What must pilots do when flying through temperature zones while under ATC control?

When flying through temperature zones while under Air Traffic Control (ATC), it is essential for pilots to notify ATC of any altitude changes. This is because differences in temperature can affect aircraft performance and the density of the air, which in turn can lead to changes in the aircraft's actual altitude compared to its indicated altitude.

By keeping ATC informed about altitude changes, pilots ensure that air traffic controllers have up-to-date information necessary to manage air traffic safely. This communication is critical for maintaining safe separation between aircraft and for ensuring that all parties involved are aware of the current flight dynamics that could affect navigation and safety.

Furthermore, altitude adjustments may be required to comply with ATC instructions or to meet the operational standards for safe flight in varying temperature zones. Prompt reporting helps to maintain the overall safety of the airspace and contributes to effective flight management.