INSTRUMENT FLIGHT RULES WORKBOOK
LOCALIZER (LOC): A VHF Directional Radio Beacon which provides azimuth
(directional guidance) for use in a nonprecision type approach. It is also used in conjunction
with an ILS providing azimuth information. (T-34 can utilize localizers through the VOR radio.
Check the legend for the appropriate symbol.)
MARKER BEACON: A 75-MHz beacon used to designate specific fixes in instrument
approaches. Fan and bone refer to the shapes of the signal patterns. Normally associated with
ILS approaches. Check the legend for the appropriate symbol.
MINIMUM ENROUTE ALTITUDES (MEAs): The MEA between navigation aids
along VOR airways is an altitude which will meet obstruction clearance requirements, and also
assure acceptable navigational signal reception.
MINIMUM OBSTRUCTION CLEARANCE ALTITUDE (MOCA): The specified
altitude between radio fixes on VOR airways, which meets obstruction clearance requirements
and which assures acceptable navigational signal reception within 22 NM of a VOR or
MINIMUM RECEPTION ALTITUDE (MRA): The lowest altitude at which an
intersection can be determined.
MINIMUM CROSSING ALTITUDES (MCAs): The lowest altitude at certain fixes at
which an aircraft must cross when proceeding in the direction of a higher minimum enroute IFR
STOP: DO NOT PROCEED FURTHER IN THIS TEXT UNTIL YOU HAVE READ AND
STUDIED THE CHART LEGEND IN ITS ENTIRETY.
IFR SUPPLEMENT, FLIGHT INFORMATION HANDBOOK, ENROUTE LOW
ALTITUDE CHARTS, GENERAL PLANNING, AND AREA PLANNING 2-23