What happened
On 26 March 2017, at approximately 1450 UTC, a Mercury trike, registration G-MYUB, was undergoing a ground engine run at Otherton Airport, Staffordshire. The pilot-owner was conducting the run to investigate a misfire that had occurred during a flight the previous day. At the time of the incident, the aircraft's wings had been removed, and the intention was not to fly.
To secure the aircraft, a chock had been positioned in front of the nosewheel, and the pilot was applying the footbrake. During the engine test, the aircraft moved forward approximately 10 feet, jumping over the placed chock. The pilot responded by applying full brake pressure and reducing the engine to idle power to stop the movement.
Distracted by the displaced chock, the pilot exited the cockpit to retrieve it from behind the aircraft. While reaching down to pick up the chock, the pilot was struck in the face by the still-rotating propeller. The impact was forceful enough to cause damage to the propeller itself. A nearby worker provided initial first aid before the pilot was transported to a hospital via air ambulance.
The investigation
The investigation established that the pilot experienced a momentary lapse in focus. Although the pilot had significant experience as a former Royal Air Force groundcrew member, he was relatively inexperienced as a pilot, with 33 total flying hours.
The investigation also noted that the pilot was not wearing a helmet, as he did not anticipate flying. He later reflected that wearing protective headgear might have mitigated the severity of his injuries. The investigation confirmed that the pilot's primary error was the decision to approach the propeller arc while the engine was still running.