What happened
On May 14, 2022, a mid-air collision occurred approximately 8 nautical miles east-southeast of Sønderborg (EKSB) involving two De Havilland DHC-1 Chipmunk Mk. 22 aircraft, registrations OY-ALD and OY-ATR. The incident took place during a private formation training flight consisting of four aircraft.
The formation was flying on an easterly course at an altitude of approximately 1,700 feet above sea level, practicing formation change maneuvers. During one of these maneuvers, the right wing of OY-ALD struck the tailwheel of OY-ATR. Following the impact, the pilot of OY-ARG experienced a partial loss of control and a loss of altitude. However, control was regained at a lower altitude, and the pilot proceeded to land at Vojens/Skrydstrup (EKSP) without further incident. The pilot of OY-ATR continued the flight to Sønderborg (EKSB), landing safely.
The investigation
The investigation focused on the structural damage sustained by OY-ALD, which suffered significant structural damage to its right wing and aileron. The investigation also reviewed the operational context, noting that the four-aircraft formation held a general dispensation from the Danish Civil Aviation Authority (Trafikstyrelsen) to fly below minimum altitudes for the purpose of training. The pilots involved had established standard operating procedures for their formation flights, and the authorities were aware of the training mission.
Following an initial safety investigation, the Danish Accident Investigation Board (Havarikommissionen) decided not to conduct further inquiries, concluding the investigation with this statement.