Which statement correctly describes altitude limits for APU bleed plus electrical load (inflight/ground)?

• A. Inflight 10,000 ft and on ground 14,000 ft.
• B. Inflight 14,000 ft and on ground 10,000 ft.
• C. Inflight 32,000 ft and on ground 40,000 ft.
• D. Inflight 41,000 ft and on ground 17,000 ft.

Answer: (A)

The key idea is how much altitude the APU can safely support when it’s supplying bleed air plus electrical load. As you climb, ambient pressure and cooling change, so the APU’s ability to deliver both bleed air and generator power becomes more limited. That’s why the maximum altitude for this combination is lower when the aircraft is in flight than when it’s on the ground.

The authorized limits are 10,000 ft for in-flight operation with APU bleed plus electrical load, and 14,000 ft when the aircraft is on the ground. This reflects the APU’s performance under different environmental conditions and load demands.

Higher numbers in the other options would imply capabilities beyond what the APU can safely sustain for this combination, which isn’t allowed by the operating limitations.