My G5 won't Auto Slew the Localizer Course

[Janat83]

Dear Mooniacs

I have Dual G5s hooked up to an Avidyne IFD440, during recent approaches, the G5 doesn't automatically turning the course to the ILS (Auto slew) , I had to manually turn the course to the Localizer approach course, I have included both settings pages of the ifd440 and G5s in the link below. 

https://photos.app.goo.gl/RdH2qUACQQgxrAVt9

Appreciating your help. 

Moustafa Janat

[201Steve]

I was just dealing with this issue. It’s intertwined into another problem I’ve been having, so you’ll have to read through, but when I went to go troubleshoot armed with new information it worked fine and I do not know what was done differently, if anything. 
 

 

[midlifeflyer]

Can you clarify what you mean by "auto slew"? Do you mean

1. the CDI us not automatically changing to green needles;
2. the green needle is not automatically pointing to the Localizer inbound course when the CDI has changed?

If your setup is new, either one might be a misconfiguration or a connection. 

[dzeleski]

Yeah I have this same install but I have no idea what auto slew means.

Are you referring to the ability of the IFD to automatically sequence from GPS to VLOC? or GPS to LPV? As in you have to manually rotate the CDI knob to move it to the NAV type?

If thats the case do you see a GPS -> VLOC or GPS -> LPV type of indication in the upper right corner when you load and activate an approach?

Auto tuning needs to be turned on in the settings of the IFD. And specific criteria need to be met in order for it to work.

https://pilotsupport.avidyne.com/kb/article/542-Approach-Procedures/

"AUTOMATIC MODE SWITCHING

† Automatic mode switching to VLOC (e.g. GPSVLOC transition) including automatically setting the inbound course, will occur if the capture criteria defined above are met and the primary nav frequency can be auto-identified. If auto tuning has not been enabled on the setup pages, or a station cannot be identified, automatic mode switching will not occur."

"On ILS/LOC approaches (Vectors-to-Final transition or the full published procedure), the IFD will automatically toggle the nav mode to VLOC when all of the following conditions have been met for 5 consecutive seconds:  The next leg or the active leg terminates at the FAF  The aircraft is on the front side of the approach  The aircraft course is within 15 degrees of the final approach course  Cross track deviation is less than half a dot  The correct station is tuned and identified"

[Mooney in Oz]

On 9/1/2022 at 12:13 AM, dzeleski said:

Yeah I have this same install but I have no idea what auto slew means.

Auto-slew is provided when the HSI course indicator automatically slews either left or right onto the appropriate track without pilot input, when passing overhead a defined point in your GPS flight plan or LLZ and is mainly used in EFIS systems.

Although the tracks or approaches can be hand flown, for full benefit the system requires a capable autopilot with GPSS roll steering.

It is useful in a high workload environment, such as during an instrument approach in IFR conditions, followed by a missed approach that might require a couple of track changes at short distance. 

[midlifeflyer]

21 hours ago, dzeleski said:

Yeah I have this same install but I have no idea what auto slew means.

It refers to the ability of the HSI course pointer to change by itself.  You are flying GPS. Your course is currently 230 and the course pointer reflects that. At the next waypoint, your flight plan course changes to 180. With autoslew, the course pointer will change automatically. Without autoslew, you have to change it manually.

[Browncbr1]

It doesn’t auto slew in obs/Loc mode.   It only auto slews for gps approaches.   If the needle is green, you’ve pressed CDI to get the loc or VOR signal and need to adjust the course.  

Edited September 12, 2022 by Browncbr1

[David Lloyd]

3 hours ago, Browncbr1 said:

It doesn’t auto slew in obs/Loc mode.   It only auto slews for gps approaches.   If the needle is green, you’ve pressed CDI to get the loc or VOR signal and need to adjust the course.  

It’s so easy to get spoiled. Every now and then, do an ILS; every other time forget to adjust the inbound course. What the heck? How hard is the wind blowing? Oh. Never happened using the KCS55 since you were always twisting the course knob.

[dzeleski]

3 hours ago, Browncbr1 said:

It doesn’t auto slew in obs/Loc mode.   It only auto slews for gps approaches.   If the needle is green, you’ve pressed CDI to get the loc or VOR signal and need to adjust the course.  

I don’t think that’s accurate. If you load an approach with an ILS or LOC it will select the correct course for you. The document I posted above states as such. My system will tune the frequency and course assuming all the requirements are met. I don’t have to touch a single button the entire time.

[Ragsf15e]

44 minutes ago, dzeleski said:

I don’t think that’s accurate. If you load an approach with an ILS or LOC it will select the correct course for you. The document I posted above states as such. My system will tune the frequency and course assuming all the requirements are met. I don’t have to touch a single button the entire time.

Agreed.  It will set the inbound course when the approach is loaded.

[Mooney in Oz]

5 hours ago, Ragsf15e said:

Agreed.  It will set the inbound course when the approach is loaded.

Modern systems do (Auto-VLOC tuning), but older systems won’t.

[Mooney in Oz]

6 hours ago, David Lloyd said:

Every now and then, do an ILS; every other time forget to adjust the inbound course. What the heck?

Before Auto-VLOC tuning came along or if I prefer to do a manual intercept, I found a good habit to get into is set the inbound course after the ILS frequency is entered into the standby or active Nav slot. 
 

[Browncbr1]

10 hours ago, dzeleski said:

I don’t think that’s accurate. If you load an approach with an ILS or LOC it will select the correct course for you. The document I posted above states as such. My system will tune the frequency and course assuming all the requirements are met. I don’t have to touch a single button the entire time.

I concede you’re right.  If the approach is activated, it will also automatically switch to LOC mode if you intercept the approach I think 1.5 miles before the FAF?    
 

in any case, sometimes I think of loading/activating the gps lpv approach and switching to LOC if they give it to me.  One time the GS disappeared from the ILS signal, so I hit the CDI button and continued the lpv gps.  I also always have ILS tuned and ready if I lose raim or something on a gps approach, i just hit the CDI button.   The proper procedure is to terminate and go around, but…