What happened
On May 19, 2016, a Robin DR-40/0-180, registration F-GXBB, was performing a long-distance visual flight from Coimbra, Portugal, to Dax/Seyresse, France. The crew, consisting of one pilot and two companions, encountered cloud cover while flying over the Vitoria control zone, forcing them to descend below 5,000 feet to maintain visual contact with the ground.
During the flight, the crew attempted to divert to Vitoria Airport, but found it closed. They subsequently expressed intentions to proceed toward San Sebastian. At approximately 18:10 local time, witnesses in the town of Arbizu reported hearing an impact in the air, followed by seeing the aircraft flying in a steep, descending spiral. The aircraft struck the roof of a three-story house and continued through a street, impacting a detached house and a garden before coming to rest in a fenced plot. The impact resulted in 3 fatalities, and the aircraft was completely destroyed.
The investigation
The CIAIAC investigation focused on the flight path, weather conditions, and the presence of wildlife in the area. Investigators recovered the carcass of a griffon vulture from a nearby field; the bird showed significant traumatic injuries consistent with an impact with an aircraft. While the wreckage was too heavily damaged to pinpoint the exact point of contact on the airframe, the absence of detached components suggested the strike did not cause structural disintegration in mid-air. The investigation also examined the crew's flight planning and the increasing population of vultures in the Iberian Peninsula.
Findings
- The primary cause of the accident was the loss of control of the aircraft, likely due to striking a griffon vulture.
- The accident was caused by the improper planning of a long-duration visual flight, specifically regarding the evaluation of weather conditions along the route and at alternate aerodromes.
- Heavy cloud cover in the Araquil Valley limited the flight ceiling, forcing the aircraft into lower altitudes.
- A high concentration of griffon vultures, estimated at approximately 200 birds, was present in the valley at the time of the accident.