The final Air Accident Investigation Unit (AAIU) report into the crash of Irish Coast Guard helicopter Rescue 116 found a number of factors had contributed to the fatal crash, which killed all four crew members.
The 350-page report laid out 12 factors which it said likely contributed to the crash, and made 42 separate recommendations for reforms.
The initial route the helicopter was navigating along was “almost coincident” with Blackrock island, 13km west of Blacksod, off the coast of Mayo.
Flying at 200 feet above the sea at night in poor weather, the crew was “unaware” of the island that was in its flight path, the report said.
The design and review of flight routes by CHC Ireland, who operate search and rescue missions on behalf of the Coast Guard, “were capable of improvement in the interests of air safety”.
Extensive activity to test flight management system route guides “was not formalised, standardised, controlled or periodic,” the report said.
Training provided to flight crews around a route guide system was “insufficient to address inherent problems” and tackle the “risk of automation bias,” it said.
The Rescue 116 pilots likely believed the route they were following on the navigation system “by design provided adequate terrain separation from obstacles,” the investigation said.
Other contributory factors included the fact neither of the pilots had recently flown into Blacksod refuelling station.
The situation was “compounded by darkness and poor weather,” it said.
There were “serious and important weaknesses” with aspects of CHC Ireland’s safety management systems, and its flight route guide, “such that certain risks that could have been mitigated were not,” the report said.
It also noted there was “confusion” at State level over who was responsible for the oversight of search and rescue operations.
The AAIU recommended CHC review its guidance, operating and training procedures around the use of the Enhanced Ground Proximity Warning System (EGPWS) database, which alerts pilots if an aircraft is in danger of hitting land.
The report stated Blackrock island was not on the EGPWS database, and so CHC should ensure crews are aware of the “limitations” of the warning system.
The company should also reform its procedures around route guide management, it said.
The report recommended Minister for Transport Eamon Ryan set up a procedure for the Coast Guard and the search and rescue operator, to deal with "mission launch concerns".
The Minister should also review the provision of “aviation expertise” to the Coast Guard, so it can provide appropriate governance to rescue operators.
The Coast Guard should also fully implement a safety management system that “encompasses all aspects of its air operations,” the report said.
It recommended the Irish Aviation Authority’s “regulator and oversight mechanisms” be reviewed.
The report said the European Commission should carry out a review into how search and rescue operations are managed across Member States, to identify minimum safety standards.
It also recommended CHC conduct an “in-depth review” of its helicopters’ cockpit environments, to examine the lighting and how information on its screens were presented to pilots.
The Department of Transport, CHC and IAA have all committed to implement the list of reforms.