On May 6, 1995, approximately 0710 mountain daylight time (mdt), a Beech 35, N3728N, registered to and being flown by a commercial pilot, was destroyed during collision with terrain while maneuvering near Bliss, Idaho. The non-instrument rated pilot sustained serious injuries and reported having no memory of the accident. No flight plan had been filed for the flight which originated at Blackfoot, Idaho, about 0600. Instrument meteoro- logical conditions prevailed at the time of the accident. The personal flight was to have been operated under 14CFR91 and was destined for Midvale, Idaho. The accident was witnessed by two people driving east on Inter- state 84 (I-84). They reported that the weather was extremely foggy with slight rain, and 1/8 to 1/4 mile visibility and that as they approached an overpass about one mile west of the Bliss exit, they "saw an airplane low to the ground banking sharply to the left just before it reached the overpass. It went into the fog out of sight for an instant then reappeared still banking. Then we saw the left wing hit the ground and the nose hit afterwards." An FAA inspector conducted an on site examination and reported that the wreckage distribution was parallel and abeam I-84 and progressed for several hundred feet from the point of initial ground contact. One propeller blade was separated at the hub, and no mechanical discrepancies were observed (refer to photo- graphs 1 through 3 and attached statement). The 0753 Boise aviation weather surface observation (located about 80 miles northwest of the accident site), reported a measured ceiling of 300 foot broken, 800 foot overcast and a visibility of 3 miles in light rain and fog.