What is the maximum distance of a flight that requires a flight plan?

The requirement for filing a flight plan is essential for the safety and coordination of air traffic, especially beyond certain distances from the departure aerodrome. The correct answer signifies that a flight plan must be filed for flights that are conducted more than 25 nautical miles (NM) from the departure aerodrome. This distance was determined to ensure that flights operating further afield can be adequately monitored and can receive proper air traffic service.

Filing a flight plan helps alert authorities to your intended route and destination, improving the chances of locating an aircraft if it fails to arrive as scheduled. This requirement assists in maintaining safety in the airspace and facilitates better management of air traffic.

The other distances mentioned do not represent the established threshold for requiring a flight plan. A flight that is less than or equal to 25 NM from the departure aerodrome is typically considered to be within an area where traffic can be managed without the necessity of a detailed plan, as routine operations can usually be conducted with simpler communication and control mechanisms. Moreover, the notion that flight plans are only required over water is misleading. While it is critical to have flight plans for over-water flights due to the extended distances without immediate landing options, the distance from the departure point still governs the requirement in