Incident Overview
On April 12, 2018, at approximately 1500 central daylight time, a Piper PA-24 airplane, registration N7386P, executed a forced landing in a field near New Braunfels, Texas. The aircraft was engaged in a training flight under 14 Code of Federal Regulations Part 91, with a flight instructor and a pilot receiving instruction on board. Both occupants sustained minor injuries, and the airplane incurred substantial damage during the landing. Visual meteorological conditions prevailed at the time.
Pilot and Instructor Accounts
The pilot reported that he was preparing for his commercial pilot check ride and had been in the traffic pattern for some time. During the final approach for landing, he configured the airplane and then felt and heard what seemed like the engine smoothly retarding to idle. He informed the instructor of the power loss. Both individuals checked the emergency checklist, verifying that the fuel pump was on, the mixture was full rich, the propeller lever was full forward, the fuel selector was on the proper tank, and the carburetor heat was selected.
The flight instructor stated that she initially thought the pilot had reduced power, but the pilot said he lost throttle authority. She then grabbed the throttle and pumped it from idle to full throttle several times without any response from the engine. Both pilots reconfirmed the configuration of the fuel system and carburetor heat settings.
Unable to reach the runway, the instructor notified the tower controller of their intention to perform a forced landing. The airplane came to a stop after colliding with a fence.
Post-Accident Examination
A Federal Aviation Administration (FAA) inspector responded to the scene and observed that fuel was present in both wing fuel tanks. The landing gear had collapsed, and the fuselage sustained substantial damage. The pilots stated that the fuel selector was positioned to the right-side fuel tank. An initial on-site fuel system test indicated that fuel would not flow when the right tank was selected.
During recovery, the airplane was placed on stands. With the NTSB Investigator in Charge (IIC), FAA inspectors, and the owner's representative present, the fuel line was disconnected near the engine and the fuel test was repeated. This time, fuel flowed when each tank was selected. The airplane was then partially disassembled and transported to a salvage facility.
Engine Run and Fuel System Inspection
On April 15, 2018, the NTSB IIC conducted an engine run on the accident airplane. The fuselage, with the wings removed, was placed on a flatbed trailer. To facilitate the run, the damaged 3-bladed propeller and carburetor air box were replaced. The exhaust pipe, crushed near the tip, had an approximately 8-inch section removed. A fuel can was attached to the fuel line near the right-wing root location. The engine was primed via the electric boost pump, started, and run to power. The fuel line was then disconnected and connected to the left-side line, and the test was repeated. The engine operated without any anomalies.
An access cover plate on the root end of the right wing was removed, and the fuel tank bladder was opened. The fuel line pickup screen was clear of blockage, and no foreign material was found inside the tank.
Carburetor Icing Considerations
The carburetor icing probability chart published in FAA Special Airworthiness Information Bulletin No. CE-09-35, "Carburetor Icing Prevention," indicated that the airplane was operating in conditions associated with a serious risk of carburetor ice accumulation at glide power settings.