The report in the 2017 crash of the R116 helicopter, which killed four crew members, provides detail in relation to earlier concerns about obstacles being missing from on-board navigational aids used by Irish Coast Guard crews.
The 350-page Air Accident Investigation Unit report looks in some detail at safety measures implemented by the company with the State contract to operate search and rescue helicopters, CHC Ireland.
It found difficulties with the company's internal reporting mechanisms; a reticence on behalf of some staff to file reports for fear of being criticised; a lack of action on some submitted reports and a preference by some staff for resolving issues in a more informal manner.
Some concerns were discussed though base flight safety meetings.
The investigation established that as well as operational "occurrences" being reported in this way, staff raised "perceived overt commercial pressure being applied to duty crew; issues around "risk fatigue management" and issues with the quality and adequacy of the cockpit moving map system.
Some map images were described as "completely blurred and unreadable".
In another instance, it was pointed out that the moving map system was inadequate in UK airspace, when paper charts had to be used instead.
CHC Ireland also provided the inquiry with a number of email threads from 2013, in which crews sought route guide updates.
On 26 June 2013, a pilot emailed several personnel "advising that the Blacksod South route [APBSS - the route used on the night of the crash] was flown last night and it was noticed that Blackrock Lighthouse was not shown on the EGPWS", an onboard obstacle warning system.
The report said that "the pilot stated that at 310 feet the lighthouse was an 'obvious hazard’". He advised that the same issue applied on the other pre-programmable route to Blacksod.
The investigation found that a different pilot emailed several of the same personnel on 27 June to advise that "Inishmurray and Black Rock (Sligo bay)" were not contained in the obstacle database.
On 28 June 2013, the EGPWS manufacturer was emailed by a pilot to inform them that "a few islands and lighthouses locally do not appear on the database". The company responded on the same day, seeking further details.
These were provided on 2 July 2013 by email. The manufacturer replied that day saying a ‘problem report’ had been opened.

A database review carried out by the company at the request of investigators found "there are no records … indicating that the group received specific actionable data on what islands and lighthouses to add".
The problem report was closed in March 2015, with no action taken.
When asked about the above correspondence, CHC told the AAIU that the issue with Blackrock should have been reported to its safety management system (called SQID).
CHC said there were no reports made in this way and that "management had not been aware of any discussions regarding the EGPWS database and Blackrock".
The report said the pilot involved in the email thread with the EGPWS manufacturer "had informed, by copied email, eight of the operator’s personnel that he was engaging with the EGPWS manufacturer about ‘getting these lighthouses added’.
"The investigation was provided with no evidence that any of those eight personnel reverted to the pilot to enquire about progress on the issue."
The report also states that the Flight Management System (FMS) Route Guides for coast guard flights contained 29 routes, three of which started close to a high obstacle.
Two of these were routes to Blacksod - known as APBSS and APBSN - started at red dot, with the numerals 282 adjacent to it. The word ‘Blackrock’ appeared to the right of the red dot.
The crew of R116 elected to use ‘Route APBSS (Blacksod South)’. It did not identify that it started at a lighthouse.
When the route was inputted into the helicopter’s FMS, associated waypoints - to define the route - are loaded.
Waypoint BLKMO is located in the water just off the eastern end of Blackrock. Essentially this meant that when approaching from the west to initiate the route, the helicopter would have to fly over Blackrock.
The report raises a number of points regarding the way CHC Ireland reviewed route guides and the way crews were trained to use them.
It said that in July 2013 there was a proposal to record all routes that had been test flown and update the guide accordingly. But while emails reviewed by the inquiry indicated a commitment to achieve this, there was no specific person assigned to drive the project.

Many personnel employed by CHC told the investigation about the different nature of operating on the east coast versus the west coast.
It is a topic referenced several times over the course of today's report.
There is better ambient light along the east coast, while the west has "much darker environment". The report also says the "tempo" of missions closer to Dublin is different too.
The AAIU highlights the differences and says individual crew familiarity with an area away from their usual base "would not be high".
That benefit of familiarity with routes close to operational bases is instanced in one example cited in the report.
It details a similar 'top cover' mission performed by R116 for the Sligo-based R118, six days prior to the accident.
Top cover is the term used when an aircraft is dispatched in support of another craft, conducting an offshore search and rescue mission.
On 8 March 2017, R116 was tasked to assist R118 on a medical evacuation from a vessel 200 nautical miles west of Blacksod.
On that occasion, the Dublin-based helicopter routed to Blacksod and refuelled, before heading out to sea.
Winch operator Paul Ormsby was also on board the 8 March flight. The commander, co-pilot and winchman who took part in the mission with him spoke to the investigation.

