GTN 750 Flight Plans questions

[RXP 2,338]

No problem Frank, I was just reporting the actual software limitations within the GTN and the GNS. These are hard coded limitations in the device software which certainly impact the capability to import flight plans, since the software must check if the number of imported waypoints won't exceed the internal limits. These 100/32 limits are for the total number of waypoints, this includes any 'generated' waypoints along the way too.

What I was trying to say with the purpose of the 'import' function is from the Garmin point of view only. I suspect this feature was initially implemented just for device to device migration, therefore, it may lack complete flight plan import support that you might find in other Garmin preferred conduits such as the 'connext' interface.

Obviously this feature is of great use for us in the sim world, so that it facilitates flight planning and adds value to the GTN and the GNS V2 products compared to other GPS simulations.

Now, there is something in the GFP format specifically for airways.

"GTN Flight Plan and User Waypoint transfer.pdf" (included in the flight plan sample pack):

p5: '.' Airway VIA Specifying the entry and exit way point for an airway.

p9: To include an airway in a flight plan, the following must be specified [...]

examples:

• :F:UBG.J126.RBL (Single Airway: Jet Airway J126 with entry waypoint UBG and exit waypoint RBL)
• :F:LAX,N33560W118259.C1318.ELKEY,N32410W122031 (Single Airway: Airway C1318 with entry waypoint LAX and exit waypoint ELKEY, with optional latitude and longitude)
• :F:LAX.T306.ELP.J183.CLL.V194.MEI (Multiple chained airways: Entry to Jet Airway T306 at LAX to ELP followed by Jet Airway J183 to CLL followed by Victor Airway V194 to MEI) 

I've not spent any time yet on using the flight planning tools and looking at the output .GFP file, but these should be a starting point. Can you post the content of the generated .GFP files for the 2 KSUS to KAPA flight plans above (the long and the short one)? We can try to manually modify then with the 'airway' specifier and see how it goes with the GTN?

[fppilot 4,358]

9 hours ago, RXP said:

Can you post the content of the generated .GFP files for the 2 KSUS to KAPA flight plans above (the long and the short one)? We can try to manually modify then with the 'airway' specifier and see how it goes with the GTN?

Cannot currently do that.  That long .gfp file was imported back in November after being created at iflightplanner.com. Unfortunately that was during a 30 day trial period. That is over and the site wants $90.00 for an annual subscription.  That .gfp file has since been deleted as it held too many waypoints and could not be imported.  That is when I discovered the shorter method. 

The GTN's .gfp file format, as in your examples above, is quite simple. It is as far as I can see a one-line file (which if long will word wrap). It starts with a short, consistent phrase: "FPN/RI:"  Next comes what appears to be the identifier of the departure airport, preceded with a "F:". (F:KDEN). Then comes the first waypoint fix, also preceded with a "F:" (F:FQF). Then come the route fixes and/or airways. Each separated with a "." (period).  Finally, after the last fix, comes the destination airport identifier preceded with a "F:" (F:KIND).  

FPN/RI:F:(DEP AIRPORT):F:(FIRST FIX).(NEXT FIX OR AIRWAY).(NEXT FIX OR AIRWAY). and so on .(FINAL FIX):F:(DEST AIRPORT)

I completed a flight from KDEN (Denver) to KIND (Indianapolis) today mostly via low route airways V4 and V14.  I constructed the .gfp file in Notepad, saving it as "KDEN-KIND 12-28-17.gfp".  (must make sure it is saved as .gfp and not as .txt). Here is how it looks:

FPN/RI:F:KDEN:F:FQF.V148.TXC.V4.STL.V14.VHP:F:KIND

It imported successfully.  Not only that, the GTN expanded the airways after the import.... The results in the GTN showed 48 interim waypoints. 

So! Here is an update to the method described in my previous message.  Note that my KDEN to KIND above did contain the airway references. In my preceding post I indicated that airways should be removed from the .gfp file and manually added by editing them into the GTN after import.  I found today that is not necessarily the case. 

