ILS freq/HDG at KDTW (example)

KDTW has two approaches for rwy ILS 4L ( Y and Z) and two ILS approaches 22R (Y and Z).
Each can be selected in the CDU ok.

The actual approaches (waypoints/transitions) for all 4 approaches show up correctly but the Freq and headings do not change (Apr Ref page) for the "Z" approaches.



 

 

 

The actual approaches (waypoints/transitions) for all 4 approaches show up correctly but the Freq and headings do not change (Apr Ref page) for the "Z" approaches.

 

This is one of two things:

1 - The nav data from the nav data provider.

2 - The extreme likelihood that your sim data (airport scenery) does not contain multiple freqs for the same runway.

I'm not familiar with KDTW and don't have the charts to hand -- but are you sure that there are actually two different ILS frequencies?

 

Y and Z procedures usually (in my experience) mean a different 'outbound' segment (i.e. one uses a racetrack whilst the other uses a base turn or direct entry) with higher letters (i.e. Z) usually indicating the procedure with the lowest minima where they differ. But the actual approach aid itself is usually the same.

As Skelsey said, typically the lettering just denotes the same navaid approach with minor changes such as missed approach procedures. However, this is the first set I've seen where they have multiple ILS systems for the same runway. I'm not sure in the other sims, but a quick trial with AFX has proven that FS9 only allows one ILS per runway. This would cause the navdata to disagree with the sim.

I have the appr plates ... yes , Y and Z approaches have different freqs / idents  and HDG.

So does the PMDG Navigraph data have correct Y and Z data.

 

But the FMS is not using it properly

 

My scenery for KDTW also has good ILS Y and Z approaches / data.

Are the different freq's reflected in the navdata?

 

Can both freq's be tuned manually and properly received? (That's for the scenery used.)

Are the different freq's reflected in the navdata?

 

Can both freq's be tuned manually and properly received? (That's for the scenery used.)

 

Yes, but the Freq and headings do not change (Apr Ref page) for the "Z" approaches ... as I mentioned in my first post.

 

Check your PMDG Navdata and see if the Y and Z  ILS freqs / HDGs are there.

The NGX is not capable of using multiple ILS freqs per runway without a change to the navdata format to add the ILS ID code to the approach.  If you look at wpNavAPT.txt you will find two entries for 4L with different frequencies, but since these are not tied to an ID the FMC simple takes the first 4L entry that it finds.  In the US this sort of thing is not common, but it is becoming so in places like Europe.  EDDF is an example.

 

DJ

With so many ILS frequencies in FSX being outdated, for me this is just another case of "overriding" an offered freq by a manual entry. (Same with planes which autotune.)

Vaughan, What scenery are you using for KDTW?

DJ,
"The NGX is not capable of using multiple ILS freqs per runway without a change to the navdata format to add the ILS ID code to the approach.  If you look at wpNavAPT.txt you will find two entries for 4L with different frequencies, but since these are not tied to an ID the FMC simple takes the first 4L entry that it finds.  In the US this sort of thing is not common, but it is becoming so in places like Europe.  EDDF is an example."



How does the ILS Z appr freq / front CRS get tied to the FMC to make the FMS use the correct data?

The LOC navaid is in PMDG Navigraph data e.g.:
Z appr DETROIT METRO WAYNE CO  IHJT ILSD 42.228311 -83.363536111.95T
Y appr DETROIT METRO WAYNE CO  IALA ILSD 42.199197 -83.385050111.75T



Note: I also now tested with the (competing) 737NG and the (Apr Ref page) displays  the selected Y or Z Apr data .. also using Navigraph data.

 

Vaughan, What scenery are you using for KDTW?

BluePrint Simulations for KDTW.

 

http://www.blueprintsimulations.com/BluePrint_KDTW.html

The Z item is the first encountered in the data set so the NGX uses it.  The other 737NG you tested has an additional data element (the ILS ID) that is tied to the ILS data and the approach data.  Ask me how I know on the other forum.

 

DJ

The Z item is the first encountered in the data set so the NGX uses it.  The other 737NG you tested has an additional data element (the ILS ID) that is tied to the ILS data and the approach data.  Ask me how I know on the other forum.

 

DJ

 

Actually ... need to check again .. but I think PMDG is using the:

Y appr DETROIT METRO WAYNE CO  IALA ILSD 42.199197 -83.385050111.75T

 

as the selected appr ILS PRM Y RWY 4L (SIMULTANEOUS CLOSE PARALLEL) ..per the plate.

Which has the offset LOC front CRS 037 deg.

It uses the first it encounters... whichever that is.  The bottom line is that it will not handle multiple ILS frequencies for the same runway without modifying the nav data and fmc code.

 

DJ

It uses the first it encounters... whichever that is.  The bottom line is that it will not handle multiple ILS frequencies for the same runway without modifying the nav data and fmc code.

 

DJ

 

Ok.

 

So the FMS will present multiple ILS approaches to select from but the pilot will not know which one will be valid (actually selected by FMS).