Which statement about the APU electrical capability is correct?

Which statement about the APU electrical capability is correct?

• A. The APU can provide electrical power up to maximum certified altitude.
• B. The APU's electrical power is available for cabin lighting only.
• C. The APU cannot provide electrical power at high altitude.
• D. The APU provides power only when the engines are running.

Answer: (B)

APU electrical capability means the APU can generate and feed power to the aircraft’s electrical system, not just a single function. On the A320, the APU provides three-phase 115/200 V AC power (about 40 kVA) to the buses, so it can supply the same loads as the engine-driven generators when the engines aren’t providing power—or when extra power is needed on the ground or in flight. Because of this, the APU can light the cabin, run avionics, and power environmental controls, among other systems, up to the airplane’s maximum certified altitude. It can operate at high altitude within that limit, rather than being restricted to ground operations or to cabin lighting only.

APU electrical capability means the APU can generate and feed power to the aircraft’s electrical system, not just a single function. On the A320, the APU provides three-phase 115/200 V AC power (about 40 kVA) to the buses, so it can supply the same loads as the engine-driven generators when the engines aren’t providing power—or when extra power is needed on the ground or in flight. Because of this, the APU can light the cabin, run avionics, and power environmental controls, among other systems, up to the airplane’s maximum certified altitude. It can operate at high altitude within that limit, rather than being restricted to ground operations or to cabin lighting only.