Inquiry fails to establish exact cause of fatal helicopter crash

PILOT inexperience or an unspecified engine problem, or both, are believed to be the most likely causes of a fatal helicopter crash in Co Longford in 1999.

However, the official report into the incident by the Air Accident Investigation Unit of the Department of Public Enterprise has been unable to establish the exact cause of the crash.

The pilot, Pat Stokes, 41, of Woodlawn Park, Churchtown, Dublin, and passenger Anthony Stephen Tebbitt, 47, from Newcastle, Co Wicklow, were killed when their Robinson R22 helicopter crashed in an accident which investigators described as “unsurvivable.” It occurred at around 10.11am on August 27, 1999, at Ballinamuck, Co Longford, during a flight between Weston Aerodrome in Lucan and Sligo to conduct aerial photography.

An examination of the debris revealed the helicopter’s main rotor had come into contact with the cabin during the flight, but investigators were not able to explain exactly why this happened. The most likely cause is an abrupt or inappropriate movement of the helicopter’s controls or the stalling of the main rotor blade due to icing on the engine carburetor.

However, the report noted that investigations into other fatal crashes involving the US-made R22 show there is a clear relationship between pilot inexperience and accidents involving contact between the main rotor and the fuselage. The report also noted the Irish Aviation Authority (IAA) had granted Mr Stokes a reduction of six hours from the 45 hours normally required to obtain a Private Pilot's Licence for helicopters because he already held a fixed-wing licence. Mr Stokes obtained his helicopter licence two months before the accident.

It is unclear if Mr Stokes was aware of a Safety Notice issued by Robinson in 1999 warning of the high risk of using the R22 for aerial photography. The manufacturers recommended that only pilots with over 500 hours flying experience of rotorcraft use the R22 for aerial photography.

The pilot had also failed to remove full dual controls which had been fitted to the craft in contravention of normal procedures for a non-training flight.

The inquiry team found no evidence of any pre-existing technical or structural defects to the helicopter.

The investigators have recommended that the IAA issue an urgent notice to all R22 operators requiring the removal of dual control joysticks for all non-training flights. It also urges the IAA to consider discontinuing the practice of granting pilots with fixed-wing experience a reduction in the required number of flying hours to obtain a helicopter licence, specifically with regard to the R22.