On June 13, 2003, approximately 2120 mountain daylight time, a Mooney M20C single-engine airplane, N6806U, was substantially damaged during a gear collapse while taxiing for take off at the Boise Air Terminal/Gowan Field, Boise, Idaho. The airplane was registered to Mooney Forfour Inc., Shawnee, Kansas, and operated by the pilot. The private pilot and his passenger were not injured. Night visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan was filed for the proposed 14 CFR Part 91 personal flight, which was destined for Seattle, Washington. In a telephone interview with the NTSB investigator-in-charge, and according to the Pilot/Operator Aircraft Accident Report (NTSB form 6120.1/2), the pilot reported that while taxiing to runway 10R for takeoff, and without any warning, the left main landing gear and nose landing gear both collapsed. The airplane skidded to a stop, coming to rest on its left wing and propeller. An FAA inspector, who examined the aircraft, reported substantial damage to the left wing, approximately one-third of the way inboard from the wing tip. The inspector also reported that all three propeller blades had been bent forward. A subsequent examination by an FAA Airworthiness Inspector revealed there was a failure of the welds on the nose landing gear retraction truss (LH).