What Is an ICAO Route String?
After you create a flight plan in NG ROUTE, a single line of text appears beneath the summary card. It might look like LGAV DCT ABLON J65 KOPAV T22 DETRA L888 LFPG. That compact string is an ICAO route — the same style controllers and airline dispatchers use when filing IFR flight plans in the real world. Understanding each token makes your simulator briefings sharper and helps you enter routes correctly in an FMS or MCDU.
The basic building blocks
An ICAO route is read left to right, from departure to destination. Every element is either:
- An airport ICAO code (four letters, e.g. LGAV, LFPG)
- A waypoint or navaid (three to five characters, e.g. KOPAV, DETRA)
- An airway designator (e.g. J65, T22, L888, V16)
- The keyword DCT meaning direct between two points
The string does not include altitude, speed, or equipment codes — those belong in other fields of a full ATC flight plan form. NG ROUTE shows the horizontal routing only, which is what most sim pilots need for loading a plan file.
Departure and destination
The first and last codes are always your airports. Everything between them is the en-route structure. In our example, the flight starts at Athens (LGAV) and ends at Paris Charles de Gaulle (LFPG).
Some real-world filings add a SID name immediately after departure or a STAR before arrival. NG ROUTE omits SIDs and STARs in the export because they vary by runway and are selected in the cockpit. Your string will typically jump from the airport to the first en-route fix via DCT or an airway.
What DCT means
DCT is shorthand for direct — fly a straight segment between the previous fix and the next fix without following a named airway. You will often see DCT right after departure because the airport is not on an airway. You may also see DCT between two fixes when no single published airway connects them efficiently.
Direct segments are normal. They do not mean the planner failed. In congested airspace, too many DCT legs would be unusual; NG ROUTE prefers airways where they exist, which is why longer routes show more J, T, or L airway tokens instead of long chains of DCT.
Reading airway segments
When an airway appears, the format is: entry fix → airway name → exit fix. Consider this fragment:
ABLON J65 KOPAV
You enter airway J65 at fix ABLON and remain on J65 until waypoint KOPAV. The nav log in NG ROUTE expands each leg with distances so you can verify the sequence fix by fix.
Airway prefixes hint at altitude band and region:
- J, Q, U — upper jet routes (HIGH level in NG ROUTE)
- V — Victor airways in North America (LOW level)
- T, L, B — regional low or high structures depending on area
Matching the string to your nav log
The ICAO route is a compressed summary; the nav log is the expanded version. Each row in the nav log shows sequence number, fix name, VIA (airway or DCT), and leg distance. If the string says T22 DETRA, find DETRA in the log with VIA column T22 and confirm the leg mileage matches your expectations.
When manually typing a route into an Airbus MCDU or Boeing FMC, pilots often work from the nav log rather than the single-line string — but both represent the same path.
Common sim pilot mistakes
- Skipping the first fix after DCT — if the string says
LGAV DCT ABLON, ABLON must appear in the flight plan before any airway. - Entering airways without endpoints — the FMS needs both where you join and where you leave an airway.
- Confusing similar fix names — KOPOS and KOPAV are different fixes; one transposed letter breaks the route.
- Ignoring cycle differences — a fix valid in NG ROUTE's current AIRAC data may be missing in an outdated sim database.
Worked example
Take EGLL DCT BOVVA UL607 KONAN UL607 KOK DCT EHAM (illustrative structure):
- Depart London Heathrow
- Proceed direct to BOVVA
- Join UL607 to KONAN, remain on UL607 to KOK
- Proceed direct to Amsterdam Schiphol
Even without flying this exact city pair, the pattern repeats worldwide: airport → join structure → follow airways → leave structure → airport.
Why it matters in simulation
Online networks like VATSIM and IVAO may ask for your filed route in ICAO format. Exporting from NG ROUTE gives you a realistic baseline. Live weather, fuel, and runway suggestions from the same plan then align with the route you will actually fly.
Next time you generate a plan, read the string aloud fix by fix before pressing export. That thirty-second habit catches most loading errors before you spawn on the ramp.
ICAO route format shown by NG ROUTE is for flight simulation briefing. File official plans through certified tools for real-world operations.