SEA85FA012

The acft collided with rising terrain about 1800 ft below the crest of a ridge while on a personal flt in wx which had multiple cloud layers obsuring the mountains. A cap acft on a search mission in the same area at the aprx time reported multiple cloud layers between medford & sunriver, OR. Both pls involved in the accident were cap members & had been on search missions in the area of medford & sunriver on previous flts. The area of the crash is heavily wooded withtrees over 150 ft high. A 4 ft section of the left wing was found near a forest service road. The main wreckage was APRX900 ft away on a 180 degree bearing (mag), at the 3750 ft level of a 5580 ft mountain. No flt plan was filed & no record of a wx briefing was found. The acft departed during a snow shower with 4 persons on board; when it failed to arrive at medford a search was initiated. The search was suspended when no flt signals were received. Six days later a hunter came upon the wreckage. No medical or mechanical reason for the accident was found during the investigation.