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The crash site was on a 22-degree upslope at an elevation of 2610 feet m.s.l. and 9,900 feet short of the approach end of Runway 4. The airport elevation is 2,628 feet m.s.l. and that of the VOR station is 2,702 feet m.s.l. At the time of impact the aircraft's heading was about 38 degrees magnetic and the elevation of the crest of the small rise ahead was 2,615 feet m.s.l. (See attachment "B".)
At impact the aircraft was in a slight left wing-down attitude of about six degrees and in a slight nose-up attitude of about four degrees. The landing gear was extended and the wing flap actuator was extended about 8-3/4; inches corresponding to 1/4 flap extension. After initial impact the aircraft began to disintegrate and continued moving for a distance of about 600 feet. Fire developed and the major portion of the aircraft was destroyed.
Examination of the airframe wreckage, systems and powerplants revealed nothing to indicate there had been any operational defect or malfunction prior to impact. The propeller slash marks in the ground were congruent with a ground speed of 137 knots.[1] The aircraft was equipped with de-icer boots on the leading edges of the wings and empennage and an alcohol anti-icing system for the propellers and windshield. It could not be determined if these systems had been in use.
Fire and other damage made it impossible to determine the readings of many instruments. However, the captain's altimeter was set at 29.47 inches and the first Officer's at 29.42 inches. The captain's Omni Bearing Selector (OBS) was set at 031; the first officer's OBS was not readable. No frequency information could be obtained from the radio controls. However, internal examination of the several units showed that the No. 1 VHF communications unit was tuned to company frequency at Miles City, the No. 2 VHF communication unit was set on the MLS FSS frequency, the No. l VHF navigation receiver was at 112.1 mcs., (the frequency of the MLS VOR), and the No. 2 VHF navigation receiver at 115.3 mcs., (the frequency of the Sheridan, Wyoming VOR). The two ADF receivers were at 362 kcs. and 247 kcs. Miles City radio—beacon frequency is 320 kcs.
Examination of the maintenance records of the aircraft indicated that maintenance had been current and as prescribed in all company and Federal Aviation Agency (FAA) directives. No item that could logically be related to than accident was disclosed. Fire at Impact and the tune interval before persons reached the crash site made it impossible to determine if airframe icing had been present at impact.
The last official weather observation taken at the Miles City Airport prior to the accident was the 2030 special observation, the values of which have been previously mentioned. Subsequent to the accident a record special observation was taken at 2055 and was in part: indefinite ceiling 500 feet, sky obscured, visibility 1 mile, light snow showers, temperature 32°F., dewpoint 32°F., wind 300 degrees, 20 knots with gusts to 30 knots, altimeter setting 29.44 inches, snow began at 2002.
The Miles City Airport has a UHF omnidirectional course and distance information facility (TACAN)[2] and a VHF omnidirectional course indicator (VOR),[3] known jointly as VORTAC[4], housed together 3-1/2 miles southwest of the airport. The TACAN was reported out of service at 2015. A technician was dispatched to the
