What is the APU's role during ground operations on the 787?

What is the APU's role during ground operations on the 787?

• A. Provide electrical power and pneumatic power for starting engines and environmental conditioning when external power is unavailable.
• B. Provide only hydraulic power.
• C. Replace the engines entirely if they fail.
• D. Provide potable water for the crew.

Answer: (A)

The main idea is that the APU on the 787 acts as a portable power source for ground operations when external power isn’t available. It supplies electrical power to run the aircraft’s systems, avionics, lighting, and cabin equipment, and it also provides pneumatic power (bleed air) used to start the engines and to support environmental conditioning. This allows the aircraft to be powered and conditioned without needing external ground support equipment. It isn’t a source of hydraulic power, it doesn’t replace the engines if they fail, and it doesn’t provide potable water. If external power is available, the APU may be left off to save fuel.

The main idea is that the APU on the 787 acts as a portable power source for ground operations when external power isn’t available. It supplies electrical power to run the aircraft’s systems, avionics, lighting, and cabin equipment, and it also provides pneumatic power (bleed air) used to start the engines and to support environmental conditioning. This allows the aircraft to be powered and conditioned without needing external ground support equipment. It isn’t a source of hydraulic power, it doesn’t replace the engines if they fail, and it doesn’t provide potable water. If external power is available, the APU may be left off to save fuel.