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IFD540 with Stec 55X

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=998
Printed Date: 18 May 2024 at 8:33am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: IFD540 with Stec 55X
Posted By: rolfe_tessem
Subject: IFD540 with Stec 55X
Date Posted: 13 Mar 2016 at 2:11pm
I have recently installed an Stex 55X autopilot in my Bonanza, along with the 540 which I've had for a year. I have flown a several test hops to explore the various autopilot modes and integration with the 540, and have a few questions for those with a similar setup.

1. When being vectored on a heading to intercept the LOC on and ILS approach, with the 540 in GPS>VLOC, what mode should the autopilot be in? Should it be in HDG-NAV or HDG-NAV gpss? How about proceeding direct to a waypoint outside the FAF and joining the LOC?

2. In this scenario, will the autopilot switch to APP mode by itself, or does it require a manual push?

3. On a related note, does it matter where in the game the 540 switches to VLOC, either manually or automatically?



Replies:
Posted By: oskrypuch
Date Posted: 13 Mar 2016 at 5:56pm
Originally posted by rolfe_tessem rolfe_tessem wrote:

1. When being vectored on a heading to intercept the LOC on and ILS approach, with the 540 in GPS>VLOC, what mode should the autopilot be in?

You should be in HDG - APR !  When you push the HDG and the APR buttons, HDG, NAV & APR will annunciate on the 55x. You need to be in ALT mode, and level. From there the 55x will intercept the LOC, and then arm ALT - GS by itself. 

So, once you push HDG - APR, you don't need to do anything else, until minimums, other than reset your throttle when you start down. 

And, that will work for ANY kind of VTF approach.

* Orest



Posted By: rolfe_tessem
Date Posted: 13 Mar 2016 at 6:15pm
Orest,

Thank you for that! I assume that you can also already be in ALT mode while taking vectors...

Do you realize that this is nowhere in the STEC manual, which is one of the worst written pieces of crap I have seen for a piece of equipment this sophisticated?

My only other question is whether the timing of the GPS>VLOC switch affects the selection of the autopilot mode. In other words, will the 55X make the turn to intercept even if the switch hasn't happened yet?

Rolfe


Posted By: oskrypuch
Date Posted: 13 Mar 2016 at 8:05pm
Originally posted by rolfe_tessem rolfe_tessem wrote:

My only other question is whether the timing of the GPS>VLOC switch affects the selection of the autopilot mode. In other words, will the 55X make the turn to intercept even if the switch hasn't happened yet?

Rolfe

If correctly wired, yes, it will. There are two different outputs on GPS/NAV units, one for LOC/GS guidance only, the other a newer one, for LOC/GS or GPS approaches. The autopilot sees no difference between an ILS and an LPV approach, when using the newer output.

In fact, you will do exactly that same thing (push HDG/APPR) if being vectored to final, straight in on a GPS approach, or a VOR approach too.

HDG/APPR, it's all you need. Yes, docs are not the best, but it is a very nice A/P. I'd much prefer a DFC90, but no STC, for my aircraft, and likely no STC any time soon.

* Orest



Posted By: rolfe_tessem
Date Posted: 13 Mar 2016 at 9:43pm
Originally posted by oskrypuch oskrypuch wrote:

Originally posted by rolfe_tessem rolfe_tessem wrote:

My only other question is whether the timing of the GPS>VLOC switch affects the selection of the autopilot mode. In other words, will the 55X make the turn to intercept even if the switch hasn't happened yet?

Rolfe

If correctly wired, yes, it will. There are two different outputs on GPS/NAV units, one for LOC/GS guidance only, the other a newer one, for LOC/GS or GPS approaches. The autopilot sees no difference between an ILS and an LPV approach, when using the newer output.

In fact, you will do exactly that same thing (push HDG/APPR) if being vectored to final, straight in on a GPS approach, or a VOR approach too.

HDG/APPR, it's all you need. Yes, docs are not the best, but it is a very nice A/P. I'd much prefer a DFC90, but no STC, for my aircraft, and likely no STC any time soon.

* Orest


Thank you! Thank you!

That has been more helpful than any of the docs or online sources I've been poring through! I had been holding out for a DFC90 as well, but I finally had to pull the trigger...

Rolfe



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