Following overnight and morning rainfall, the grass runway was notably wet and slippery. The pilot, utilizing a pre-planned mental decision point, intended to abort the takeoff if the airspeed had not reached 60-6 and knots by a specific distance along the runway.
During the takeoff roll on runway 12, which features a downhill slope, the pilot applied full power and extended the flaps to 10°. Upon reaching the predetermined decision point, the pilot noted the airspeed was only approximately 45 knots. Deciding to abort the takeoff, the pilot reduced power to idle and applied full wheel brakes. During this sequence, the aircraft began veering uncontrollably to the right. The aircraft exited the side of the runway in a sideways skid, entering a soaked field. The nose wheel sank into the soft ground, causing the aircraft to rotate over its propeller and left wingtip, eventually coming to rest upside down. There were no injuries to the pilot or the passenger.
The investigation
The Danish Accident Investigation Board examined the aircraft's performance capabilities, the runway conditions, and the pilot's decision-making process. The investigation reviewed the aircraft's mass and balance, the meteorological conditions, and the specific characteristics of the EKFU airstrip. Investigators analyzed the impact of the wet, slippery grass and the downhill slope of runway 12 on the required takeoff distance. The investigation also looked into the availability of wind indicators at the aerodrome and the pilot's operational knowledge of the site.
Findings
- The takeoff attempt was performed under marginal conditions due to the combination of a downhill runway slope, wet and soft grass, and a potential tailwind.
- The pilot's mental calculation for the stop/go decision point failed to account for the significantly increased ground roll and takeoff distance caused by the slippery, soaked surface.
- The lack of a windsock at the airstrip prevented the pilot from obtaining accurate real-time wind information, leading to reliance on outdated observations from earlier in the day.
- The aircraft's excursion was likely exacerbated by the pilot applying significant backpressure on the control wheel during the braking maneuver, potentially causing a tail strike.
- Limited operational knowledge of the private airstrip and a language barrier regarding available information contributed to inadequate pre-flight planning.
Safety action
- The AIB noted that the absence of a windsock at the private airstrip represents a significant downgrade in flight safety.
- The investigation highlighted the importance of thorough pre-planning when operating at non-certified aerodromes where standardized safety equipment may be lacking.