The pressure indicator will flash red when ___________ remains inside of the cabin.

The pressure indicator will flash red when ___________ remains inside of the cabin.

• A. Residual Pressure
• B. Cabin Pressure
• C. Oxygen is low
• D. Door seal failure

Answer: (A)

Residual pressure is the air that remains trapped inside the cabin after the system begins venting to ambient pressure. The pressure indicator flashes red to warn you that some pressure difference still exists inside the cabin, even though the cabin may feel unpressurized. This matters because opening doors or hatches while residual pressure is present can cause a rapid rush of air, potentially injuring personnel or causing equipment damage. Treat the red flash as a sign that the cabin has not yet equalized to ambient; wait for the indication to stop flashing and follow established procedures before performing any door operations or accessing the cabin. The other options don’t describe what the warning indicates in this context: cabin pressure would imply normal pressurization, oxygen is low points to the crew oxygen system, and door seal failure would present a different warning or fault condition.

Residual pressure is the air that remains trapped inside the cabin after the system begins venting to ambient pressure. The pressure indicator flashes red to warn you that some pressure difference still exists inside the cabin, even though the cabin may feel unpressurized. This matters because opening doors or hatches while residual pressure is present can cause a rapid rush of air, potentially injuring personnel or causing equipment damage. Treat the red flash as a sign that the cabin has not yet equalized to ambient; wait for the indication to stop flashing and follow established procedures before performing any door operations or accessing the cabin. The other options don’t describe what the warning indicates in this context: cabin pressure would imply normal pressurization, oxygen is low points to the crew oxygen system, and door seal failure would present a different warning or fault condition.