Investigation Summary
The investigation into the crash of the 'Theodore Roosevelt' focused on why the crew deviated from their cleared flight path into a fatal bank. Despite being cleared for a right turn, the aircraft banked sharply to the left. Investigators identified two primary mechanical possibilities: a failure of the captain's artificial horizon (attitude indicator) or a malfunction in the right-hand aileron trim tabs. Either failure, occurring shortly after takeoff in night conditions, would have made spatial orientation extremely difficult. The aircraft's steep bank angle, reported to be 90 degrees or more, suggests the pilot may have been reacting to false instrument readings or a physical control jam that prevented recovery. The investigation also highlighted crew fatigue as a significant factor; the crew had been on duty for approximately 22 hours at the time of the accident, having flown from the United States to West Germany and then back to Ireland with minimal rest. The airline, a supplemental carrier that had recently acquired its operating certificate from California Eastern Airways, ceased operations shortly after the disaster.
Final Conclusions
The probable cause was the captain's failure to maintain control of the aircraft after becoming airborne. This loss of control was attributed to either a defective artificial horizon or a fault in the right-hand aileron tabs. Contributing factors included poor weather conditions at the time of departure and possible crew fatigue.
Photographic Evidence (1)
Video Analysis
President Airlines DC-6 (N90773) Crash Aftermath Footage — Historical footage showing the aftermath and recovery efforts following the 1961 crash of a President Airlines DC-6 into the River Shannon.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
The captain was found to have been on duty for an excessive period, contributing to potential fatigue.
First Officer
Flight Engineer
Systems & Failure Modes
Attitude Indicator
Also known as the artificial horizon; a suspected failure of this instrument may have provided the pilot with false bank information.
Aileron Trim Tabs
A potential mechanical fault in the right-hand aileron tabs was cited as a possible cause for the uncontrollable roll.
Interesting Facts
- 01The crash is the deadliest aviation accident to occur on Irish soil.
- 02The aircraft was named 'Theodore Roosevelt'.
- 03The flight was a non-scheduled international charter carrying 77 passengers and 6 crew.
- 04The aircraft was manufactured in 1953 and had previously been operated by American Airlines.
- 05The airline went out of business shortly after the accident.
Safety Actions & Advisories
Supplemental Air Carrier Oversight
The accident led to increased scrutiny of supplemental air carriers (charter airlines) regarding their maintenance standards and crew rest requirements, as President Airlines was found to have had deficiencies in its operational oversight.