The
Irish Examiner reports:-
It is believed the aircraft suffered engine difficulty and was struggling to gain height.
The pilot tried to turn around and get the plane back to the airfield but was unable to do so.
Instructor and student killed as light aircraft plunges to ground | Irish Examiner
This seems consistent with the impact pattern, as shown in an earlier report in the same paper.
Fatal aircrash inquiry underway | Irish Examiner
The reason for the engine problems won't be known for some considerable time. Continental 0-200s, however, are notorious for induction icing, and the chart shows that conditions at the time carried a risk of serious carburettor ice at all power settings.
http://www.atsb.gov.au/media/56519/carb_icing.pdf
Could be a lot of other things, of course, but the above scenario does seem a possible one in light of the known facts at present.