The four crew onboard died when their helicopter went down near Blackrock Island

It's one year since Rescue Helicopter 116 crashed off the Mayo coast - killing all four crew members.

Last night around 100 attended a vigil to remember the victims, while a mass and wreath laying ceremony will take place later this morning.

At 12.46am on the March 14th 2017, Rescue 116 went down near Blackrock Island.

The bodies of Captain Dara Fitzpatrick and Captain Mark Duffy were recovered.

Despite a 42-day search, their colleagues Paul Ormsby and Ciarán Smith remain lost at sea.

Late last night family, friends, members of the Irish Coast Guard and emergency services gathered to mark the anniversary.

Among them was Gerard O’Flynn, Search and Rescue Operations Manager with the Irish Coast Guard. 

He explained: "It's your worst nightmare in terms of the job that you do. 

"Losing four professional colleagues so soon after we'd lost a volunteer, Catriona Lucas, was a terrible shock - that memory is still very alive, and coming up to the first anniversary brings it all back for everybody."

Dara Fitzpatrick's sister Niamh said there is an 'unbelievably tough time ahead', but added she has also seen 'never-ending kindness' from others in the wake of the tragedy: 

Later this morning a mass will take place to remember the four crew members, followed by a wreath laying ceremony off Blackrock Light.