What is required by regulations if a planned flight cannot be completed?

The correct answer is that regulations require a pilot to land at the nearest airport if a planned flight cannot be completed. This requirement ensures that safety is prioritized and that aircraft do not remain aloft longer than necessary, which could complicate situations such as fuel exhaustion, equipment failure, or other emergencies.

When a pilot determines that a flight cannot be completed, the most prudent action is to divert to the nearest airport to maintain the safety of the crew and passengers. This action allows for a controlled landing and enables the pilot to assess and address any issues that may be affecting the flight. Furthermore, by landing at the nearest airport, the aircraft can be secured and assistance can be sought as needed.

Other options, such as filing a flight plan with ATC or notifying ground control, may be part of standard operational procedures but do not directly address the requirement to land. Additionally, being out of the vicinity of an airport is not a regulatory requirement but more of a situational context and does not focus on the necessary actions if a flight cannot be completed.