The discussions and examples in this section will be based primarily on the IFR (Instrument Flight Rule)
Enroute Low Altitude Charts. Other IFR products use similar symbols in various colors (see Section 3 of this
guide). The chart legends list aeronautical symbols with a brief description of what each symbol depicts. This
section will provide a more detailed discussion of some of the symbols and how they are used on IFR charts.

FAA charts are prepared in accordance with specifications of the Interagency Air Cartographic Committee
(IACC), and are approved by representatives of the Federal Aviation Administration and the Department of
Defense. Some information on these charts may only apply to military pilots.

AIRPORTS
Active airports with hard-surfaced runways of
3000' or longer are shown on FAA IFR Low Altitude
Enroute Charts for the contiguous United States. Airports
with hard or soft runways of 3000' or longer are
shown on IFR Low Altitude Alaska Charts. Airports with
runways of 5000' or longer are shown on IFR High Altitude
Enroute Charts. Airports with hard or soft runways
of 4000' or longer are shown on IFR High Altitude
Alaska Enroute Charts. Active airports with approved
instrument approach procedures are also shown regardless
of runway length or composition.

Charted airports are classified according to the
following criteria:

Blue – Facilities with an approved Department of Defense
(DoD) Low Altitude Instrument Approach Procedure
and/or DoD RADAR MINIMA published in the
DOD FLIP (Flight Information Publication or the FAA
U.S. Terminal Procedures Publication (TPP).

Green – Facilities with an approved Low Altitude Instrument
Approach Procedure published in the FAA
TPP volumes.

Brown – Facilities without a published Instrument Approach
Procedure or RADAR MINIMA.
Airports are plotted in their true geographic
position unless the symbol conflicts with a radio aid
to navigation (NAVAID) at the same location. In such
cases, the airport symbol may be displaced, but the
relationship between the airport and the NAVAID is retained.
Airports are identified by the airport name. In
the case of military airports, the abbreviated letters
AFB (Air Force Base), NAS (Naval Air Station), NAF
(Naval Air Facility), MCAS (Marine Corps Air Station),
AAF (Army Air Field), etc., appear as part of the airport
name.

Airports marked "Pvt" immediately following the
airport name are not for public use, but otherwise meet
the criteria for charting as specified above.

Runway length is the length of the longest active
runway (including displaced thresholds but excluding
overruns) and is shown to the nearest 100 feet
using 70 feet as the division point; e.g., a runway of
8,070' is labeled 81.

The following runway compositions (materials)
constitute a hard-surfaced runway: asphalt, bitumen,
concrete, and tar macadam. Runways that are
not hard-surfaced have a small letter "s" following the
runway length, indicating a soft surface.