"Fly Visual" segment on an ILS!

"Fly Visual" segment on an ILS!

Postby Keith Smith » Thu Feb 01, 2018 10:57 am

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"Fly Visual" segments don't get a lot of attention. They're pretty rare, after all. Let's look a bit more closely at the ILS Y approach into Jackson Hole (JAC). It is, in fact, the only PRECISION approach with a Fly Visual segment that we've ever encountered. If anyone else has examples, please let us know!

First thing's first, since the ILS Z has lower minimums, why not fly that instead of the ILS Y? Two reasons spring to mind: 1) ILS Z requires higher climb gradient on the missed (235ft/nm up to 10,300ft). 2) RNAV required to fly the full ILS Z, although that's less of an issue if you're able to get vectors to final.

So, if you are going to fly the ILS Y, how do you fly it? It's business as usual until reaching DA (decision altitude). Normally, you may not leave the DA/MDA on a precision/non-precision approach (respectively) unless you have the runway environment in sight (or the approach lighting system in some cases).

The Fly Visual segment removes that requirement, though. This means you can reach DA, and as long as you are clear of the clouds, proceed visually towards the airport, which you don't technically need to have in sight. Tthis is particularly interesting at Friedman Memorial, SUN, which has a LONG Fly Visual segment of 5.2nm. That said, the visibility requirements in the minimums tend to more or less match the length of the Fly Visual segment (see the NDB approach at KSUN and the ILS Y at KJAC for examples of this).

In any case, reaching minimums, we fly visually towards the airport and can descend as low as we please, so long as we remain in visual conditions. A fantastic question at this point would be, "what happens if you go missed?" While it is indeed a fantastic question, it's really NOT a fantastic time to go missed.

Your terrain and obstacle separation turned into a pumpkin back at DA, so the missed is technically not an option once you begin the Fly Visual segment. If you need to go around, you need to remain visual. If you end up in IMC, confess immediately and see what you can arrange with ATC. In a pinch, the ODP for the airport might be a handy reference.

What does this look and feel like in practice? It's really just a normal ILS, except the minimums are higher than usual (612ft AGL). If you do break out prior to reaching the DA, the airport will be 2nm+ away which will feel odd if you're not prepared for it. You're good to continue from that point if you're confident you can remain visual. If the weather is dodgy and you only have fleeting glimpses of the airport then go missed while you can, because if you start the visual segment, the missed option goes away.

Let's say you completely missed the FLY VISUAL segment during the approach brief? Not to worry...if you fly it as a traditional ILS with the normal criteria for going below the DA then no harm will come to you. The only difference is that you might miss an opportunity to have continued the approach had you utilized the Fly Visual segment correctly.

Sorry (#notsorry) for the long post, but since Fly Visual segments are not particularly common, and since an ILS with a Fly Visual is practically non-existent, we thought it was worthy of a deep dive.
Keith Smith
 
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Re: "Fly Visual" segment on an ILS!

Postby AZJim320 » Wed Feb 21, 2018 7:03 am

Hey Keith, This is a challenging place to fly into. I have only flown in there once in the real world. Glad it is on the PE network could use the practice before I fly there again. Here is some extra guidance attached to help with planning.
Jim
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AZJim320
 
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Re: "Fly Visual" segment on an ILS!

Postby Keith Smith » Wed Feb 21, 2018 7:28 am

Thanks for posting the notes, Jim, that was good stuff! I'm a little surprised here is no reference to the Fly Visual segment on that ILS approach in any of the notes as it's rather unusual to have such a segment on a precision approach.
Keith Smith
 
Posts: 9356
Joined: Sat Oct 09, 2010 8:38 pm
Location: Pompton Plains, NJ

Re: "Fly Visual" segment on an ILS!

Postby AZJim320 » Wed Feb 21, 2018 8:02 am

Yes I agree. I just remember when I flew there they really want you to avoid flying over the visitor center. We flew the ILS initially then broke off to avoid the visitor center.
Jim
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