Investigators focus on possible 'electrical failure' in tragic Rescue 116 crash
- Signal from black box found near lighthouse
- Hopes that divers can start salvage today
- Three crew members still missing
- No mayday call because of 'catastrophic failure' on board
The probe into the loss of Coast Guard Rescue 116 helicopter is currently centring on whether "electrical failure" on the helicopter caused the crash.
Investigators have also looked into the possibility the helicopter collided with the lighthouse at Blackrock, six miles off the coast of Mayo.
However, this theory is now discounted as there was no evidence of a collision with the rock and there was no wreckage around the lighthouse.
"There was no paint or debris on the lighthouse. There are 100 theories going around," a senior source involved in the investigation said.
This morning, Newstalk Breakfast reports that the Defence Forces confirmed in a statement that they were initially asked to provide top cover for this mission.
However, the request was denied due to the fact it was outside normal hours and there was a lack of "experienced personnel" available.
The request was logged at 10:06pm and the Air Corps was not able to carry out the mission as the fixed wing aircraft was unavailable.
Rescue 116 was subsequently dispatched instead.
The statement further added "plans are in place to deal with the shortages in personnel being experienced by the Air Corps."
The full-scale search is now homing in on an area near the lighthouse where the black box is now believed to be located.
The crash claimed the life of Captain Dara Fitzpatrick while her crew of three, Ciaran Smith, Mark Duffy and Paul Ormsby, are still missing.
Officials believe there was no mayday call because of a "catastrophic failure" on board.
"It takes two seconds to press the mayday button. The fact they did not press the button 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 Captain Fitzpatrick.
"She would never leave a stone unturned," they added.
The scale of the debris field from the downed helicopter has led to fears it may have disintegrated on impact with the sea or suffered a catastrophic collision around 1pm on Tuesday.
The revelation came as an underwater signal was successfully detected from the 'black box' of the downed Rescue 116 Sikorsky S-92A helicopter 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 permitting, divers will attempt to examine the debris field identified today.
Jurgen Whyte, chief inspector of the Air Investigation Unit, said the signal was coming from an area of difficult water with a 40m depth.
"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 with what is a signal.
"That means that the recorder has activated its beacon and we're now using sophisticated scanning equipment to home in on this signal itself," Mr Whyte said.
Meanwhile the Air Accident Investigation Unit (AAIU) will also liaise with the 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 is "baffling".
The last available flight record showed the helicopter heading in the general direction of the lighthouse at 90 knots (167kmh) around 12.45am en route to refuel at Blacksod.
The Commissioners of Irish Lights, which operates the Blackrock facility, will be one of a number of agencies now assisting the AAIU with its investigation.
CIL official Captain Robert McCabe confirmed all aids to navigation on the lighthouse were fully operational at the time.
Transport Minister Shane Ross visited the area yesterday and praised the family members of the three missing men for their "extraordinary bravery" in recent days.