Ils Y ??

[Traumahawk]

Anyone know what an ILS Y is?

 

[groundpointsix]

It's a second ILS approach to the same runway using the same localizer/glide slope. They used to name the different approaches (much like published visual approaches) but switched to the reverse-order lettering for standardization. Often you'll only see the ILS (or VOR/NDB/LDA etc.) 'Z' in your plates as the other letters belong to an approach approved only for a specific operator (like the military or an airline). Go to the AIM chapter on instrument approaches for more information.

 

[Traumahawk]

What brought it to my attention was the 2 ILS's @ Eglin AFB in FL...(kVPS)
have both an ILS Y 19 and ILS Y to 30

Where would the ILS Z come in? these are the only ones shown for each runway. If there is a second, is it not noted and these are military only? Still kinda confused as to where the second ones are to the runway....and why would they start @ Y and not Z

T-hawk

 

[A Squared]

Traumahawk,

If there's an ILS Y, I'm pretty sure that there's an ILS Z someplace, it's just not published in your book. There are many approaches that the general public will never see in a NACO IAP book. They may be special equipment or special aircrew qualification, or they may be private approaches, owned by a private comapny.

Get the DoD/NIMA FLIP book, it may show the ILS Z approach.

The lettering starts at Z and proceeds backward, in a similar fashion to circling only approachs which start at A and proceed forward (VOR-A, VOR-B, etc)

It used to be that straight in approaches using the same facility were named using numbers. You can still find approaches names ILS 1 RWY XX and ILS 2 RWY XX. I believe that the number system was dropped in favor of the letter system to reduce possible confusion with the runway number.

 

[rainman_02]

What brought it to my attention was the 2 ILS's @ Eglin AFB in FL...(kVPS)
have both an ILS Y 19 and ILS Y to 30

Where would the ILS Z come in? these are the only ones shown for each runway. If there is a second, is it not noted and these are military only? Still kinda confused as to where the second ones are to the runway....and why would they start @ Y and not Z

T-hawk

The ILS Z approaches at KVPS are not produced in your IAP book because of the TACAN requrement. The full procedure requires an arc based off the TACAN on the field, whereas the ILS Y approaches are built off the local VORTACs.