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VLOC stays yellow

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oskrypuch View Drop Down
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    Posted: 26 Sep 2015 at 4:53pm
Just read the VLOC thread "Check Navaid ID".

I'm afraid that I am not seeing VLOC transition from yellow to green. Jake, you mentioned the following criteria ...


To trigger the transition from armed VLOC to active VLOC, all of the following capture criteria must be met:

·         The tuned frequency in the nav radio matches that of the approach navaid;

·         The Morse code decoded by the tuned nav radio matches the identifier of the approach navaid;

·         The aircraft track is within 15 degrees of the final approach course;

·         The course to the active waypoint is within 45 degrees of the final approach course;

·         The radio deviations are at most 50% of full scale for 5 consecutive seconds;

·         The active leg is part of the approach up to and including the final approach fix.



The tuned freq matched the navaid (no CAS alert), the correct Morse ID was showing, I was precisely on track on the LOC on the final approach course, inbound to the FAF, intercepted about 5 miles outside the FAF.

This was a VTF transition on the ILS 15 into CYXU.

Any thoughts?

* Orest

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AviJake View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AviJake Quote  Post ReplyReply Direct Link To This Post Posted: 26 Sep 2015 at 7:23pm
Should have worked.  Send me/us your datalogs and we'll see if the explanation is hidden in there.
Steve Jacobson
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oskrypuch View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oskrypuch Quote  Post ReplyReply Direct Link To This Post Posted: 26 Sep 2015 at 8:15pm
Thanks, will do.

* Orest

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Post Options Post Options   Thanks (0) Thanks(0)   Quote AviJake Quote  Post ReplyReply Direct Link To This Post Posted: 28 Sep 2015 at 8:22pm
Any chance you were tripped up by this Pilot Guide note:

Exception to Automatic Nav Mode Switching                                           If VLOC mode had been previously manually selected to be the nav mode (e.g. cross-tuning a VOR) and then an approach is activated in the flight plan that would have normally resulted in a GPS à VLOC nav mode indication, the nav mode will NOT toggle to GPS à VLOC.  Instead, it will stay at VLOC since it is assumed the pilot intended to keep using the previous function.   Likewise, the approach nav frequency will be inserted into the #1 standby nav frequency slot but not the active nav frequency position.  Both the nav mode transition and the swapping of the nav frequencies will have to be manually performed by the pilot.

Steve Jacobson
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oskrypuch View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oskrypuch Quote  Post ReplyReply Direct Link To This Post Posted: 28 Sep 2015 at 10:19pm
No, it was VTF on an ILS approach. Modes were all switched automatically, the VLOC just stayed yellow.

I'm going to fly a few more ILS approaches, and pay attention to this. But, I am pretty sure I noticed this at least once before, just ignored it that time.

Will get the logs to you.

* Orest



Edited by oskrypuch - 28 Sep 2015 at 10:28pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote wookie Quote  Post ReplyReply Direct Link To This Post Posted: 08 Oct 2015 at 3:56pm
Originally posted by AviJake AviJake wrote:

Any chance you were tripped up by this Pilot Guide note:

Exception to Automatic Nav Mode Switching                                           If VLOC mode had been previously manually selected to be the nav mode (e.g. cross-tuning a VOR) and then an approach is activated in the flight plan that would have normally resulted in a GPS à VLOC nav mode indication, the nav mode will NOT toggle to GPS à VLOC.  Instead, it will stay at VLOC since it is assumed the pilot intended to keep using the previous function.   Likewise, the approach nav frequency will be inserted into the #1 standby nav frequency slot but not the active nav frequency position.  Both the nav mode transition and the swapping of the nav frequencies will have to be manually performed by the pilot.



The G-1000 does this also... kind too smart by one half!!
BH
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Post Options Post Options   Thanks (0) Thanks(0)   Quote warrenc Quote  Post ReplyReply Direct Link To This Post Posted: 11 Oct 2015 at 5:38pm
Originally posted by oskrypuch oskrypuch wrote:

No, it was VTF on an ILS approach. Modes were all switched automatically, the VLOC just stayed yellow.

