Every trip support desk keeps a list of how far ahead each country wants an overflight or landing permit request. Most keep it in a spreadsheet that one person updates. This guide sets out how to build that list properly, what to record for each country, and where the usual traps are.
Lead times change, and authorities publish them in their AIP and on their own sites. Treat the figures in this guide as an example structure, not as current rules, and confirm with the authority or your local agent before every new routing.
What a lead time really means
A lead time is not just a number of days. For each country you need four things:
- The minimum notice, usually in working days, sometimes in hours.
- The working week of the issuing office. In much of the Gulf the weekend is Friday and Saturday or Saturday and Sunday depending on the country; in Europe it is Saturday and Sunday.
- Office hours and time zone. A request filed at 1500Z may arrive after the office has closed for the day.
- What restarts the clock. Some authorities treat a schedule change as a new request; others accept a revision within a tolerance window.
Build a lead-time library
Record each country as one row with these columns:
| Field | Example | | --- | --- | | Country and FIR | France, LFFF / LFEE / LFMM / LFRR / LFBB | | Permit types | Landing permit for some non-scheduled flights; check the current rules for your aircraft and operator | | Minimum notice | Working days or hours, as published | | Working week and hours | Mon–Fri, local office hours | | Validity window | e.g. ± 24 hours from the requested time | | Documents | Airworthiness, registration, insurance, AOC, noise certificate, crew licences | | Submission route | Authority portal, email, local agent | | Revision rule | What counts as a change, and how to submit it |
In Aviagrid this library sits behind the permits module. When a routing such as OMDB → LFPB is entered, the countries along the route are listed with their permit types, deadlines and checklists.
The usual traps
- Holidays. Public holidays in the issuing country stop the clock. Keep a holiday calendar per country next to the lead time.
- Validity windows. A permit valid for a tight window around the requested time lapses quietly if the departure slips. Check every permit against the new times whenever the schedule changes.
- Document expiry. An insurance certificate that expires mid-trip can invalidate the request. Record expiry dates against each document, not just the file.
- Diplomatic and state flights. These follow different routes and much longer lead times. Flag them at intake.
- Multiple FIRs. Large countries have several FIRs; make sure your routing lists each one the flight crosses.
A simple planning rule
For each leg, take the longest lead time among the countries on the routing, add the weekend and holiday days of that country, and add a day of margin for your own review. That date is when the permit request must leave your desk. Put it on the board as a deadline with an owner.
Keep it current
Assign one person to review the library monthly and after any authority notice. Record the date each row was last checked. In Aviagrid every change to the library is in the audit log, so you can see who changed what, and when.