What role do bleed air check valves play in an aircraft?

The role of bleed air check valves in an aircraft is primarily to prevent the reverse flow of air into the engine. Bleed air is tapped from the engine's compressor section and is utilized for various functions, including pneumatic systems like environmental control, starting systems, and de-icing systems. The check valves ensure that this pressurized air flows in the desired direction and does not flow back into the engine, which could potentially disrupt engine operations and negatively affect performance. By containing the flow and maintaining a one-way direction, check valves play a critical role in the safe and efficient operation of these systems.

While other options mention functions related to control and distribution, they do not accurately represent the specific purpose of bleed air check valves. Their primary function centers on safeguarding against reverse air flow, ensuring that the systems relying on bleed air operate correctly and reliably.