On July 14, 2007, about 0915 Pacific daylight time, a Beech 58, N141DH, experienced a landing gear collapse while on the departure roll from the Chino Airport, Chino, California. Threshold Technologies was operating the airplane under the provisions of 14 CFR Part 91. The certificated flight instructor (CFI), the sole occupant, was not injured; the airplane sustained substantial damage. Visual meteorological conditions prevailed, and no flight plan was filed. The local personal flight was originating at the time of the accident with a planned destination of John Wayne-Orange County Airport, Santa Ana, California. In a telephone conversation with a National Transportation Safety Board investigator, and in his subsequent written report, the pilot stated that as the airplane was accelerating down the runway for departure, he recognized the odor of burring electrical wire. As the airplane approached rotation speed around 50 to 60 knots, the odor became stronger. The nose of the airplane began to rise and he retarded the throttle controls to the idle position. The landing gear collapsed and the airplane skid to a stop. He noted that the circuit breakers were in the closed position and the landing gear handle was in the down position. The Federal Aviation Administration (FAA) inspector that examined the wreckage following the mishap stated that the airplane incurred structural damage during the accident sequence. The airplane was not examined for 6 months after the accident, as there was an ongoing dispute between the insurance company and the owner. The airplane remained in storage at a repair station in Chino. An FAA certificated airframe and powerplant mechanic and airline transport pilot, examined the airplane and provided a statement of the findings. He reported that a mechanical inspection and evaluation was conducted in accordance with the manufacturer's maintenance manual and procedures. The examination revealed no mechanical malfunctions or anomalies with the electrical system or landing gear. Upon activation of the system, the landing gear operated as designed. He opined that during the attempted departure, the landing gear handle was in the retracted (up) position. He further stated that if the landing gear handle were in this position the landing gear would retract as the airplane became airborne.