Which component provides bleed air for the air conditioning packs and electrical power?

Which component provides bleed air for the air conditioning packs and electrical power?

• A. The main engine
• B. The cabin air system
• C. The APU
• D. External ground equipment

Answer: (C)

The APU (Auxiliary Power Unit) is designed to supply both bleed air for the air conditioning packs and electrical power for the aircraft when the main engines aren’t running or on the ground. Bleed air from the APU feeds the environmental control system, letting the packs condition cabin air without needing engine bleed. At the same time, the APU drives a generator to provide electrical power to aircraft systems during start or when engines aren’t supplying power. The main engines can supply bleed air when they’re operating, but they aren’t the onboard source of electrical power in those situations, and the cabin air system is the distribution path, not the source. External ground equipment can supply air and power on the ground, but the onboard source that handles both bleed air and electrical power is the APU.

The APU (Auxiliary Power Unit) is designed to supply both bleed air for the air conditioning packs and electrical power for the aircraft when the main engines aren’t running or on the ground. Bleed air from the APU feeds the environmental control system, letting the packs condition cabin air without needing engine bleed. At the same time, the APU drives a generator to provide electrical power to aircraft systems during start or when engines aren’t supplying power. The main engines can supply bleed air when they’re operating, but they aren’t the onboard source of electrical power in those situations, and the cabin air system is the distribution path, not the source. External ground equipment can supply air and power on the ground, but the onboard source that handles both bleed air and electrical power is the APU.