On November 24, 2015, about 1600 eastern standard time, a Piper PA-28-180, N3971R, operated by a private individual, was substantially damaged during a forced landing into trees, following a total loss of engine power during initial climb from Gwinnett County Airport (LZU), Lawrenceville, Georgia. The flight instructor was seriously injured and the student pilot incurred minor injuries. The instructional flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the planned local flight. According to the flight instructor's written statement, shortly after turning onto the crosswind leg in the airport traffic pattern for runway 7, the engine lost all power. The flight instructor then took control of the airplane and elected not to attempt to glide back to the airport as the airplane was about 500 feet above ground level. He subsequently performed a forced landing straight ahead into trees. According to the student pilot's written statement, earlier during the day of the accident, they departed LZU with approximately 34 gallons of fuel on a round-trip cross-country flight. After landing at the destination airport, which was about 60 miles from LZU, they completed two more full-stop landings before returning to LZU. After landing uneventfully at LZU, the flight instructor wanted the student pilot to perform one more good landing before concluding the lesson. Everything seemed normal until the student pilot turned the airplane onto the crosswind leg of the airport traffic pattern, at which time the engine lost all power without any sputtering or roughness. He further stated, "It sounded like we had turned off the engine after a lesson: just a smooth shutdown as if the mixture was dropped to full lean after parking…" The student pilot added that the flight instructor tried to restart the engine and it "nearly caught, but then shut off again." Examination of the wreckage by a Federal Aviation Administration (FAA) inspector revealed damage to both wings and the fuselage. Both fuel tanks were compromised during the impact and the inspector was unable to determine fuel quantity. The inspector subsequently performed a successful test-run of the engine at a recovery facility. The four-seat, low-wing, fixed tricycle-gear airplane, serial number 28-7105076, was manufactured in 1971 and was powered by a Lycoming O-360, 180-horsepower engine, equipped with a two-blade Sensenich propeller. It had a total fuel capacity of 50 gallons, which was stored in the main fuel tanks located in each respective wing and were individually selectable through a cockpit fuel selector. Review of the airplane's logbooks revealed that its most recent annual inspection was completed on November 13, 2015. At that time, the airplane had accumulated 6,783 total hours of operation. The engine had accumulated 579 hours since major overhaul. During interviews with the inspector, both pilots stated that they did not switch fuel tanks following the total loss of engine power. The student pilot further stated that they "ran out of gas." Review of performance information for the make and model airplane revealed that the engine consumed about 10 gallons of fuel per hour at 75 percent power. Based on the student pilot's estimation of 34 gallons onboard at the beginning of the day, the airplane should have had 5 to 10 gallons of fuel remaining at the accident site; however, all of the remaining fuel may have been in one fuel tank. Although the flight instructor provided a written statement to the FAA, he failed to submit a completed NTSB Pilot/Operator Accident Report form after several verbal and written requests.