What is the maximum altitude at which the APU bleed use is allowed?

What is the maximum altitude at which the APU bleed use is allowed?

• A. 10,000 ft
• B. 15,000 ft
• C. 20,000 ft
• D. 25,000 ft

Answer: (B)

The amount of bleed air the APU can reliably provide is limited by altitude. For the ERJ-175, the APU bleed source is approved for use only up to 15,000 feet. Above that altitude, the APU cannot guarantee the necessary bleed air pressure and flow to supply the environmental control system, so you must rely on engine bleed or electric packs instead. This limit protects the pneumatic system from insufficient air supply and potential abnormal operation.

The amount of bleed air the APU can reliably provide is limited by altitude. For the ERJ-175, the APU bleed source is approved for use only up to 15,000 feet. Above that altitude, the APU cannot guarantee the necessary bleed air pressure and flow to supply the environmental control system, so you must rely on engine bleed or electric packs instead. This limit protects the pneumatic system from insufficient air supply and potential abnormal operation.