SEA84FA110

The load/ground crew reported that the plt planned to make 1 more spray run before flying back to the home base. When the acft did not return to the loading area, they assumed he had returned to the base. They drove 20 mi back to the base, but found neither the acft nor the plt, S0 they returned to the spray area. The acft was found where it had crashed on rolling/hilly terrain (at dusk). An exam revealed the propeller had contacted the ground appx 386 ft west of the principal impact point. There was evidence that the left wing spray boom had intermittently contacted the ground in a 10 to 15 deg circular arc to the north. The left main gear then contacted the uneven terrain. Beyond that, the acft crossed a gully/ditch, impacted rising terrain & came to rest in an inverted position. No preimpact part failure or malfunction was found. This was the plt's 1st spray mission for the operator. About 18 mi east at burley, ID, the 1845 MDT wx was in part: 200 ft partial obscured, 3000 ft broken.