The Manx2 plane which crashed at Cork Airport killing six people was put through a full maintenance check in Spain last week, it has emerged.
Airline chairman Noel Hayes said he is absolutely satisfied the flight crew - co-pilot Andrew Cantle from York and Spanish pilot Jordi Gola Lopez - were fully qualified.
Their full training records and qualifications have been passed to inspectors at Ireland's Air Accident Investigations Unit.
"The last 24 hours have been a very long and dark 24 hours for me but I know they were probably a longer and darker 24 hours for the families of the bereaved and my heart goes out to them," Mr Hayes said.
"I offer my sincere condolences for yesterday's tragic accident."
Arriving at Cork Airport, Mr Hayes said the doomed 19-year-old Fairchild Metroliner aircraft had been inspected last week but he declined to comment on whether it was properly equipped to land in dense fog.
Mr Hayes signed a book of condolence at the airport before travelling to see four survivors at Cork University Hospital along with Northern Ireland Deputy First Minister Martin McGuinness.
The cockpit voice recorder, which has tapes of the pilot's and co-pilot's conversations with air traffic control, will be sent to Farnborough, Hampshire, for specialist downloading. The flight data recorder, the black box, with all the data on speed, engine information, flight heights and approaches, is being sent to the Air Accident Investigation Unit (AAIU) lab in Dublin.
Both recorders were intact. At least 16 crash investigators from Ireland, the UK, the US and Spain are at Cork Airport, which reopened on Friday night.
Jurgen Whyte, AAIU chief inspector, said: "It's like a big jigsaw and we are looking at all of the information from air traffic control, recorders, radar and we are building a picture from that." A preliminary report with the basic facts will be complete inside a month but Mr Whyte would not disclose if investigators had established exactly where the plane touched down.