On October 23, 2003, at 1714 central daylight time, a Piper PA-24-250, N5920P, registered to J Douglas Properties Inc, operating as a 14 CFR Part 91 instructional flight, collided with trees and the ground during a forced landing in the vicinity of Troy Municipal Airport, Troy, Alabama. Visual meteorological conditions prevailed and no flight plan was filed. The airplane received substantial damage. The certified flight instructor, private pilot receiving instruction, and one passenger reported no injuries. The flight originated from Acadiana Regional Airport, New Iberia, Louisiana, on October 23, 2003, at 1445. The certified flight instructor stated they departed from Texas enroute to New Iberia, Louisiana, on an instrument flight rules flight plan. The time enroute was 1 hour 30 minutes and the airplane used 25 gallons of fuel enroute. The airplane was flown at a higher power setting than normal (75 percent power) due to cylinder changes on the engine. Upon landing in New Iberia, fuel was added to the left and right main fuel tanks just below the tabs. The flight instructor estimated they had 26 gallons of fuel per side in both the left and right main fuel tanks on departure. The flight departed New Iberia and climbed to 5,500 feet with the pilot receiving instructions flying the airplane. Forty-five minutes later, the fuel selector valve was switched to the left main fuel tank. They flew on the left main fuel tank for 40 minutes and switched back to the right main fuel tank. They were about 25 miles from Troy, Alabama, flight following with Atlanta Center, when they descended to 3,500 feet. They were instructed by Atlanta Center to contact Cairns Approach Control, however they had visual contact with Troy Municipal Airport and they continued their descent to 1,400 feet. The landing gear and flaps were lowered and they entered left traffic for runway 25. They turned final and were about 200 feet and 1/2 mile from the end of the runway when the engine quit. The flight controls were transferred to the flight instructor, and he moved the fuel selector valve to the left main fuel tank and attempted an engine restart with negative results. The flight instructor stated he raised the gear and flaps, and the airplane collided with trees and the ground. An additional interview with the flight instructor and the pilot receiving instruction revealed neither pilot could definitely remember which fuel tank they had started out on. Examination of the wreckage at the crash site revealed the airplane was in line with an approach to runway 25. The flaps were in the retracted position and the landing gear was down. The right wing was detached at the wing root and the fuel connection was severed. The fuel tank was not ruptured and no fuel leakage was present on the ground. About five gallons of fuel was removed from the right fuel tank. The left fuel tank was not ruptured and no fuel was present in the fuel tank or on the ground. All linkage from the throttle, mixture, and propeller controls to the engine was intact and operable. The flight instructor received flight instruction and a high performance sign off in the airplane on the morning of the accident flight. A local flight instructor and former pilot of the accident airplane provided the flight instruction. The flight instructor stated the total flight time for the instructional flight was 30-minutes. The flight instructor's total flight time in the PA-24-250 4 hours 30 minutes. The pilot receiving instruction's total flight time in the PA-24-250 was 4 hours. The wreckage was examined at Atlanta Air Recovery on November 20, 2003. Water was added to the right fuel tank to the top of the filler neck to perform a leak test and no leaks were observed. The left main fuel bladder was removed from the left wing. Water was added to the left fuel bladder to perform a leak test and no leaks were observed. The fuselage was placed in an aircraft dolly and a test propeller was installed. A fuel line from an external fuel source was connected at the left wing fuel finger screen. The fuel selector valve was placed on the left fuel tank. The engine started, ran, and developed power. A fuel line from an external fuel source was connected at the right wing fuel finger screen. The fuel selector valve was placed on the right fuel tank. The engine started, ran, and developed power. The wreckage was released to Atlanta Air Recovery on November 20, 2003.