Pat Buckley (Cork East, Sinn Fein) | Oireachtas source

There is also the aviation authority. It mentions three of them. Much of this is copied and pasted. Annex 13 to the Convention on International Civil Aviation states:

5.1.2 The State of Occurrence shall institute an investigation into the circumstances of a serious incident when the aircraft is of a maximum mass of over 2 250 kg.

That is a small plane.