On June 12, 2007, at approximately 1050 Pacific daylight time, a Quad City Ultralight Aircraft, Challenger II experimental light sport aircraft (ELSA), N204DC, was substantially damaged when its right wing separated in flight near Lodi, California. The sport pilot, the sole occupant in the aircraft, was not injured. The pilot/owner was operating the aircraft under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the personal, local flight, which had originated approximately 5 minutes before the accident. A flight plan had not been filed. The pilot said that he was maneuvering at 2,000 feet above the ground when the right wing separated from the aircraft. He said that the aircraft was equipped with a Ballistic Recovery System (BRS) emergency parachute, which he immediately deployed. The pilot said that the fuselage and left wing came to rest in a grape vineyard, and he was able to walk away uninjured. Postaccident examination of the wreckage, by a fellow Challenger II pilot, revealed that the "rony bracket" that attaches the forward lift strut to the fuselage had failed. The bracket was not attached per the Challenger II building manual. The manufacturer's instructions state that the bolt should only be snug. It also warns to not over tighten these bolts holding the brackets to the hollow tubes and that there should be no more than two threads showing past the nut. The bolt on this rony bracket, on the accident aircraft, had at least five to six threads showing. Additionally, the end of the hollow tube was deformed into an oval shape and not round. The remaining rony brackets did have only two threads showing and they could be rotated by hand, per the manufacturer's instructions.