What must be provided for requested altitude when it is not available?

When the requested altitude is not available, providing a different expected altitude is crucial for ensuring safety and maintaining proper air traffic management. This procedure allows pilots to understand the current airspace capabilities and plan their flight paths accordingly. By supplying an alternative altitude, air traffic control communicates the best available option, minimizing disruptions and helping the pilot adjust their flight strategy.

This approach supports situational awareness for both the pilot and air traffic controllers, enhancing overall flight efficiency. It is particularly important for maintaining vertical separation between aircraft, ensuring compliance with air traffic regulations, and minimizing the chances of congestion within the airspace. This alternative altitude serves as an interim solution while ensuring safety and adherence to standard operating procedures.