Cancels out of ILS
Printed From: Avidyne
Category: Avidyne General
Forum Name: IFD 5 Series & IFD 4 Series Touch Screen GPS/NAV/COM
Forum Description: Topics on Avidyne's IFD 5 Series and IFD 4 Series Touch Screen GPS/NAV/COM
URL: http://forums.avidyne.com/forum_posts.asp?TID=1047
Printed Date: 14 May 2024 at 9:22am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com
Topic: Cancels out of ILS
Posted By: cavu
Subject: Cancels out of ILS
Date Posted: 17 Apr 2016 at 7:20pm
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I think this topic was asked before but I can't find it. I was arriving KRME in VFR conditions with an out of date navdata database. I selected the ILS 33 approach,, and activated it, it automatically populated the ILS frequency in the active and the IAF UCA VOR was in the standby (manually entered) and GPS -> VLOC (in blue) appeared upper right corner of the IFD. I noticed that neither the UCA VOR nor the I-RME ILS auto identified (even inside the IAF). As I was about to intercept the localizer, the GPS->LVOC dropped and GPS just appeared. GPS flag showed on the CDI the entire time. This was very disconcerning. What should have been my action at that point. 1) Go missed 2) manually toggle the IFD to VLOC and fly the ILS approach (manually ID it) 3) Switch to the GPS 33, (overlay of the ILS) 4) ? Does the out of date nav data have anything to do with it? If the IFD can't ID the ILS, does it just boot you out of the ILS and go GPS to RW33? |
Replies:
Posted By: mfb
Date Posted: 17 Apr 2016 at 8:50pm
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Was your ILS indicator showing flags? If not, my vote would be for option 2 - manually toggle to VLOC and identify by ear the old-fashioned way. The other alternative would be to go missed and sort it out at your leisure. Option 3 is not a good one; you're not briefed or prepared for that approach. The 540 takes a while to identify nav signals. I think it's supposed to improve in 10.2. Until then you should be ready to switch to VLOC manually. Mike
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Posted By: cavu
Date Posted: 18 Apr 2016 at 9:28am
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The GS flag was up and the NAV source showed GPS. I agree with your assessment. Thanks A warning message should come up on the IFD that says LOCLIZER NOT IDENTIFIED, USE ANYWAY? selecting the message would change the NAV source to VLOC. The way it works now is confusing and can slip by unnoticed in a busy cockpit. |
Posted By: AviJake
Date Posted: 23 Apr 2016 at 12:18pm
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From the Avidyne perspective: 1. We agree with the behavior recommendations suggested above by Mike. 2. I can't tell from here why your VOR or LOC did not decode quickly enough for you but that was almost certainly the reason why the system did not auto switch to VLOC. 3. It is the decoding and visual presentation of the identifier that is designed to help you with the Tune-Identify-Monitor functions that a PIC is responsible for. 4. It is definitely true that the speed to decode the Morse Code and present an identifier is much faster in Rel 10.2. 5. We spent a great deal of time debating the various design aspects of our system during it's development. There are quite literally dozens of considerations that went into the system that led us to conclude that your Warning message suggestion was not prudent and therefore didn't add that, nor would be likely to conclude otherwise at this time. We'll be very interested to hear if your experience is improved with the faster decode times in Rel 10.2. ------------- Steve Jacobson sjacobson@avidyne.com |
Posted By: cavu
Date Posted: 25 Apr 2016 at 9:54pm
I'm curious now. Why would having an approach selected and activated with the GPS > VLOC showing in the upper left that WITHOUT NOTICE drops the VLOC and goes with a GPS only mode BE PREFERRED over having a screen prompt that warns that the VLOC was not identified and gives the pilot an option to select the VLOC anyway or revert to GPS (the pilot chooses)?
I'm missing something here. |
AviJake wrote:Posted By: brou0040
Date Posted: 25 Apr 2016 at 10:38pm
I'll add my vote that when GPS->VLOC is selected, the anticipation is that at some point, the unit will ID and transition to VLOC. If for any reason, the system reverts back to GPS (or anytime it does something unanticipated), an alert should be presented. Perhaps you don't have to present a continue with VLOC anyways option, but an alert with an audible chime should bring your attention to the IFD that something needs to be addressed.
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Posted By: luchetto
Date Posted: 30 Apr 2016 at 5:08pm
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I flew an approach in Zurich today and the ILS has been identified early enough yet the gps-vloc switch happens basically at the intercept, way too late in my view. In my case the late switching has never been associated with a lack of identification. Don't know what 10.2 will change in my case. Placido |
Posted By: mfb
Date Posted: 01 May 2016 at 3:57pm
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There are several conditions that have to be met before the VLOC switch occurs. ILS identification is one, another is that you have to be close to intercepting the localizer (no more than 50 percent needle deflection). See the Pilot Guide chapter 5 for details. It could be that your equipment is working as it's supposed to. Mike |
Posted By: luchetto
Date Posted: 02 May 2016 at 2:57pm
| 50 percent needle deflection would be ok but the switch happens practically at the intercept. |
Posted By: marktrav
Date Posted: 06 May 2016 at 2:26pm
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I'm glad I ran across this thread. I always run into this problem flying in to KPDK on the ILS. The first problem has always been that it's trying to fly the procedure turn inbound. (My fault as I needed to load vectors to final). Then I almost always have to activate the VLOC manually as it changes from GPS-VLOC to GPS. The only indication is I'm expecting the G/S needles on my Aspen to come alive at the appropriate point, but they don't, and that's when I discover the need to switch over manually. I'm always at the appropriate altitude. I guess I need to study Chapter 5 much more closely.
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