“We're gone.”
Those were the last words from the Irish Coast Guard Sikorsky S-92A, designated Rescue 116 and being operated by CHC, that crashed into the sea off Black Rock at 1 a.m. local time March 14. The helicopter was on approach to refuel at Blacksod after being dispatched from Dublin. Capt. Dara Fitzpatrick was recovered but later died in the hospital. The body of chief pilot Mark Duffy was later recovered from the sunken cockpit, but the remains of winchmen Paul Ormsby and Ciarán Smith are still missing.
Rescue 116 was flying cover for another Coast Guard S-92 that had been dispatched from Sligo to conduct a medical evacuation from a UK-registered fishing vessel 150 miles west of Eagle Island in County Mayo.
The Air Accident Investigation Unit (AAIU) of Ireland has released its preliminary report into the accident. It paints a tense narrative of an unsure crew operating in poor weather with suspect data. During the arrival brief, both the aircraft commander, who was the pilot flying, and the chief pilot acknowledged that it “had been a while” since they had landed at Blacksod. At no time during the briefing, according to the conversations from the CVR, did the crew mention the presence of the lighthouse, obstacles or terrain.
Unclear Obstacle Information
Black Rock is in the North Atlantic Ocean, to the northwest of Achill Island, County Mayo, on the west coast of Ireland. It is the largest of a group of rocks lying nine nm west of Blacksod Bay, County Mayo. A lighthouse painted white, 50 feet in height stands on Black Rock. The Irish Aviation Authority (IAA) Aeronautical Chart West shows an elevation of 282 feet for the lighthouse.
The helicopter was equipped with a Honeywell Mk XXII EGPWS, but the system's databases did not include Black Rock or the obstacles (among them the lighthouse) on Black Rock, Honeywell told Irish authorities. “Honeywell’s terrain data is sourced from our supplier [named supplier]. It is a digitized topographic map-derived data set. It does not include Black Rock. We have looked at alternate sources, including SRTM and ASTER. While Black Rock is present in these alternate data sets, the actual altitude of Black Rock is considerably higher than what is indicated in these alternate data sets. Our obstacle data for the Ireland region is sourced from our Type 1 LOA supplier, [named supplier]. This data is originated by the [named source], and does not include obstacles on Black Rock.”
The low-altitude switch on the EGPWS was activated at the time of the crash. Among other things, the low-altitude switch inhibits warnings above 100 feet agl, significantly reduces warning boundaries and shortenslook-ahead terrain advisory distances.
The report also noted, “The commander set the rad alt to 180 feet and the auto-hover height to 150 feet. The Primus 701 weather radar was set to the GMAP2 ground mapping mode; the system manufacturer’s manual indicates that this mode provides the best sensitivity for ground mapping of targets. This mode disables all ground clutter and sea clutter reduction modes (*CR1 and *CR2 modes). A weather radar range of 10 miles was requested by the commander and the copilot confirmed this selection.”
The crew also had access to a moving map and a company-produced route guide to Blacksod. The commander was using the moving map on her multifunction display while the copilot was using weather radar to identify terrain features. According to the report, “The helicopter was equipped with a EuroAvionics EuroNav 5 moving map display that had a number of maps/charts available for selection. The exact information in relation to Black Rock and Lighthouse varied from none, to detailed, depending on the selected map/chart.” The route guide included designations and coordinates, hazards, obstacles and other comments and showed the lighthouse at Black Rock with an associated height of 310 feet.
The AAIU has recommended that CHC Ireland “review/re-evaluate all route guides in use by its SAR helicopters in Ireland, with a view to enhancing the information provided on obstacle heights and positions, terrain clearance, vertical profile, the positions of waypoints in relation to obstacles and EGPWS database terrain and obstacle limitations.”
In response, CHC said, “A review of all route guides in use is well under way as part of our own internal action. We will continue to fully support the AAIU investigation.”
Accident Sequence
The dialogue among Fitzpatrick, Duffy and one of the winchmen in the last 34 seconds suggests some confusion as to the helicopter's precise location. At 26 seconds before impact the radar altimeter emits an automated altitude callout. Fitzpatrick seems to think it is an out island when analysis later reveals it to be an outcropping 0.65 miles from Black Rock itself. Then one of the winchmen, believed to be assisting with navigation by the EO/IR camera, advises the commander, 13 seconds before impact, “You want to come right.”
Commander: “OK, come right, just to confirm?”
Rear crew: “About...twenty degrees right yeah.”
Commander: “OK, come right, select heading, select heading.”
Copilot: “Roger...heading selected.”
Rear crew: “Come right now come right COME RIGHT (urgently)”
Automated altitude callout, loud noise, smoke in baggage automated callout.
Copilot: “We're gone.”
The report noted the position of the debris. The horizontal stabilizer was found on the rock, adjacent to an outhouse close to the lighthouse. The outhouse roof had associated damage. The trailing edge of the root separated from the main structure. Fractured sections of the intermediate gearbox were also found on the rock. Fractured pieces of a wheel rim were found close to the helipad. The main wreckage was found in 130 feet of water off the southeast side of Black Rock.