Page:Aviation Accident Report, Western Air Lines Flight 1.pdf/5

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Terrain

Fairfield is located about 35 miles almost due south of Salt Lake City, in the approximate center of Cedar Valley, at an elevation of between 4000 and 5000 feet. Cedar Valley is approximately 30 miles wide. The Lake Mountains lie due east of Fairfied and are approximately 7000 feet high; the Oquirrh Mountain Range lies north-northwest of Fairfield. The valley is rolling prairie land. Western #1 was observed in flight directly over Fairfield at 1:20 a.m. and the accident occurred about two minutes later, at 1:22 a.m. The barograph card showed Western #1 to have been flying at 10,200 feet and it had registered a sharp or immediate descent to the ground. It was determined, therefore, that it would been impossible for the aircraft to have collided with any mountain peaks. Investigation did not reveal any other aircraft in the vicinity at or near the time of the accident.

Weather

The weather at Fairfield at 1:30 a.m. was: High broken clouds, ceiling and visibility unlimited, temperature 25°, dew point 22°, wind west estimated 4 m.p.h. Approximately three days previous to the time of the accident a cool dome of Polar Pacific air (high pressure) moved into Utah and adjacent states. This air mass immediately began undergoing subsidence resulting in diminishing winds, both on the surface and aloft, and a lapse rate becoming increasingly stable. By the time of the accident the air mass had become very stable and the wind generally light. The nearest measurement of wind aloft was at Salt Lake City where light to calm air was recorded from the surface to 8000 feet above sea level and with the velocity gradually increasing above that elevation. At 10,000 feet the wind was estimated to be northwest 15 m.p.h. There was no indication of a turbulent layer aloft resulting from wind shear. This type of air mass is favorable for rather rapid loss of heat at the surface at night producing shallow layers of cold air in the valleys. Where there is sufficient moisture available this results in ground fog. Ground fog did exist in some localities near Salt Lake City but had not formed in the Fairfie1d area. Such cloudiness as was reported within several hundred miles of the accident was the type connected with stable air conditions.

Witnesses

Lieutenant Arthur G. Gardner, U.S.M.C.R., one of the two survivors of the accident, is a qualified military pilot and had had accumulated approximately 250 hours of flight time and an estimated 150 hours as observer in military service. Part of this 250 hours included one month of advanced training in DC3 equipment at the American Airlines Naval Training School at Fort Worth, Texas, and about two months of additional experience as copilot with American Airlines in cargo operations between El Paso, Texas, Memphis, Tennessee, and New York, New York. This cargo experience was in DC3 and C-46 type equipment.