Learn what an AIRAC cycle is, what navdata it changes, when flight simulators need updates, and how to prevent FMS, chart and route mismatches.
An AIRAC cycle is the aviation industry’s 28-day schedule for publishing coordinated changes to navigation data, such as waypoints, airways, navaids and instrument procedures. Flight simulators use AIRAC-based databases so an aircraft’s FMS, flight planner, charts and online ATC all refer to the same routes and procedures.
What does AIRAC mean?
AIRAC stands for Aeronautical Information Regulation and Control. Strictly, it is a standardised publication schedule rather than a file format or one universal database. Simmers commonly use “AIRAC cycle” to mean the navigation-data snapshot effective during a particular 28-day period.
Cycles are usually labelled YYNN: the first two digits identify the year and the final two identify that year’s cycle sequence. The effective cycle matters more than the date on which a file was downloaded.
What information changes with an AIRAC cycle?
A simulator’s AIRAC navdata may update the following operational information:
- Waypoint names, coordinates and removals
- Airways and the fixes connecting them
- VOR, DME and NDB identifiers, positions and frequencies
- Runway identifiers and airport reference data
- SIDs, STARs, instrument approaches and missed approaches
- Holding patterns, altitude restrictions and speed constraints
- Controlled airspace and other data used by compatible planning tools
Complex procedures are stored as coded legs rather than pictures. Our explanation of how an RNP approach is loaded and flown shows why having the correct procedure coding in the FMS matters.
| Component | What AIRAC affects | Typical mismatch |
|---|---|---|
| Simulator database | Navaids, fixes, airways and supported procedures | The world map and cockpit disagree |
| Aircraft FMS or GPS | Routes, procedures and coded restrictions | NOT IN DATABASE or a missing SID |
| External flight planner | Route generation and airway validation | An exported route cannot be loaded |
| Charts | Published frequencies, tracks and procedures | The chart shows a runway or approach absent from the aircraft |
| Airport scenery | Usually not corrected by navdata alone | Old runway signs or taxiways remain visible |
AIRAC data does not normally replace terrain, buildings, runway textures, weather or aircraft performance data. Updating navdata therefore cannot rebuild an outdated airport.
Do flight simulators need the latest AIRAC cycle?
A flight simulator does not always need the newest AIRAC cycle; it needs compatible data across the tools being used.
- Use a recent matching cycle when flying with up-to-date charts, planning present-day routes or using online ATC.
- Keep an older matching cycle when recreating historical operations or using an aircraft that cannot accept newer data.
- Accept the simulator’s included data for casual visual flying where current procedures and airway routing are unimportant.
Consistency often prevents more problems than updating one component to the newest cycle. Simulator navdata, aircraft databases and external planners may each require separate updates. We explain the legal AIRAC update options and limits of free data; commercial database files should not be copied between products unless their licences and formats permit it.
Why do AIRAC mismatches cause FMS and route errors?
An AIRAC mismatch means one part of the setup knows about a navigation item that another part does not recognise.
A planner might export a waypoint created in a newer cycle, while the aircraft’s older FMS rejects it. A SID or STAR may have been renamed, an airway connection altered, or a runway renumbered after magnetic variation changed its published designation. Typical results include route discontinuities, invalid waypoint messages, missing procedures and apparently incorrect approach choices.
ILS discrepancies need extra care because the frequency, course, airport scenery and simulator facility data can come from different sources. Follow our method for checking ILS frequencies, courses and chart compatibility before assuming the receiver is faulty.
How do you keep AIRAC data matched?
The reliable method is to choose one target cycle and confirm that every independently managed database uses it.
- Identify each cycle. Check the aircraft’s FMS status or identification page, the simulator’s navdata information and the planner’s database details. Page names vary by aircraft.
- Choose the target cycle. Use a current cycle for present-day charts and online operations, or one common older cycle when a component cannot be updated.
- Update separate databases. Do not assume that updating the simulator also updates every add-on aircraft or planner. Some aircraft read the simulator database; others carry their own.
- Check for conflicting packages. An older navdata package or airport add-on may override part of the intended data. Disable duplicate sources rather than stacking several releases.
- Verify a known procedure. Compare the cycle identifier, then check one waypoint, runway and SID or approach in both the planner and aircraft. A matching label alone does not prove every component is reading the intended database.
When using an external planner, database alignment is just as important as the aircraft update. For example, matching Little Navmap’s scenery and navigation databases prevents routes from being built with fixes or procedures the simulator cannot reproduce.
Can one AIRAC update cover every aircraft and planner?
No single AIRAC installation necessarily updates the whole flight-simulation setup. Microsoft Flight Simulator, X-Plane, Prepar3D, individual aircraft and external planning tools can obtain their data from different locations.
If one component cannot use the chosen cycle, generate a route compatible with its older database or enter an amended route manually. Updating only the planner is the mistake we see most often: the route looks valid before departure, then fails as soon as it is entered into the cockpit.