Accident Overview
On December 27, 2020, at approximately 1300 eastern standard time, a Piper PA-22-150, registration N5939D, was substantially damaged during an accident near Cleveland, Georgia. The pilot and passenger on board received minor injuries. The flight was conducted as a personal flight under Title 14 Code of Federal Regulations Part 91.
Pilot Account
According to the pilot, a preflight inspection indicated the airplane had 16 gallons of fuel. After starting the engine, it idled for 4 minutes to warm up. The pilot then taxied to the departure end of the runway and performed an engine run-up without noting any anomalies. Total ground idle time was approximately 10 to 12 minutes. The pilot subsequently taxied onto the runway, applied full engine power, and initiated takeoff. During the initial climb, the engine lost power, and the airplane began to settle. The pilot applied carburetor heat and switched the fuel selector from the right to the left tank, causing the engine to surge momentarily before losing total power again. The pilot then turned off the carburetor heat and pitched the airplane downward to maintain airspeed. The airplane continued to descend until it impacted treetops, resulting in substantial damage to the wings and fuselage.
Post-Accident Examination
A Federal Aviation Administration inspector examined the engine on the airframe at a salvage facility. A test run revealed no anomalies. Examination of the carburetor also showed no anomalies.
Weather and Carburetor Icing Conditions
At 1735, the weather reported at Toccoa Airport – RG Letourneau Field (TOC), located about 21 miles east of the accident site, included a temperature of 11°C and a dew point of -3°C, yielding a calculated relative humidity of 40%. Review of the carburetor icing probability chart from FAA Special Airworthiness Information Bulletin CE-09-35 indicated that the atmospheric conditions at the time of the accident were "conducive to icing at glide and cruise power."
FAA Advisory Circular AC 20-113 provides guidance to prevent induction system icing. It recommends that pilots regularly use carburetor heat under conditions known to be conducive to atmospheric icing and remain alert for indications of icing. The AC further advises that when relative humidity exceeds 50%, pilots should apply carburetor heat briefly immediately before takeoff, particularly with float-type carburetors, to remove any ice that may have accumulated during taxi and runup. It also emphasizes remaining alert for induction system icing during takeoff and climb-out, especially when relative humidity is above 50% or when visible moisture is present.