What happened
On October 8, 2023, a Schempp-Hirth Ventus bT glider, registration OY-NMX, was performing a landing at Kalundborg (EKKL) under visual flight rules. During the landing phase, the pilot reported a headwind on runway 09 and intended to land on the grass area east of the paved runway to facilitate taxiing toward the hangar area.
Simultaneously, a person on the ground was operating a car with a trailer, tasked with moving winch cables from the western end of the airfield to the eastern end. As the vehicle approached the runway crossing point, the driver scanned the approach sector and determined no landing traffic was present. The driver then proceeded to cross the runway from south to north.
During the landing rollout on the grass, the pilot of OY-NMX observed the approaching vehicle and attempted an evasive maneuver using wheel brakes and a leftward ground loop. Despite these efforts, the glider's right wing struck the front of the vehicle, causing the aircraft's fuselage to subsequently impact the left side of the car. The collision resulted in significant damage to the glider and minor damage to the vehicle. No injuries were reported among the pilot or the person in the vehicle.
The investigation
The investigation examined the environmental conditions, communication protocols, and the driver's observations. It was noted that the sky was partly cloudy with a blue and white background, and the glider was white. The investigation also looked into the driver's visibility, noting that the vehicle's windows were dirty and greasy. Furthermore, the investigation reviewed the communication setup, finding that while the pilot was communicating via Kalundborg Radio, the driver was not monitoring these transmissions and was instead using an internal radio system that did not include air traffic information.
Findings
Several contributing factors led to the collision:
- Limited visibility caused by dirty vehicle windows and potential blind spots within the car.
- Reduced scanning effectiveness because the vehicle crossed the runway at a 45-degree angle rather than a perpendicular 90-degree angle.
- Difficult visual detection of the white glider against the white and blue sky background.
- Lack of situational awareness due to the driver's focus on the task at hand and the absence of radio communication regarding arriving or departing traffic.
- Lack of integrated communication, as the driver was not monitoring the airfield's active radio frequency.