What happened
On 16 September 2021, a MA Scale F4 Phantom turbine-powered model aircraft was conducting its maiden test flight near Kenyon Hall Farm Airfield in Warrington, Cheshire. The flight, which was a private operation, initially proceeded normally, reaching an altitude of approximately 200 ft agl. During the flight, the pilot observed sluggish aileron response and found it necessary to apply continuous up-elevator trim to maintain level flight.
While performing a 180-degree downwind turn, the aircraft suddenly veered toward a north-west heading. Despite the pilot's attempts to correct the movement with aileron inputs, the aircraft lost control, entered a spin, and flew beyond visual line of sight behind a tree line. The aircraft eventually came to rest on a railway track adjacent to the airfield, near a pedestrian crossing, where it was run over by a passing train. The impact resulted in the aircraft being destroyed, though no injuries were reported.
The investigation
The AAIB investigation examined the flight history, the club's safety procedures, and the site's proximity to the railway. The pilot noted that the airspeed had dropped too low while they were focused on managing the elevator trim. The investigation also reviewed the model flying club's risk assessment and operational protocols. While the club's procedures advised members to avoid flying toward the railway track, the investigation found that the risk assessment did not specifically account for a loss of control event that could result in an aircraft landing on the tracks. Furthermore, the club's procedures lacked instructions for notifying authorities if an aircraft landed on the railway or how to handle the retrieval of models from such areas.
Findings
- The pilot allowed the airspeed to decrease excessively while attempting to correct the aircraft's trim.
- The loss of control led to the aircraft exiting the pilot's visual range.
- The club's risk assessment failed to identify the specific hazard of an aircraft crashing on or near the railway line.
- There was no established protocol for notifying Network Rail of objects on the tracks or for safely retrieving aircraft from the railway boundary.