If the APU door is not closed or the limit is unknown, what condition applies?

• A. 220 KIAS or APU must remain in operation
• B. 200 KIAS
• C. FL370
• D. 0 KIAS

Answer: (A)

When the APU door isn’t closed or its limit isn’t known, the safest rule is to either keep the APU running or stay within a defined maximum airspeed. The door status directly affects the tail’s aerodynamics and the APU’s exhaust flow. If the door isn’t fully closed, high-speed airflow can stress the door or create unwanted drag, so the procedure keeps the APU on to control exhaust and ensure power and bleed air are available until the door is confirmed closed. The other options describe conditions that don’t address the door situation (different speed, altitude, or an impossible zero-speed scenario).