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RNAV approaches - GS and minima

It says that it affects all GNS boxes. Not just the ones with a certain SW version.
The text in the Service Advisory 1047 Rev A: LNAV/VNAV and LNAV+V Full Scale Deflection

Which indicates to me that he issue is not yet fixed.

But maybe they never update the text in service advisories and that some GNS SW release note, or similar, says that the issue described has been fixed.

ESTL

EKRK GPS 03 on a GTN 750 gives GS indication all the way to threshold.

Did a test with instructor and ATC approval and in VMC: EKRK GPS 03 continued approach to 50’ with LLZ and GS on center dot – runway was straight ahead.

Last Edited by Michael_J at 18 Dec 12:46
EKRK, Denmark

@Michael_J Interesting. Your actual experience when flying the EKRK RNAV 03 approach contradicts what the GTN 650 said when I looked at the approach.

Do you remember what your GTN750 said when you selected the EKRK RNAV RWY 03? Did it say LNAV or LNAV+V? See my first post.

How can this be made so complicated?
It’s like Garmin, Jeppesen, EASA, FAA and national aviation authorities have ganged up with the intention of deliberately making this incomprehensible for regular pilots.

ESTL

Here is the relevant service bulletin information for the GNS400W/500W for version 5.10 software upgrade:

* Resolved an issue with the lateral CDI scaling as described in Service Advisory 1344, “LPV and LNAV/VNAV Approach Full Scale Deflection.”
* Resolved an issue with approaches with a glide slope of zero as described in Service Advisory 1372 “Unavailable RNAV (GPS) approaches due to lack of VDA.”

Here is the relevant service bulletin information for the GTN for version 5.13 software upgrade:

The following service documents have been resolved:
* Service Advisory 1344: Corrected issue where CDI (Course Deviation Indicator)/HSI (Horizontal Situation Indicator) scaling on a limited number of LPV and LNAV/VNAV approaches was incorrect
* Service Advisory 1372: Corrected issue where RNAV approaches are unavailable for selection when the approach includes LP minima and also has no published vertical descent angle (VDA)

So, dependent on your system’s software version, you can see different results. I have not seen a service bulletin for G1000 systems.

KUZA, United States

Anders wrote:

Do you remember what your GTN750 said when you selected the EKRK RNAV RWY 03? Did it say LNAV or LNAV+V? See my first post.

It is not an LNAV (or +V), it has a GP and a DA. Odd that even on the Jepp chart it is not clear if it is LNAV/VNAV or LPV. In practice it doesn’t matter that much.

These are all old RNAV approaches that do not appear to have been updated to the modern terminology.

And if you get an offical GP (LPV or LNAV/VNAV) or an advisory (+V) it will always take you to the runway. They do not stop (nor do they become less reliable as you go below DA unlike ILS GS)

Last Edited by JasonC at 18 Dec 13:49
EGTK Oxford

There is no assurance that the +V path will avoid obstacles below the MDA. The LPV or LNAV/VNAV provide for obstacle clearance to the runway if you remain on the centerline and on the GS. I use an example of an approach that has +V that if followed will take you thru a ridge line, 100 feet below the crest.

KUZA, United States

NCYankee wrote:

There is no assurance that the +V path will avoid obstacles below the MDA. The LPV or LNAV/VNAV provide for obstacle clearance to the runway if you remain on the centerline and on the GS. I use an example of an approach that has +V that if followed will take you thru a ridge line, 100 feet below the crest.

Of course, this is why it is unofficial. It will however draw a line in space right to the runway and fly it. That was the point I was making in response to @Michael_J

Last Edited by JasonC at 18 Dec 14:54
EGTK Oxford

So I just flew into EKRK today.

Your GPS looked like this:

Mine looked like:

Interesting that the G1000 showed the +V.

Last Edited by JasonC at 29 Dec 01:13
EGTK Oxford

Really interesting. Thanks JasonC for posting the picture on how it looks on the G1000.

Could I be seeing LNAV instead of LNAV+V on the GTN650 because of the LOI – Loss of Integrity? I was in the hangar trying to load different approaches.
I have also emailed Garmin and asking about why I only see LNAV and pointing out that it shows LNAV+V on the G1000.

ESTL

Anders,

What is the main software version on your GTN?

KUZA, United States
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