I'm going to fly a few more ILS approaches, and pay attention to this. But, I am pretty sure I noticed this at least once before, just ignored it that time.

Will get the logs to you.

* Orest


Orest
I have had this happen, but only on certain ILS approaches.  I just got my plane back 10 days ago from the install.  I flew the  ILS at Brooksville, FL (KBKV) and VLOC stayed yellow.  Went back to my installer at Tampa Exec, (KVDF) and it was blue.  Trip Taylor, of 540 Webinar fame, flew in to give me instruction on the new stack last Friday.  Our ILS at BKV, yellow with correct id on the freq page.  Flew the ILS at Ocala, (KOCF), also yellow.  Then back down to Tampa Exec (kvdf), VLOC was blue.  He has a call in to Avidyne but hasn't heard back.  The autopilot flew perfect approaches with VLOC yellow.
Warren
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oskrypuch View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oskrypuch Quote  Post ReplyReply Direct Link To This Post Posted: 11 Oct 2015 at 6:53pm
Yes, there is something going on here.

I am going to fly a few local ILSes, observe what happens, and send some logs in.

* Orest



Edited by oskrypuch - 11 Oct 2015 at 6:58pm
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oskrypuch View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oskrypuch Quote  Post ReplyReply Direct Link To This Post Posted: 25 Oct 2015 at 11:15am
Well, I can say that I have NEVER seen a change from yellow -> green on the VLOC indicator, on an ILS approach -- VLOC remains YELLOW throughout. I've done a number of such approaches at different (Canadian) airports.

I'll get a data dump and send it in. Which logs do you need?

But, perhaps I can open this up, do most folks see VLOC transition from yellow to green, running 10.1?

* Orest

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oskrypuch View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oskrypuch Quote  Post ReplyReply Direct Link To This Post Posted: 25 Oct 2015 at 11:01pm
OK, forwarded ALL of the logs by FTP.

* Orest

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Post Options Post Options   Thanks (0) Thanks(0)   Quote roltman Quote  Post ReplyReply Direct Link To This Post Posted: 26 Oct 2015 at 10:17am
Originally posted by oskrypuch oskrypuch wrote:

Well, I can say that I have NEVER seen a change from yellow -> green on the VLOC indicator, on an ILS approach -- VLOC remains YELLOW throughout. I've done a number of such approaches at different (Canadian) airports.

I'll get a data dump and send it in. Which logs do you need?

But, perhaps I can open this up, do most folks see VLOC transition from yellow to green, running 10.1?

* Orest



I honestly haven't flown an ILS since 10.1, but I'll try and make it a point this week to do so for nothing more than another data point, unless Avidyne comes back with this being a known issue.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 94S Quote  Post ReplyReply Direct Link To This Post Posted: 27 Oct 2015 at 1:32pm
Originally posted by oskrypuch oskrypuch wrote:

Well, I can say that I have NEVER seen a change from yellow -> green on the VLOC indicator, on an ILS approach -- VLOC remains YELLOW throughout. I've done a number of such approaches at different (Canadian) airports.

I'll get a data dump and send it in. Which logs do you need?

But, perhaps I can open this up, do most folks see VLOC transition from yellow to green, running 10.1?

