When will the rear oxygen masks drop automatically?

When will the rear oxygen masks drop automatically?

• A. Cabin altitude greater than 10,000 feet
• B. Cabin altitude greater than 14,800 ± 200 feet
• C. Cabin altitude greater than 18,000 feet
• D. Cabin altitude greater than 20,000 feet

Answer: (B)

Oxygen masks in the cabin are tied to the aircraft’s cabin altitude. When the cabin altitude rises to about 14,800 feet, with a tolerance of roughly ±200 feet, the rear oxygen masks automatically deploy so passengers can get supplemental oxygen quickly during a depressurization event. This threshold is chosen to ensure oxygen is available promptly as pressure is lost, without triggering mask drop during normal climbs or shallow descents. Setting the trigger much lower (around 10,000 feet) would cause masks to deploy too early, potentially during routine ascent. Waiting for a much higher altitude (18,000 or 20,000 feet) could delay oxygen delivery when hypoxia can begin to affect thinking and coordination. So the specified range around 14,800 feet ±200 feet is the designed point for automatic deployment.

Oxygen masks in the cabin are tied to the aircraft’s cabin altitude. When the cabin altitude rises to about 14,800 feet, with a tolerance of roughly ±200 feet, the rear oxygen masks automatically deploy so passengers can get supplemental oxygen quickly during a depressurization event. This threshold is chosen to ensure oxygen is available promptly as pressure is lost, without triggering mask drop during normal climbs or shallow descents.

Setting the trigger much lower (around 10,000 feet) would cause masks to deploy too early, potentially during routine ascent. Waiting for a much higher altitude (18,000 or 20,000 feet) could delay oxygen delivery when hypoxia can begin to affect thinking and coordination. So the specified range around 14,800 feet ±200 feet is the designed point for automatic deployment.