What happened
On 12 October 2009, a Pilatus PC-9M aircraft, registration 265, was engaged in a Visual Flight Rules (VFR) navigational training exercise. Operating under the Irish Air Corps, the aircraft departed Casement Aerodrome in Baldonnel, Co. Dublin, as part of a formation of three aircraft. The flight plan involved navigating via Carrigallen and Maum, with a final destination of Galway Airport.
At approximately 16:39 UTC, the crew reported being over Carrigallen at 1,500 feet. The aircraft was last tracked by Shannon radar at 16:55 UTC, positioned over Lower Lough Mask at an altitude of 1,300 feet while proceeding toward Maum. Shortly thereafter, reports of an aircraft crash were received from residents in the Crumlin Valley area. While a secondary aircraft attempted a search, deteriorating visibility and a lowering cloud base forced the search to be suspended.
Local residents eventually discovered the wreckage on the mountainside at Maum Dearg. The impact occurred on the crest of a ridge in Crumlin East, approximately one nautical mile north of the intended flight path. The aircraft was destroyed upon impact, and the two crew members sustained fatal injuries.
The investigation
The investigation was complicated by the presence of armed ejection seats, which had not been deployed. Because the explosive devices within the seats could not be safely neutralized in the dark, investigators could not access the wreckage until the following morning.
On-site examination revealed a debris trail spanning 300 feet down a slope, a pattern consistent with a high-speed impact. Witnesses in the valley observed the aircraft flying east through the valley, performing a steep northward turn and then climbing, amidst rapidly changing visibility and cloud heights.
Investigators successfully recovered the memory unit from the Cockpit Voice and Flight Data Recorder (CVFDR) from the debris field. This unit was transported to the manufacturer in the United States for data retrieval. At the time of this preliminary report, no technical malfunctions had been identified as a cause for the crash.