ERA20LA335

The noninstrument-rated pilot departed into instrument meteorological conditions and returned to the airport about 20 minutes later, communicating to a witness via radio that he could not see the ground. The witness attempted to guide the pilot back to the airport; however, the pilot stated he was having “engine trouble” and the airplane impacted trees in the vicinity of the airport. A postimpact fire ensued, which consumed most of the fuselage. The propeller did not exhibit any rotational scoring and the carburetor air box was consumed by fire. There were no preimpact mechanical malfunctions or failures with the airplane or engine that would have precluded normal operation. Based on the temperature and dew point about the time of the accident, the conditions were favorable for serious carburetor icing at a cruise power setting. It is likely that the engine lost power as a result of carburetor icing, and since the pilot reported to the local mechanic that he never used carburetor heat, the carburetor icing likely continued to accumulate until the engine lost total power.

On September 27, 2020, about 0900 eastern daylight time, a Piper PA-28-151, N33859, was destroyed when it was involved in an accident near Union, South Carolina. The private pilot was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to a witness, the noninstrument-rated pilot told him that he had an appointment in Georgetown, South Carolina. The witness advised the pilot multiple times to, “leave the airplane on the ground” because of the “heavy fog” conditions. The pilot departed, and the witness stated that, about 20 minutes later, the pilot came back and announced over the radio that he could not see the ground. The witness talked to the pilot using the airport’s common traffic advisory frequency and attempted to guide him back to the airport; however, the pilot stated that he was having “engine trouble” and impacted trees in the vicinity of the airport. Multiple witnesses reported hearing “popping sounds” and that the engine “didn’t sound good” before the accident. A Federal Aviation Administration (FAA) inspector who responded to the accident site reported that the airplane came to rest in a wooded area and a postimpact fire ensued, which consumed most of the cabin. The wings separated from the fuselage and the leading edges exhibited impact damage. The propeller did not exhibit rotational scoring or bending of the blade tips. The carburetor air box was consumed by fire. Engine crankshaft and valvetrain continuity were confirmed. Compression was obtained on all cylinders. The spark plugs were examined, and the Nos. 1 and 2 bottom spark plug electrodes were impact-separated. There were no other anomalies noted with the engine that would have precluded normal operation before the accident. The mechanic who worked at the airport stated that he called the pilot after the accident and asked if he used carburetor heat during the flight. The pilot reported to the mechanic that he “never” used carburetor heat. At 0855, the weather reported at Laurens County Airport (LUX), Laurens, South Carolina, about 19 miles southwest of the accident site, indicated a temperature of 15°C and a dew point of 15°C. Review of the carburetor icing probability chart contained within FAA Special Airworthiness Information Bulletin CE-09-35 revealed the atmospheric conditions at the time of the accident were "conducive to serious icing at cruise power." According to FAA Advisory Circular 20-113, "To prevent accident due to induction system icing, the pilot should regularly use [carburetor] heat under conditions known to be conducive to atmospheric icing and be alert at all times for indications of icing in the fuel system." The AC recommended that when operating in conditions where the relative humidity is greater than 50 percent, "…apply carburetor heat briefly immediately before takeoff, particularly with float type carburetors, to remove any ice which may have been accumulated during taxi andrunup." It also stated, "Remain alert for indications of induction system icing during takeoff and climb-out, especially when the relative humidity is above 50 percent, or when visible moisture is present in the atmosphere."