IFD 5 Series & IFD 4 Series Touch Screen GPS/NAV/COM

OBS mode unavailable

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=2532
Printed Date: 09 May 2025 at 8:32am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com

Topic: OBS mode unavailable

Posted By: rpostmo
Subject: OBS mode unavailable
Date Posted: 04 Jun 2023 at 2:13pm

IFD 540 IFD 440 GI275 x 2 GFC500.

I also kept a backup CDI and had the shop wire that for VOR/ILS approaches.

My mode switch works correctly from GPS to VLOC on both 540 and 440.

The ILS and VOR work correctly on the backup CDI.

Pushing the OBS button on either the 540 or the 440 does nothing.

My autopilot won''t track a VOR.

I believe the shop told me I could have either the 275 or the backup CDI

but not both. Is the wiring this way preventing OBS mode on the Avidynes?

And also preventing the GFC 500 from tracking the VOR?

Bob

Replies:

Posted By: rpostmo
Date Posted: 12 Jun 2023 at 12:35pm

Operator error!

CRS button on the 275 must be pressed for OBS to work.

It defaults to HDG whenever a change is made in course

or the HSI indicator is changed and must be pressed again when OBS function is desired.

The OBS mode will persist appropriately if other nav changes are not made.

Both the GI275 and the backup CDI will show 3 axis course on

the ILS simultaneously, or like I prefer, the ILS shows on the CDI

and I leave magenta needles on the 275. The GFC500 tracks

all of these correctly: GPS, VOR, Localizer, Glideslope, LPV glidepath.

All in all an amazing combination once all the intricacies are

realized (and practiced).

Bob