The lowest altitude at which an intersection can be determined. Minimum en route altitude. The lowest published altitude between radio fixes that assures acceptable navigational signal coverage and meets obstacle clearance requirements between those fixes. The altitude meets IFR obstacle-clearance criteria. It may be utilized for radar vectoring only upon the controller's determination that an adequate radar return is being received from the aircraft being controlled.
Charts depicting minimum vectoring altitudes are available only to the controllers.
Marked on an IFR en route chart to denote the point at which to switch from one VOR to another. Altitudes depicted on approach charts which provide at least 1,000 feet of obstacle clearance for emergency use within a specified distance of a navigational facility upon which a procedure is predicated. A published altitude representing the maximum usable altitude or flight level for an airspace structure or route segment. It is the highest altitude on a federal airway, jet route, area navigation route, or other direct route for which an MEA is designated at which adequate reception of navigation aid signals is assured. When making your initial call to ATC for VFR advisories, try to reference your position from a prominent IFR waypoint.