First dives are planned from dawn on Friday on the wreckage of Rescue 116 off the north Mayo coast as the search continues for three missing Irish Coast Guard helicopter airmen.
The Naval Service diving section led by Lieut Daniel Humphries hopes to gain access to the main fuselage of the Sikorsky S-92 helicopter which crashed 10 days ago if conditions are safe to do so.
Rescue agencies remain hopeful that the bodies of the missing airmen – co-pilot Capt Mark Duffy, winch operator Paul Ormsby and winchman Ciaran Smith – can be found in or near the aircraft.
It is lying in 40m of water off Blackrock island, 13km west of the north Mayo coast.
The location poses many hazards, as it is in a narrow channel exposed to strong tides and sea surges off the southeast tip of the island.
However, Lieut Cdr Darragh Kirwan of the LÉ Samuel Beckett – providing on-scene co-ordination – said that visibility was "reasonably good" and an invaluable underwater map had been created of the area.
The Navy divers working in pairs will have an eight-minute limit on the seabed to minimise decompression requirements, and will use several local boats, including the Gearoidín and Ros Anne skippered by local fishermen.
“This local expertise of Blackrock’s tides, current, swell is invaluable to us,” Lieut Cdr Kirwan said.
An underwater remotely operated vehicle (ROV) was deployed for a second day in a row on Thursday from the Irish Lights ship Granuaile, having been guided to the helicopter wreckage on Wednesday morning by the distinctive faint chirp from the aircraft's black box transponder.
At a briefing on Thursday night, Supt Tony Healy of Belmullet said the new ROV footage was being examined to ascertain if the bodies of the three missing airmen were present.
“Tomorrow will be a big step forward,” said Supt Healy, stating that “the hope is that the three men will be in or near the wreckage”.
Air Accident Investigation Unit chief inspector Jurgen Whyte said the priority was the recovery of the three men, then the flight recorder and "after that, it might be related to lifting a certain amount of the wreckage".
Mr Whyte said that the weather window had opened for the next few days, and he remained “confident”.
Irish Coast Guard incident manager Derek Flanagan said the relatives were being informed at every stage.
Minister of State for Regional Economic Development Michael Ring and his colleague, Minister of State for Defence Paul Kehoe, were briefed on the LÉ Samuel Beckett in Blacksod Bay on Thursday afternoon.
Mr Ring paid tribute to the strong community support for the families of the three missing airmen and the late Capt Dara Fitzpatrick – the only one of the four to have been recovered after the crash in the early hours of March 14th,
“I want to offer my sympathies to the families who have lost loved ones. This is a major tragedy for the families but a big tragedy for the State as well,” Mr Ring said.
“I’m here to pay tribute to the local community, to [chairman of local community action group Forbartha Ionaid Deirbhala] John Gallagher and his team, and everybody from this community that have responded,” he said.
Mr Ring emphasised the role played by local fishermen, shores searchers, and the sustenance provided by a team of volunteers led by Annette Gallagher in Halla Naomh Bhreandaín in nearby Eachléim village.
Food has been cooked in the hall every day since the search began, and one Indian take-away owner based on Achill Island arrived with prepared meals this week.
A 10-year old Castlebar schoolgirl, Katie Frazer, sent a letter with buns she baked which has been pinned on the hall wall. “It’s nothing big, it’s only a couple of buns, but I wanted to help in any way possible,”she wrote.