Aeronautical Chart Users’ GuideChart Users’ Guide · 9 July 2026

Section 10

IFR ENROUTE LOW / HIGH ALTITUDE SYMBOLS (U.S., PACIFIC AND ALASKA CHARTS)

22 pagesPages 75–96

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AIRPORTS

Airport Data - Low/High Altitude

Civil Charts: High/Low Seaplane - Civil Charts: Low Civil And Military Charts: High/Low Heliport Charts: Low Military Charts: High/Low Emergency Use Only Pacific Only Facilities in BLUE or GREEN have an approved Instrument Approach Procedure and/or RADAR MINIMA published in either the FAA Terminal Procedures Publication or the DoD FLIPs. Those in BLUE have an Instrument Approach Procedure and/or RADAR MINIMA published at least in the High Altitude DoD FLIPs. Facilities in BROWN do not have a published Instrument Procedure or RADAR MINIMA. Facilities in BLACK are foreign airports. All IAP Airports are shown on the Low Altitude Charts. Non-IAP Airports shown on the U.S. Low Altitude Charts have a minimum hard surface runway of 3000’. Airports shown on the U.S. High Altitude Charts have a minimum hard surface runway of 5000’. Airports shown on the Alaska High Altitude Charts have a minimum hard or soft surface runway of 4000’. Associated city names for public airports are shown above or preceding the airport name and city name are the same only the airport name is shown. City names for military and private airports are not shown. The airport identifier in parentheses follows the airport name or Pvt. Pvt - Private Use

AIRPORT DATA DEPICTION

Low Altitude 1. Airport elevation given in feet above or below mean sea level 6. Associated city names for public airports are shown above or preceding the airport name. If airport name and city name are 2. Pvt - Private use, not available to general public the same, only the airport name is shown. The airport identifier in parentheses follows the airport name. City names for military and 3. A solid line box enclosed the airport name indicates FAR 93 private airports are not shown. Special Requirements - see Directory/Supplement 7. Airport Ident ICAO Location Indicator shown outside contiguous 4. “NO SVFR” above the airport name indicates FAR 91 fixed- U.S. wing special VFR flight is prohibited. 8. AFIS Alaska only 5. or following the airport identifier indicates Class C or Class D Airspace High Altitude - Alaska High Altitude - U.S.

LIGHTING CAPABILITY Lighting Available Part-time or on request Pilot Controlled Lighting No lighting available At private facilitiesindicates no lighting information is available

NAVAIDS VOR VOR/DME TACAN DME NDB NDB/DME Reporting Function Non Compulsory Reporting or Off Airway Compulsory Reporting Note: VHF/UHF is depicted in Black. LF/MF is depicted in Brown. RNAV is depicted in Blue Compass Roses VHF/UHF LF/MF Compass Roses are oriented to Magnetic North of the NAVAID that cannot be adjusted to the charted isogonic values.

Compass Locator Beacon LOW ALTITUDE Chart Example : Enroute Low L-27 US

LOW ALTITUDE ILS Localizer Example with Back Course ILS LOCALIZER (Chart: Enroute Low L-1 US) ILS Localizer Course with additional navigation function ILS Localizer Back Course with additional navigation function HIGH ALTITUDE - ALASKA VOR/DME RNAV WAYPOINT DATA Coordinates Frequency Radial/Distance (Facility to Waypoint) Identifier Reference Facility Elevation NAVIGATION AND COMMUNICATION BOXES - COMMON ELEMENTS LOW ENROUTE CHARTS HIGH ENROUTE CHARTS RCO Frequencies RCO Frequencies NAVAID Name NAVAID Name, SSV(s) Frequency, Ident, SSV(s), Channel FREQ, Ident, CH, Morse Code Latitude, Longitude Latitude, Longitude Controlling FSS Radio or FSS Name (AK) Controlling FSS Radio or FSS Name (AK)

COMMON ELEMENTS (HIGH AND LOW CHARTS) RCO Frequency Single Frequency Multiple Frequencies Frequencies transmit and receive except those followed by R and T: R - Receive Only T - Transmit Only VHF/UHF LF/MF NAVAID Box Thin line NAVAID boxes without frequency(s) and FSS radio name indicates no FSS frequencies available. (AK only) Shadow NAVAID box indicates NAVAID and Flight Service Station (FSS) have same name.