* Orest



I get a green VLOC annunciation when tuned to a VOR, but I don't think I've ever gotten one when tuned to a LOC/ILS.  I thought this was related to the fact the IFD will not pull the NAV flag on the KI-209A (an integration issue specific to the KI-209A) when tuned to a LOC/ILS.  It works perfectly when tuned to a VOR, but not when tuned to LOC frequency.  Weird, right?  It's my understanding from tech support that a fix has been developed for this KI-209A quirk, but from the list AviJake posted of the fixes, I don't think it's included in 10.1.1.0.  Hopefully 10.1.2.0!!!
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oskrypuch View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oskrypuch Quote  Post ReplyReply Direct Link To This Post Posted: 27 Oct 2015 at 2:38pm
The answer from Avidyne tech support ...

~~~~~~~~~~~~~~~~~~~~

The IFD540 continuously uses the active nav frequency and the decoded Morse code in an attempt to find VHF navaids in the vicinity of the aircraft that have matching frequency and identifier.  The nav database makes a distinction between "VHF Navaids" and "ILS Navaids", though there are some ILS navaids included in the VHF navaid list.  That distinction is present in the source data that we get from Jeppesen.  For the ILS at CYHM (identifier IAB), the ILS is coded as an ILS navaid.  Therefore, the IFD540 doesn't find it in the list of VHF navaids.  The IFD540 will only turn the VLOC indication green when this process finds a matching navaid and since none was found in this case, VLOC remains yellow.

 

As I mentioned, there are several ILSs included in the VHF Navaid list.  One example in that same area exists at the CYZT airport (Toronto).  The ILS there is 110.15 and has an identifier of ITZ.  If you were to fly the ILS 08 there, the VLOC indication would indeed turn green.

 

Note that the yellow VLOC just indicates that the IFD540 isn't sure that the proper navaid is tuned, so you should verify that it's correct before using it.  The IFD540 will still use the signal that it's receiving, but the VLOC will remain yellow.  So, it's still perfectly safe to use VLOC guidance, it's just not as convenient because the IFD540 isn't doing the station verification for you.

 

I will be discussing this further with Jake and the rest of the engineering team.  Don't know if this can be added as a future feature in our 540 software or if it is better addressed at some other step (at Jeppesen and/or subsequent data processing).  

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Post Options Post Options   Thanks (0) Thanks(0)   Quote DavidBunin Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 2015 at 10:02am

I'm not sure I understand. Are they saying that VLOC will always stay yellow when flying certain ILS approaches, because of the way the navaid is coded in the database? Is there a way for me to know before the flight, which approaches are "perma-yellow" and that this is normal operation? In other words, how would I be privy to the data base coding of navaids?

David Bunin

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Post Options Post Options   Thanks (0) Thanks(0)   Quote oskrypuch Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 2015 at 11:04am
It is kind of a cool feature, gone wrong, because the database is missing most of the LOC IDs, although it is complete for VORs. As far as I know, there aren't any "blank" entries, just missing entries, so hard to determine what is not represented.

So, yes, as a result on most ILS approaches, the VLOC will remain yellow.

So, Avidyne's options:

1) Remove the feature altogether, no database confirmation for yellow -> green transition
2) Have the lookup only for VOR approaches
3) Get Jepp to complete the database (good luck)

Maybe something else ingenious.

For now, option #1 is probably the most practical, it removes ambiguity and potential pilot misunderstanding.

* Orest




Edited by oskrypuch - 28 Oct 2015 at 11:07am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bellanca1730a Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 2015 at 4:37pm
How about a "verify" prompt, with whatever legalese would be necessary, wherein the subsequent "acknowledge" entry clears the prompt and triggers green provided all other criteria for green are met?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ddgates Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 2015 at 4:52pm
Yes, something should be changed, if for no reason that the amber/yellow color suggests caution for a problem; a yellow indication WRT an approach has the wrong psychology.
David Gates
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cavu Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 2015 at 6:23pm
I vote a "verify VLOC" prompt and when dismissed, go to Green  or Blue or just stay yellow.  Or better yet, have the prompt tell us what data is missing to warrant green so I, as the pilot, can verify.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oskrypuch Quote  Post ReplyReply Direct Link To This Post Posted: 28 Oct 2015 at 7:02pm
Originally posted by cavu cavu wrote:

I vote a "verify VLOC" prompt and when dismissed, go to Green  or Blue or just stay yellow.  Or better yet, have the prompt tell us what data is missing to warrant green so I, as the pilot, can verify.

I like that.

* Orest

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Post Options Post Options   Thanks (0) Thanks(0)   Quote AUXAIR Quote  Post ReplyReply Direct Link To This Post Posted: 29 Oct 2015 at 9:53am
Good suggestion
David E.
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