MEA

The Minimum Enroute Altitude is the lowest published altitude on a defined airway segment that ensures both obstacle clearance and adequate reception of the navigation aids used to define that airway. In mountainous or high-terrain environments, MEAs can reach well above 10,000 feet, while over flat terrain they may be as low as 2,000 or 3,000 feet. MEAs are published on IFR enroute charts (low and high altitude) for each individual airway segment between fixes, and the applicable MEA changes at each waypoint or fix along the route. The MEA guarantees 1,000 feet of obstacle clearance in non-mountainous areas and 2,000 feet in designated mountainous terrain. It also ensures that the aircraft is within the usable reception range of the VOR, NDB, or RNAV signal that defines the airway - meaning that at or above the MEA, the navaid will be reliably received for navigation purposes. When an MEA cannot be met due to performance limitations, the crew must advise ATC and request an amended clearance. If terrain clearance but not navaid reception is the concern, a separate Minimum Obstruction Clearance Altitude (MOCA) may be published that provides terrain clearance but does not guarantee signal coverage.

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In Virtual Airline Operations

MEAs are relevant to Virtual Air Canada Airline flights whenever crews are flying airways at lower altitudes, particularly during departure climbs, step-climbs, and descents in mountainous areas such as the Canadian Rockies. SimBrief automatically accounts for MEAs when generating flight plans, selecting altitudes above the applicable minimums for each airway segment. Understanding MEA helps crews evaluate whether a requested ATC altitude restriction is safe relative to terrain and navaid requirements.

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Related Terms

• MSA - Minimum Sector Altitude
• LNAV - Lateral Navigation
• IAF - Initial Approach Fix