Minimum En-Route Altitude

Minimum En-Route Altitude (MEA) is the lowest published altitude for an airway segment that provides adequate obstacle clearance (at least 1,000 ft in non-mountainous areas, 2,000 ft in mountainous areas) and ensures acceptable navigation signal reception.

• Published on IFR en-route charts for each airway segment
• Guarantees both obstacle clearance and VOR/NDB signal reception
• MOCA (Minimum Obstruction Clearance Altitude) provides obstacle clearance only — navaid reception is guaranteed only within 22 NM of the VOR
• ATC may assign altitudes at or above MEA
• In mountainous terrain, MEA can be significantly higher than surrounding segment altitudes
• Grid MEAs or off-route obstacle clearance altitudes (OROCA) apply outside published airways