On April 10, 2002, about 0830 mountain standard time, an unregistered, experimental homebuilt Cox Aeros Ltd. Skyranger, collided with the ground during a forced landing at Gila Bend, Arizona. The owner/operator was operating the airplane under the provisions of 14 CFR Part 91. The private pilot sustained minor injuries and the passenger sustained serious injuries; the airplane sustained substantial damage. The purpose of the flight was to practice touch-and-go landings. Day visual meteorological conditions prevailed, and no visual flight rules (VFR) flight plan had been filed. Through a written statement, the pilot stated that after departing runway 22 to practice touch-and-go's, approximately 300 yards beyond the end of the runway a computer malfunction resulted in instant shutdown of the engine; consequently, the pilot made a forced landing in the rough, desert terrain. The pilot further stated that upon touchdown, the nosegear collapsed and the cowling and windshield were damaged. The speed of the airplane was between 40-45 miles per hour. According to a local law enforcement report, the pilot had departed to the west from the municipal airport. The runway is oriented 040/220 degrees, according to the Southwest U.S. Airport/Facility Directory. About 150 to 200 feet above the ground (agl), the engine lost power and a forced landing ensued. According to the engine manufacturer, if the computer does not receive power from the battery, the engine will quit. The two-place ultralight trainer airplane was registered with the United States Ultralight Association but the owner/operator did not apply for a waiver as required by Federal Aviation Regulations Part 103.