Where is the fuel system pressurized in the Cessna 172?

The fuel system in the Cessna 172 is pressurized from the fuel reservoir onward, which means that the fuel is maintained under pressure as it travels from the fuel tanks to the engine. This pressurization ensures a consistent flow of fuel to the engine and helps to prevent issues such as vapor lock, especially during high-temperature conditions or high-power settings.

Pressurizing the fuel system from the fuel reservoir onward takes advantage of gravity and the mechanical processes within the fuel system, allowing a steady supply without the need for excessive pressure. The system is designed to optimize fuel delivery efficiency and reliability, which are critical for the aircraft's performance during different phases of flight.

This approach means that the other options do not accurately describe the pressurization points in the fuel system. For example, while the engine does help manage fuel flow, it does not directly pressurize the fuel. The carburetor itself distributes the fuel but does not serve as a pressurization point either. Lastly, pressurization at the fuel tank alone wouldn’t be sufficient to maintain the necessary fuel flow and operational integrity required by the engine during flight, as it would not ensure that the proper pressure is maintained throughout the entire fuel delivery system.