The inquests into the deaths of four Coast Guard crew members, five years ago, have been adjourned for the night and will resume in the morning.

At the conclusion of evidence today, the eight person jury retired briefly, before seeking more time to consider its verdict in the morning.

The Dublin based R116 aircraft crashed into Blackrock Island in Co Mayo, on 14 March, 2017, with the loss of all crew members on board.

It had been dispatched to assist another helicopter, which was travelling to a vessel off the west coast.

In the days that followed, the bodies of Captain Mark Duffy and Captain Dara Fitzpatrick were recovered. The remains of their colleagues, winch operator Paul Ormsby and winchman Ciarán Smith, remain lost at sea.

Throughout the day, jurors heard evidence about the events that led to the Coast Guard rescue helicopters being tasked on the night in question.

The decision to dispatch air support to an assist an injured crewman, who had a severed thumb, has been central to investigations into the R116 tragedy.

Last November's Air Accident Investigation Unit report into the crash found that procedures governing the tasking of Coast Guard helicopters were not conducted in sequence. Instead, it said, the scenario was framed for the doctor, who would usually give guidance on whether to send a helicopter.

Today, a radio operator at Malin Head marine rescue sub centre defended the initial dispatch, saying it was made on the basis of information provided to him by the skipper of the fishing vessel. Ian Scott said he would make the same decision, if faced with the same circumstances today.

But a medic who was consulted about the injuries, said she felt the decision to task had been made before she was called. Dr Mai Nguyen described the injury as minor in nature and said she would not have sent the Coast Guard to the trawler.

A recording of calls between the Kings Cross vessel, Malin Head and Dr Nguyen confirmed this.

After giving the skipper, William Buchan, advice on how to handle the casualty, Dr Nguyen asked Mr Scott if a 'medevac' was being carried out. He responded that it was.

The inquest is being held in Belmullet

Evidence was also given about a rapid deterioration in visibility off the Mayo coast, in the minutes before the fatal accident. Lighthouse attendant at Blacksod, Vincent Sweeney, said a deadly fog had come down, shortly before the helicopter was expected to land to refuel.

At around the same time, Rescue 116 was heading directly for Blackrock Island, unaware of the obstacle on the pre-programmed flight path they were using, to reach Blacksod.

Evidence from more than 20 witnesses was heard during the day. The jury retired to consider its verdict shortly after 5pm.

It returned soon afterwards, to seek an adjournment until tomorrow morning when deliberations will resume.

AAIU made 42 safety recommendations

Last November, the Department of Transport's AAIU completed its probe into the crash.

Over 350 pages, it set out the chain of events that led to the crash and found a number of issues relating to the navigational aids being used by the crew on the night of the accident.

A total of 42 safety recommendations were made by the AAIU.

Nineteen of those were addressed to the company with the contract to operate air search and rescue (SAR) operations, CHC Ireland.

These included suggestions regarding a review of navigation aids, enhanced crew training and improved monitoring of missions and decision making.