Which altitude is defined as the lowest altitude between radio navigation aids that provides acceptable coverage?

The acronym MEA stands for Minimum Enroute Altitude, which is defined as the lowest altitude that provides acceptable navigation signal coverage and safe obstacle clearance between radio navigation aids along an airway or route. This altitude ensures that an aircraft can receive navigational signals from ground-based aids while maintaining a safe vertical distance above terrain and obstructions.

Choosing the MEA is crucial for pilots as it guarantees that there are no obstacles within a specified vertical distance from the aircraft, and it also facilitates navigation by ensuring adequate signal reception from navigation aids along the planned route. In scenarios involving flight planning and enroute navigation, understanding the MEA is vital for maintaining safety and ensuring compliance with regulatory altitude standards.

While the other terms, such as MOCA, MORA, and MSA, describe various altitudes with different purposes—like providing obstacle clearance in relation to ground features or ensuring navigational signal reception to a lesser extent—they do not specifically represent the lowest altitude that guarantees coverage between navigation aids like the MEA does.