Just a bump up post, really. It would be great to get a yes or no from Tim. Right now this seems to be in limbo...

- Chris.

I said in page 2 that there is not a solution to this that we can give you. We are not willing to produce flightplans in a format that we know is not ICAO-compliant, as various organisations would instantly reject such flightplans. Airfield ICAO codes, towns and VRPs are things which absolutely are not allowed in the route section of a flightplan.

We don't plan on adding an option which would generate such plans because even if we did, there would be disagreement about the format of VRP names. Instead we will generate an ICAO-compliant machine-readable flightplan and you are free to manipulate it as you wish before it is filed.

Well, that's a clear message at least. Tim, can you point me to the source from where you determine what is or isn't ICAO compatible, please? I (and others) seem to have differeing information on this.

The reason I ask is because I just checked ICAO document PANS-ATM, 4444 which defines the standard format of an ICAO flight plan. (If you want to check, a simple Google search will get you there.) The assertion of yours, that route points have to be specified as coordinates, is simply not supported by ICAO standard. It clearly says (and I quoted from it before) that for flights not following prescribed ATS routes, significant points along the route should be added as

The coded designator (2 to 5 characters) assigned to the point (e.g. LN, MAY, HADDY), or, if no coded designator has been assigned, one of the following ways:

-- Degrees only (7 characters)

-- Degrees and minutes (11 characters)

-- Bearing and distance from a significant point

Specifically, regarding the specification of border crossing points, so called "boundary points" the ICAO standard document says:



So, clearly, if I choose a point for my route for which a coded designator has been assigned then I am REQUIRED to use that designator in the route definition. Strictly speaking, the flight plan SD generates by substituting coordinates in cases where a coded designator exists are not ICAO compliant.

Also, the use of GOLVA as border crossing point in the example I gave near the beginning of the thread is fully compliant with the ICAO standard.

You wrote:

Airfield ICAO codes, towns and VRPs are things which absolutely are not allowed in the route section of a flightplan.

I hope I was able to convince you that airfield codes and VRPs are REQUIRED to be used as such in an ICAO flight plan. About towns I fully agree with you. The rule is that you have to use the CODED DESIGNATOR if one exists. If there's none then you use one of the other methods (geographical coordinates, abbreviated geographical coordinates or distance/bearing from a significant point).

Regarding the use of "DCT" in the route description the standard document has this to say:

Insert DCT between successive points unless both points are defined by geographical coordinates or by bearing and distance.

In this respect we were both wrong. Since SD gives all points as geographical coordinates there shouldn't be a DCT interspersed between them. And as I, in my own flight plans, give those points as coded designators I should have DCT between successive points.

I realize, of course, that you are the "Game Master" in as far as you can evolve SD in any direction you like. No qualms about that. And, by the way, I do love SD and think it is currently the best flight planning software out there for European VFR pilots.

But if you point to ICAO requirements as justification for only allowing route points as coordinates then that is something that is not supported by ICAO standard.

-- Chris.

Hello Tim,

I got an answer from ICAO regarding this issue. As a reminder - I asked whether I can use 4 letter ICAO codes of airports in the Route section. The ICAO officer confirm that I can.

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Dear Mr. Smid.

Thanks for your consultation.

Your interpretation on how to fill Item 15 (route) of the FPL form is correct.

Regarding the interpretation of “Significant point” I’d like to highlight that you also have the definition of “Reporting point” and in your case, the airport 4 letters designator is considered a reporting point instead of a significant point due to the definition of both.

Reporting point is a ”Specified geographical location in relation to which the position of an aircraft can be reported.”

Significant point , although has the same use, is defined as a ground-based navigation aid, an intersection and/or waypoint. And in this context, intersection is a significant point expressed as radials, bearings and/or distances from ground-based navigation aids.

As you can see there is a slight difference, in terms of definition, between the two, but again, your interpretation on the way to fill Item 15 is correct.

Best regards,

Saulo

Saulo Silva

Technical Officer

International Civil Aviation Organization

Air Traffic Management Section