Which stages provide bleed air to the aircraft's pneumatic systems?

• A. 2nd and 3rd stage
• B. 8th and 9th stage
• C. 6th and 10th stage
• D. 6th and 10th stage.

Answer: (D)

Bleed air for the aircraft’s pneumatic systems is taken from specific stages of the engine’s high-pressure compressor. The two stages chosen provide the right balance of pressure and flow across a wide range of engine speeds, and they offer redundancy so that the pneumatic system can be supplied even if one source is limited. In many engines, those reliable sources are the 6th and 10th stages. Lower stages would deliver too little pressure for packs, anti-ice, and other systems, while other stage combinations don’t align with how bleed ports are arranged or sized in typical engines. So, the 6th and 10th stages are the standard bleed-air sources for pneumatic systems.