Divers expected to go down around now.
From RTE:
"Naval Service divers are due to commence their investigations at the wreckage of Coast Guard Rescue Helicopter 116 shortly.
Sea conditions are favourable and fair weather expected for the area around the search site.
Teams of specialist Naval Service divers will embark in pairs and will stay underwater for ten-minute periods.
The operation is being coordinated by the LÉ Samuel Beckett, which is located close to the wreckage at Blackrock Island.
It is hoped that the three missing crew members - Captain Mark Duffy, Winch Operator Paul Ormsby and Winchman Ciarán Smith may still be in the wreckage.
Detailed mapping of the undersea conditions has been carried out in recent days and images gathered by specialist cameras have been reviewed by the multiple agencies involved in the operation.
The wreckage is located in waters 60m off the western face of Blackrock, at a depth of around 40m.
Wind conditions in the area have eased considerably and the forecast is for fair or fine weather with good visibility.
Specialist equipment was loaded onto boats at Blacksod pier yesterday evening in anticipation of those favourable sea conditions.
All the agencies involved are stressing that safety concerns will take precedence throughout the operation.
At a briefing at Blacksod Lighthouse last night, Superintendent Tony Healy said the hope was that the three crew were in or near the wreckage.
He said the conditions for underwater exploration of the helicopter were the best that search teams had experienced so far.
Chief Investigator with the Air Accident Investigation Unit Jurgen Whyte said a lot of information had been gathered and that everything possible was being done to assist the dive process.
He said he was confident that dive conditions would be good for a number of days.
Mr Whyte said the priority was to recover the three crew members before efforts were made to access the flight recorder."