What is the minimum acceptable pressure on the POB gauge during preflight?

What is the minimum acceptable pressure on the POB gauge during preflight?

• A. 500 PSI
• B. 1,000 PSI
• C. 1,500 PSI or above
• D. 2,000 PSI

Answer: (C)

Ensuring there is enough oxygen on board for the planned flight by checking the POB pressure is what this question tests. The minimum acceptable pressure is 1,500 psi or above. This threshold provides a comfortable oxygen reserve for the duration of the flight and accounts for regulator performance and any small leaks or increased flow that might occur in use. If the gauge reads below 1,500 psi, the POB may not last for the expected duration or in an emergency, so it shouldn’t be relied upon. Readings as low as 500 psi or 1,000 psi would typically be insufficient to cover normal usage and contingencies, making them unsafe as minimums. A reading of 2,000 psi would exceed the minimum, which is fine, but it isn’t the rule for minimum acceptable pressure.

Ensuring there is enough oxygen on board for the planned flight by checking the POB pressure is what this question tests. The minimum acceptable pressure is 1,500 psi or above. This threshold provides a comfortable oxygen reserve for the duration of the flight and accounts for regulator performance and any small leaks or increased flow that might occur in use. If the gauge reads below 1,500 psi, the POB may not last for the expected duration or in an emergency, so it shouldn’t be relied upon.

Readings as low as 500 psi or 1,000 psi would typically be insufficient to cover normal usage and contingencies, making them unsafe as minimums. A reading of 2,000 psi would exceed the minimum, which is fine, but it isn’t the rule for minimum acceptable pressure.