What is the purpose of the check valve on the 6th stage bleed line?

• A. Allows backflow from 10th stage air into the engine when the HPV is open.
• B. Prevents back flow of 10th stage air into the engine when the High Pressure Bleed Valve is open.
• C. Backflow prevented from 6th stage to 10th stage.
• D. Stops water ingress into bleed line.

Answer: (B)

A check valve is a one-way valve that prevents air from flowing backward in a line. In the bleed air system, multiple bleed sources can be connected to a common manifold, and the High Pressure Bleed Valve may open to supply air to the system. The check valve on the 6th stage bleed line stops air from the 10th stage side from pushing back into the engine when the HP bleed is open. This keeps the engine protected from reverse flow and ensures bleed air goes outward to the system rather than back toward the engine core.