What does MEA indicate in aviation navigation?

MEA stands for Minimum Enroute Altitude. In aviation navigation, it is used to designate the lowest altitude that an aircraft can be flown along a particular route segment while still meeting the required obstacle protection and, in most cases, ensuring adequate communication coverage with air traffic control.

The MEA is essential for ensuring safety, as it helps pilots avoid terrain and obstacles and maintains a safe vertical separation from other aircraft. It is also critical for navigation, especially in areas where there might be limited radar coverage. By adhering to the MEA, pilots can ensure they are flying within safe altitude limits, which is vital for flight planning and navigation along airways.

Other options, while related to altitude concepts, do not accurately define MEA. The terms might describe different types of altitudes relevant to aviation, but they do not meet the specific criteria of the definition associated with Minimum Enroute Altitude.