The recent number of accidents involving small aircraft or helicopters is unprecedented, according to the Department of Transport's chief investigator.
Jurgen White, the chief air accident investigator with the department's air accident investigation unit, was speaking after visiting the scene of the latest fatality in north Kerry where a light aircraft pilot lost his life on Sunday.
John Keane (57), Clonlara, Co Clare, died when his single-engine Stinson Skybolt, an aircraft designed for aerobatics, crashed into farmland north of Ardfert. He had been taking part in an air display as part of the Ardfert summer festival.
He was the sole occupant of the aircraft which came down in a field between the villages of Ardfert and Causeway at about 4.30pm. Gardaí said he was on his way back to Coonagh airbase in Co Limerick when he crashed. They are appealing for any video footage that might have been taken by spectators.
Mr White said the number of accidents involving aircraft and helicopters in the last number of weeks was unprecedented for such a short period of time.
On average two people a year are killed in air accidents here. However, this year so far, four people have died. Mr White said this was due to the increase in numbers of helicopters and aircraft now flying in Ireland.
He added that the Stinson Skybolt was designed for air shows and aerobatic display. Mr Keane had an air display permit issued by the Irish Aviation Authority and was fully certified to conduct a display at Ardfert.
Investigators were now looking at three key areas - technical failure, sudden pilot incapacitation and "an error of judgment in carrying out a manoeuvre". The weather was good and not considered a factor. Eyewitnesses were being interviewed.
There had been plenty of fuel in the aircraft, Mr White added, and it had not caught fire. The wreck will be brought to the unit's test facility at Gormanston, Co Meath, where the engine will be examined to determine the cause of the accident.
Mr Keane had only recently completed a flight from Naples to Limerick to mark the 60th anniversary of his local airfield.
Limerick Flying Club's website yesterday acknowledged the passing of their colleague and instructor, describing his death as "terrible news".
Mr Keane is survived by his wife, Ann, and their three children, Paul, Aishling and Suzanne.