What are the three distinct segments that bleed-air ducting can be classified into?

• A. engine bleed-air manifolds, crosswing/main manifold, branch ducting
• B. engine bleed-air manifolds, crosswing/main manifold
• C. crosswing/main manifold, branch ducting
• D. engine bleed-air manifolds, branch ducting, cabin ducts

Answer: (A)

Bleed-air ducting is organized into three functional segments: engine bleed-air manifolds, crosswing (or main) manifold, and branch ducting. The engine bleed-air manifolds are where bleed air is collected from the compressors of the aircraft’s engines. The crosswing or main manifold acts as the central distribution point, merging the bleed air from the engines and routing it into the system’s primary distribution path. The branch ducting carries bleed air from that main distribution to the various subsystems that use it, such as cabin conditioning, pressurization, and anti-icing.

Seeing these three parts together shows why the complete description includes all of them. If you leave out any one segment, you’re missing a crucial piece of how bleed air gets from the engine to its end-use applications.