What happened
On September 22, 2017, a Flight Design CTSL Supra Light, registration UR-STAS, departed Alexandroupolis Airport as part of a two-aircraft formation. The flight was destined for Bucharest, Romania, cruising at an altitude of 10,500 feet. The second aircraft in the formation, led by another identical aircraft (UR-FOX), was responsible for all radio communications with ground stations because the pilot of UR-STAS did not speak English.
While approaching the RODIP waypoint near the Bulgarian border, the pilot of UR-STAS transmitted a request to the lead aircraft to reduce speed. This was the final communication received from the aircraft. Shortly thereafter, at approximately 10:15 UTC, the aircraft crashed in the Kerasia area of Rodopi, roughly 12 km northwest of Komotini. The wreckage was found scattered across a large area, with parts of the fuselage and wings separated by hundreds of meters.
The investigation
The investigation focused on the sudden loss of control and the mid-air breakup of the aircraft. Investigators examined the debris field, which covered approximately 500,000 square meters, noting that the heavy components like the engine and cabin were located in the southern section while wings were found dispersed to the east and west. An eyewitness reported hearing an explosion and observing the aircraft falling in a spin.
Physical evidence at the crash site included a partially consumed bottle of alcohol. Forensic analysis of the pilot's blood revealed an alcohol concentration of 2.24% gr/lt, which was significantly higher than the legal limit of 0.20% gr/lt. Additionally, investigators found that the aircraft's GPS unit had been powered off during the flight, preventing any data recording of the final moments.