The Sligo-based Coast Guard Rescue Helicopter has airlifted an ill passenger from a cruise ship, almost 400km west of Eagle Island in Co Mayo.
The mission was carried out by crew members on Rescue 118, with top cover provided by the Dublin-based R116 helicopter.
The 70-year-old man was airlifted from the Marco Polo cruise ship and taken to hospital in Co Sligo after he took ill late last night.
While the vessel was in UK territorial waters at the time, the Coast Guard at Malin Head was asked to assist, given the proximity of the ship to Irish waters.
A request to the Air Corps to provide top cover, essentially a back up service to the responding crew, could not be facilitated, as its Casa fixed-wing aircraft had two 'Priority 1' air ambulance requests to carry out last night.
It is understood this involved separate flights to London, with patients awaiting transplants.
For that reason the Dublin-based Rescue 116 crew were asked to provide top cover.
It is the first time the Dublin unit has acted in support of their Sligo colleagues since the tragic death of four of their crewmates, during a similar mission last March.