Decode airport chart symbols and abbreviations for runways, taxiways, hold points, frequencies, altitude limits and approach procedures.
Airport chart symbols and abbreviations identify runways, taxiways, holding points, lighting, radio frequencies, navigation aids, altitude limits and procedure fixes. For flight simulation in general, read each item against the chart publisher’s legend: airport diagrams, SID/STAR charts and approach plates share notation, but their colours and symbol shapes are not fully universal.
Which type of airport chart are you reading?
The chart title and layout tell you which symbol system is in use. “Airport chart” can refer to several documents, each answering a different part of the flight.
| Chart type | Main purpose | Typical information |
|---|---|---|
| Airport diagram | Ground movement | Runways, taxiways, stands, holding positions, hotspots and buildings |
| SID or departure chart | Leaving the terminal area | Tracks, fixes, altitude and speed restrictions, radio frequencies |
| STAR or arrival chart | Entering the terminal area | Arrival routes, transitions, restrictions and expected runways |
| Approach chart | Flying an instrument approach | Final approach course, fixes, vertical profile, minima and missed approach |
Our guide to interpreting aeronautical chart legends and notation explains the broader symbols shared with en-route and airspace charts.
What do the common airport diagram symbols mean?
Airport diagram symbols show where the aircraft may move and where it must stop. Exact colours differ, especially between official and commercial chart formats, so the printed legend takes priority over appearance.
| Symbol or marking | Usual meaning | Practical interpretation |
|---|---|---|
| Long numbered rectangle | Runway | 09 points approximately towards 090° magnetic; L, C and R distinguish parallel runways. |
| Narrow route labelled with letters | Taxiway | A, B and combinations such as A3 identify taxi routes and connectors. |
| Two solid and two dashed lines | Runway holding position | Stop before the solid lines when approaching a runway. Do not cross without clearance at a controlled airport. |
| Labelled ILS hold or critical area | Protected ILS signal area | Holding here prevents aircraft from disturbing localiser or glideslope signals during low-visibility operations. |
Outlined or highlighted area marked HS | Hotspot | An intersection with a known risk of confusion or runway incursion. Read the corresponding hotspot note. |
| Arrowheads before a threshold | Displaced threshold | Landing begins at the displaced threshold. The preceding pavement may have restricted take-off, landing or taxi use. |
| Chevrons or separately marked pavement | Blast pad or stopway | Not normal runway surface. A stopway may contribute to declared stopping distance, while a blast pad is unavailable for routine aircraft movement. |
Large X | Closed runway or taxiway | Do not use it. Temporary closures may be missing from an older chart or simulator scenery. |
| Circle or point with height figures | Obstacle | The principal figure is commonly elevation above mean sea level; a parenthetical figure may show height above ground, depending on the chart format. |
Airport diagrams are often not suitable for measuring exact distances or turn points from the screen image. For a practical explanation of stands, holding points and hotspots, see our airport-diagram taxiing guide.
What do the most common airport chart abbreviations mean?
Most airport chart abbreviations fall into five groups: surfaces, communications, navigation equipment, altitude references and procedure points.
| Abbreviation | Meaning |
|---|---|
RWY, TWY | Runway and taxiway |
TWR, GND, CLNC DEL | Tower, ground control and clearance delivery frequencies |
ATIS, AWOS, ASOS | Recorded airport information or automated weather services |
CTAF, UNICOM | Advisory frequencies used at airports without an active control service; they do not provide an ATC clearance |
ILS, LOC, GS, GP, DME | Instrument landing system, localiser, glideslope, glide path and distance-measuring equipment |
VOR, NDB, RNAV, RNP | Navigation aids or area-navigation specifications |
SID, STAR | Standard instrument departure and standard terminal arrival route |
SFC, AGL, MSL, FL | Surface, above ground level, mean sea level and flight level |
ELEV, TDZE, TCH | Airport elevation, touchdown-zone elevation and threshold-crossing height |
IAF, IF, FAF, FAP, MAPt | Initial, intermediate and final approach fixes or points, followed by the missed-approach point |
DA, DH, MDA, MDH | Decision altitude or height and minimum descent altitude or height |
RVR, VIS | Runway visual range and visibility requirements |
MSA deserves special care: it can expand to minimum sector altitude or minimum safe altitude according to the charting system. It provides obstacle clearance within a stated area but is not automatically an authorised procedure altitude.
How are approach-chart symbols interpreted?
Approach-chart symbols must be read across the plan view, vertical profile and minima box rather than in isolation. Triangles, circles and other fix symbols identify waypoints or navigation aids; arrows and lines show tracks, while bars or adjacent figures impose altitude and speed restrictions.
- Altitude restrictions: a value may mean mandatory, at or above, or at or below. Underlines, overlines and boxes vary by publisher, so never guess from the line style.
- Courses and bearings: these are normally magnetic unless marked as true, but the chart notes are authoritative.
- Distance figures: these are commonly nautical miles and may be measured from a DME facility, runway threshold or named waypoint.
- Racetrack shapes: these depict holding patterns or course-reversal procedures, with inbound course, direction of turn and limits shown nearby.
- Missed approach: the route, climb requirement and holding fix are stated separately from the landing minima. Do not stop reading at the decision altitude.
Commercial Jeppesen formatting places information differently from many state-produced charts. Our breakdown of Jeppesen approach plates covers the briefing strip, profile view, minima and missed-approach notation.
Are airport chart symbols the same worldwide?
No; international standards provide a common foundation, but national authorities and commercial publishers use different colours, line styles and shorthand. A symbol learnt on one chart should not be transferred blindly to another.
The simulator does not determine the notation. The chart source does. Look for its legend or chart user guide, especially when interpreting altitude constraints, runway declared distances, obstacle heights and approach minima.
How should you decode an unfamiliar chart?
The safest method is to establish the chart format and its measurement conventions before following any route.
- Verify the airport and revision. Check the airport identifier, chart title, runway and effective date so that you do not brief the wrong procedure.
- Identify the chart type. Decide whether it is an airport diagram, departure, arrival or approach chart.
- Consult that publisher’s legend. Confirm unfamiliar symbols instead of relying on colour or shape alone.
- Establish units and references. Check whether dimensions use feet or metres, whether heights are AGL or MSL, and whether tracks are magnetic or true.
- Trace the route in sequence. Follow each taxiway, waypoint, altitude, speed restriction and missed-approach instruction in the order it will be flown.
Why does the chart not match the flight simulator?
A chart and a simulator airport can disagree because scenery, navigation data and charts are separate datasets. The most common mismatch is not a misread symbol but an old runway, taxiway name, frequency or procedure.
- Runway renumbering: magnetic variation can cause a real runway designation to change while older scenery retains the previous number.
- Outdated navigation data: the aircraft database may lack a waypoint or use a superseded procedure even though the scenery looks correct.
- Older airport scenery: new taxiways, terminals and displaced thresholds may be absent or differently labelled.
- Conflicting add-ons: two active versions of the same airport can produce duplicated markings, misplaced surfaces or an incorrect layout.
Confirm that the airport identifiers match, compare runway and taxiway designations, then align the chart, aircraft navigation data and scenery as closely as the simulator permits. If the physical scenery still differs, do not blindly taxi through buildings or across a missing surface simply because the chart shows a route there.