Minimum enroute altitude
Encyclopedia
Minimum en route altitude (MEA), alternately spelled as Minimum enroute altitude, is the lowest published altitude between radio navigation fixes that assures acceptable navigational signal coverage (see MRA
) and meets obstacle clearance requirements (see MOCA
) between those fixes.
The definition given here is that of the United States
Federal Aviation Administration
. Details may vary in other jurisdictions.
or segment, RNAV low or high route, or other direct route applies to the entire width of the airway, segment, or route. MEAs for routes wholly contained within controlled airspace
normally provide a buffer above the floor of controlled airspace consisting of at least 300 feet within transition areas and 500 feet within control area
s. MEAs are established based upon obstacle clearance over terrain and man-made objects, adequacy of navigation facility performance, and communications requirements, although adequate communication at the MEA is not guaranteed.
Minimum reception altitude
In aviation, minimum reception altitude is the lowest altitude on an airway segment where an aircraft can be assured of receiving signals from navigation aids like VOR or NDB. Typically, the greater the distance between navigation aids, the higher the MRA...
) and meets obstacle clearance requirements (see MOCA
Minimum obstacle clearance altitude
Minimum Obstacle Clearance Altitude, or MOCA, is the lowest published altitude in effect between fixes on VOR airways, off-airway routes, or route segments that meets obstacle clearance requirements for the entire route segment. Within the United States, this altitude also assures acceptable...
) between those fixes.
The definition given here is that of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
Federal Aviation Administration
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...
. Details may vary in other jurisdictions.
Overview
The MEA prescribed for a Federal airwayAirway (aviation)
In aviation, an airway is a designated route in the air. Airways are laid out between navigational aids such as VORs, NDBs and Intersections ....
or segment, RNAV low or high route, or other direct route applies to the entire width of the airway, segment, or route. MEAs for routes wholly contained within controlled airspace
Controlled airspace
Controlled airspace is an aviation term used to describe airspace in which ATChas the authority to control air traffic, the level of which varies with the different classes of airspace. Controlled airspace is established mainly for three different reasons:...
normally provide a buffer above the floor of controlled airspace consisting of at least 300 feet within transition areas and 500 feet within control area
Control area
A control area is an aviation term that describes a volume of controlled airspace that exists in the vicinity of an airport. It has a specified lower level and a specified upper level. It usually is situated on top of a control zone and provides protection to aircraft climbing out from the airport...
s. MEAs are established based upon obstacle clearance over terrain and man-made objects, adequacy of navigation facility performance, and communications requirements, although adequate communication at the MEA is not guaranteed.