How late can an aircraft on an IFR flight plan be considered overdue?

An aircraft on an IFR flight plan is considered overdue if it does not arrive at its destination or a compulsory reporting point within a time frame of 30 minutes past its clearance void time, estimated time of arrival (ETA), or a specified reporting point. This 30-minute window is a standard guideline used by air traffic control to maintain safety and ensure timely response in case an aircraft encounters difficulties.

This procedure is crucial as it allows for proactive measures to be taken in the event that an aircraft experiences an emergency or communication failure. The factors considered, including the clearance void time and reporting points, are important because they establish relevant timelines based on expected navigational checkpoints and operational safety protocols.

Options that specify times such as 10 minutes past ETA or 20 minutes past clearance void time do not encompass all scenarios where an aircraft might be deemed overdue, while referencing only a specific point in time does not reflect the universal standard used in air traffic control practices. Thus, the consideration of multiple checkpoints and clearance times within a 30-minute window ensures a comprehensive approach to aircraft monitoring and safety.