ils chart

TGatch

Well-Known Member
i would like to know what do letters X, Y & Z symbolize on an instrument approach chart?
umm...specifically? I'd need an example or whereabouts on the chart I'm kinda lost with just three letters...maybe I'm just rusty and it's a big DUH.
 

Nismaxdan

Well-Known Member
i would like to know what do letters X, Y & Z symbolize on an instrument approach chart?
If you are talking about something like VOR-B or LOC-A... then, if I remember correctly, it means that the criteria for a straight -in landing minimum is not met.

Now I was trained using the Jep charts so if you are referring to government charts I am not sure.
 

pwttogfk

Well-Known Member
If it's in the procedure title, it means that there's more than one charted instrument approach of that type for that runway. For instance, at BFI, there's an RNAV Y and an RNAV Z to 13R if memory serves. There are all sorts of reasons why a runway could have more than one GPS, VOR, or ILS procedure; take a look at some procedures on Airnav and you'll see various ones.
 

Polar742

All the responsibility none of the authority
I think it has to do with database access.

As the procedures are slightly different, it allows the database to have an ILS25RZ and ILS25RY. When the approach is loaded up it reduces the chance of programming the improper transition.

Just a SWAG though....
 

Nismaxdan

Well-Known Member
Oh I didn't read the post correctly, my bad.

The X, Y, Z is different procedures for the same runway using the same nav aid.
 

fish314

Well-Known Member
Oh I didn't read the post correctly, my bad.

The X, Y, Z is different procedures for the same runway using the same nav aid.
This is exactly right. Letters at the back of the alphabet moving forward are multiple approaches of the same type to the same runway. For example, if there are two ILS 13C approaches (two approaches based on the ILS to runway 13 center) they will be titled ILS Z 13C and ILS Y 13C. If they build a third one, that becomes ILS X 13C, and so on.

Letters from the FRONT of the alphabet are used for Circling only approaches. "A" is used for the first circling only approach, "B" for the second, and so on. Unlike the X,Y,Z example above, the A, B, C (circling approaches) won't have a a runway in the title. (VOR A, TACAN B, VOR/DME C versus ILS Z RWY 13C). Also, unlike the X,Y,Z's, the A,B,C's can show up on different types of approaches at the same field.

In other words, a field could have a VOR A, and a TACAN B, (there wouldn't be a VOR A and a TACAN A).
 

Barty

Well-Known Member
This is exactly right. Letters at the back of the alphabet moving forward are multiple approaches of the same type to the same runway. For example, if there are two ILS 13C approaches (two approaches based on the ILS to runway 13 center) they will be titled ILS Z 13C and ILS Y 13C. If they build a third one, that becomes ILS X 13C, and so on.

Letters from the FRONT of the alphabet are used for Circling only approaches. "A" is used for the first circling only approach, "B" for the second, and so on. Unlike the X,Y,Z example above, the A, B, C (circling approaches) won't have a a runway in the title. (VOR A, TACAN B, VOR/DME C versus ILS Z RWY 13C). Also, unlike the X,Y,Z's, the A,B,C's can show up on different types of approaches at the same field.

In other words, a field could have a VOR A, and a TACAN B, (there wouldn't be a VOR A and a TACAN A).
That's it! My old home drome had a VOR/DME-A approach. If you did everything right, you'd end up roughly at midfield with the runway perpendicular to your flight path. I hated flying that approach, not because it was particularly difficult, but the VOR was 27 miles from the field. You could either fly to the VOR and intercept the radial inbound, or fly to one of the other IAFs and fly a DME arc. It took about 15-20 minutes to fly the entire procedure!

http://204.108.4.16/d-tpp/0812/05931VDA.PDF
 

zhopalu

Well-Known Member
thanx everyone for the reply, in particular nismaxdan and fish 314. i suppose i have the answer. i guess my question was too cryptic the first time around. what i meant was what do X, Y, Z stand for in a case like ILS X RWY 09, ILS Z RWY 09 or VOR X RWY 09 etc? i hope the answer remains the same nonetheless?
 

Nismaxdan

Well-Known Member
thanx everyone for the reply, in particular nismaxdan and fish 314. i suppose i have the answer. i guess my question was too cryptic the first time around. what i meant was what do X, Y, Z stand for in a case like ILS X RWY 09, ILS Z RWY 09 or VOR X RWY 09 etc? i hope the answer remains the same nonetheless?
Yes the answer remains the same
 
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