At what stage must a pilot report a change in altitude or speed during IFR operations?

During Instrument Flight Rules (IFR) operations, a pilot is required to report any change in altitude or speed that exceeds specific thresholds set by air traffic control (ATC). This is crucial for maintaining safe separation between aircraft, as well as for ensuring that the pilot follows the flight plan and adheres to the assigned clearances.

When the pilot makes a change that crosses predetermined limits—such as climbing above or descending below a particular altitude, or making significant speed adjustments—they must communicate this information to ATC. These thresholds may be defined by altitude changes or speed changes that can impact the separation standards.

This reporting protocol helps ATC manage airspace effectively and maintains situational awareness among pilots operating in the vicinity. It ensures that all aircraft are accounted for and operate safely, minimizing the risk of conflicts in the airspace.