SEARCH teams off the Mayo coast have detected a signal from the black box recorder of the Coast Guard Helicopter Rescue 116, RTÉ is reporting this evening.
According to the report, the signal was identified in 40 metres of water, around 60 metres from Blackrock lighthouse at around 4.30 p.m.
It has been described as a very important step in the recovery effort.
Work is commencing to establish the exact position of the signal and, once that is clear, diving to that location.
Sensing equipment is being moved as close as possible to the target, in the hope that the wreckage is directly beneath that.
Specialist equipment is being brought from the UK this evening, with specialist investigators to pin point the wreckage, the RTÉ report added.