by the Civil Aeronautics Board

“ Unless the pilot is highly skilled in instrument flying and can reorient himself by use of the other instruments in the cockpit, this period of disorientation can be fatal.
All pilots who have received instrument training utilizing the artificial horizon are advised not to rely upon the attitude gyro unless sufficient experience has been gained under simulated instrument conditions to insure competence with this instrument. ”

“ Since Peterson had received his instrument training a in aircraft equipped with the conventional type artificial horizon, and since this instrument and the attitude gyro are opposite in their pictorial display of the pitch attitude, it is probable that the reverse sensing would at times produce reverse control action. This is especially true of instrument flight conditions requiring a high degree of concentration or requiring multiple function, as would be the case when flying instrument conditions in turbulence without a copilot. ”

“ If the directional gyro were caged throughout the flight this could only have added to the pilot's confusion.
Conclusion
At night, with an overcast sky, snow falling, no definite horizon, and a proposed flight over a sparsely settled area with an absence of ground lights, a requirement for control of the aircraft solely by reference to flight instruments can be predicated with virtual certainty. ”

“ Temperatures along the airway route from Mason City to Fargo were below freezing at all levels with an inversion between 3,000 and 4,000 feet and abundant moisture present at all levels through 12,000 feet. The temperature and moisture content was such that moderate to heavy icing and precipitation existed in the clouds along the route. Winds aloft along the route at altitudes below 10,000 feet were reported to be 30 to 50 knots from a southwesterly direction, with the strongest winds indicated to be closest to the cold front. ”

“ He was advised by the communicator that all these stations were reporting ceilings of 5,000 feet or better and visibilities of 10 miles or above; also, that the Fargo terminal forecast indicated the possibility or light snow showers after 0200 and a cold frontal passage about 0400. ”

“ This area or band moving southeastward about 25 knots. Cold front at 2335 from vicinity Winnipeg through Minot, Williston, moving southeastward 25 to 30 knots with surface winds following front north northwest 25 gusts 45. Valid until 0335." Another advisory issued by the U. S. Weather Bureau at Kansas City, Missouri, at 0015 on February 3, was: "Flash Advisory No. 1. Over eastern half Kansas ceilings are locally below one thousand feet, visibilities locally 2 miles or less in freezing drizzle, light snow and fog. ”