Inbound course setting on LOC based approaches

[Brantel]

Any reason why the inbound course needs to be manually selected on the HSI when transitioning from GPS Nav to VLOC on a localized based approach? This is with a 430w and HS34.

 

[Brantel]

I have the CDI button disabled on the 430w if that matters.

 

[dynonsupport]

A localizer is a radio beam with no heading direction information, just "you're left/right of the middle of the course (which can be in any direction)" information. So you need to spin course manually. You'll notice that even if you don't, the deflection of the needle is still correct.

 

[Brantel]

I get that 100% but....

There is no reason why you should not be able to automatically set the inbound course from the info provided from the 430w when there is a flight plan/approach loaded and we switch from the 430W GPS Nav source to the VLOC source.

This is an extra step that is very distracting at a critical time on a LOC based approach.  not the time to be trying to set the inbound course.

I know you don't even have to set the inbound course but if you don't, it makes the HSI harder to interpret.  The 430w will also squawk at you to set the correct inboard course so it knows it is not correct.

Several of the competition set it automatically....just trying to bring more value to the Dynon system.....

 

[dynonsupport]

So you can't do it unless you have knowledge of the localizer's direction, which bascially means GPS + frequency correlation. It's not impossible, but it's also not information provided by the 430, and it's not trivial either.

Who claims to do that, incidentally?

 

[Brantel]

Who claims to do that, incidentally?

I did not want to speak too much of the competition but AFS does this as well as GRT.  AFS has a video showing how they sequence to an ILS and they discuss the inbound course being automatically synced since the 430W has a fp/approach loaded.  It happens like they say on their video.  They also automatically change from GPS to VLOC mode from data from the 430W somehow.  I do think they use a different ARINC subset from the 430W than what Dynon recommends but I am not sure.

I have reports from GRT that theirs also automatically syncs the course as well but this is unconfirmed....

Don't get me wrong, love the bang for the buck the Dynon and 430W provides...just trying to do my part to make it better for the end user which means more value in the system....

 

[Brantel]

Who claims to do that, incidentally?

I also confirmed that the G3X sets the inbound course for you when the 430W has a localizer based approach active and their is a valid loc signal.

They call it Auto-slewing the course.  Page 70 of their manual talks about it.

Looks like they only use ARINC connections between them and the 430W.  Looks like they use the same ARINC standard as well.  They do also have the serial port connected but they are only using Aviation data so not sure this helps them get this functionality.  Looks like they do it on the info available via ARINC.

 

[Brantel]

Today I came up with an unexpected workaround that ends up serving the same purpose....

Seems that the course setting in the D100 is sort of global in a sense that it stays set wherever it was until something changes it and this holds true even if you change the input source of the HSI.  

What can change the course setting depends on what overlay is active on the HSI and what mode the GPS is in and if it is a handheld or not.

For the NAV overlay and with the 430W Nav active as the source, the course knob on the HS34 does a fine job setting the course for VOR and LOC modes.

For the GPS overlay, if the GPS is in OBS mode, the course can be adjusted by the HS34 course knob.  If the GPS is not in OBS mode or if the GPS source is a handheld GPS, the course knob does not work at all on the HS34.  The GPS controls the course.

The work around I came up with is this:

Since the course remains stable globally until something changes it, I changed my 430W to be GPS#2 in the display order of the HSI.  This means that if I am using the 430W GPS to get established on the LOC course for a LOC based approach then switching to the NAV overlay on the HS34 once established inbound, the course is automatically set on the HSI due to the fact that I did not activate any other HSI source that could change the course setting on my way to the NAV overlay.

Prior to figuring this out, I had the 430W set as GPS#1 and the handheld set to GPS#2 so when I was switching from GPS#1 to the NAV overlay, I would cross the GPS#2 and it would set my course to whatever it was outputing and then the LOC course would be incorrect requiring a manual setting of the inbound course.


Prior HSI Source select rotation/order:

NAV#1 = 430W Nav Radio (HSI needs course set when on LOC)
GPS#1 = 430W GPS (automatically sets HSI course when not in OBS mode)
GPS#2 = Aera 510 ((automatically sets HSI course) this would overwrite the course setting of the 430W GPS when cycling around to the NAV source)
DG = No course setting
repeat



Current HSI Source select rotation/order:

NAV#1 = 430W Nav Radio (HSI needs course set when on LOC but the GPS#2 set it automatically prior to this source being selected if using the GPS#2 to get established inbound....)
GPS#1 = Aera 510 (automatically sets HSI course)
GPS#2 = 430W GPS (automatically sets HSI course when not in OBS mode)
DG = No course setting
repeat

 

[Brantel]

Scratch all of this above. It works...sometimes...sometimes not.

I can't nail down a pattern that is repeatable in flight so all that stuff in the last post is worthless.

Back to adjusting the course manually.