GTN750xi shows magenta CDI in VLOC mode

[rbp]

Its common practice for GPS indications to use magenta and VOR/LOC indications to use green.

While flying an ILS partial panel (ha ha) on my G3X/G5/GTN750 setup, with the breaker pulled on the G3X, i was using the G5 for attitude and the 750 for navigation

Flying the ILS27 into SWF, I had VLOC (green) selected as the CDI on the 750, but the navigation line and CDI deflection bar show magenta, indicating that it is tracking GPS and not the LOCalizer. 

I would have expected that the CDI deflection bar would show up as green, as it does on the G3X, so I get localizer precision. 

Also -- I don't get any GS or GP indication on the 750, so with the G3X out, I can't fly a precision approach? 

Thoughts?

Edited April 30, 2022 by rbp

[Marauder]

Its common practice for GPS indications to use magenta and VOR/LOC indications to use green.
While flying an ILS partial panel (ha ha) on my G3X/G5/GTN750 setup, with the breaker pulled on the G3X, i was using the G5 for attitude and the 750 for navigation
Flying the ILS27 into SWF, I had VLOC (green) selected as the CDI on the 750, but the navigation line and CDI deflection bar show magenta, indicating that it is tracking GPS and not the LOCalizer. 
I would have expected that the CDI deflection bar would show up as green, as it does on the G3X, so I get localizer precision. 
Also -- I don't get any GS or GP indication on the 750, so with the G3X out, I can't fly a precision approach? 
Thoughts?

Its common practice for GPS indications to use magenta and VOR/LOC indications to use green.
While flying an ILS partial panel (ha ha) on my G3X/G5/GTN750 setup, with the breaker pulled on the G3X, i was using the G5 for attitude and the 750 for navigation
Flying the ILS27 into SWF, I had VLOC (green) selected as the CDI on the 750, but the navigation line and CDI deflection bar show magenta, indicating that it is tracking GPS and not the LOCalizer. 
I would have expected that the CDI deflection bar would show up as green, as it does on the G3X, so I get localizer precision. 
Also -- I don't get any GS or GP indication on the 750, so with the G3X out, I can't fly a precision approach? 
Thoughts?

What it looks like it is doing is tracking LNAV guidance, hence the magneta line. Since MOLN is 4.9 nm from the FAF, it may be tracking the GPS overlay until it is within 3 nm of the FAF.

Does the LNAV go away at all? Have you tried cycling the CDI when you are within 3 nm of the FAF?


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[PT20J]

It’s a Garmin thing. The GTN map and CDI always show GPS course and deviation regardless of the CDI selection, hence the magenta. These indications are supposed to be for reference and not primary navigation. The CDI selects the input to the external indicator which is supposed to be used for navigation. If the G3X is failed, you should get LOC and GS displayed on the G5 with the GTN CDI set to VLOC. The GFC 500 should revert to the G5, also.

[rbp]

2 hours ago, PT20J said:

It’s a Garmin thing. The GTN map and CDI always show GPS course and deviation regardless of the CDI selection, hence the magenta. These indications are supposed to be for reference and not primary navigation. The CDI selects the input to the external indicator which is supposed to be used for navigation. If the G3X is failed, you should get LOC and GS displayed on the G5 with the GTN CDI set to VLOC. The GFC 500 should revert to the G5, also.

Aha. This makes sense. I’ll look at the G5 next time