How to make sure your ICAO flight plan doesn’t get rejected by ATC

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The ICAO flight plan form requires you to identify each part of your avionics configuration.

Mobile apps and online flight planning services have made filing IFR flight plans nearly effortless, thanks to intuitive interfaces and the availability of ATC previously cleared routes between airports in the U.S. There’s no question that this technology eased the required transition for pilots from the domestic to ICAO flight plan format a few years back.

That’s not to say the system is perfect though, and there are some limitations to keep in mind when filing an IFR route, regardless of which app or third-party filing service you use. Fortunately, ForeFlight developed a helpful ICAO Quick Reference Guide which includes a series of tips for preventing common filing errors. Here are some highlights:

  1. When filing with ForeFlight for the first time, make sure you specify your N number including the N. In the US, if the tail number begins with a number, then you must file using an optional call sign which always begins with an alpha character. When you file using a call sign, ForeFlight will copy your tail number to the REG/ field in field 18 (Other information). For example, if your N number is N12345 and your call sign is FFL025, FFL025 will be in the Aircraft ID field of the flight plan and REG/N12345 will be in Other Information. You are then known to ATC as FFL025, or ForeFlight Zero Two Fife.
  2. Filing a SID without a transition fix that is specified in the SID or on the common route. SIDs must always be the very first entry in a route, the departure airport must be valid and not a point, and the SID must have the transition fix specified either with a dot or without one. For example, “KCLT” must be the departure airport and BARMY3.BARMY or NUTZE, RDU, or TYI may be used as the first item in the route. If you just file BARMY3, whatever you enter next in the route will be interpreted as the transition fix and, if not a valid one, will result in a rejection.
  3. Filing a STAR without a transition fix that is specified on the STAR or on the common route. STARs must be the last element in the route and preceded by the transition fix. The destination must be a valid airport identifier. For example, filing the PARQ3 STAR at KCLT the route must end with PARQ3 and the STAR must be preceded by one of the transition fixes that are on the common route. If you don’t file an appropriate transition fix, ATC will interpret the fix just prior to the STAR as the transition fix and, if it is not valid, the flight plan will be rejected
  4. Don’t file to Computer Navigation Fixes. These are indicated on procedures and charts inside parenthesis, start with CF, and are not pronounceable.
  5. Don’t file using an ILS DME Localizer fixes such as IUZA.
  6. Do not add a K to non-ICAO airport identifiers, so 35A is not K35A. The latter will be rejected by ATC.
  7. Duplicating the departure or destination airport identifier in the route string will result in ATC rejecting the route.
  8. All ATC routes (eg: V, T, Q, J, etc) should be coded with an entry fix on the airway, followed by the route designation, followed by the last fix on the route where you are going to exit the route.
  9. Avoid using any fixes on an approach that are not an IAF as they are high risk to not being known by the ATC computer. Stick to using waypoints that are in the enroute system and found on an enroute chart.
  10. Avoid filing from a fix such as a VOR, especially near Center boundaries or your flightplan may get rejected as Centers have private agreements with each other for airspace coverage and will reject flightplans that they don’t cover. It is always better to file from an airport and pick up your flightplan en route, with the same Center or TRACON that owns the airport. All airports are assigned a Center (in a published table), so filing from an airport will get routed to the correct center. A table does not exist to indicate Center assignments for VORs and waypoints, so ownership is determined by the Center boundaries.
  11. Avoid Filing any SID or STAR that is ATC only by NOTAM or there is a chart note to the effect “Assigned by ATC only.”
  12. As a jet flier, do not file procedures that are for Prop or Turboprop Only and vice versa.
  13. Don’t file the destination airport as an alternate.

The best advice for those using ForeFlight is to use the Route Advisor tool (on Maps or Flights view) to select your route and use Procedure Advisor (on Maps) to enter departure and arrival procedures. This ensures that when you send a route to Flights or Proceed to File, the syntax is correct and any waypoints that need to be converted to a lat/long will be converted using the proper format for filing. Route Advisor and Procedure Advisor help prevent errors that could be introduced from manually typing route and procedure strings.

For more information:

How to set up aircraft profiles and equipment codes to file VFR/IFR flight plans

ForeFlight ICAO Quick Reference Guide

Flight Service ICAO Flight Plan Validation (starts on page 69)