Investigators from the Air Accident Unit say weather conditions at the time of a plane crash in Co Wicklow last year were very difficult.
Four people died when the private plane, which was en route from Gloucestershire Airport in the UK to Kilrush Airfield in Kildare - crashed on October 25.
The aircraft was found impacted into boggy terrain near the summit of Corriebracks Mountain.
Officials from the AAIU say the plane stalled while flying at low level across the mountains.