Investigation Summary
Flight 5 was on the leg of its journey between Minneapolis and Fargo when it encountered severe icing conditions. The investigation focused on the rapid accumulation of ice, which significantly altered the aerodynamic properties of the DC-3's wings, leading to a loss of lift and control. The aircraft crashed into a ravine and caught fire, though approximately 100 pounds of the 750 pounds of mail on board were eventually salvaged by postal clerks. The accident was the deadliest aviation disaster in Minnesota history at the time of the occurrence. Notably, the sole survivor, Captain Clarence Bates, perished almost exactly one year later while test-flying a B-24 Liberator in St. Paul.
Final Conclusions
The Civil Aeronautics Board determined the probable cause of the accident was the accumulation of a heavy load of ice on the wings of the aircraft, which occurred while the pilot was attempting to land at Fargo under icing conditions. This accumulation resulted in a loss of lift and an increase in stalling speed, causing the aircraft to stall at an altitude from which recovery was impossible.
Video Analysis
No video analysis linked for this case file yet.
Crew Experience
Captain
Clarence F. Bates (Sole survivor)
Systems & Failure Modes
Wings
The primary lifting surfaces of the DC-3, which failed to maintain lift due to heavy ice accumulation.
De-icing Equipment
Systems intended to clear ice from leading edges, which were insufficient to overcome the rate of accumulation during this encounter.
Interesting Facts
- 01The crash was the deadliest aviation accident in Minnesota history at the time of the occurrence.
- 02The aircraft was carrying over 750 pounds of mail, of which 898 pieces (weighing approximately 100 pounds) were salvaged from the fire.
- 03Captain Clarence Bates was the sole survivor of the 15 people on board.
- 04The flight attendant, Bernice Blowers, had reportedly declined a request from her fiance to find a substitute for the flight so they could go dancing.
- 05The co-pilot, Alden Onsgard, had previously left dentistry school to pursue aviation.
Safety Actions & Advisories
Icing Research and De-icing Procedures
The accident highlighted the dangers of rapid ice accumulation on the DC-3. Following this and similar icing accidents in the early 1940s, the industry and regulators increased focus on the limitations of pneumatic de-icing boots and the necessity of maintaining higher airspeeds during approaches in known icing conditions.
Location
ACCIDENT SITE · Coordinates taken from the wikidata coordinate.