Investigation Summary
The flight departed Northolt at 17:25 local time, maintaining a consistent ground speed and reporting progress at several waypoints. At 19:12, the crew reported being over Nefyn and requested a descent from 6,500 feet to 4,500 feet. Investigators believe the pilot sought a lower altitude to escape icing conditions, as the de-icing equipment was found switched on. However, the aircraft was not over the Irish Sea as the crew believed; it had unknowingly deviated approximately 18 miles off course and was instead in the immediate vicinity of the Snowdon mountain range. The descent placed the aircraft directly into a powerful mountain wave downdraft. The resulting extreme turbulence caused the starboard wing to fail structurally, breaking off and landing 200 feet from the main impact crater. The aircraft entered a vertical dive, impacting a bog at Cwm Edno at approximately 1,200 feet elevation. The impact was so severe that many victims were buried deep in the peat, and a fire broke out in the crater.
Final Conclusions
The investigation concluded the probable cause was the encountering of a powerful down-current of air on the lee side of Snowdon. This forced the aircraft into an area of extreme turbulence where the pilots lost control. The aircraft's presence over mountainous terrain instead of the sea was attributed to an undetected course deviation.
Video Analysis
Dublin's Lost Flight: Remembering the 1952 Aer Lingus Disaster — A documentary visit to the crash site memorial and the mass grave in Wales, detailing the loss of the Aer Lingus Dakota 'Saint Kevin' in the mountains of Eryri.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Systems & Failure Modes
De-icing System
The aircraft's de-icing equipment was found in the 'on' position, suggesting the crew was actively battling ice accumulation prior to the descent.
Starboard Wing Structure
The wing failed under extreme aerodynamic loads caused by severe turbulence and downdrafts on the lee side of Snowdon.
Interesting Facts
- 01This was the first fatal accident in the history of Aer Lingus.
- 02The aircraft was named 'Saint Kevin'.
- 03One of the only items found intact at the crash site was a four year old girl's doll.
- 04The aircraft carried six bags of mail from various European cities; much of it was salvaged and delivered with special explanatory labels.
- 05The starboard wing was found 200 feet away from the main impact crater, indicating mid-air structural failure.
Safety Actions & Advisories
Mountain Wave Research
Source ↗The accident highlighted the dangers of mountain waves and lee-side downdrafts to relatively low-powered piston-engine aircraft. The investigation emphasized the need for pilots to maintain greater vertical clearance when crossing mountain ranges in high-wind conditions to avoid being forced into areas of extreme turbulence.