The Irish Coast Guard says it is extending shore checks for the two missing Rescue 116 air crew from Cleggan in Galway to Donegal.
It also plans to resume sub-sea scans of the helicopter crash site 13km west of the north Mayo coast when weather settles on Thursday.
A Naval Service patrol ship is being retained in Blacksod Bay to co-ordinate sea searches for Irish Coast Guard winch team Paul Ormsby (53) and Ciaran Smith (38), who were on board the Dublin-based Sikorsky S-92 when it crashed off Blackrock island over three weeks ago.
Capt Dara Fitzpatrick (45) and copilot Capt Mark Duffy (51) are the first two confirmed casualties. Hopes that their two winch team colleagues were still within the wreckage faded on Sunday evening when there was no trace of them within a key section lifted from the seabed.
The wreckage section, including the helicopter’s rotor head, main gearbox, one engine and “associated” pieces, was due to be offloaded by the Irish Lights ship Granuaile on Tuesday night.
It is in the custody of the Air Accident Investigation Unit (AAIU), which plans to examine it at its facility in Gormanston, Co Meath. The AAIU has already ruled out mechanical fault in its initial analysis of the helicopter's "black box" data.
Granuaile returns
The Granuaile will return to north Mayo for Thursday morning to deploy the Marine Institute’s remotely operated vehicle at the crash location in the narrow channel between Blackrock island and Parrot rock.
Irish Coast Guard helicopter bases in Shannon and Sligo and the Air Corps will continue to provide air support, according to Irish Coast Guard operations manager Gerry O'Flynn.
Irish Coast Guard shore units from Cleggan to Donegal will monitor key coastal areas, and Civil Defence units will continue to deploy drones, Mr O’Flynn said, and he paid tribute to the work of the RNLI.
The Killybegs Fishermen's Organisation, Irish Fish Producers' Organisation and Erris Inshore Fishermen's Organisation have pledged support for a co-ordinated search at the weekend, following an appeal by Orla Smith, sister of winchman Ciaran Smith.
Individual fishermen have spent considerable time at sea for the past three weeks as volunteers with RNLI lifeboats, extending from Mayo's Ballyglass and Achill to Sligo, Bundoran and Arranmore, Co Donegal.
Ms Smith emphasised that safety was a prime consideration in searches, and this was reiterated on Tuesday by Supt Tony Healy of Belmullet gardaí.
“We are very conscious of offers of help, but we cannot have people in rigid inflatable boats who are not experienced and qualified,” Supt Healy said.
Caitlín Uí Aodha, chairwoman of the Lost at Sea Tragedies (Last), also emphasised safety. Ms Uí Aodha, who visited Blacksod early this week, noted that three weeks was still “very early” in the lifetime of a search at sea.
Her late husband, Michael, was one of the last two casualties to be found – in the fourth week of searching – when the Tit Bonhomme sank off Union Hall, Co Cork, in January 2012.
“Fishermen really appreciate being asked to help, and this is about closure for the families and for the wider community which has been involved in this from the outset,”she said.
