Oxygen Pressure Low (Yellow) occurs at what PSI threshold?

• A. <900 PSI
• B. <960 PSI
• C. <1000 PSI
• D. <1100 PSI

Answer: (B)

Oxygen Pressure Low is a warning tied to a specific bottle pressure in the system. The aircraft’s oxygen supply uses high‑pressure bottles, and as oxygen is used, the bottle pressure falls. A pressure switch is set to illuminate the Oxygen Pressure Low indicator when the pressure falls below 960 psi. This amber warning gives you time to confirm oxygen flow, don your mask, and plan to switch sources before the supply is exhausted. The 960 psi threshold is chosen to provide an adequate safety margin, so the warning appears whenever the pressure drops to 960 psi or lower. Thresholds higher than that would warn too late, while thresholds well below would not provide timely notice.