What is the function of the 2.0 PSI outflow valve in the fuel vent system?

The 2.0 PSI outflow valve in the fuel vent system serves the function of allowing air to escape from the fuel tank. This mechanism is crucial for maintaining safe pressure levels within the tank, especially as fuel is consumed during flight. When fuel is used, a vacuum can develop inside the tank due to the reduction in fuel volume. The outflow valve enables the necessary air to enter the tank, preventing the creation of a vacuum that could impede fuel flow to the engine. By facilitating air escape and maintaining proper pressure inside the fuel tank, the outflow valve ensures optimal fuel delivery and engine performance.