The accident occurred during an early morning charter flight from Ballynahinch castle to Shannon Airport. The pilot and the four passengers were killed instantly when the helicopter struck the ground some distance North of the direct overland route. Radiation fog was widespread in the area.
When the accident occurred the helicopter was being manoeuvred at low altitude in conditions of varying and restricted visibility.
No pre-crash defects were found in the helicopter and the accident probably occurred when the pilot lost adequate visual references and permitted the helicopter to strike the ground because of induced false sensations arising from spatial disorientation.
The probable cause of the accident was the pilots attempt to continue flight in deteriorating visibility. Reasons or contributory factors were not determined. There may have been some anxiety to complete the flight. Also important were the changing visual conditions actually experienced by the pilot.