CEN19LA232

While in cruise flight at 3,500 ft, the pilot and flight instructor-rated passenger heard the engine begin to run rough. They completed the emergency checklist for a loss of engine power and chose to return to the departure airport; however, the engine continued to lose power and the pilots performed a forced landing to a field, during which the airplane impacted a barbed wire fence. The atmospheric conditions at the time of the accident were conducive to the development of serious carburetor icing at descent power; however, the engine was operating at cruise power at the time of the accident. The airplane's engine was test run at the accident site; the engine started and ran with no anomalies noted. The reason for the loss of engine power could not be determined based on the available information.

On July 21, 2019, about 1241 central daylight time, a Cessna 152 airplane, N48410, impacted terrain and fencing during a forced landing following an inflight loss of engine power near Fredericksburg, Texas. The private pilot and the pilot rated passenger were uninjured. The airplane sustained substantial damage to its empennage and fuselage. The airplane was registered to Aeronautical LLC and operated by the pilot as a Title 14 Code of Federal Regulations Part 91 personal flight. Day visual meteorological conditions prevailed in the area about the time of the accident, and the flight was not operated on a flight plan. The flight originated about 1220 from the Gillespie County Airport (T82), near Fredericksburg, Texas, and was destined for the Georgetown Municipal Airport (GTU), near Georgetown, Texas. According to the pilot, the purpose of the flight was to fly from GTU to T82 and return to GTU in the same day. The pilot was flying with a family member who was a flight instructor. They fueled at GTU just before the flight and flew to T82 without incident. The airplane was performing "well" during the flight. They had lunch at the diner on the field at T82. Following lunch, they conducted a preflight inspection of the airplane, performed an engine run-up, and took off as "usual." Everything sounded "normal." The airplane was level at 3,500 ft where the pilot asked the pilot rated passenger to takeover the airplane controls so the pilot could conduct activities not associated with flying the airplane. Both pilots then heard the engine starting to run rough. They both concurred that the engine sounded rough, and it continued to sound rough; engine speed was also decreasing. They looked at the distance to GTU and considered the options in conducting the flight. The pilots "went" through the emergency checklist, evaluated the instruments, and decided to return to T82. The airplane subsequently lost additional engine power and altitude. They established the best glide airspeed for the airplane. They elected to land on a field that was bounded by a powerline. The terrain was soft. After touchdown, they applied full brakes. However, they were unable to stop the airplane before it impacted a barbed wire fence. The airplane's emergency procedures, in part, stated: ENGINE FAILURE DURING FLIGHT 1. Airspeed -- 60 KIAS [knots indicated airspeed]. 2. Carburetor Heat -- ON. 3. Primer -- IN and LOCKED. 4. Fuel Shutoff Valve -- ON. 5. Mixture -- RICH. 6. Ignition Switch -- BOTH (or START if propeller is stopped). A Federal Aviation Administration inspector examined the wreckage at the accident site and took pictures. He subsequently performed a test run of the engine at the site. The engine started and was operational "with no issues." The inspector also examined the carburetor's filter and it did not contain any debris. The inspector stated that the visible damage present to the tail section was substantial damage. At 1255, the recorded weather at T82 was: Wing190° at 9 kts gusting to 16 kts; visibility 10 statute miles; sky condition clear; temperature 32° C; dew point 17° C; altimeter 30.00 inches of mercury. The recorded local temperature and dew point spread data near the time of the engine power loss was plotted on a carburetor icing chart. The charted data showed that the weather in the area was conducive to serious carburetor icing at descent power. The pilot, in part, stated: There were a few factors that helped this rough landing not be worse. My copilot is an experienced pilot and CFII and we had good communication and teamwork throughout our flight. The airplane has new tires that helped on the rough surface of the field. What surprised us was that the engine lost power so quickly. The Pilot's Handbook of Aeronautical Knowledge, in part, states: When conditions are conducive to carburetor icing during flight, periodic checks should be made to detect its presence. If detected, full carburetor heat should be applied immediately, and it should be left in the ON position until you are certain that all the ice has been removed. If ice is present, applying partial heat or leaving heat on for an insufficient time might aggravate the situation. In extreme cases of carburetor icing, even after the ice has been removed, full carburetor heat should be used to prevent further ice formation. A carburetor temperature gauge, if installed, is very useful in determining when to use carburetor heat.