What happened
On 3 June 2018, a CEA DR221B Dauphin, registration G-RRCU, was performing solo circuit training at Tatenhill Airfield in Staffordshire. The weather was sunny with an ambient temperature of 24°C. Following a completed circuit and landing, the pilot retracted the flaps and initiated a takeoff roll from Runway 26 using full power.
As the aircraft reached the point where the tail lifted off the runway, the pilot experienced an intense cramp in his right leg. In an attempt to manage the sudden pain, the pilot straightened his leg, which inadvertently applied increased pressure to both the right brake and the right rudder pedal. Although the pilot reacted by quickly reducing the throttle, the asymmetric braking and steering caused the aircraft to veer 90 degrees across the runway. As the aircraft decelerated, the left landing gear collapsed, leading to a further rotation of the airframe and causing the propeller to graze the ground. There were no injuries to the pilot.
The investigation
The investigation was based on the aircraft accident report submitted by the pilot. Investigators examined the circumstances surrounding the physical onset of the cramp and the subsequent control inputs. The pilot noted that the cabin environment had very little airflow, which, when paired with the high external temperature and insufficient fluid intake, likely created conditions conducive to muscle cramping.