Accident Details
Probable Cause and Findings
A total loss of engine power due to of carburetor ice. Contributing to the accident was the pilot’s failure to apply carburetor heat.
Aircraft Information
Registered Owner (Current)
Analysis
On September 13, 2022, about 1132 eastern daylight time, a Cessna 172, N388TC, was substantially damaged when it was involved in an accident near Chattanooga, Tennessee. The airline transport pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
According to the pilot, during a previous off-airport landing on an unimproved surface, the right tire impacted an object and was losing air pressure. He ultimately elected to land at Lovell Field Airport (CHA), Chattanooga, Tennessee. He declared an emergency with air traffic control and advised them he intended to make multiple low passes over a grass area adjacent to runway 20 to determine the best touchdown point. He made two low passes over the area he selected, initiating a go-around after the second low pass. During climbout, with the airplane about 350 ft above ground level and at 65 mph, the engine lost power. Engine power was briefly restored before being lost again. The airplane impacted uneven terrain outside the airport fence.
According to a Federal Aviation Administration inspector, an examination of the airplane revealed that the wings and forward fuselage sustained substantial damage.
Fuel was drained from the wings, 7 gallons of fuel was drained from the left wing, 1/2 gallon was drained from the right wing. The carburetor contained 5 ounces of fuel. All fuel drained was free of contaminants. A postaccident examination and engine test run did not reveal any anomalies consistent with a preimpact failure or malfunction.
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.
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# ERA22LA413