N2071K

On September 4, 2021, about 1430 eastern daylight time, a Luscombe 8A airplane, N2071K, was substantially damaged when it was involved in an accident near Fort Wayne, Indiana. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

According to the pilot, he and the pilots of three other airplanes were conducting a cross-country return flight to Pennsylvania. After refueling, the airplanes taxied to runway 23, and the pilot completed his preflight checklist. Shortly after takeoff, about 200 to 300 ft above ground level, the engine began operating rough, which included some surging, and then lost power. The pilot attempted to land on runway 5, which resulted in a landing with a 9-to-12 knot tailwind. Due to the tailwind, the airplane touched down near the end of runway 5. Realizing the airplane would not stop before the end of the runway, the pilot turned the airplane to the right and exited the runway surface. The airplane entered a soybean field and nosed over. The airplane sustained substantial damage to the fuselage and vertical stabilizer. The pilot stated he used carburetor heat during the engine run-up and noticed a drop in engine rpm but did not use carburetor heat during the taxi and before takeoff.

Postaccident examination by a Federal Aviation Administration (FAA) inspector and a mechanic revealed that both magnetos produced spark on all spark plugs. A cylinder compression check revealed one cylinder that showed low compression; however, the low compression was attributed to a cold compression check. The carburetor, venturi, and throttle valve were intact, and no anomalies noted. The oil filter was clear of contaminants.

According to the carburetor ice probability chart, the atmospheric conditions at the time of the accident were conducive to serious icing at glide power. FAA Special Airworthiness Information Bulletin (CE-09-35) – Carburetor Icing Prevention, stated that:

…pilots should be aware that carburetor icing doesn't just occur in freezing conditions, it can occur at temperatures well above freezing temperatures when there is visible moisture or high humidity. Icing can occur in the carburetor at temperatures above freezing because vaporization of fuel, combined with the expansion of air as it flows through the carburetor, (Venturi Effect) causes sudden cooling, sometimes by a significant amount within a fraction of a second. Carburetor ice can be detected by a drop in rpm in fixed pitch propeller airplanes and a drop in manifold pressure in constant speed propeller airplanes. In both types, usually there will be a roughness in engine operation.

FAA Advisory Circular (AC 20-113) – Pilot precautions and procedures to be taken in preventing aircraft reciprocating engine induction system and fuel system icing problems, stated that: …(4) When the relative humidity is about 50 percent and the temperature is below 70° F., 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. Generally, the use of carburetor heat for taxiing is not recommended because of possible ingestion of foreign matter on some installations which have the unfiltered air admitted with the control in the HOT or ALTERNATE AIR positions.