On June 16, 2002, at 1545 eastern daylight time, a Piper PA-28R-200, N15143, registered to a partnership and operated by the pilot, collided with an irrigation sprinkler during a forced landing in a field following a loss of engine power in Bethlehem, Georgia. The personal flight was operated under the provisions of Title 14 CFR Part 91 with no flight plan filed. Visual meteorological conditions prevailed at the time of the accident. The private pilot and passenger were not injured, and the airplane sustained substantial damage. The local flight departed Gwinnett County - Briscoe Field in Lawrenceville, Georgia, at 1515. The pilot was practicing commercial flight maneuvers at 3,000 feet mean sea level (MSL) with the fuel selector on the right tank. The pilot completed steep turns at 2400 rpm and 19 inches of manifold pressure. The pilot stated the first turn was for about one and a half complete circles, and the second turn was in the opposite direction for one full circle. The pilot then pulled the power back to 15 inches and made a turning descent for ground-reference maneuvers. At 2,100 feet MSL, which was about 1,100 feet above the ground, the pilot added power, but there was no change in performance. The pilot established glide airspeed toward a field and completed the emergency procedures, but engine power did not return. The pilot then contacted Gwinnett County Tower to transmit a mayday before landing in the field. The pilot estimated the field was 800 feet long and surrounded by trees. The pilot slowed the airplane to 80 knots over the trees and extended the landing gear. The pilot then saw the irrigation sprinklers and small berms. The airplane touched down on the main gear first and sank deeply into the soft soil. The airplane slid about 50 yards, the left wing struck an irrigation sprinkler, and the airplane slid another 25 yards before coming to a stop. The pilot stated both fuel tanks were filled to the tabs at departure, which is about 17 gallons in each 25-gallon tank. Fueling records indicate the airplane received 15 gallons of 100 LL aviation fuel the day of the accident. The fueling was a top-off, and the airplane was flown twice by two other pilots after the fueling and prior to the accident flight for 1.4 hours and 0.6 hours, respectively. Fuel burn for the airplane at economy cruise (mixture leaned) at 75 percent power is 10.15 gallons per hour. Examination of the wreckage revealed the airplane was in a low area of a harvested wheat field of soft, wet soil. The left main gear was collapsed, the nosewheel was separated, and the left wing sustained crush damage. Fuel was observed leaking near the fuel strainer and was contained by emergency response personnel. During recovery efforts, approximately five to six gallons of fuel was recovered from the right tank, and three to four gallons of fuel was recovered from the left tank. The Piper Cherokee II Information Manual states in Section 7-1, Operating Tips, Item 15: "The shape of the wing fuel tanks is such that in certain maneuvers the fuel may move away from the tank outlet. If the outlet is uncovered, the fuel flow will be interrupted and a temporary loss of power may result. Pilots can prevent inadvertent uncovering of the outlet by avoiding maneuvers which could result in uncovering the outlet. Prolonged slips or skids which result in excess of 2,000 feet of altitude loss, or other radical or extreme maneuvers which could cause uncovering of the fuel outlet must be avoided as fuel flow interruption may occur when tank being used is not full." The engine was examined on June 21, 2002, and was run on the airframe with no abnormalities nor evidence of mechanical defect observed during its operation.