What is the minimum psi required for checking fuel?

The minimum psi required for checking fuel is 20 psi. This pressure is necessary to ensure that the fuel system is adequately pressurized during checks, allowing for accurate readings and safe handling practices. Using the correct pressure prevents inaccurate measurements that could lead to miscalculations in fuel management, which is crucial for the safe operation of the aircraft. A pressure lower than 20 psi may not provide sufficient force to properly check the fuel system and could result in fuel system components not being properly engaged or checked. Thus, 20 psi is the standard minimum required to ensure reliable and safe fuel checks.