Soar to New Heights with the 2026 Commercial Pilot License (CPL) Practice Exam – Ready for Takeoff!

Carburetor icing is a phenomenon that can occur in aircraft engines, particularly when humidity is high and temperatures are low, often in conditions of 20°F to 70°F. A common indication of carburetor icing is the loss of RPM or manifold pressure. This occurs because ice formation in the carburetor restricts the flow of air and fuel, disrupting the engine's proper operation. As the ice blocks the fuel-air mixture, the engine may not receive enough power to maintain its usual RPM or manifold pressure, leading to noticeable changes in performance.

Recognizing this symptom is crucial for pilots, as it may indicate the need for corrective action such as applying carburetor heat. Carburetor heat helps melt the ice and restore normal airflow, allowing the engine to regain power and proper RPM. Understanding this relationship is vital for maintaining aircraft performance and safety during flight.

The other choices do not directly associate with the specific consequences of carburetor icing as clearly as the loss of RPM or manifold pressure does. While fluctuations in oil pressure or increases in fuel consumption can occur due to various engine performance issues, they are not specific or direct indicators of carburetor icing. Similarly, an increase in RPM can suggest improved engine performance, which contradicts