What type of O2 masks are installed for the pilot and copilot?

• A. Diluter-demand masks
• B. Continuous-flow masks
• C. Pressure-demand masks
• D. Oxygen-preserving masks

Answer: (A)

Oxygen masks for the pilot and copilot are diluter-demand masks. The idea behind this type is to deliver oxygen primarily on inhalation and mix it with the surrounding air to achieve a breathable concentration without wasting supply. The mask has a regulator that opens as you breathe in, providing just enough oxygen to bring your inhaled mix up to the needed level as altitude changes. This is efficient for crew use in the PC-12 NGX, giving comfortable breathing and adequate oxygen delivery while conserving oxygen compared with a continuous-flow system. Continuous-flow masks deliver a constant stream of oxygen regardless of inhalation, which wastes gas. Pressure-demand masks supply oxygen only at a higher than ambient pressure and are used at very high altitudes, not common for standard crew operation. Oxygen-preserving masks reduce flow during exhalation with a reservoir, which is another efficiency approach but not the standard installation described.