What controls the speed of air entering and exiting an aircraft engine?

• A. Throttle
• B. Fuel control unit
• C. Mixture control
• D. Turbocharger

Answer: (A)

The throttle is the device that regulates how much air can enter the engine. By opening the throttle plate, more air flows into the intake, increasing the mass of air available for combustion, which raises the engine speed and overall power. Conversely, closing the throttle restricts air flow, lowering the RPM. The other options don’t directly set the rate of air entering or leaving the engine: a fuel control unit meters fuel, the mixture control adjusts the air-fuel ratio, and a turbocharger increases air density but doesn’t by itself determine the speed at which air moves through the engine. Therefore, the throttle best explains how the speed of air entering and exiting the engine is controlled.