What happened
During a flight to visit a private airstrip, the pilot attempted an easterly approach using fully extended flaps. The approach was unstable, characterized by excessive airspeed and altitude, which caused the aircraft to touch down deep into the grass runway. In an attempt to recover, the pilot aborted the landing and applied full throttle.
As the aircraft type climbed to an altitude of approximately 10 to 20 meters, the airspeed dropped significantly. Despite the pilot applying left aileron to correct the flight path, the aircraft veered to the right and struck a pile of cut birch trees located roughly 50 meters from the end of the strip. The occupants of the aircraft escaped the wreckage without any injuries, though they encountered difficulty exiting due to partially obstructed doors.
The investigation
SHK examined the characteristics of the airstrip, which measured 270 meters in length and 30 meters in width. While the aircraft's manual specifies a required rolling distance of 107 meters for landing, it does not provide a specific landing distance from a 50-foot height.
To understand the flight dynamics, SHK conducted a reference flight using an identical aircraft model. The investigation established that when full throttle is applied while the aircraft is trimmed for idle and flaps are fully extended, the airspeed decreases to the point of a stall if no corrective control inputs are made. Crucially, the flight testing revealed that the aircraft's attitude during this full-flap stall is nearly identical to a normal climbing attitude with retracted flaps. This similarity likely prevented the pilot from recognizing the onset of the stall.
Findings
- The primary cause of the accident was the decision to continue the landing despite an unstable approach.
- The touchdown occurred too far down the runway, necessitating a forced go-around.
- The loss of control was driven by a stall occurring during the go-around, which went undetected because the aircraft's attitude during the stall closely resembled a standard climb.
Safety action
- It is recommended that the Swedish Transport Agency encourage instructors and inspectors to emphasize and practice the concept of stabilized approaches during flight training, proficiency checks, and skill tests.