Building a VFR/IFR Route
How AeroCopilot builds VFR and IFR routes against FAA charts, CIFP procedure data, preferred routes, and the AIRAC cycle — what the planner uses and why.
A flight plan in AeroCopilot is more than a string of waypoints — it is the substrate every other tool reasons against. The route you build feeds the briefing engine, the hazard filter, the AI Copilot's narrative, and the printable kneeboard package. This page explains what the route builder is grounded in so you can trust what comes out of it.
Source data
The route builder reads from FAA-published datasets ingested on official cycles:
- VFR Sectional Charts (FAA) — refreshed every 56 days on the AIRAC cycle, served as MBTiles for the planning map.
- VFR Terminal Area Charts (TAC) (FAA) — high-detail charts for Class B terminal areas, auto-loaded when zoomed in close.
- IFR Low Enroute Charts (FAA) — for operations below 18,000 ft, refreshed every 56 days.
- IFR High Enroute Charts (FAA) — for operations at or above 18,000 ft (Class A).
- CIFP — Coded Instrument Flight Procedures (FAA) — ARINC 424 procedure encoding refreshed every 28 days, powering the IFR template builder and equipment-string generator.
- FAA Preferred IFR Routes — published preferred routes between major city pairs, refreshed every 56 days.
- Instrument Approach Procedures (FAA) — IAP plates, departure procedures, and arrivals (STARs), refreshed every 28 days.
- AIRAC Cycle Schedule (FAA) — checked daily; drives all chart, CIFP, and procedure rotation.
The map renderer is MapLibre GL with a 2D fallback path so the planner remains usable on older hardware.
What the planner does
The route is stored as an ordered list of fixes — airports, navaids, named waypoints, or lat/long points — and rendered as a magenta great-circle line. For long-haul routes the line is interpolated across 32 slerp steps so curvature is visible at chart scale. The line renders dashed while a leg is unresolved and solid once every fix is matched against the underlying datasets. The map auto-fits bounds with 10% padding so labels are not clipped.
For IFR planning, the builder consults CIFP to expand SIDs, STARs, and approach legs into their coded waypoints; it consults the Preferred IFR Routes catalog to suggest filed strings between common city pairs; and it generates an equipment string consistent with what the procedure requires.
For VFR planning, the route is checked against published airspace boundaries (Class B/C/D/E, MOAs, restricted, prohibited, warning areas — refreshed every 56 days) and surfaces transitions in the briefing.
Templates
Recurring routes can be saved as IFR templates (FlightPlanTemplate). The AI Copilot can enumerate saved templates via the read-only listSavedIfrTemplates tool when you ask it to file a frequent run.
What feeds off the route
Once a route is built, downstream features filter their data against it rather than dumping everything in your area:
- PIREPs are filtered to a 25 NM corridor, last 6 hours.
- TFRs are geofiltered to a 20 NM corridor with a transparency line stating how many additional TFRs are active elsewhere.
- NOTAMs are pulled per departure, destination, and alternate, FDC-first, capped at 15 with a "Show all" expand.
- Winds aloft are sampled at the cruise altitude declared in the route.
The route also drives the printable briefing's data-route-loaded attribute so the print pipeline waits for the route to resolve before paginating.
When to rebuild
The AIRAC cycle rolls every 28 days for procedures and every 56 days for sectionals and enroute charts. AeroCopilot checks the cycle schedule daily and rotates underlying data automatically; you do not need to refresh manually. If you saved a template against a procedure that the FAA has since amended, the builder will flag the affected legs on the next open.