What is the maximum altitude deviation allowed for route changes above FL310?

The maximum altitude deviation allowed for route changes above Flight Level 310 (FL310) is plus or minus 4,000 feet. This standard is established primarily for safety reasons to ensure adequate separation between aircraft operating at high altitudes.

When aircraft are flying at high altitudes, specifically above FL310, there are established altimeter settings and air traffic rules that facilitate the navigation and separation of aircraft. Allowing a deviation of up to 4,000 feet provides a balance between flexibility for pilots to adjust their altitude during flight and maintaining safety standards. It ensures that aircraft can maneuver effectively to avoid hazards such as turbulence and other traffic, while still being within a controlled and safe vertical space in the air traffic system.

Hence, this range of deviation is recognized and standardized to provide pilots with the necessary leeway for operational needs while ensuring safety across the airspace system.