Navigation and Communication Boxes - Common Elements NAVAID STANDARD SERVICE VOLUME (SSV) CLASSIFICATIONS

(VL), (T), etc. indicate SSV. See “NAVAID STANDARD SERVICE

(T) (L) (VL) (H) (VH) (DL) (DH) VOLUME (SSV) CLASSIFICATIONS” on page 66 or the Chart Supplement for SSV Altitude and Range Boundaries.

DISTANCE MEASURING EQUIPMENT

(Y) Facilities that operate in the “Y” mode for DME reception

VOICE COMMUNICATIONS VIA NAVAID Voice Transmitted No Voice Transmitted

AUTOMATED WEATHER BROADCAST SERVICES VHF/UHF LF/MF ASOS/AWOS - Automated Surface Observing Station/Automated Weather Observing Station

LATITUDE AND LONGITUDE LOW ENROUTE HIGH ENROUTE Latitude and Longitude coordinates are provided for those NAVAIDs that make up part of a route/airway or a holding pattern. All TACAN facilities will include geographic coordinates.

Navigation and Communication Boxes - Examples LOW ENROUTE CHARTS HIGH ENROUTE CHARTS VOR VOR R - Receive only 122.1R Controlling FSS Name - ANDERSON (T) - Service Volume Receive & Transmit on 122.35 (T) - Service Volume Latitude and Longitude Controlling FSS Name - MACON

Navigation And Communication Boxes - Examples (Continued) LOW ENROUTE CHARTS HIGH ENROUTE CHARTS VOR/DME VOR/DME No Voice Communications Off Route (Greyed NAVAID Box (Y) Mode DME and NAVAID) R - Receive only 122.1R DME in Y Mode Controlling FSS Name - BUFFALO (AK only) Shadow NAVAID Box (AK only) Shadow NAVAID Box FSS Associated with NAVAID FSS Associated with NAVAID

TACAN TACAN TACAN Channels are without Off Route voice but not underlined Off Route - Part Time NAVAID Part Time NAVAID (Greyed NAVAID Box and NAVAID)

VORTAC VORTAC Shutdown status Off Route (Greyed NAVAID Box and NAVAID)

DME DME DME Channel, Ident, Morse Code, DME Channel, Ident, VHF Frequency VHF Frequency

NDB NDB A - ASOS/AWOS Available Shutdown status

NDB/DME NDB/DME No Voice Communications No Voice Communications (Y) Mode DME (Y) Mode DME (AK only) Shadow NAVAID Box (AK only) Shadow NAVAID Box FSS Associated with NAVAID FSS Associated with NAVAID Notes: Morse Code is not shown on High NAVAID Boxes.

Stand Alone Flight Services and Communication Outlets

LOW CHARTS HIGH CHARTS Stand Alone FSS Stand Alone FSS Stand Alone FSS Associated Stand Alone FSS Associated with an Airport with an Airport Part-time FSS

Flight Service Station (FSS) - Alaska Only Shadow NAVAID boxes indicate Flight Service Station (FSS) locations. Frequency 122.2 (Conterminous U.S) and 121.5 and 243.0 (Alaska) are available at many FSSs and are not shown. All other frequencies are shown above the box.

Certain FSSs provide Local Airport Advisory (LAA) on 123.6. Frequencies transmit and receive except those followed by R and T:

R - Receive Only
T - Transmit Only
Remote Communications Outlet (RCO)

Thin line NAVAID boxes without frequencies and controlling FSS name indicate no FSS frequencies available. Frequencies positioned above the thin line boxes are remoted to the NAVAID sites. Other frequencies at the controlling FSS named are available, however altitude and terrain may determine their reception.

Stand Alone RCO Stand Alone RCO RCO Associated/Co-located RCO Associated/Co-located with an Airport with an Airport MON DOUGLAS Converse County (DGW) CASPER 122.4

Stand Alone AWOS & ASOS

AIRSPACE INFORMATION

Airway/Route Types

Low and High Enroute Airway Data:

Low Enroute Charts

Military Training Routes (MTR)

MTRs 5NM or less both sides of centerline MTRs greater than 5NM either or both sides of centerline Arrow indicates direction of route See MTR tabulation for altitude range information All IR and VR MTRs are shown except those VRs at or bleow 1500’ AGL CAUTION: Inset charts do not depict MTRs

Alaska Capstone Routes (R Routes) ”R” Routes (R2010, R2015, R2020, R2025) are RNP 1 Navigation Specification. Users must have specific FAA authorization, through Operations Specification or Letter of Authorization, obtained from Flight Standards to use these routes. The aircraft’s lateral deviation display scaling must support the RNP 1 Enroute operation.

