On September 17, 2004, about 1341 Pacific daylight time, a Hebb Avid Magnum, N970JH, collided with the ground 15 seconds after takeoff at Bryant Field, Bridgeport, California. The owner was operating the airplane under the provisions of 14 CFR Part 91. The private pilot was seriously injured and the airplane was destroyed. The personal cross-country flight departed Bryant Field with the intended destination of Nevada County Air Park, Grass Valley, California. Visual meteorological conditions prevailed, and a flight plan had not been filed. In a telephone interview with a National Transportation Safety Board investigator, the pilot reported that he arrived at the Bridgeport airport around 1200. He experienced light turbulence crossing the surrounding mountains, but classified the arrival to Bryant Field as smooth. During preflight preparations for the accident flight, the pilot noted a crosswind from the left that he estimated to be greater than 10 nautical miles per hour, and at 90 degrees to the departure runway 34. Concerned about the crosswind, the pilot decided not to take passengers on the flight, as he had previously planned. The pilot stated that he was familiar with operating the airplane in similar crosswind conditions, and did not encounter difficulty taxing the airplane to the departure runway. After beginning the takeoff roll and becoming airborne, the airplane was upset and the pilot experienced a loss of control. The pilot reported no preimpact mechanical malfuncitions or failures with the airplane. In a telephone interview with a Safety Board Investigator, a witness reported that the airplane took off toward the east, with an estimated 90-degree crosswind to the runway. The windsock was about 90 percent full. During takeoff, the airplane drifted to the left, and climbed to about 100 feet. The airplane then rolled to the right and impacted terrain nose down, 30 to 40 feet east of the runway. The witness stated that the rudder was deflected fully to the right, and the right aileron was fully deflected down just before the airplane rolled off to the right and hit the ground.