Crew was trained, experienced and qualified. Aircraft was equipped for the task. I don't buy the "there but for the grace of god, everyone messes up sometime, etc" arguments. Operations procedures are meant to be boilerplate, to tolerate the "human errors" that can creep in. "It's 1am and we're all a little tired, lets double check all the FMS entries and get all the gear front and back working for us" - it is called threat and error management. I don't doubt that all other civilian SAR operations have had to stand in front of their CEO's and assure them that this would not have happened in their organization. The "system", from the IAA on down, simply cannot tolerate any kind of unaddressed risk. The "swiss cheese" model is an explanation of operations management failure to address all risk, and falls under the responsibility of the company SMS system and S&Q that is charged with auditing effectiveness of the current and anticipating the worst in the future.
To land at Blacksod on that night you had to get under the weather. If that was the plan at the outset then they could have dropped out just west of Fahy Lough, nice 10x2nm corridor. From the radio transmissions it sounds more uncertain, they may have gone out a ways to try contact 118 before deciding to come back for a refuel. Pprune will know soon enough, some may know already.
Us Canadians can't seem to fly without a map Garmin on the panel, but the 92 had lots of mapping capability. Rear crew with their detailed maps showing own position and communicating to the front. EGPWS will paint shorelines and obstacles, so will radar, RadAlts plus GPS altitude if required, user waypoints can be defined as airports and will show up on the flightplan screen (almost Garmin-like), and finally the iPads with any number of apps that map. JeppFD strangely enough shows Blackrock but with an elevation of only 46' - anybody else confirm?