Low and High Enroute Charts

Oceanic Route VHF/UHF Data is depicted in Black. LF/MF Data is depicted in Brown. RNAV Route data is depicted in Blue

High Enroute Charts

RNAV Q Routes Alaska Q Routes require GNSS and radar surveillance. Within the CONUS, GNSS or DME/DME/IRU RNAV required, unless otherwise indicated. DME/DME/IRU aircraft require radar surveillance.

Substitute Route All relative and supporting data See NOTAMs or appropriate shown in brown. publication for specific information.

FIXES REPORTING FUNCTION WAYPOINTS VHF/UHF LF/MF Compulsory Position Reporting RNAV

Fix or Waypoint Coordinates Fix Coordinates are shown for compulsory, offshore and holding fixes. Waypoints Coordinates are shown when waypoint is not part of a RNAV route and when located on or beyond the boundary of the U.S. Continental Control (12 mile limit).

Off-set arrows indicate facility forming a fix N/A - Arrow points away from the VHF/UHF NAVAID - Arrow points towards the LF/MF NAVAID

Distance Measuring Equipment (DME) Fix N/A Denotes DME fix (distance same as airway / route mileage)

Distance Measuring Equipment (DME) Fix VHF/UHF RNAV Denotes DME fix (encircled mileage shown when not other- N/A wise obvious)

Example:

First segment, 5NM; second segment 10NM; total milage N/A provided in encircled DME arrow.

Total Mileages between Compulsory Reporting VHF/UHF LF/MF Points or NAVAIDs RNAV Note: All mileages are in Nautical Miles N/A

MILEAGE BETWEEN OTHER FIXES, NAVAIDs AND/OR MILEAGE BREAKDOWN

Mileage Breakdown or Computer Navigation Fix (CNF) N/A Five letter identifier in parentheses indicates CNF with no ATC function

FACILITY LOCATOR BOATS N/A Crosshatch indicates Shutdown status of NAVAID

RADIAL OUTBOUND FROM A VHF/UHF NAVAID N/A N/A All Radials are magnetic.

BEARING INBOUND TO AN LF/MF NAVAID N/A N/A All Bearings are magnetic.

MAGNETIC REFERENCE BEARING, outbound from N/A N/A a NAVAID or Fix Note: Not shown on joint Victor/RNAV or Jet/RNAV Routes.

VHF/UHF LF/MF MINIMUM ENROUTE ALTITUDE (MEA) RNAV LOW CHARTS LOW CHARTS All Altitudes Are MSL Unless Otherwise Noted. LOW CHARTS Directional MEAs HIGH CHARTS HIGH CHARTS HIGH CHARTS MEAs are shown on IFR High Altitude Charts when MEA is MEA for GNSS RNAV other than 18,000’. aircraft MEA- 24000G MEA- 29000 MEA-FL240 MEA for DME/DME/IRU RNAV aircraft MEA- 24000D

LOW CHARTS MINIMUM ENROUTE ALTITUDE (MEA) GAP N/A MEA is established when there is a gap in navigation signal coverage. HIGH CHARTS TWISP MEA- 24000 MEA G AP $J505$ 65 ₁₀₈ 91 279

Maximum Authorized Altitude (MAA) LOW / HIGH LOW / HIGH LOW / HIGH All Altitudes Are MSL Unless Otherwise Noted. CHARTS CHARTS CHARTS MAAs are shown on IFR High Altitude Charts when MAA is other than 45,000’.

Minimum Obstruction Clearance Altitude (MOCA) LOW CHARTS LOW CHARTS LOW CHARTS All Altitudes Are MSL Unless Otherwise Noted.

Minimum Turning Altitude (MTA) and Minimum LOW CHARTS LOW CHARTS Crossing Altitude (MCA) LOW CHARTS See Low Enroute Chart Example below for examples of both MTAs and MCAs.

