What happened
On 13 February 2017, a Rotorsport UK MT-03 gyroplane, registration G-RTIN, was engaged in a training flight at Turweston Aerodrome in Northamptonshire. The flight objective involved a series of short-duration takeoffs and landings, known as "hops," on Runway 09. Following the fifth landing, the aircraft was stopped and prepared to taxi back to the takeoff point via a right-hand turn.
During this taxiing maneuver, the control stick moved rapidly to the right without restraint. Because the wind was blowing from the left of the aircraft's nose, this movement caused the rotor disc to be exposed to the wind, leading to a sudden roll to the right. The instructor was unable to intervene or correct the stick position before the rotor assembly struck the ground, causing the aircraft to overturn onto its right side. There were no injuries to the two crew members on board, though the aircraft sustained severe damage to the rotor assembly, propeller, vertical stabilizer, nosecone, and right wheel spat.
The investigation
The AAIB examined the sequence of events, focusing on the handover of controls between the student pilot and the instructor. During the flight, the instructor had been managing the throttle while the student maintained stick inputs. The investigation looked into the communication regarding control authority and the physical movement of the control stick during the taxiing turn.
It was noted that the student pilot believed the instructor was in control of the stick due to the frequent exchanges of control throughout the session. Conversely, the instructor believed the student was in full control of the stick, though he was monitoring it to prevent rearward movement. The investigation also assessed the aerodynamic impact of the wind direction relative to the rotor disc during the turn.