Which statement describes altitude limits for APU electrical load only?

• A. 41,000 ft
• B. 17,000 ft
• C. 10,000 ft
• D. 14,000 ft

Answer: (A)

APU electrical load is limited by altitude to ensure the unit can still generate power reliably while staying within its cooling and speed-capability margins. When the APU is used to supply electrical power only, the design allows operation up to a high altitude—41,000 ft—so the electrical generation system remains within safe operating limits. Beyond that altitude, the air is too thin to maintain the necessary turbine speed and generator cooling, making electrical power production unsafe or unreliable.

The other altitude numbers correspond to limits for other APU modes (such as starting, bleed air, or air conditioning), which have lower ceilings. So the statement that matches the APU electrical load only is the 41,000 ft figure.