ALTITUDE CHANGE MEA, MOCA and/or MAA change at other than NAVAIDs

LOW / HIGH LOW / HIGH CHANGEOVER POINT CHARTS CHARTS N/A 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)

Enroute Chart Examples Low Enroute Chart

MCA and MRA at a Fix 2 MCA at SABAT on V298 of 11,100 traveling East. MRA at SABAT of 10000.

Example of MOCA and directional MEAs along a Victor 3 Route Traveling East from DBS, MEA 13,000’ the first two segments, 15,000 along third segment. Traveling West from QUIRT, MEA of 15,000’ the first segment, MEA of 10,000 the second segment and MEA of 9,000 the third segment. MOCA for DBS to SABAT and SABAT to LAMON segments of 8100

4 MCA Example MCA at OSITY on V330. MCA of 9500’ traveling East on V330 from Idaho Falls (IDA) VOR-DME.

Enroute Chart Examples Low Enroute Chart (Continued)

Reference Number Description 5 MEA VHF and RNAV Example MEA for aircraft utilizing VHF NAVAID of 15000’ MEA for aircraft utilizing RNAV of 13300’ MOCA of 13300’ MCA and MTA Example at a NAVAID 6 MCA for aircraft traveling West along V520 to cross JAC at 15200’ MCA for aircraft traveling West along V330 to cross JAC at 13400’ MTA for aircraft crossing over and turning at JAC: Aircraft traveling NE on V465 and turning to V330 on a W heading or turning to V520 on a W heading must turn at altitude of 16000’ or higher Aircraft traveling E on V520 and turning to V330 on a W heading must turn at altitude of 14200’ Aircraft traveling E on V330 and turning to V520 on a W heading must turn at altitude of 16000’ or higher Aircraft traveling NW on V328 and turning to V465 on a SW heading must turn at altitude of 15100’ or higher.

Enroute Chart Examples High Enroute Chart

1 2 3 Reference Number Description High RNAV Route with MEA for DME/DME/IRU RNAV Aircraft MEA of 24,000’ 1 Preferred Directional Jet Route with Time Restrictions Jet Route 34 available between 1100 - 0300Z 2

Airspace - U.S.

Class A
Open Area (White)
High Chart Only

That airspace from 18,000’ MSL to and including FL 600, including the airspace overflying the waters within 12 NM of the coast of the contiguous United States and Alaska Controlled and designated offshore areas, excluding Santa Barbara Airspace Island, Farallon Island, the airspace south of latitude 25° 04’00” N, the Alaska peninsula west of longitude 160°00’00” W, and the airspace less than 1,500’ AGL. That airspace from 18,000’ MSL to and including FL 450, including Santa Barbara Island, Farallon Island, the Alaska peninsula west of longitude 160°00’00” W, and designated offshore areas.

Mode C Area
A Solid Blue Outline

Example:

Low Chart Only

That airspace within 30 NM of the primary airports of Class B airspace and within 10 NM of designated airports. See Chart example above.

Controlled
Mode-C transponder and ADS-B Out equipment is re-
Airspace quired. (See FAR 91.215)

Airspace - U.S. (Continued)

CLASS C Screened Blue with a Solid Blue Dashed Outline Example: Low Chart Only Controlled Airspace That airspace from the surface to 4,000’ (unless otherwise designated) above the elevation of selected airports (charted in MSL). The normal radius of the outer limits of Class C airspace is 10NM. Class C airspace is also indicated by the letter C in a box following the airport name. CLASS D Open Area (White) Example: Low Chart Only Controlled Airspace That airspace from the surface to 2,500’ unless otherwise designated) above the airport elevation (charted in MSL), surrounding those airports that have an operational control tower. Class D airspace is indicated by the letter D in a box following the airport name.

AIRSPACE - U.S.

CLASS E
Low Chart Only
Controlled Airspace
CLASS G
Open Area (White)

The controlled airspace below 14,500’ MSL that is not Class B, C or D.

Federal Airways from 1,200’ AGL to but not including 18,000’ MSL (unless otherwise specified).

Other designated control areas below 14,500’ MSL.

Not Charted

That airspace from 14,500’ MSL to but not including 18,000’ MSL, including the airspace overflying the waters within 12 NM of the coast of the contiguous United States and Alaska and designated offshore areas, excluding the Alaska peninsula west of longitude 160°00’00” W, and the airspace less than 1,500’ AGL.