NTSB Identification: WPR11FA221
14 CFR Part 91: General Aviation
Accident occurred Monday, May 09, 2011 in Miles City, MT
Probable Cause Approval Date: 12/05/2012
Aircraft: AIR TRACTOR INC AT-802A, registration: N8523H
Injuries: 1 Fatal.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

The instrument-rated pilot departed to reposition the airplane, which was configured for visual flight rules (VFR) operations only, to its base of operation about 316 miles northwest of the departure airport. Weather conditions at the departure airport were VFR, however, the destination airport and throughout the western portion of the route had deteriorating weather conditions and low cloud ceilings. There was no record of the pilot obtaining a weather brief for the flight; however, while filing a VFR flight plan, the pilot informed the weather briefer that he already had weather information and declined any additional weather information offered by the briefer. A witness located near the accident site heard the sound of an airplane flying low and fast from the east to the west past her home. Shortly after hearing the airplane, she heard a "poof" sound and immediately looked outside for the airplane. The witness stated that she did not see the airplane or any smoke in the area; however, she observed a cloud layer covering the top of the mountain ridge where the accident site was later located.

The global positioning system (GPS) track for the flight indicated that during the later portion of the flight, the airplane descended from an altitude of about 5,869 feet mean sea level (msl) to 3,054 feet msl, while conducting several course changes from the northwest to the southwest, most likely as a result of the pilot attempting to avoid or remain clear of the deteriorating weather conditions. The GPS data further showed a climb to an altitude of about 3,241 feet msl before turning left to a westerly heading. About 2 minutes later, the data showed a left turn to the southwest at an altitude of about 3,406 feet msl, where a descent was initiated. The last recorded data point was recorded at an altitude of about 3,284 feet msl. The accident site was located about 0.15 miles southwest of the last recorded GPS position at an elevation of about 3,077 feet msl.

A weather report in the area of the accident showed a visibility of 2 miles, mist, overcast cloud layer at 700 feet, and a variable ceiling from 400 feet to 1,100 feet.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot's continued visual flight rules flight into deteriorating weather conditions in an airplane not equipped for instrument flight, which resulted in a collision with terrain.

Full narrative available

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