What happened
On 8 April 2015, a Rotorsport UK Calidus gyroplane, registration G-PCPC, was participating in a private flight at Damyns Hall Aerodrome, Essex. The pilot intended to practice rotor management and wheel balancing on the grass runway. During the pre-rotation phase, the pilot attempted to increase engine revolutions to reach a target rotor speed of 200 rpm. However, the rotor speed failed to exceed 150 rpm.
As the aircraft began to move forward against the applied brakes, the pilot decided to transition into a ground run. To do this, the pilot moved the control stick to the full aft position. Shortly after releasing the brakes and accelerating, the rotor blades struck the tailplane, causing intense vibrations and a loud series of impacts that detached a portion of the fin.
Following the strike, the aircraft veered left. Despite attempts to use right rudder to correct the path, the pilot struggled with directional control due to the severe vibration. The right landing gear subsequently caught in a furrow next to the runway, causing the gear to break off. The gyroplane then tipped onto its right side, resulting in the propeller striking the ground. The pilot escaped the aircraft uninjured.
The investigation
The AAIB examined the sequence of events leading to the rotor strike and the subsequent loss of control. The investigation focused on the pilot's actions during the transition from pre-rotation to the ground run. The inquiry established that the pilot had moved the control stick fully aft while the rotor rpm was insufficient for the maneuver. The investigation also looked into the mechanical damage sustained by the rotor blades, propeller, tailplane, and landing gear.