Question

What causes "carburetor icing," and what are the first indications of its presence?

A. It is caused by high engine temperatures, with no early indications
B. It is caused by ice crystals forming in the carburetor and the first indication is a reduction in engine RPM
C. It is caused by overuse of the carburetor, leading to engine overheating
D. It is caused by water condensation in the fuel tanks and is indicated by increased fuel flow.

Answer 1

Carburetor icing is caused by the vaporization of fuel and the condensation of air humidity within the carburetor, leading to potential ice formation. The first signs include engine roughness and a decrease in engine propeller RPM or manifold pressure.

Step-by-step explanation:

Carburetor icing is a phenomenon that occurs in piston-powered aircraft engines and is caused by the cooling effect that happens when fuel vaporizes in the carburetor and air humidity condenses, potentially turning into ice. This usually takes place under conditions of high humidity and temperatures between 0 and 20 degrees Celsius. As ice builds up, it can restrict air flow to the engine, causing a drop in engine power and possible engine stoppage if not addressed.

The first indications of carburetor icing may include engine roughness, a decrease in RPM (in fixed-pitch propeller aircraft), or a decrease in manifold pressure (in constant-speed propeller aircraft). Unlike the suggestion that increased fuel flow is the initial indication, this symptom actually appears after the pilot has attempted to compensate for the power loss due to icing.