Once you are on the ground at a large or unfamiliar aerodrome, the most dangerous part of the flight can be the taxi. An aerodrome chart is the map that keeps you oriented among the runways, taxiways and holding positions, and reading one before you move is the single best defence against getting lost or, worse, blundering onto a live runway.
This is general educational information, not operational, legal, or regulatory advice. Rules differ by authority and change over time. Always verify against current official sources and follow your operator's approved procedures.
What an aerodrome chart is
An aerodrome chart is a scaled plan of the aerodrome: the runways, taxiways, aprons, stands and buildings, drawn to scale so you can see how the airfield fits together. The standards for it sit in ICAO Annex 4, and the physical design it depicts in ICAO Annex 14. It is published in the aerodrome's section of the AIP, and at a busy field there may be several related charts: the main aerodrome chart, a ground movement chart, and parking and docking charts for the stands.
As with every chart, the legend is the key, defining the symbols and line styles, and you orient the chart with north and its scale before reading it. It is a plan view of the ground, the complement to the airspace charts that map the sky above it.
The runways
The runways are the dominant feature. The chart shows each runway's designator at both ends, its length and width, and the position of its thresholds, including any displaced threshold where the landing area starts in from the paved end. It often carries the runway elevations and, in the associated data, the declared distances, the TORA, TODA, ASDA and LDA that tell you how much runway is usable for each purpose. Reading the runways first fixes the big landmarks the rest of the airfield hangs off.
Taxiways and holding positions
The taxiways are drawn with their letter designators, so taxiway Bravo is labelled B on the chart and on the signs on the ground. Tracing the routes between the apron and the runways is how you build a taxi plan: a string of taxiways from your stand to the holding point for your departure runway. The chart also marks the runway-holding positions, the boundaries where you stop and hold short of a runway unless cleared to cross or enter. Matching the holding positions on the chart to the markings and signs you will see on the ground is exactly how you avoid a runway incursion.
Hot spots
A particularly useful feature is the hot spot. These are locations on the aerodrome with a history or heightened potential for confusion or a runway incursion, a complex intersection, a taxiway that crosses a runway at an awkward angle, a place where aircraft have gone astray before. They are flagged on the chart, often with a distinctive symbol and a reference, so you know in advance where to slow down and concentrate. Briefing the hot spots on your taxi route before you move turns a surprise into an expectation.
Aprons, stands and the reference point
The chart shows the aprons, stands and terminals, so you can find where you are parked and where you are going. It also marks the aerodrome reference point (ARP), the designated geographic centre of the aerodrome, with its coordinates, and the aerodrome and runway elevations. These data points anchor the chart to the real world and to your navigation systems, and the elevations feed your altimetry and performance. At a large field, the parking and docking detail may be on a separate chart, but the principle is the same: the chart tells you where everything is.
Using it to plan a taxi
The real value of the chart is realised before you move. You plan your taxi route from the stand to the runway as a sequence of named taxiways and holding positions, and you brief it, ideally out loud, so the route is in your head before the aircraft is rolling. Then, when ATC issues a taxi clearance, you can read it against your mental picture, query anything that does not match, and follow it confident of where each instruction takes you. A taxi route planned on the chart and briefed in advance is the difference between taxiing with situational awareness and taxiing by following signs you read at the last second.
ICAO chart and US airport diagram
As with the en-route charts, the ICAO aerodrome chart and the US airport diagram do the same job with their own symbology, the latter described in the FAA Aeronautical Chart Users' Guide. The layout information, runways, taxiways, holding positions, hot spots and aprons, is universal, but the way it is drawn differs, so at an unfamiliar field in an unfamiliar country you read the chart by its own legend rather than assume the symbols match your home one.
Ground movement and low-visibility operations
At a large or busy aerodrome the main chart is often backed by a separate ground movement chart, which shows the taxiway network and the standard routes in more detail than the cluttered main plan can. When the weather closes in, low-visibility procedures (LVPs) come into force, and the chart's features take on extra importance: the stop bars, rows of red lights across a taxiway at a holding position, must be obeyed absolutely, and movement is restricted to protect the runway's sensitive areas for aircraft on the approach. Knowing from the chart where the holding positions and stop bars are is what lets you taxi safely when you can barely see them.
The chart also underpins runway incursion prevention in plainer conditions. Reading it lets you anticipate where your taxi route crosses a runway, where the hot spots are, and where you will be asked to hold, so that a clearance to "hold short" or "cross" lands on a mental map you already have rather than a layout you are seeing for the first time. The busier and the worse the visibility, the more the few minutes spent reading the aerodrome and ground movement charts before you move are repaid.
A worked example
You have landed at a large, unfamiliar aerodrome and need to taxi to the general-aviation apron. Before you clear the runway, you have already read the aerodrome chart: you oriented it with north, identified your landing runway and the taxiways leading off it, and found your stand on the apron.
You traced a route, off the runway at the first available taxiway, along taxiway B, holding short at the marked holding position before crossing the other runway, then onto the apron. You noted a hot spot at the intersection where the two runways nearly meet, and made a mental note to slow there. When the ground controller issues your taxi clearance, it matches the route you planned, so you read it back confidently and follow it, stopping at the holding position exactly where the chart said it would be. You taxied an airfield you had never seen with the calm of one you knew, because the chart had already shown it to you.
Common pitfalls
- Taxiing without a plan. Reading the chart and briefing the route before moving prevents getting lost and prevents incursions.
- Skipping the hot spots. The known confusing locations are flagged for a reason; brief them on your route.
- Not matching the chart to the signs. The taxiway letters and holding positions on the chart are the ones on the ground; cross-check them.
- Forgetting the displaced thresholds and declared distances. The runway you read on the chart may not be fully usable for landing or take-off.
- Assuming an airport diagram matches an ICAO aerodrome chart. Their symbology differs; read each by its own legend.
In Pilot EFB
Pilot EFB is a study and planning companion that keeps the aerodrome charts and the rest of a briefing in one offline-first place, so a briefing you have already pulled stays readable away from a signal. It helps you study the layout and plan a taxi before you fly, but it does not show your position on the airfield, taxi the aircraft, or replace the official chart, and pulling fresh charts needs a connection. Pilot EFB is not a certified Electronic Flight Bag, so treat it as a study and planning aid and taxi from your official source of record.