What happened
On 19 July 2015, an Enstrom 280FX, registration N280CH, crashed near Carlingford, Co. Louth, Ireland. The flight began from a private landing site adjacent to the pilot's home, following an earlier flight from Derryogue Airfield. Shortly after departing the site, the pilot observed an 'overboost' warning light, indicating that the engine manifold pressure had exceeded the 39 IN.HG limit.
In an attempt to rectify the high pressure, the pilot lowered the collective lever. This action caused the engine and main rotor RPM to increase. As the pilot attempted to reduce the RPM, the aircraft experienced a sudden yaw to the left because the necessary tail rotor pedal input was not applied instantaneously. The pilot subsequently performed a forced landing in a nearby field. The impact with the uneven ground caused substantial damage to the aircraft, specifically to the main rotor blades and the right-hand landing skid. The pilot escaped the wreckage without injury.
The investigation
The AAIU examined the aircraft's mechanical systems, the pilot's flight experience, and the regulatory framework regarding the pilot's credentials. The investigation reviewed the manufacturer's guidelines for the Enstrom 280FX, specifically regarding engine RPM management and the use of tail rotor pedals during power adjustments. Investigators also assessed the meteorological conditions, noting that while official reports indicated a light breeze, the pilot and responders described the air as generally calm. Additionally, the investigation scrutinized the validity of the pilot's US-issued Student Pilot Certificate under Irish and UK aviation laws.