Accident Overview
On September 27, 2020, about 0900 eastern daylight time, a Piper PA-28-151, registration 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 personal flight under Title 14 Code of Federal Regulations Part 91.
Witness Accounts
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 “heavy fog” conditions. The pilot departed, and about 20 minutes later, the pilot returned and announced over the radio that he could not see the ground. The witness attempted to guide the pilot back to the airport using the airport’s common traffic advisory frequency; 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.
Postaccident Examination
A Federal Aviation Administration (FAA) inspector reported that the airplane came to rest in a wooded area and a postimpact fire ensued, consuming 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. No other anomalies were 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.
Weather Conditions
At 0855, the weather reported at Laurens County Airport (LUX), 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 that 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 and runup.” 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.”