In many respects the scale of the Rescue 116 tragedy is reflected in the breadth of the two investigations under way into the accident.
Just days after the families of Captain Dara Fitzpatrick, Captain Mark Duffy, Winch Operator Paul Ormsby and Winchman Ciarán Smith, marked the first anniversary of their passing, the Air Accident Investigation Unit (AAIU) has published an interim statement on the progress of its ongoing investigation.
A second investigation is being conducted by gardaí and the Health and Safety Authority into all aspects of the events leading to the crash and its aftermath.
Both inquiries are expected to continue for several months.
Today's interim report from the AAIU gives a meticulous overview of the work carried out by investigators so far and makes three new safety recommendations.
Since the crash in the early hours of 14 March 2017, a lot of data has been gathered and analysed.
That process is ongoing, in conjunction with a review of interview transcripts and reference to the helicopter wreckage.
Each and every piece of the Sikorsky helicopter that has been recovered from the sea, or that was washed ashore in the months since the crash, is catalogued and inspected.
We get a further insight today into the recorded data from the fatal flight of R116. The AAIU says some of the information regarding the latitude and longitude provided a "coarse" record of the aircraft's position. As a result, it's recommending that the data values on the flight recorder (MPFR) be examined and enhanced. This would mean that all relevant material would be available in the event of future investigations of this nature.
The report also says that an infra red camera that was onboard Rescue 116 yielded no material when it was recovered from the sea off Blackrock.
The second recommendation today concerns the Safety Management Systems (SMS) at CHC - the company with the contract to operate the Coast Guard helicopter service.
The AAIU says that such systems should be " designed to improve safety by identifying hazards...collecting data...and continually assessing safety risks". Having reviewed documents and meeting minutes provided by CHC, the report says there are concerns about its safety guidelines. It recommends the company's SMS be reviewed to make sure they are "sufficiently robust" to consider all possible risks.
The third and final recommendation today relates to the oversight of Search and Rescue helicopter operations here. Again, a huge volume of data has been analysed in this regard by the Air Accident Investigation Unit. This includes Irish Aviation Authority (IAA) safety plans, practices and guidelines; EU regulations, the maritime SAR frameworks and Departmental involvement.
The report says the IAA has acknowledged that issues surrounding offshore helicopter operations have been put in sharp focus as a result of the Rescue 116 crash. When it published a State Safety Plan last year, the Authority pointed out that SAR was excluded from the regulatory framework of civil aviation and highlighted the need for gaps in oversight to be addressed.
This is a long standing problem. As far back as 2010, an audit of the State's compliance with international civil aviation conventions pointed out that "the Department of Transport has not established a mechanism to ensure that effective safety oversight is being carried out for those entities for which it is responsible".
The audit, by the International Civil Aviation Organisation, recommended the Department should take action to address this. There was some follow up on this between 2011 and 2012 but today's report shows there's still a confused approach when it comes to ultimate responsibility.
It says "greater clarity is needed regarding the individual and collective oversight of SAR aviation operations". The Minister for Transport, Shane Ross has said that an immediate, independent review will be carried out to ensure international best practice is adhered to.
This is a staging post in the AAIU Investigation. A detailed analysis is underway into things like cockpit ergonomics during night flights, warning systems, navigational aids and warning systems.
There's also a focus on tasking procedures - examining what exactly led to the decision to first dispatch the Sligo Coast Guard helicopter to a trawler some 300 km off shore on the night of 13 March 2017. That call followed a request to airlift an injured crew member from a Russian registered vessel.
It was followed soon afterwards by the tasking of R116, when the Air Corps was not in a position to provide the necessary 'top cover' for a mission so far out at sea.
On a clear spring day across Blacksod Bay, the lighthouse at Blackrock Island is clearly visible from the short. It's a continual reminder of the dangers of the sea and now a permanent monument to the four Coast Guard crew members who gave their lives in the service of others.
The process continues. The questions remain.