The body of one of the three air crew from Rescue 116 has been located in the cockpit of the helicopter off Blackrock island in north Mayo.
Supt Tony Healy of Belmullet gardai confirmed late on Friday night that Naval Service divers had located one crew member in the aircraft wreckage which is lying at a depth of 40m on the seabed, 13km west of the Mullet peninsula.
He said operations would continue overnight on the Irish Lights ship Granuaile at the location supported by the Naval Service patrol ship LE Samuel Beckett and Garda divers.
Supt Healy said he could not confirm the identity of the crew member, but it was a "major step forward" to recover the flight data recorder and confirm location of one of the three airmen, co-pilot Capt Mark Duffy and winch team Paul Ormsby and Ciarán Smith.
Efforts would be made as soon as conditions allowed to recover the body, and the search area would be “further extended” at this location for the two missing men, he said.
The ROV is on standby for further deployment from the Granuaile, he said.
The investigation into the crash has taken a step closer to finding the cause, following the retrieval of its “black box” flight recorder off the north Mayo coast.
Naval Service divers took the combined voice and data recorders from the aircraft wreckage to the surface at 4.30pm on Friday, according to Air Accident Investigation Unit (AAIU) chief inspector Jurgen Whyte.
The three airmen have been missing since the Coast Guard Dublin-based Sikorsky S-92 helicopter crashed on an approach to Blacksod in the early hours of March 14th. Pilot Capt Dara Fitzpatrick, who died in the crash, is the only member of the crew to have been recovered from the sea.
At a briefingearlier on Friday at Blacksod pier, Belmullet Garda Supt Tony Healy said divers were still “actively working” on the primary aim of recovering the three men and black-box recovery was a “significant step”.
Mr Whyte explained that it was always the priority to recover the three missing air crew, but protocols within the AAIU’s work dictated that when the flight recorder was seen it must be recovered.
“That was achieved quite fast, late in the day, it was not particularly difficult to recover it but the concern was that if we didn’t take it at that time we might never get it,” he said.
Mr Whyte confirmed that the helicopter’s data recorder was “visually in good condition” with no apparent external damage.
The combined cockpit voice recorder and flight data recorder has been taken on board Granuaile which has been providing a platform for the dive team, along with several smaller vessels, throughout Saturday.
Mr Whyte said the device was in the possession of AAIU investigator-in-charge Paul Farrell and it would be taken under escort to Casement Aerodrome and flown on Saturday to the British air accident investigation branch.
“There it will be prepared for download hopefully by Tuesday or Wednesday of next week,”he said.
Supt Healy said that the Granuaile would be "working throughout the night". It may deploy the remotely operated vehicle when divers are safely out of the water.
Coast Guard incident manager Michael O’Toole said there was an increased aerial, sea and shore search focus, and this increased tempo was to take advantage of the benign weather, he said.
The Civil Defence had also deployed drone crews to assist in shore search, Mr O’Toole said.
The RNLI Achill and Ballyglass lifeboats put to sea early Friday morning to conduct shore searches.
The Naval Service diving section led by Lieut Daniel Humphries undertook its first in relay of descents at 11.30am on the helicopter wreckage, in a concerted bid to find the missing men during a four-day period of calm weather.
On-scene co-ordination is being provided by LÉ Samuel Beckett under the command of Lieut Cdr Darragh Kirwan..
AAIU investigators confirmed early this week that a tail section of the helicopter recovered from the plateau had evidence of contact with rock on the western side of the island.
A preliminary report would be published by the AAIU within 30 days as part of international requirements, Mr Whyte said.