Investigation Summary
The flight originated in Paris and was bound for New York with a scheduled stop at Shannon. During the descent into Shannon, the crew encountered poor weather conditions, including 10/10 cloud cover at 400 feet and a lower layer of 4/10 at 250 feet, with visibility limited to one mile. At 02:06, the crew reported being over the range station at 1,200 feet. However, due to a critical maintenance oversight, the static pressure lines for the pilot's instruments had been cross-connected or incorrectly installed. This error caused the altimeters to lag or show significant errors, leading the pilots to fly the aircraft into the ground while attempting to stay above what they believed was a safe altitude. During a left turn onto final approach, the aircraft's port wing-tip struck the ground on Inishmacnaughton, a small island near the airport. The aircraft broke up and was consumed by fire. Despite the severity of the crash, 14 of the 23 occupants survived, including both the Captain and First Officer.
Final Conclusions
The official investigation determined the primary cause was the incorrect assembly of the instrument static pipelines during maintenance. This mechanical discrepancy, combined with poor weather conditions and low visibility, led to a Controlled Flight Into Terrain (CFIT). A 1947 amendment to the Civil Aeronautics Board (CAB) report clarified the fatality count, noting that nine passengers died, though other records suggest a split of four crew and five passengers.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Systems & Failure Modes
Static Pressure System
The system provides ambient air pressure to the altimeter and airspeed indicator. Incorrect assembly of the static pipelines caused the altimeter to provide false altitude readings to the crew.
Altimeter
A flight instrument that measures altitude based on atmospheric pressure. On this flight, the altimeter indicated the aircraft was higher than its actual elevation due to the static line error.
Interesting Facts
- 01The aircraft was a Lockheed L-049 Constellation named 'Cairo Skychief'.
- 02The crash occurred approximately 1.5 kilometers west-northwest of Shannon Airport.
- 03Maintenance errors resulted in the incorrect assembly of the static pipelines for the flight instruments.
- 04The flight was carrying mail, which was reportedly retrieved from the wreckage.
- 05Captain Herbert W. Tansey and First Officer Clifford V. Sparrow survived the accident with serious injuries.
Safety Actions & Advisories
Maintenance Procedure Review
The investigation highlighted the critical nature of instrument plumbing, leading to stricter oversight of static system assembly and testing during maintenance cycles.
Known Controversies & Unanswered Questions
Fatality Discrepancy
Reference ↗Initial reports stated four crew members and five passengers died, but a 1947 CAB report amendment stated that nine passengers were the fatalities.