Chief, Investigation Section; Earl Smith, Air Safety Investigator; R. P. Parshall, Senior Air Safety Investigator; and B. C. Haynes, Air Specialist (Meteorology). Upon the basis of all the evidence disclosed by the investigation, the Board now makes its report in accordance with the Act.
II.
SUMMARY AND ANALYSES OF EVIDENCE
Air Carrier
At the time of the accident, Northwest was an air carrier operating under currently effective certificates of public convenience and necessity and air carrier operating certificates. These certificates authorized it to engage in air transportation over various routes, including Chicago, Illinois, to Seattle, Washington; Spokane, Washington to Portland, Oregon; Fargo, North Dakota, to Winnipeg, Canada; and Twin Cities to Duluth, Minnesota.
Airplane and Equipment
Aircraft NC 21714 was a Douglas, model DC-3A, manufactured by the Douglas Aircraft Company, Inc., of Santa Monica, California, and purchased by Northwest in June 1939. It was powered with two Pratt & Whitney S1C3G engines, and was equipped with Hamilton Standard, constant speed, hydromatic, full-feathering propellers. This model airplane had been approved by the Civil Aeronautics Administration for air carrier operations over the routes flown by Northwest with 21 passengers and a crew of 4. It had been certificated for operation with a standard weight of 24,400 pounds and a provisional weight of
