On May 7, 2000, at 1307 hours Pacific daylight time, an amateur built McCoy Glasair III airplane, N1ML, veered off the runway and collided with a taxiway sign on the landing rollout at the Burbank-Glendale-Pasadena Airport, Burbank, California. The airplane, owned and operated by the commercial pilot under the provisions of 14 CFR Part 91, sustained substantial damage. The personal, local area flight, originated from the Whiteman, California, airport at 1245. The commercial pilot, sole occupant, was uninjured. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that he was practicing touch-and-go landings on runway 12 at Whiteman. On final approach, he experienced a downdraft and the airplane dropped approximately 75 feet. He added power to initiate a go-around, but was unable to gain altitude. The pilot heard a "thud" and realized that the right main landing gear had struck a telephone pole and had separated from the airplane. He performed a low approach by the Air Traffic Control Tower (ATCT) and they confirmed that his right landing gear was missing. He then requested to make an emergency landing at the Burbank Airport (approximately 5 miles southeast) due to the availability of ARFF personnel. After performing a low approach, for Burbank ATCT to observe the damage, the pilot was cleared to land on runway 15. On the landing roll the remaining landing gear collapsed, and the airplane veered off the runway, striking a taxiway sign with the right wing. Review of the aviation surface observations for the hour before and after the accident revealed winds out of the west at 7 knots. No unusual meteorological conditions were reported.