What does the fuel selector valve control in the Cessna 172?

The fuel selector valve in the Cessna 172 is crucial for directing the flow of fuel from the aircraft's fuel tanks to the engine. By adjusting the position of the selector valve, the pilot can choose which fuel tank—typically the left tank, right tank, or both tanks—will supply fuel to the engine for combustion. This is essential for managing fuel consumption, maintaining balance in the aircraft, and ensuring that the engine receives an adequate fuel supply.

The other options pertain to different fuel system functions that the fuel selector valve does not directly control. The fuel flow rate refers to the quantity of fuel being delivered to the engine and is regulated by other components in the fuel system, such as the fuel pump. The amount of fuel used is monitored with fuel gauges and is not directly controlled by the selector itself. Lastly, fuel pressure levels are managed by the fuel pump and pressure regulators within the system, not by the selector valve. Understanding the role of the fuel selector valve helps ensure proper fuel management in the Cessna 172, which is critical for safe flight operations.