What happened
On a day dedicated to air traffic control training, two Avro Anson aircraft were conducting a combined exercise. The first aircraft, registered NK380, was flying with one pilot on board. It was operating alongside a second Avro Anson, registered EG251, which also carried a single pilot. Both crews were participating in an ATC school exercise when the incident occurred.
During the flight, the pilot of the EG251 initiated a turn. As this maneuver was executed, the aircraft collided with the NK380. The impact caused both airplanes to lose control immediately. They subsequently dived into the ground and crashed in the area of Uffington, Berkshire. Both airframes were destroyed upon impact.
Findings
The official investigation determined that the collision occurred because the pilot of the EG251 began a turn without having an accurate knowledge of the position of the other aircraft. This lack of situational awareness regarding the NK380 led directly to the mid-air collision. Both pilots were killed in the accident.