GI-275 HSI- no glide slope indicator on RNAV?

[cowman]

I’m still playing with my new setup, for those who don’t know I replaced my AI and HI with a pair of gi-275s.

Today I was out fooling around and shot a couple of RNAV approaches one LNAV/VNAV and the other LPV. I got no glide slope indicator on the gi-275 HSI. The approach was activated and my old CDI indicator did show a glide slope but nothing on the 275. Strangely it will show one on an ILS if I switch to CDI.

The DB on my 530w was expired as I hadn’t really planned on doing any IFR today so I’m wondering if it won’t show up because of that? Hoping it was user error somehow and I don’t have yet another discrepancy to take it back in for.

 

[Captain Sweet T]

Did you change the mode to OBS?

 

[cowman]

Did you change the mode to OBS?

It was showing the horizontal guidance and waypoints in magenta. When I switch to CDI the line turns aqua so I would assume so unless there’s some other mode switch I’m missing.

 

[Captain Sweet T]

So for my 275 to do it.....I have to select obs mode on my gnx375, then change the 275 to crs. I know its a different system but I hope that helps.

 

[cowman]

So for my 275 to do it.....I have to select obs mode on my gnx375, then change the 275 to crs. I know its a different system but I hope that helps.

It might, I’ll have to play with it more I guess.

Before the 275s I would normally be flying a GPS enroute course and be on OBS so when I loaded an approach there was nothing to change. The only time I’d ever switch would be to fly an ILS or track a VOR. I was assuming this setup works the same way but maybe I have an additional button push now?

Just seems counter-intuitive to me that I’d be looking at the runway waypoint on the approach on the HSI and have to do something else to get the glide slope.

 

[AA5Bman]

I have a feeling this is setup error. You should get a “VNAV” glide slope when on final approach with an RNAV approach loaded (in Nav/GPS mode), or when on an ILS when in CDI/OBS mode (“green” line, or turquoise or whatever). If I have an ILS approach loaded, and am flying in Nav (GPS) mode, I will still get a glide slope, but it will be grey, showing that it is either coming from the ILS or calculated by the GPS - can’t remember which. In either case, the glideslipe indication is just that little diamond on the right hand side of the display, it could be bigger.

 

[Captain Bubba]

Not sure which installation you have. If you have an ADI for your AI you can display it there which might be worth a try. I suspect if it's not displaying on the HSI, it won't be on the ADI either.

Enabling/disabling deviation display on the 'ADI' Page:
1) From the 'ADI' Page, open the menu and select Options > NAV Options.
2) Select the CRS Devs Button to toggle displaying lateral and vertical deviation
information.

 

[cowman]

Here’s a shot from when I picked it up, don’t have an approach loaded but that’s how the screens look.

 

[AA5Bman]

In the above photo, with no approach loaded, you would get no glide slope - were you expecting one? If you had an ILS turned to the right frequency, you would get one but you’d have to switch the unit to CDI by clicking the “CDI” button just under the magenta line (it might show as greyed out in this mode as I described above, but I don’t remember).

 

[cowman]

In the above photo, with no approach loaded, you would get no glide slope - were you expecting one? If you had an ILS turned to the right frequency, you would get one but you’d have to switch the unit to CDI by clicking the “CDI” button just under the magenta line (it might show as greyed out in this mode as I described above, but I don’t remember).

No that’s just the picture I had. I expect a glide slope when I’m on an active LPV approach and I’m not getting one. Since the enroute mode in the picture is on GPS I would expect to see that without changing modes once I load and activate an approach. I *do* get a glide slope when I switch to CDI mode and intercept an ILS.

 

[WDD]

Question on your AHRS. The two yellow bars are above the horizon / white line - indicating pitch up. But your VSI shows level flight.

Should it not look like this?

 

[AA5Bman]

I may have misunderstood your original post. Are you saying you get the RNAV glideslope on your old CDI? When you said old CDI and glideslope, my mind just jumped to that indication coming from an ILS but in re-reading it I think you mean that you had an RNAV approach loaded and got the *RNAV* glideslope on the *old* CDI. Did you have a previous GPS that utilized that CDI? Seems like maybe they maintained that connection/output and forgot to move it over.

If you for sure had an RNAV+vertical guidance approach loaded AND were receiving an RNAV glideslope on your old CDI AND had the GI275 in NAV (magenta line) mode and still didn’t get a glideslope on the 275, then I would agree it seems like there is a setup issue.

 

[cowman]

Went back to the shop today. It was a configuration issue on the 530. Glideslope is there now.