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Aeronautical Chart Users’ Guide

FAA Chart Users’ Guide Version 9 July 2026
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IFR Enroute Low/High Altitude Symbols

IFR low- and high-altitude enroute chart legends, symbols, examples, and procedures.

FAA aeronautical chart visual associated with “Minimum Enroute Altitude (MEA) — RNAV Low Charts” (source page 83).
Minimum Enroute Altitude (MEA) — RNAV Low Charts — source page 83.
FAA aeronautical chart visual associated with “MEA for GNSS RNAV aircraft” (source page 83).
MEA for GNSS RNAV aircraft — source page 83.
FAA aeronautical chart visual associated with “MEA for DME/DME/IRU RNAV aircraft” (source page 83).
MEA for DME/DME/IRU RNAV aircraft — source page 83.
FAA aeronautical chart visual associated with “RNAV Maximum Authorized Altitude” (source page 83).
RNAV Maximum Authorized Altitude — source page 83.
FAA aeronautical chart visual associated with “RNAV Minimum Obstruction Clearance Altitude” (source page 83).
RNAV Minimum Obstruction Clearance Altitude — source page 83.
FAA aeronautical chart visual associated with “RNAV Minimum Turning or Crossing Altitude flag” (source page 83).
RNAV Minimum Turning or Crossing Altitude flag — source page 83.
FAA aeronautical chart visual associated with “RNAV altitude change symbol” (source page 83).
RNAV altitude change symbol — source page 83.
FAA aeronautical chart visual associated with “RNAV holding pattern with magnetic-reference bearing” (source page 83).
RNAV holding pattern with magnetic-reference bearing — source page 83.
Airspace Information (Continued) VHF/UHF LF/MF LOW CHARTS LOW CHARTS HIGH CHARTS HIGH CHARTS MEA- 29000 MEA-FL240 LOW CHARTS HIGH CHARTS 65 279 $J505$ 91 MEA G AP MEA- 24000 108 TWISP LOW / HIGH LOW / HIGH CHARTS CHARTS LOW CHARTS LOW CHARTS LOW CHARTS LOW CHARTS LOW / HIGH LOW / HIGH CHARTS CHARTS MINIMUM ENROUTE ALTITUDE (MEA) All Altitudes Are MSL Unless Otherwise Noted. Directional MEAs MEAs are shown on IFR High Altitude Charts when MEA is other than 18,000’. MINIMUM ENROUTE ALTITUDE (MEA) GAP MEA is established when there is a gap in navigation signal coverage. Maximum Authorized Altitude (MAA) All Altitudes Are MSL Unless Otherwise Noted. MAAs are shown on IFR High Altitude Charts when MAA is other than 45,000’. Minimum Obstruction Clearance Altitude (MOCA) All Altitudes Are MSL Unless Otherwise Noted. Minimum Turning Altitude (MTA) and Minimum Crossing Altitude (MCA) See Low Enroute Chart Example below for examples of both MTAs and MCAs. MINIMUM RECEPTION ALTITUDE (MRA) ALTITUDE CHANGE MEA, MOCA and/or MAA change at other than NAVAIDs CHANGEOVER POINT Changeover Point giving mileage to NAVAIDs (Not shown at midpoint locations.) HOLDING PATTERNS RNAV Holding Pattern Magnetic Reference Bearing is determined by the isogonic value at the waypoint or fix. Holding Pattern with maximum restriction airspeed 210K applies to altitudes 6000’ to and including 14000’. 175K applied to all altitudes. Airspeed depicted is Indicated Airspeed (IAS) RNAV LOW CHARTS HIGH CHARTS MEA for GNSS RNAV aircraft MEA- 24000G MEA for DME/DME/IRU RNAV aircraft MEA- 24000D N/A LOW / HIGH CHARTS LOW CHARTS LOW CHARTS N/A N/A
Source page 84

AIRSPACE INFORMATION (Continued)

Enroute Chart Examples

FAA aeronautical chart visual associated with “Low Enroute Chart example with numbered references” (source page 84).
Low Enroute Chart example with numbered references — source page 84.
AIRSPACE INFORMATION (Continued) Enroute Chart Examples Low Enroute Chart 1 2 3 4 5 6
Source page 85

AIRSPACE INFORMATION (Continued)

Enroute Chart Examples

FAA aeronautical chart visual associated with “Multiple minimum crossing altitudes at the DUBOIS NAVAID” (source page 85).
Multiple minimum crossing altitudes at the DUBOIS NAVAID — source page 85.
FAA aeronautical chart visual associated with “MCA/MRA at SABAT on V298 — MCA 11,100 eastbound; MRA 10,000” (source page 85).
MCA/MRA at SABAT on V298 — MCA 11,100 eastbound; MRA 10,000 — source page 85.
FAA aeronautical chart visual associated with “MOCA and directional MEAs on Victor route — DBS/SABAT/LAMON/QUIRT” (source page 85).
MOCA and directional MEAs on Victor route — DBS/SABAT/LAMON/QUIRT — source page 85.