They told how weather conditions were good on the night in question and how they had conducted an initial briefing en route for using the APBSS route into Blacksod for fuel.
This was the same route that the R116 crew would use days later, with fatal consequences.
One of the crew members on board had previously been based in Sligo and informed colleagues "that there was a large rock [Blackrock] on the route". This led to further consultations and a plan to fly the route at a higher altitude of 900 feet above ground level.
It subsequently transpired that visibility was so good that the crew were able to fly directly to Blacksod without using the pre-programmed route.
After refueling, the crew "inspected Blackrock using both FLIR (Forward Looking Infra Red) and the naked eye as they passed it at a safe altitude of 1,000 ft".
The winchman, who was operating the infra red camera, signalled to Winch Operator Ormsby that the image on screen was the rock formation the pilots were discussing at the time.
The report says that the winchman on the March 8 flight did not think the image or the conversation "would have made such an impression on the Winch Operator that he would have been sensitised to the presence of Blackrock when he returned there on the accident flight".
The report also provides additional detail on the conversations among the R116 crew in the hour before the crash.
At 11.36pm, Captain Dara Fitzpatrick told Captain Mark Duffy she was "going to re-familiarise myself with Blacksod ... south ... okay…I think we just plug that in".

As she entered the route into the Flight Management System, she was recorded complaining about poor lighting in the cabin. Captain Duffy concurred.
Both pilots agreed on the flight plan and confirmed with rear crew members that they were happy too.
The winch operator said that he was looking forward to seeing the staff at Blacksod for the second time in a week. He described a previous mission for R116, involving a similar supporting role.
After this discussion, the flight continued for a time "with minimal extraneous conversation".
At 11.52pm, the crew discussed previous visits to Blacksod. Captain Fitzpatrick remarked: "God, I'd say I haven't been in Blacksod in about 15 years" to which Ciarán Smith replied: "Yeh, it’s been a while for me too alright".
Mark Duffy then told his crew mate that it had been a while since he was there as well.
The voice recordings also detail frustration at efforts to contact R118 during this time.
The report says between "23.54 hrs and 00.05 hrs the four crew members were involved in combined efforts to contact R118 via the different communications options on board. R116 was unable to establish communications with R118 during this period."
19 safety recommendations for helicopter operators
Nineteen of the 42 safety recommendations made at the conclusion of the report are addressed to CHC Ireland.
These include suggestions regarding a review of navigational aids; enhanced crew training in relation to route guides and improved monitoring of missions and decision making.
The AAIU says the company should ensure adequate time is given for staff to attend safety related meetings.
It recommends specific guidance be given to crews about assessing visibility in conditions of darkness or poor weather and says an in-depth study of the cockpit environment of the S-92A helicopters needs to be carried out, so data needed to ensure safe operations is "optimised".
The report also says CHC should have a 'fatigue risk management system' in place and review training, so that crews are aware of the risk of ‘automation bias’ when they are on missions.
A further 15 recommendations are made to the Minister for Transport.
Investigators say he should ensure those involved in decisions to launch SAR helicopter missions take account of the protocols and expertise of other agencies they work with.
Several other recommendations are aimed at ensuring better administration and oversight of Irish Coast Guard operations, with a particular focus on air rescue services.
In addition, there should be appropriate governance arrangements in place to oversee the coast guard. This would ensure issues are addressed in a timely fashion, so systems are "sufficiently comprehensive and robust".
The AAIU said the minister should review processes regarding the requesting and tasking of top cover.
It calls for a review of the department’s in-house expertise so that there are internal skills to oversee SAR aviation and all activities of the Irish Aviation Authority.
The report calls for a detailed review of the IAA’s regulatory and oversight mechanisms, so they are clearly defined and understood by both the IAA and the entities it regulates.
In turn, five of the recommendations are addressed to the IAA. These cover monitoring of exemptions granted by the authority, a review of its procedures for overseeing SAR services and an examination of CHC Ireland’s shift patterns.
The AAIU report also calls on the European Commission to review how search and rescue operations are managed across the EU, in order to identify minimum safety standards.
The unit said there was a particular need for enhanced guidance and regulation when it comes to the use of civil registered aircraft for SAR.
Confusion over role of IAA
The report points towards a level of confusion, regarding the role of the Irish Aviation Authority (IAA) in overseeing search and rescue (SAR) flights.
The IAA approved CHC Ireland to conduct search and rescue missions, as well as Helicopter Emergency Medical Services. But it told the investigation that operational SAR flights, under a rescue callsign, were subject to oversight by the Coast Guard.
The inquiry also quizzed the authority on 27 alleviations granted to CHC Ireland in respect of SAR flights. The regulatory body said these were issued to allow crews to complete missions and that decisions around exemptions to guidelines rested with the aircraft commander.
These alleviations allow SAR crews to operate "below normal operational rules of the air applicable to civil aircraft".
The AAIU had a particular focus on an exemption permitting some missions to be undertaken with lower Visual Flight Rules (VFR) than specified.
Investigators asked what evidence or control measures had been demanded, in order for the authority to be satisfied that alleviations did not "erode the operational safety margins available to crews".
The IAA cited EU legislation and said "operational safety margins for SAR flights rest with the operator and the aircraft commander".
The report identifies gaps in the way the Irish Coast Guard was able to oversee the search and rescue helicopter service. It informed the Investigation that it did not have aviation expertise available on its staff.
Instead, it had contracted an external consultancy to provide it with aviation expertise, advice and auditing of the operator's bases. But that contract expired in January 2017 and had not been renewed at the time of the accident.