What happened
On January 14, 2006, at Chavenay Aerodrome, a mid-air collision occurred between a Cessna 150 (registration F-BSIX) and a Colomban MC15 Cricri (registration F-PHMN). The Cessna, an aircraft used for flight instruction, was on its final approach to runway 10 with an instructor and a student pilot on board. Simultaneously, the Cricri was positioned at the holding point, awaiting clearance for departure.
At approximately 13:32 UTC, the tower controller authorized the Cricri for an immediate takeoff. Shortly thereafter, the controller instructed the Cessna pilot to perform a go-around. During the Cricri's initial climb, the two aircraft collided above the runway. The propeller of the Cessna struck the vertical stabilizer of the Cricri, causing the latter to crash at the threshold of runway 28. The pilot of the Cricri was killed in the accident, while the Cessna sustained minor damage and landed safely on runway 23.
The investigation
The investigation focused on the sequence of movements on the airfield and the management of traffic by the tower controllers. Investigators examined the movements of a third aircraft, a taildragger, which had been clearing the runway just prior to the collision. The investigation also reviewed the controller's decision-making process regarding the timing of the Cricri's departure clearance and the subsequent go-around instruction given to the Cessna.
Findings
- The controller authorized the Cricri for an immediate takeoff while the Cessna was on final approach, intending to clear the runway before the Cessna's arrival.
- The delay caused by a third aircraft clearing the runway prevented the expected separation.
- The controller authorized the takeoff of the Cricri before the Cessna had passed the runway threshold, creating a conflict between the climbing Cricri and the approaching Cessna.
- The instructor pilot of the Cessna attempted a go-around to avoid the conflict, but the collision occurred during the Cricri's steep initial climb.