If given a speed assignment for approach and not yet cleared for approach, when can speed adjustments be made?

The correct answer is based on the rules governing speed assignments during flight operations. In scenarios where a pilot has been given a speed assignment for approach but has not yet been cleared to initiate the actual approach procedure, the pilot is expected to maintain the current speed until an appropriate point of reference—such as a fix—is passed.

This practice is crucial for maintaining safe separation between aircraft and ensuring that speed adjustments do not interfere with the overall flow of traffic. When a fix is passed, the pilot can then adjust the speed as per the assigned directive. This method also provides a clear point for the pilot to execute the speed change, minimizing the risk of deviation from the expected flight path.

Adjustments prior to reaching the assigned fix may create complications and inconsistency in maintaining the correct approach trajectory, leading to potential safety issues with other aircraft. Therefore, awaiting the passing of the fix before making speed changes is a standard operating procedure in aviation.

The other options imply that adjustments can be made at any time, based on altitude, or only upon explicit instructions from ATC, which can lead to confusion or miscommunication in managing approach sequences. Understanding this aspect helps reinforce the importance of following procedural guidelines in controlled airspace.