On September 3, 2001, at 1701 eastern daylight time, a Piper PA-22-160, N3516Z, owned and operated by an individual, operating as a Title 14 CFR Part 91 personal flight impacted the ground during a forced landing near the Spruce Creek Airport, Daytona Beach, Florida. Visual meteorological conditions prevailed. No flight plan was filed. The airplane was substantially damaged. The private-rated pilot and one passenger reported no injuries. The flight departed Vandenberg Airport, Tampa, Florida, at 1600. The pilot stated that while on a "gradual descent" at an altitude of about 900 feet msl, and in preparation for entry into the traffic pattern at the airport, "...the aircraft commenced an abrupt, uncommanded roll to the right." The pilot corrected the situation and regained level flight by applying "full left aileron and full left rudder," however the airplane remained in a "right wing" low attitude and "gradual right turn." The pilot stated that she realized that "directional control was compromised," and that due to the "high density" of housing in the area of the airport, she elected to attempt a forced landing in the "only" area that was clear of houses trees and cattle. After landing the airplane impacted an "overgrown" drainage ditch not visible from the air. According to the FAA inspector's statement, the pilot said the right wing suddenly dropped (lost lift), and the engine was at 2100 rpm. The landing was made in a cow pasture west of the airport. In addition, the passenger told the FAA inspector he turned off the ignition just prior to impact with the ground. The airplane came to rest in a "shallow" drainage ditch about 50 feet from initial touchdown. Examination of the airplane's fuel system revealed that the forward fuel filter bowl was slightly displaced from the top of the filter assembly. The fuel tanks were not breached, and the left fuel tank was full of fuel. A rubber hose had to be inserted into the lowest point of the right fuel tank in an attempt to recover fuel from the tank. No fuel was found in the right fuel tank. Examination of the fuel selector handle in the cockpit revealed that the fuel selector was positioned on the "right tank." About "1 ounce" of fuel was drained from the forward fuel filter, and about "1/3 of a pint" of fuel was drained from the aft fuel filter. Examination of the flight controls revealed that they "...operated normally and found to be in serviceable condition." Examination of the propeller revealed that one propeller blade was bent aft 30 degrees and scratched, the other blade was straight and clean.