Air navigation services run by the Irish Aviation Authority (IAA) have not been adequately resourced and were still suffering from staffing shortages for at least two years after the Rescue 116 helicopter crash, according to a Government review.
The review for the Department of Transport also calls for a "just culture body" which is "robust" to be implemented as soon as possible to protect pilots and other crew members who make confidential reports on safety concerns.
And it criticises delays in separating the State aviation authority's conflicting functions of safety regulation and commercial operations.
The lack of accurate air navigation charts available to Irish Coast Guard helicopter search and rescue crews was one of the key issues highlighted after the Rescue 116 crash which claimed the lives of Capt Dara Fitzpatrick, Capt Mark Duffy, Paul Ormsby and Ciaran Smith off north Co Mayo on March 14, 2017.
The final report into the crash has still not been published as an unidentified stakeholder has been granted a review of the final draft report by Minister for Transport Shane Ross.
In late 2017, the IAA had invited search and rescue and other pilots to help correct aeronautical charts after it conceded charts published three months after the crash were inaccurate, with lighthouses in wrong locations and obscure symbols.
Although the IAA is responsible for providing aeronautical charts under State safety plans, it has said it does not guarantee their accuracy or completeness and disclaims all liability.
The Dublin-based Sikorsky S-92 had been asked to provide "top cover" to its Sligo counterpart on a medical evacuation mission from a fishing vessel off the west coast, and was making a seaward approach into north Mayo's Blacksod lighthouse to refuel when it crashed into Blackrock island, nine nautical miles west of Blacksod.
The Air Accident Investigation Unit preliminary report noted that Blackrock, at 94.5 metres including its lighthouse, was identified on the helicopter route guide, but electronic maps aboard the helicopter gave "varied to no" information on it. It recommended a review of route guides used by CHC Helicopters, holder of the Irish Coast Guard contract.
At the time, the Irish Airline Pilots Association (IALPA), representing 1,200 pilots including search and rescue crew, expressed frustration over the IAA's failure to fully consult it on maps, charts and other safety-related issues.
The review of the IAA technical and safety performance by Helios and Egis Avia consultants during the second and third quarters of 2019 found the IAA air navigation division staff were having to work "extended hours", as posts could not be filled after one inspector left and one took maternity leave.
The review cast doubt on whether efforts to increase resources for air navigation would "fully materialise" and noted the resource shortages hampered holding workshops and engaging with stakeholders to implement latest regulations on air traffic management and air navigation.
The "slow pace" of separating safety regulation from money-making commercial activities within the IAA and the potential workload increase for IAA staff as a result of Brexit are other issues flagged in the review.
Minister for Transport Shane Ross agreed to separate out safety regulation from commercial operations in the IAA in 2017, but the pace of this has been "slower" than expected, the review says and it recommends it be "concluded quickly along agreed timelines".
Aviation contributed to over €4.1bn of the Irish economy in 2017, with more than 250 companies employing around 42,000 full-time staff.
The technical and safety review is meant to take place every three years, and IALPA had been critical of the fact there were no reviews between 2007 and 2014.
The review highlights poor communication between the IAA and IALPA. The IAA has been involved in a number of High Court actions against members of the pilots' union.
The consultants note that many recommendations from the 2015 review had been completed but the IAA is facing "significant challenges".
Among its 16 recommendations are additional resources for the safety regulation division and establishment of an independent "just culture" body to protect air staff who wish to highlight safety issues in a confidential manner.
IALPA said it welcomed the report, and hopes the Government will implement its findings.
The IAA said the review "confirms" its "continued excellent performance in... delivery of its aviation safety regulatory functions and the delivery of its air traffic management functions in a safe manner" and said all of the recommendations are accepted and "many" have been completed since the audit.