On June 17, 2020, about 1800 eastern daylight time, a Cessna 152, N25449, was substantially damaged when it was involved in an accident near McAlpin, Florida. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that he performed a preflight inspection of the airplane and an engine runup before departure with no discrepancies noted. After the engine runup was performed, he asked his passenger if he wanted to follow the rudder control inputs by placing his feet on the rudder pedals and he said he did. He advised his passenger of the takeoff profile, taxied into position, and applied full throttle to begin the takeoff roll with 10° of flaps extended. The pilot noted that the airspeed indicator was "not alive," which he thought was unusual, but he continued the takeoff roll expecting it to increase. When the pilot saw the windsock out of his peripheral vision, which was about midway along the 2,600 ft long grass runway, he noted that the airspeed indicator showed about 45 knots instead of 50 knots, which was the normal value for that point along the runway. The pilot later reported that he considered aborting the takeoff at this point, indicating that “he could have aborted” because his hand was on the throttle; however, he elected to continue and rotated at 50 knots. The airplane remained in ground effect, and he pushed the yoke to increase airspeed while flying through a gap in trees past the departure end of the runway. The airplane climbed at an airspeed of 50 to 55 knots to an altitude of about 35 ft above ground level; however, it subsequently struck trees, stalled, and impacted the ground, which resulted in substantial damage to the wings and fuselage. After exiting the airplane, the pilot noted smoke from a small fire in the engine compartment area, which was later attributed to fuel from the carburetor (which had broken off during impact). The fire was extinguished by the fire department. A pilot-rated witness who was at the airport reported hearing no discrepancies during the engine runup before takeoff. He heard the takeoff roll and noted the airplane was still on the ground when it was 2/3 down the runway. He thought to himself the pilot should have aborted but when the pilot did not, it sounded to the witness like the “engine was not revving like it should.” He believed the airplane became airborne at the very end of the runway in an effort to clear a 3 ft fence/sign. While in ground effect, the airplane continued to the west and landed among trees. The witness added that when the airplane traveled past his position, the engine was running smoothly, but he felt it was not developing full power. Following the accident, the pilot initially questioned whether the passenger had his feet on the brakes; however, the passenger confirmed to the NTSB that his feet were never on the rudder pedals and they were on the floor for the entire flight. The passenger further indicated that he was briefed by the pilot before departure to, “don’t touch the pedals and keep your feet on the floor.” The pilot was asked during a postaccident phone interview if he recalled the magneto decrease during the engine runup before takeoff. He indicated he did not remember specifically but thinks when he checked the first magneto he switched back to both, but when he checked the other magneto, he may have failed to switch back to both. He added that he, “thinks [he] took off on 1 magneto.” He indicated that when he got out of the airplane he left the ignition key in the ignition switch, but when he went back to the airplane the next day to check the position of the ignition switch, the ignition key was on the floor. A representative of the company that recovered the airplane 2 days after the accident reported the ignition switch was in the OFF position. A total of 4 gallons of 100 low lead fuel were drained from each fuel tank with no contaminants reported. Postaccident examination of the engine revealed extensive heat damage to the fuel metering and ignition systems, which precluded operational testing. The No. 4 cylinder exhaust valve clearance was 0.002 inch greater than specified. No evidence of preimpact failure or malfunction of the engine assembly was noted. Weight calculations were performed based on the latest empty weight (1,188.0 pounds), the reported weights of the pilot (173) and passenger (230), respectively, and the amount of fuel drained during airplane recovery (48 pounds). The airplane weight at engine start was about 31 pounds below maximum certificated takeoff gross weight.