On September 10, 2014, about 2021 eastern daylight time, a Cessna 172P, N63835, was substantially damaged when it collided with trees and terrain following a total loss of engine power on approach to Spruce Creek Airport (7FL6), Spruce Creek, Florida. The flight instructor /owner and the commercial-rated pilot receiving instruction sustained minor injuries. Night visual meteorological conditions prevailed, and a composite VFR/IFR flight plan was filed for the instructional flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Both pilots were interviewed by telephone, and each provided a written statement. According to the instructor, the purpose of the flight was to log a number of instrument approaches for the pilot receiving instruction in order to meet certificate requirements in his home country. The pilot receiving instruction stated he did not have a checklist for the airplane, and relied on the instructor's "knowledge of the airplane" to complete the preflight inspection. He stated the fuel tanks were "almost full" prior to the flight, and that the instructor told him the available fuel would provide 6 hours of fuel endurance. The airplane departed 7FL6 at 1657 for West Palm Beach, Florida (PBI), and Vero Beach, Florida (VRB). The crew performed touch-and-go landings at PBI and VRB before returning to the departure airport, and the airplane was on final approach for landing at 7FL6 when the engine stopped producing power. The instructor said he attempted an engine restart and ensured that best glide speed was maintained before the airplane struck trees and the ground. The pilot receiving instruction stated that the fuel selector was in the "Both" position throughout the flight. On final approach to 7FL6, he noticed that the fuel selector had been switched to the "Right" tank position, and he moved the selector back to "Both." Shortly thereafter, the engine stopped producing power. The instructor stated that on final approach the pilot inadvertently selected the "Off" position when he moved the selector from the "Right" tank position and the engine quit. He attempted to restart the engine and helped the pilot maintain best glide speed until the airplane collided with the trees. According to Federal Aviation Administration (FAA) air traffic control records, multiple one-leg flight plans were filed for the accident flight. The estimated fuel endurance filed for the first leg, and each of the subsequent legs, was 3 hours and 20 minutes. While fuel was available at each of the airports where the airplane performed approaches and touch-and-go landings, the airplane was not serviced with fuel at any point along the flight. In the NTSB Form 6120.1 Pilot/Operator Aircraft Accident Report form, the instructor/owner/operator stated there were 30 gallons of fuel on board at departure. The instructor held a flight instructor certificate with ratings for airplane single engine and instrument airplane. His most recent FAA first-class medical certificate was issued on July 3, 2013, and he reported 250 hours of flight experience on that date. When interviewed, he reported about 314 total hours of flight experience, of which 212 hours were in the accident airplane make and model. The pilot receiving instruction held a commercial pilot certificate with ratings for airplane single engine land, multiengine land, and instrument airplane. His most recent FAA first class medical certificate was issued July 15, 2011. According to FAA records, the airplane was manufactured in 1981. Its most recent 100-hour inspection was completed December 11, 2013, at 8,312 total aircraft hours. According to the pilot's operating handbook, the airplane's fuel capacity was 43 gallons, of which 40 gallons were usable. The fuel consumption rate at 66 percent power given the conditions of the accident flight was 7.4 gallons per hour in cruise. The fuel required for the multiple full-power takeoffs and climbs during the flight was not computed. At 2053, the weather conditions reported at Daytona Beach, Florida (DAB), 6 miles west of the accident location, included few clouds at 2,400 feet, visibility 10 miles, temperature 27 degrees C, dew point 23 degrees C, and an altimeter setting of 30.03 inches of mercury. The wind was from 080 degrees at 6 knots. The wreckage was examined by an FAA inspector at the accident site, which revealed a separated right wing and damage to the cabin and empennage. Control continuity was established to all flight control surfaces, and the examination revealed no preimpact mechanical anomalies. The left wing fuel tank was intact, and contained no fuel. The right wing tank was intact, and contained about 3 gallons of fuel. A test run of the engine was performed following the accident utilizing the fuel found in the right wing tank. The engine started immediately, accelerated smoothly, and ran continuously with no anomalies observed.