What would I be doing (perhaps improperly in FMC setup) that would cause the ND route track to loop or show a strange pattern (other than the

acceptable straight line) between waypoints especially early in the route near the departure. Sorry I don't have a screen cap. Just hoping

someone else may have seen this and / or know why it occurs.

Thank you,

Ken Boardman

Winn 7-64, FSX Accel

Sometimes it happens when adding SIDs, for example the HON1Y out of EGCC always shows a loop when I use the NGX, which is why you need your charts in handy

 

 

The eaxct reason I'm not sure but maybe something with the nav data? I don't know to be honest, but I recognise the issue.

Thank you for responding Johan. I believe that the subject issue has appeared only in my SIDs also (but not 100% sure).

Ken Boardman

It's usually to do with the way SIDs and STARs are coded in the navdata. The code can specify a turn direction, and if that is wrong this will create a loop in the wrong direction. You can fix these loops by removing the direction from the turn command. That allows the FMC to decide which way to turn to follow the procedure.

Kevin,

Can these turn commands be corrected easily (using the FMC perhaps?), or must the NavData file(s) be altered?

Thank you,

Ken

The FMC just does the best it can with the information it's given by the NAVDATA. You have to edit the .TXT file for the airport in the PMDG\SIDSTARS folder. They are only text files and if you copy the original you can't lose anything. I'm more familiar with fixing this problem in the Level D 767 which uses a different data format (XML), but you could try deleting the TURN LEFT and TURN RIGHT text in the affected SID definition and see if that helps.

Hi Ken

It can also happen when you connect an ILS approach with a STAR and then use an entry point for the ILS with an approach segment that also is present in the STAR. It will then put the the two identical segments in your plan and thus create a loop. I use the PLAN button on the FCP and scroll through my approach, deleting the double segment.

 

Perhaps useful, or not...

 

Morten

 

Edit: You should always pick the STAR first according to the documentation (and other sources) but I'm unsure if this helps (I seldom fly STARS or plug them into my plan, got a thing for manual approaches )

Thank you Kevin and Morton.

Kevin, I've examined several of the SID and STAR text files and see the left turn and right turn statements in them so next time

this happens I'll have something new to play with

You are quite correct Morton, and I routinely use Plan mode to verify the plan and eliminate redundancies prior to each flight (and

sometimes during flight if plan changes are necessary).

Best regards,

Ken

Got a screenshot?

 

Best regards,

Robin.