Accident Overview
On August 14, 2020, at 1235 mountain daylight time, a Piper PA-28-140, registration N317LB, was substantially damaged when it collided with terrain during a takeoff from Harlowton, Montana. The private pilot and three passengers sustained minor injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Pilot Report
The pilot reported that the engine had not performed as expected during the summer months compared to winter. An airframe and powerplant mechanic (A&P) inspected the engine and tachometer and found them operational and within manufacturer specifications. Two days before the accident, the pilot and one passenger performed three takeoffs and landings in the traffic pattern, confirming normal engine oil temperature, oil pressure, and rpm. Subsequently, they departed on a 75-nautical-mile visual flight rules cross-country flight to Harlowton. After landing, the pilot added two more passengers.
For the departure from Harlowton, the pilot selected runway 27 (4,200 ft) with a headwind. He performed a short-field takeoff with two notches of flaps (25°). During the takeoff roll, he kept the airplane on the ground until the indicated airspeed reached 77 mph. The airplane lifted off and climbed to about 100 ft above ground level, but then would not climb further. The pilot decreased pitch attitude, and the airplane descended. It touched down on soft grass in a livestock pasture about one mile west of the airport, collided with a barbed wire fence, and nosed over.
The pilot stated that no engine components malfunctioned but that the engine was not producing the expected power. He affirmed three combined factors as the cause: airplane gross weight, atmospheric conditions, and engine power.
Weight and Balance
The airplane's maximum gross weight was 2,150 pounds. The pilot reported the weight at takeoff as exactly 2,150 pounds. However, a review using the pilot-supplied weights of passengers, baggage, and 31 gallons of fuel indicated the actual weight was about 2,197 pounds.
The owner's handbook specifies for a short-field takeoff without obstacle clearance: lower flaps to 25°, accelerate to 55-60 mph, rotate, then after breaking ground, accelerate to best rate of climb speed (85 mph) and slowly retract flaps while climbing.
Weather and Performance
The meteorological aerodrome report at the accident airport indicated wind from 300° at 13 knots gusting 22 knots, temperature 73.4°F, field elevation 4,312 ft, altimeter 30.18 inHg, pressure altitude 4,073 ft, and density altitude 6,035 ft about the time of the accident.
With the airplane at maximum gross weight and operating at a density altitude of 6,035 ft, with zero flaps and no wind, the handbook states a ground roll of 1,600 ft and 3,300 ft needed to clear a 50-ft obstacle, with a climb rate of 425 ft per minute. The manual does not provide distances or climb rates for flap configurations.
Postaccident Examination
A postaccident examination of the cockpit revealed a rich mixture control position, the carburetor heat control partially backed out, and the throttle control backed out from the full-power position. An FAA inspector commented that PA-28 throttle quadrants are susceptible to throttle creep during takeoff and climb-out if friction is not set properly and the pilot does not keep a hand on the throttle. A photograph taken shortly after the accident showed the wing flaps remained extended.
The pilot reenacted his actions for FAA inspectors, indicating he was in the habit of adding full power and immediately moving his right hand from the throttle to join the left hand on the yoke. He confirmed he did not verify the throttle remained fully open after realizing he could not maintain airspeed and altitude. He reported keeping both hands on the yoke for the duration of the flight after initiating the takeoff roll and did not manipulate any engine controls after the accident.
The mechanic who inspected the engine and tachometer stated the engine produced between 2,200 and 2,300 rpm. The tachometer inspection confirmed normal operation. The engine had 1,268 hours since its last overhaul and 159 hours since its last annual inspection.