What happened
On 21 January 2001, an AS300B2 Ecureuil, registration G-OROZ, was performing a private flight from County Fermanagh to County Mayo. The aircraft was carrying a pilot and four passengers. During the return leg, the flight encountered deteriorating weather conditions characterized by low cloud and fog.
As the helicopter approached the Enniskillen area, it was observed by witnesses flying at a very low altitude beneath a low cloudbase. The aircraft was seen performing turns and eventually descending out of the cloud in a nose-down attitude. The helicopter then plunged into a group of trees near Monea. The impact caused the aircraft to be destroyed. The crash resulted in 1 fatal injury and 2 serious injuries, while one passenger survived.
The investigation
The investigation focused on the cause of the loss of control and the potential for technical failure. Air Traffic Control (ATC) had noted a continuous warning horn during the final radio transmissions from the cockpit. Investigators examined the hydraulic and engine systems extensively but found no evidence of a mechanical failure in the flight-critical systems. The engine and rotor components were found to be functional at the time of impact.
Investigators also analyzed the aircraft's GPS data, which showed the helicopter reducing speed and performing orbits, consistent with a pilot navigating through difficult weather. The investigation also examined the structural integrity of the cabin, specifically noting that the fibreglass front seats detached from the cabin floor during the impact, which contributed to the severity of the injuries sustained by the occupants.
Findings
- The primary cause of the accident was the pilot losing control of the aircraft due to disorientation following an inadvertent entry into IMC (Instrument Meteorological Conditions).
- The weather conditions were rapidly changing, with a low cloudbase that made maintaining Visual Flight Rules (VFR) extremely difficult.
- While the reason for the activation of the warning horn could not be determined, its presence likely increased the pilot's stress levels during the critical moments of the flight.
- The hydraulic test switch was found in the 'test' position, which may have contributed to the sounding of the warning horn.