Final answer:
The fuel pump system on a Cessna 172 uses a mechanical fuel pump, an electric fuel pump, and a fuel selector valve.
Step-by-step explanation:
The fuel pump system on a Cessna 172 uses a mechanical fuel pump, an electric fuel pump, and a fuel selector valve.
The mechanical fuel pump is driven by the engine and delivers fuel from the fuel tank to the carburetor or fuel injection system. It is typically located on the engine itself.
The electric fuel pump provides additional fuel pressure and is usually located near the fuel tank. It helps maintain a consistent fuel flow, especially at high altitudes. The electric fuel pump is typically controlled by a fuel pump relay.
The fuel selector valve allows the pilot to select fuel from different fuel tanks or sources. This is important for maintaining balance when there are multiple fuel tanks or in case one tank becomes contaminated. The fuel selector valve is usually located in the cockpit.