UPDATE: One crew member of the missing Coast Guard helicopter has been found alive

RTE reports that one member of the missing Coast Guard Helicopter crew has been found and is believed to be in critical condition.

One injured person has been found in a critical condition as search continues for three other crew members of Coast Guard helicopter

— RTÉ News (@rtenews) March 14, 2017

The Coast Guard helicopter was returning to base after performing a medical evacuation when it fell out of contact at 1am this morning, six miles west of Blacksod in Mayo. In a statement, a spokesman for the Coast Guard said: "The Sligo based Coast Guard helicopter R118 completed an early morning medical evacuation of a crewman requiring urgent medical attention from a UK registered fishing vessel approximately 150 miles west of Eagle Island in County Mayo. SAR helicopters from Sligo and Shannon are involved in this morning's search, along with an Aer Corps plane, lifeboats from Ballyglass and Achill and five local fishing boats.