What is the maximum pressure allowed to the pilot's mask by the pressure relief valve?

The maximum pressure allowed to the pilot's mask by the pressure relief valve is set at 80 mm Hg. This design choice is crucial for the safety and efficacy of the pilot's oxygen delivery system. The pressure relief valve serves to prevent excessive pressure buildup in the mask, which could be uncomfortable or even harmful to the user. By capping the pressure at this level, the system ensures that the oxygen is delivered at a safe and manageable pressure while still providing the necessary supply for high-altitude operations.

In the context of the other values, while they might represent potential pressure limits, they do not align with the engineering standards and safety protocols established for aviators. Setting the threshold at 80 mm Hg balances both the operational requirements and the safety of the pilot, making it the correct choice in this scenario.