AIRAC Cycle Calendar

A globally synchronized 28-day publication rhythm defined by ICAO Annex 15: states publish aeronautical changes (procedures, airways, frequencies) so they take effect only on AIRAC effective dates, giving data houses and avionics a predictable pipeline. Identifiers encode year and sequence — 2603 is 2026's third cycle. Thirteen cycles fit most years; the schedule is fixed years ahead, which is what lets this calendar compute rather than fetch it.

For IFR navigation the clean answer is: the data must be current or verified. US operators lean on AC 90-100A-style guidance permitting expired-database use IFR only after verifying the specific procedures against current charts — workable for a cycle, miserable as a habit. Many cycles change nothing in your operating area, but the only way to know is checking the change notices; subscriptions exist because verification labour usually costs more than the data.

Almost always a cycle mismatch: one device updated to the new cycle, the other still runs the old one, and a procedure amended at the boundary differs between them. The fix is procedural — update everything to the same cycle on the same day, and make the cycle identifiers' match part of the preflight flow. This calendar's countdown exists so that update day is planned, not discovered.

Everything you enter is saved in your browser's local storage on your own device — nothing is uploaded to any server. Your records stay completely private, work offline, and load instantly. Use the CSV export regularly to keep an off-device backup copy.

Yes — one click exports your complete cycle schedule as a CSV file that opens in Excel, Google Sheets or Numbers. The export preserves every column exactly as entered, so you can print it, attach it to paperwork, or hand it to an inspector, buyer or insurance underwriter as a supporting summary alongside your official records.