If the APU door is stuck open or its position is uncertain, what must be done?

• A. Reduce airspeed below 180 knots and descend
• B. Continue normal operations with no action
• C. Maintain a max airspeed of 220 knots or run the APU continuously
• D. Shut the APU off and descend

Answer: (C)

When the APU exhaust door is stuck open or its position is uncertain, you can’t rely on normal APU operation to provide bleed air and electrical power without risk. The safer approach is to manage the situation by either limiting the aircraft’s load through a controlled speed or by keeping the APU running to ensure power availability.

Maintaining a maximum airspeed of 220 knots helps reduce the thermal and aerodynamic stress around the APU area and prevents excessive cooling or exhaust issues while you continue to operate and troubleshoot. If you determine that the APU can safely power essential systems, running it continuously avoids losing those systems and provides a known source of bleed air and electrical power until you can land and secure the fault.

This approach prioritizes keeping critical systems powered and minimizing risk from an uncertain or stuck-open APU exhaust door, rather than continuing normally or shutting the APU off and descending without power.