On May 7, 2025, about 1600 eastern daylight time, a Diamond Aircraft DA 40 NG, N499BW, was substantially damaged when it was involved in an accident near Sanford, North Carolina. The pilot and passenger were seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the passenger, who also served as the mechanic for the airplane, he completed the annual inspection on the airplane the week before the accident flight. He further stated that the pilot approached him on the day of the accident and asked him to check his gearbox oil level. The pilot stated it appeared to be lower than normal. The mechanic checked and found the oil plug gasket had a tear in it and replaced the gasket with a new one. He then cleaned and ran the engine to check for leaks. The engine check was good, and the pilot asked the mechanic to go for a test flight around the airport traffic pattern with him for a touch-and-go landing, and then a full-stop landing. They departed runway 21 at Raleigh Executive Jetport at Sanford-Lee County Airport (TTA), Sanford, North Carolina. Runway 21 was 6,501 ft long, 100 ft wide, and consisted of asphalt. They circled around to perform a touch-and-go landing on runway 21; however, before landing the pilot decided to do a “go around” and leveled off the airplane above the runway. As they were flying down the runway, the engine “popped” like a “backfire” and the pilot tried to land on the remaining runway. They were going too fast and did not have enough runway length left. The pilot bounced the airplane twice and said they were going to go around. The pilot applied engine power, and the mechanic heard the engine rpm increase. Then the pilot turned the airplane left and they “fell” and impacted the ground. He did not recall anything after that. Due to his injuries, the pilot was unable to provide a statement. The wreckage has been retained for further examination.