When the High Pressure Bleed valve on the 10th stage is providing air, what effect does this have on the 6th stage?

• A. 6th stage air will be blocked by closure of the one-way check valve, preventing 10th stage air from backing up into the N2 compressor
• B. 6th stage air will flow freely into 10th stage
• C. No effect on 6th stage
• D. 6th stage bleed valve opens wider

Answer: (A)

In bleed air systems, preventing reverse flow between stages is essential, so a one-way check valve is used to isolate paths. When the high-pressure bleed at the 10th stage is delivering air, that check valve closes the path back toward the N2 compressor, stopping any backward flow. The result is that 6th stage air is effectively blocked from flowing back into the N2 compressor, protecting the compressor and keeping the 10th stage bleed air from backing up into unintended parts of the system. The other options don’t fit because the system is designed to prevent reverse flow with the check valve, not to allow free flow between stages or to leave the 6th stage unaffected in terms of reverse flow.