What happened
On August 30, 2020, a Rockwell Commander 114B, registration D-EQCA, was involved in a fatal accident during a private VFR pleasure flight near Fur (EKFU), Denmark. The flight was intended to proceed from the private airstrip at Fur to Billund.
Prior to departure, the pilot evaluated the wind and runway conditions. Despite the presence of a tailwind, the pilot elected to use runway 12. During the takeoff roll, the pilot noted a good initial acceleration but perceived that acceleration had ceased once the aircraft reached approximately 65 knots. The pilot attempted to rotate the aircraft at this speed, likely expecting the increasing downslope of the runway to assist. Upon liftoff, the aircraft's stall warning was briefly activated. To avoid trees and structures at the end of the runway, the pilot executed a steep right turn. The aircraft subsequently struck trees, resulting in a crash and a post-impact fire.
Of the occupants on board, there were 3 fatal injuries and 1 serious injury.
The investigation
The Danish Accident Investigation Board examined the takeoff performance, environmental factors, and the pilot's decision-making process. The investigation included a wind tunnel test and a review of the airstrip's characteristics.
Investigators found that the grass runway at EKFU had a significant downslope on runway 12. While the pilot estimated a tailwind of 2 to 5 knots, the investigation suggested the actual tailwind component was likely higher. Furthermore, the wind sock at the private airstrip was non-standard in size, which may have hindered an accurate assessment of wind speed and direction. Calculations performed by the AIB demonstrated that the required takeoff distance for the Rockwell Commander 114B under these conditions exceeded the available 600 meters of runway.
Findings
- The primary cause of the accident was that the required takeoff distance was longer than the available runway length, leading to the collision with trees.
- The pilot's focus on the decision to take off with a tailwind, combined with a perception of the runway slope, likely led to an underestimation of the necessary takeoff distance.
- An attempt to rotate the aircraft at an insufficient airspeed may have increased drag, further extending the ground roll.
- The aircraft was destroyed in the collision and subsequent fire.