During holding, how is timing calculated?

Timing during holding is calculated as the time from the outbound leg to the inbound leg. This is crucial because holding patterns are designed to keep an aircraft in a fixed racetrack pattern, allowing it to manage airspace effectively and maintain separation from other traffic.

The outbound leg typically lasts for a specific period of time, usually one minute for aircraft at or below 14,000 feet. Upon reaching the end of the outbound leg, the aircraft will turn inbound, and timing is resumed until the aircraft has completed the turn to maintain the desired separation. This method ensures that the aircraft remains within a controlled section of airspace during periods of delay.

The other choices do not accurately reflect how timing is regulated within a holding pattern or are focused on elements outside of the actual timing calculation during holding. For instance, timing from an approach fix to a missed approach point pertains to different phases of the flight and does not focus on the specifics of holding pattern timing. Additionally, timing based on altitude or from the initial descent to landing is irrelevant in the context of the holding pattern itself.