Slats/ flaps limits: Enroute or above which altitude is prohibited?

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

Answer: (B)

Slats and flaps are high-lift devices used for low-speed flight during takeoff and landing. They increase lift but also add a lot of drag and change the wing’s handling characteristics. In enroute or high-altitude flight, the airplane operates at higher speeds with the devices kept retracted to minimize drag and preserve performance. The limits in the aircraft’s certification and POH set a boundary: beyond 15,000 feet enroute or above that altitude, extending slats or flaps is prohibited to prevent excessive drag, potential handling issues, and to keep the airplane within its certified operating envelope.