'Catastrophic' electrical fault could have led to rescue 116 falling into sea
The investigation into the mystery of the downed Rescue 116 helicopter is focusing on whether an electrical failure may have caused it to crash into the sea.
The full-scale search is honing in on an area near the Blackrock Lighthouse, six miles off the coast of Mayo, where the aircraft's black box is now believed to be located.
The crash claimed the life of pilot Captain Dara Fitzpatrick while the crew of three - Ciaran Smith, Mark Duffy and Paul Ormsby - are all still missing.
There were emotional scenes at Blacksod yesterday as the families of the missing and Capt Fitzpatrick gathered for updates.
It has emerged that officials believe there was no Mayday call from the four-person crew because of a "catastrophic failure" on board.
"It takes two seconds to press the Mayday button. The fact that they did not press it shows the suddenness of the impact. They only had seconds before the crash," a source said.
Coast Guard officials also point to the impeccable safety record of Capt Fitzpatrick.
"She would never leave a stone unturned," one official said. The scale of the debris field from has led to fears the helicopter might have disintegrated on impact with the sea or suffered a catastrophic collision at around 1am on Tuesday.
The revelation came as an underwater signal was detected from the black box of the downed Sikorsky S-92A shortly after 4pm yesterday.
Rescuers detected the signal from the multi purpose flight recorder (MPFR) in water some 40 metres deep and just 60 metres from Blackrock Lighthouse.
The location is around 12km offshore from Blacksod Bay where the helicopter had planned to refuel early on Tuesday morning. Naval Service and Irish Coast Guard officials hope the main fuselage of the helicopter is at the same spot.
The failure to locate the missing men on the sea surface has led to fears the trio may not have been able to escape the fuselage of the helicopter before it sank.
Locating a signal from the MPFR is described as a critical breakthrough in the investigation and recovery effort.
Weather conditions permitting, divers will attempt to examine the debris field today.
Air Accident Investigation Unit (AAIU) chief inspector Jurgen Whyte said the signal was coming from an area of difficult water at a depth of 40m.
"Its hugely significant. Other investigation authorities have spent months literally trying to do the same thing and we've been very lucky that, within less than 36 hours, we've picked up a signal," he said.
"That means that the recorder has activated its beacon and we're now using sophisticated scanning equipment to home in on this signal."
Meanwhile the AAIU will also liaise with helicopter manufacturer Sikorsky to determine precisely what caused the worst tragedy in the history of the specialised search and rescue model.
US aviation engineers will assist AAIU inspectors in solving the mystery of what brought down an aircraft designed to defy the elements and to operate in the toughest flying conditions. One aviation source admitted the Rescue 116 tragedy was "baffling". The last available flight record showed the helicopter heading in the general direction of Blackrock Lighthouse at 90 knots (167kmh) at around 12.45am en route to refuel at Blacksod.
The Commissioners of Irish Lights (CIL), which operates the lighthouse, will be one of a number of agencies now assisting the AAIU with its investigation into the tragedy.
CIL official Captain Robert McCabe confirmed that all aids to navigation on the lighthouse were fully operational at the time. The family of the missing men gathered at a property near the co-ordination site in Blacksod yesterday afternoon, where they met rescue workers and politicians including Transport Minister Shane Ross.
Mr Ross praised the family members of the three missing men for their "extraordinary bravery" in recent days.
Superintendent Thomas Healy, of Belmullet Garda Station, added that a specialist family liaison officer had been appointed to the relatives of the three missing men and that they were being briefed on any updates that were available.