The family of Dara Fitzpatrick, who lost her life in the Rescue 116 crash, say they were badly let down by the operator CHC.
They hope a report by the Air Accident Investigation Unit (AAIU) into the incident will ensure those responsible will urgently implement the necessary changes to ensure such an accident will never happen again.
Dara Fitzpatrick, Mark Duffy, Paul Ormsby and Ciaran Smith all lost their lives in the crash off the Mayo coast in March 2017.
The report by the AAIU found they were unaware that a lighthouse and terrain were on the flightpath, as neither databases nor imagery detected it.
A Fitzpatrick family statement says: "The AAIU report and the report of the review board highlight many failings in the operation of the Air Sea Rescue Service operated by CHC Ireland.
"We should not forget that the crews of these SAR helicopters are frequently required to operate in extreme weather conditions".
The statement adds that they often operate at night, and "in circumstances where they might be fatigued".
"They are required to operate into bases or refuelling sites that have no aids to navigation to assist them."
The family say while there is a "weighty responsibility" on the operator to minimise the risk to the crew "this was not done on this occasion".
The statement says: "CHC provided the crew with a low-level approach chart that started right above a fatal hazard.
"That hazard was not adequately highlighted on charts and the charts had no vertical profile to provide crew with safe crossing heights".
The family adds "other failings" include not training the crew on all specific approaches on simulators, and ensuring they had "prescribed recent experience" of different landing sites.
"We believe that Dara and the other crew members of Rescue 116 were badly let down by the Operator CHC not providing them with the safe operating procedures and training that they were entitled to expect", the statement concludes.
"We hope that the AAIU final report and the review board report will ensure that those responsible for this operation... urgently implement the necessary changes, and that in the future pay attention to feedback that they get from flight crew as to any inadequacies and hazards in the operation".
'Fully accept recommendations'
The Irish Aviation Authority (IAA) again offered "greatest sympathy" to the families and friends of the four crew members.
It says it welcomes the AAIU report, which it believes "will contribute to the prevention of future aviation accidents both in Ireland and indeed globally.
"We have reviewed and fully accept the recommendations addressed to the IAA, which have already been implemented or are proceeding to full implementation.
"We will verify our progress in this regard to the AAIU", the IAA adds.
The IAA also says it supports a recommendation the EU Commission review search and rescue safety standards at European level.
While Transport Minister Eamon Ryan says: "The completion of the investigation and the publication of the report is a key step in ensuring that such accidents are prevented in the future.
"I wish to acknowledge the investigative work that has been done by the AAIU that has culminated in this report.
"This is clearly reflected in the level of detail and wide-ranging nature of the report, with safety recommendations that cover all aspects of SAR aviation, both nationally and internationally."
