On August 14, 2020, at 1235 mountain daylight time, a Piper, PA-28-140, N317LB, was substantially damaged when it was involved in an accident near Harlowton, Montana. The private pilot and the three passengers sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that while operating the airplane during the summer months, the engine was not performing like it had during the winter. The airplane’s engine and tachometer were inspected by an airframe and powerplant mechanic (A&P). The A&P determined that the engine and tachometer were operational and met the manufacturer specifications. Two days later, the pilot and one passenger boarded the airplane, took off, and remained in the airport traffic pattern completing three takeoffs and landings. The pilot confirmed that the airplane’s engine oil temperature, oil pressure, and rpm remained in the green, ascertaining that the engine was operating normally. Subsequently, they departed the traffic pattern on a 75 nm, visual flight rules cross-country flight to Harlowton, Montana. After landing at Harlowton, the pilot onboarded two additional passengers. The pilot selected runway 27 (length 4,200 ft) for the departure with what he ascertained was into a direct headwind. He chose to perform a short-field takeoff with two notches of flaps (25°). During the takeoff roll, the pilot kept the airplane on the ground until the indicated speed reached 77 mph. The airplane departed and began to climb before reaching the end of the runway. The airplane had reached about 100 ft above ground level (agl), but seconds later, it would no longer climb. The pilot decreased the airplane’s pitch attitude and the airplane descended. The airplane continued to descend and about one mile west of the airport, the airplane touched down on the soft grass surface of a livestock grazing pasture, collided with a barbed wire fence, and nosed over. The pilot reported that while no component of the airplane’s engine malfunctioned during takeoff, it was not producing the power that he had expected. He affirmed that three combined factors caused the accident: airplane gross weight, atmospheric conditions, and the engine power. The airplane’s maximum gross weight was 2,150 pounds. The pilot reported that at the time of the accident, the airplane’s gross weight was exactly 2,150 pounds. However, review of the airplanes total weight using the pilot-supplied approximate weight of the passengers, baggage, and 31 gallons of fuel, revealed that the airplane weight was about 2,197 lbs at takeoff. The airplane’s owner handbook stated that for short-field takeoffs requiring no obstacle clearance, the pilot will lower the flaps to 25° (second notch), accelerate to 55-60 mph and ease back on the control wheel to rotate. After breaking ground, accelerate to the best rate of climb speed, 85 mph, and slowly retract the flaps while climbing out. The meteorological aerodrome report located at the accident airport reported that about the time of the accident, the wind was out of 300° at 13 knots and gusting to 22 knots. The temperature was 73.4° F, the field elevation was 4,312 ft and the altimeter setting was 30.18 inches of mercury. The pressure altitude was 4,073 ft and the density altitude (DA) about the time of takeoff was 6,035 ft. With the airplane loaded to its maximum gross weight, and operating at a density altitude of 6,035 ft, with zero flaps, and no wind, the ground roll would have been 1,600 ft, with 3,300 ft needed to clear a 50 ft obstacle. Under the same conditions, the climb rate would have been 425 ft-per-minute. The manual does not provide a distance or climb rate when the airplane is configured with flaps applied. The mechanic who performed the engine and engine tachometer inspection informed the pilot that the engine produced between 2,200-2,300 rpm. The engine tachometer inspection confirmed normal operation by the mechanic. The pilot reported that the engine was operated 1,268 hours since the last engine overhaul and that the engine had accumulated 159 hours since the last annual inspection. During a conversation between the pilot and Federal Aviation Administration (FAA) aviation safety inspectors, the pilot provided the accident sequence of events by reenacting his actions during the flight. The pilot’s actions indicated that he was in the habit of lining up on the runway, adding full power and immediately moving his right hand from the throttle control to join his left hand on the yoke. When asked, the pilot confirmed that he did not verify that the throttle control remained in the fully open position after realizing that he could no longer maintain the airplane’s airspeed and altitude. He reported that both hands remained on the yoke for the duration of the flight after initiating the takeoff roll and he did not manipulate any engine controls after the accident. A postaccident airplane examination of the airplane’s cockpit configuration revealed a rich mixture control position, the carburetor heat control was partially backed out, and the throttle control was backed out from the full-power position. An FAA inspector stated PA-28 throttle quadrants are “very susceptible” to throttle creep during takeoff and climb-out if the throttle friction is not set properly and the pilot does not keep his hands on the throttle. A photograph of the accident airplane taken shortly after the collision revealed that the wing flaps remained extended.