An Air Corps flight which crashed killing a trainee pilot and instructor struck a mountainside about 200ft below standard flying levels, it emerged today.
Experienced Captain Derek Furniss and Cadet David Jevens died when their two-seater light aircraft went down in a remote valley in Connemara last month as weather closed in.
A preliminary report into the tragedy on the edge of Lough Mask found weather conditions, including cloud cover and visibility, rapidly changed around the time of the crash.
Air accident investigators said the wreckage was strewn across a ridge in Crumlin Valley, known as Maum Dearg, at about 800ft.
Normal flying height is above 1000ft but it is understood the Air Corps may be given permission to fly below that altitude in some areas.
The Air Accident Investigation Unit found no technical problems with the small Pilatus PC-9M craft which had been on a visual navigation training flight.
The plane crashed one mile north from its intended route and the debris was strewn across a 300ft area on the downslope of the remote peak.
Investigators said the slight departure from the planned course was well within the normal margin for error.
The aircraft had been conducting cross-country navigational training from Casement Aerodrome in Baldonnel to Galway Airport via Co Cavan and Maum on October 13.
Two other aircraft were also taking part in the exercise, flying at 15-minute intervals behind.
The crew radioed to Shannon Air Traffic Control from Carrigallen, Co Cavan, about 20 minutes before the crash and travelling at 1,500ft, that it was setting course for Maum, the final planned point before stopping to refuel in Galway.
It was last recorded on radar by Shannon over lower Lough Mask at an altitude of 1300ft, eight miles from the crash site and minutes before it went down.
A resident in Crumlin Valley reported hearing a plane crash and contacted fire officers in Castlebar, Co Mayo.
Air traffic control requested one of the other training planes to conduct a search, but the pilot was forced to call it off because the weather closed in with clouds coming down and visibility deteriorating.
Residents later found the crashed plane on the mountainside and directed gardaí and the emergency services to the site.
Information from the flight data recorder has been downloaded and is being examined by crash scene investigators before a final report into the crash is published late next year.
Three Air Corps officers are assisting investigators.
Captain Furniss was a highly regarded instructor while Cadet Jevens was due to graduate with Military Pilot Wings and Officer Commission later this year.