Experts from Sweden and Britain have been called in to assist in the investigation into last month's helicopter crash in Tramore, which killed four members of the Air Corps.
It will be several months at least before the investigation team is able to produce a draft report on the cause of the accident, the worst in the Air Corps's 77-year history.
Interested parties including members of the victims' families will be invited to comment on the initial findings before the final report is published.
The investigation is the first of its kind in that it is headed by a member of the Air Corps, Lieut Col Tom Moloney, but is being conducted under civil regulations with the involvement of the air accident investigation unit of the Department of Public Enterprise.
One of those brought in to assist in the inquiry is a "human factors" expert, Ms Kristina Pollock, who is director of military safety in Sweden and has been involved in over 100 air accident investigations.
She will provide a report on aspects such as the kind of pressure the helicopter's pilots were working under and the decision-making process involved.
The investigators will not, however, seek to apportion blame for the crash.
Mr Kevin Humphreys, who heads the air accident investigation unit at the Department of Public Enterprise, said the purpose was to find out what happened "and hopefully learn whatever lessons are needed to ensure it doesn't happen again."
The second foreign expert employed, Mr Richard Whidborne, is a principal inspector at the UK's air accident investigation branch in Farnborough. He is a helicopter specialist and will also provide a report for the investigation team.
Further specialist analysis will be carried out in France, under the supervision of Lieut Col Moloney and his team, by the manufacturers of the Dauphin helicopter and its engine.
Capt Dave O'Flaherty (30), from Tullamore, Co Offaly; Capt Mick Baker (28), Enniscorthy, Co Wexford; Sgt Paddy Mooney (34), Stamullen, Co Meath; and Cpl Niall Byrne (24), Killiney, Co Dublin, all died instantly when their helicopter crashed into a sand dune near Tramore beach in Co Waterford.
They were returning from a successful search-and-rescue mission off the south-east coast but dense fog had prevented them from landing the helicopter at their base at Waterford Regional Airport.
