What happened
On May 8, 2018, a PIPER PA28 180, registration OY-BBJ, was conducting a local VFR pleasure flight from Randers Airport (EKRD) with three passengers on board. During the takeoff roll on runway 25, the pilot utilized the full length of the runway and opted to use flaps for the departure. Despite a sensation that the aircraft was not accelerating as expected, the pilot continued the takeoff roll.
The aircraft became airborne at an estimated speed of 60-70 knots, but immediately after liftoff, it was unable to accelerate or climb despite full engine power and a nose-up attitude. The aircraft flew at a very low altitude, approximately 7 to 8 meters, benefiting from ground effect. As the aircraft passed the threshold of runway 07, it entered a developed stall and struck a field with a high vertical sink rate. All occupants were able to evacuate the aircraft following the impact, which resulted in minor injuries.
The investigation
The investigation by AIB Denmark focused on the aircraft's performance, the pilot's preparation, and the environmental conditions. Investigators performed theoretical weight and balance calculations and analyzed the aircraft's flight performance relative to its power curve. The investigation also examined the pilot's recent training status and the technical configuration of the aircraft, including the use of flaps and the engine's power output.
Findings
Several contributing factors led to the accident:
- The pilot failed to perform a weight and balance calculation prior to departure. Calculations performed by investigators revealed that the actual weight and balance of the aircraft were outside of its certified limits.
- Environmental factors, including a high takeoff mass, temperatures above standard, and a lack of headwind, degraded the aircraft's takeoff performance.
- The pilot's recent flight experience was low, with only 24 minutes of flight time in the previous ten months, which may have influenced aircraft handling based on past habits rather than current conditions.
- The aircraft was operating in the "region of reversed command," where the low airspeed and high nose attitude prevented effective acceleration and climbing.
- The pilot's decision to continue a prolonged takeoff roll, potentially influenced by a misinterpretation of airspeed (confusing knots with mph on the airspeed indicator), contributed to the loss of control.
- The extremely low altitude at the time of the stall made it impossible to recover the aircraft before impact.