Accident
On May 13, 2017, about 1500 central daylight time, a Piper PA-28-140 single-engine airplane, N3976K, sustained substantial damage during a forced landing following a partial loss of engine power during cruise flight near Muskogee, Oklahoma. The private pilot was not injured and his passenger sustained minor injuries. The airplane was registered to and operated by the pilot under 14 Code of Federal Regulations Part 91 without a flight plan. Day visual meteorological conditions prevailed for the local flight that departed Davis Field Airport (MKO), Muskogee, Oklahoma, about 1440.
Pilot Report
The pilot reported that he had flown from Robert S. Kerr Airport (RKR) in Poteau, Oklahoma, to MKO earlier that day. He observed the fuel level was below the filler tab in each wing tank before departing RKR, estimating 10 to 12 gallons per tank. The cross-country flight to MKO was uneventful; he switched fuel tanks from right to left about halfway through the 45-minute flight. After landing at MKO, the pilot met a friend and her two children. He provided two short flights: the first was about 10 minutes in the traffic pattern; the second was over Muskogee. About 20 minutes into the second flight, at 3,000 ft mean sea level over downtown Muskogee, the engine experienced a partial loss of power. The pilot applied carburetor heat, switched fuel tanks from left to right, activated the electric fuel pump, and verified magneto operation. Despite these actions, the engine continued to operate at 500 rpm. The pilot chose to make a forced landing on the southbound lanes of US Highway 64. Shortly before the landing flare, the left wing struck a road sign, causing the airplane to swerve left into the grass median. The nose landing gear fork then separated from the strut, and the airplane came to rest in a nose-down attitude.
Aircraft Examination
A Federal Aviation Administration airworthiness inspector examined the airplane after it was recovered to MKO. Substantial damage to the main wing spar was observed immediately outboard of the left wing tank. The fuel selector was positioned to the right tank, which contained about 10 gallons of fuel; the fuel level was about 1.5 inches below the filler tab. The left wing tank contained less than 1 quart of usable fuel (no usable fuel). The fuel from the left tank was blue and free of water or particulates. The left tank was intact with no apparent damage, and no evidence of a fuel leak from either tank was found. The fuel supply line between the engine-driven fuel pump and the carburetor contained no fuel; the carburetor bowl had residual fuel. When the inspector turned on the electric fuel pump with the selector on the left tank, the pump cavitated and discharged minimal fuel. Switching to the right tank caused the pump to cavitate for a few seconds before establishing typical flow. The discharged fuel was blue and free of contaminants.