According to the owner of the aerial application company, the single engine airplane was loaded with 430 gallons (approx 3440 lbs) of liquid insecticide for its mission. The airplane departed from a satellite airstrip about 0400 mountain standard time (MST), in order to spray an agricultural field located approximately 5 miles east of the airstrip. When the airplane failed to return to the airstrip at the expected time, the loader became concerned. He telephoned the owner, and the owner initiated a search for the airplane. About 0545, the wreckage was located, approximately 125 feet above, and 1/2 mile to the west of, the field being sprayed, on rocky, rising terrain. Examination by a Federal Aviation Administration (FAA) inspector revealed that airplane struck the terrain in a relatively level attitude, while on an approximate track of northwest, and came to rest facing southwest. The commercial pilot stated that he completed several passes on the field, and was maneuvering the airplane for another pass, when the wind shifted. The airplane was unable to out climb, and subsequently impacted, the terrain. The pilot sustained serious injuries. The pilot reported that he had about 28,500 total hours of flight experience, including 1,388 hours in the accident airplane make and model, and he had been conducting agricultural spraying in the area for the previous 4 months. When asked by the FAA inspector, the pilot stated that if he could change anything about the flight, he would have applied the agent on north-south tracks instead of east-west tracks, in order to provide more clearance from the rising terrain to the west. US Naval Observatory data indicated that local sunrise was about 0612 MST. The automated weather observation at an airport located approximately 20 miles west of the accident site included winds from 020 degrees at 3 knots; visibility 10 miles; clear skies; temperature 24 degrees C; and a dew point of 12 degrees C.