An engine fault was a contributing factor in the death of a Royal Navy serviceman during a training exercise, an investigation has concluded. Lieutenant Rhodri Leyshon was killed when a Merlin Mk4 helicopter ditched at sea on September 4, 2024.
Three crew members were aboard the helicopter, based at Royal Naval Air Station (RNAS) Yeovilton in Somerset, for night-flying exercises when the incident occurred around 8:50 p.m. GMT. The aircraft ditched approximately 25 nautical miles south of Lyme Regis, Dorset.
According to the service inquiry, Lt. Leyshon, who was the right-hand seat pilot, sustained serious injuries upon impact and was unable to escape the aircraft as it entered the water. The inquiry report states that a diaphragm inside the helicopter's engine split, allowing fuel to flow into it. This excess fuel caused the engine to operate at an unusually high speed.
The crew members mistakenly concluded that two of the helicopter's engines had failed. They manually shut down these engines, which in turn caused the remaining engine to exceed its overspeed trip threshold and deactivate. The loss of power from all three engines led to the aircraft descending into the sea.