Flight Profile
After crossing The Dalles at an altitude of 12,500 feet MSL, the pilot reported to Air Route Traffic Control Center (ARTCC) that he was entering solid clouds. He subsequently reported leveling off at 3,000 feet MSL, followed by the transmission: "if ah we can't stay VFR we'll go ahead and climb up to about five and file IFR."
Observations
The aircraft was observed flying in and out of patches of "light fog" at approximately 450 to 500 feet AGL near an interstate highway and close to mountains. A witness reported that the top third of the mountains adjacent to the gorge was obscured. The aircraft ultimately impacted a steep sloping ridge.
Pilot Experience
The cross-country flight originated in Alabama. On previous portions of the flight, the pilot had flown in instrument flight rules (IFR) conditions and had executed an instrument approach. The pilot's logbook indicated a total of 16.6 hours of actual instrument time.
Aircraft Loading
The aircraft's center of gravity (CG) was estimated to be approximately 0.6 inches behind the aft limit. Two of the occupants were small children weighing 31 and 37 pounds.