The issue with the GTN unable to import long routes is for those routes that are expanded into a large number of waypoints at the flight planning source before it creates the .gfp file.  My .gfp today file was constructed as described in the second paragraph above. Took me about 30 seconds and I had my .gfp file for a long route ready to import, letting the GTN expand the airways after the import.  Again, the result was 48 waypoints after the GTN expanded the airways.  That would not have imported if expanded at an external flight planning tool before using it to export or write the .gfp.
 

[RXP 2,338]

10 hours ago, fppilot said:

I completed a flight from KDEN (Denver) to KIND (Indianapolis) today mostly via low route airways V4 and V14.  I constructed the .gfp file in Notepad, saving it as "KDEN-KIND 12-28-17.gfp".  (must make sure it is saved as .gfp and not as .txt). Here is how it looks:

FPN/RI:F:KDEN:F:FQF.V148.TXC.V4.STL.V14.VHP:F:KIND

It imported successfully.  Not only that, the GTN expanded the airways after the import.... The results in the GTN showed 48 interim waypoints. 

So! Here is an update to the method described in my previous message.  Note that my KDEN to KIND above did contain the airway references. In my preceding post I indicated that airways should be removed from the .gfp file and manually added by editing them into the GTN after import.  I found today that is not necessarily the case. 

Thank you for your time trying and reporting success with this! The GFP format provisions for airways references in a concise manner, it is up to the flight planning tools to fully exploit the format properly.

[fppilot 4,358]

5 hours ago, RXP said:

it is up to the flight planning tools to fully exploit the format properly.

Fully agree. And great that for those who use those tools that have exploited the format, your product provides an import function.  That's a great selling point!

[albar965 1,041]

besides procedures LNM exports the airways in GFP flight plans:

FPN/RI:F:EDDF:F:MOVUM,N49570E008316.T109.HAREM,N49371E009249.T104.WLD,N48348E011078.T702.OLETU,N48280E011363:F:EDDM

the coordinates after the comma are just to help the GTN to resolve duplicates. I do not save coordinates for the airports because these can be off depending on simulator and will keep the GTN from loading the departure or destination.

Alex

[fppilot 4,358]

59 minutes ago, albar965 said:

the coordinates after the comma are just to help the GTN to resolve duplicates.

So Alex, does your use of the coordinates eliminate the GTN issue with importing flight plans where a waypoint name has duplicates in the database.  If so that is an outstanding feature of your flight planning program!

[albar965 1,041]

22 minutes ago, fppilot said:

So Alex, does your use of the coordinates eliminate the GTN issue with importing flight plans where a waypoint name has duplicates in the database. 

It should according to manual. Honestly, I did not test that very special case since it is very hard to find a flight plan that triggers this problem.

But it has no negative consequences except for the airports where it is disabled as mentioned above.

Alex

[fppilot 4,358]

9 hours ago, albar965 said:

Honestly, I did not test that very special case since it is very hard to find a flight plan that triggers this problem.

Alex. Try the plan I referred to in a post earlier in this Topic.

FPN/RI:F:KBMG:F:RACYR:F:BUNKA.V221.BIB.V12.TOY:F:KSUS

BUNKA appears to present a conflict to the GTN as it is a duplicate of another waypoint BUNKA, at Ivory Coast, in the world database.  Of course to test you would need to be using the worldwide database.

[albar965 1,041]

Thank you Frank. Very helpful.

Thats the result when I export KBMG RACYR BUNKA V221 BIB V12 TOY KSUS:

FPN/RI:F:KBMG:F:RACYR,N39067W086538:F:BUNKA,N39050W087091.V221.BIB,N38552W088289.V12.TOY,N38443W089551:F:KSUS

The GTN loads the file without warnings. No complaints about BUNKA. Using Garmin stock database that came with the trainer.

 

Wish you a happy new year,

Alex