ERA23LA127

Before takeoff, the student pilot and flight instructor performed a preflight inspection and an engine run-up that included checking the carburetor heat before taxiing the airplane into position; they noted no anomalies. After takeoff, about 200 ft above ground level, the engine lost total power. The flight instructor initiated a left turn and the airplane impacted the ground near a parallel runway, resulting in substantial damage to the wings and fuselage. Postaccident examination of the engine revealed no evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation. The weather conditions at the time of the accident were conducive to the formation of serious carburetor icing at glide (idle) engine power settings. Furthermore, the engine data monitor indicated that the carburetor temperature decreased to 38°F just before the loss of engine power. Thus, it is likely that during the taxi and engine run-up, a period during which the engine would typically be operating at low power, carburetor ice formed and subsequently resulted in a total loss of engine power during the initial climb.

On February 16, 2023, about 1431 eastern standard time, a Piper PA-28-181, N103AV, was substantially damaged when it was involved in an accident at Dekalb-Peachtree Airport (PDK), Atlanta, Georgia. The flight instructor sustained serious injuries and the student pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. According to the student pilot, he and the flight instructor conducted a preflight inspection, start up, taxi, and engine run-up, which included two checks of the carburetor heat system. Then, once they received their takeoff clearance, they began the takeoff roll on runway 21R and, after rotation while around 200 ft above ground level, the engine started to “sputter.” The flight instructor took over control of the airplane as the engine lost total power. The flight instructor stated that after the engine lost total power, he initiated a left turn to avoid colliding with structures. The airplane impacted the ground on the right side of runway 3R, resulting in substantial damage to the fuselage and wings. Postaccident examination of the engine revealed that internal and valvetrain continuity was established when the crankshaft was rotated by hand. Examination of the cylinders with a lighted borescope revealed no anomalies. The fuel inlet screen and fuel filter were examined and no debris was noted. The carburetor was disassembled, residual fuel was in the carburetor bowl, and no anomalies were noted with the system. The engine-driven fuel pump was actuated by hand and functioned normally. The engine oil, engine oil filter, and engine oil pickup screen were all absent of debris. Both magnetos produced spark at all towers. Data downloaded from an Electronics International MVP-50P engine data monitor began at 1419 and ended at 1434. The data indicated that carburetor temperature decreased to 40°F and then increased twice before the takeoff. Then, during the takeoff, the rpm increased to 2,600 rpm and the carburetor temperature decreased to 38°F for about a minute. The fuel flow at the same time increased, surged three times, and then decreased to 0. Furthermore, the engine rpm remained around or below 1,500 rpm for the majority of the accident flight except two times, when the rpm increased to 2,000 rpm and 2,600 rpm respectively. At 1444, the weather reported at PDK included a temperature of 23°C and a dew point 14°C. The calculated relative humidity at this temperature and dewpoint was 57%. Review of the icing probability chart contained within Federal Aviation Administration (FAA) Special Airworthiness Information Bulletin CE-09-35 revealed the atmospheric conditions at the time of the accident were "conducive to serious icing at glide [idle] power." According to FAA Advisory Circular (AC) 20-113, "To prevent accidents due to induction system icing, the pilot should regularly use [carburetor] heat under conditions known to be conducive to atmospheric icing andbe 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%, "…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 climbout, especially when the relative humidity is above 50%, or when visible moisture is present in the atmosphere."