G3X with G175 and KFC 150?

[Steve Dawson]

I have a Mooney Bravo. Has anyone installed a G3X with a GI275 that has a KFC 150 autopilot ? Our local avionics shop is telling me that it can't be done because the GI 275 would have to be the primary. The auto pilot is working great so I didn't want to change it out until it needs to be. Secondly I maybe installing the EIS with the G3X

Thanks

[Mooney Dog]

My understanding of the G3x is that it cant drive the rate based autopilots such as the KFC150. Thats where the 275 would come in, as its able to drive rate based autopilots. In theory it shouldnt make a difference to you if the 275 or the g3x is feeding the unit, so long as both of the units are linked inside the aircraft. It would more be that if the 275 where to fail, so would the AP at that point. That would be something you'd have to discus more with the shop it sounds like. Im only guessing here though. I dont know a whole lot about the G3X. 

 

As for EIS. Absolutely. Its a great, almost needed, upgrade to have in modern airplanes. 

[Steve Dawson]

Thanks Moon dog, I should have added that our shop thinks that the G3X can't be used because the GI275 is the primary. So My question now is, does this curtail any functions of the G3X now that using the GI275 as primary? Any issues with being legal? 

[Warren]

Your installer is correct.   The GI275 has to be the primary for the autopilot and provide all references.  Unfortunately, the G3X is not an approved backup indicator for the GI275 and it would be hard to argue that a large glass panel was the "backup".  If you want to move to the 275's and keep the KFC150, you could simply install a pair if 275's for now.  When and if you decide to upgrade the autopilot, you can then move to the G3x and keep one or both GI275's as backups.

[PJClark]

The G3X CAN drive legacy autopilots.  You just won't get the annunciation on the G3X, and no FD,  and you must still make autopilot selections on the legacy control cranium.

https://buy.garmin.com/en-US/US/p/682215#additional

Scroll down and expand "interfaces".

[Steve Dawson]

So you're saying that the G3X (10") will show the functions of the AI and the HSI but not the FD. If the GI 275 is installed will it be acceptable as a standby instrument and be able to show the FD? Where can I find the functions listed of the G3X if the original instruments are removed and the KFC autopilot is maintained? 

I should mention that I'll have a GTN 750xi with the remote audio panel installed and currently have a GTX 345. I don't mind using the legacy instruments to control the preselects and I would like to remove the two vacuums. 

[PJClark]

The GI275 can be the backup for G3x touch:

https://www.garmin.com/en-US/aviationalerts/gi-275-approved-as-a-standby-instrument-for-g3x-touch/#:~:text=This STC Service Bulletin announces,improvements to the STC documentation.

The G3X will show EVERYTHING you need for navigation, control of the GTN750, control of the GTX345 (if it's a 345R--idk if it can control the regular one), course guidance for anything including all approaches, synthetic vision, ADSB in data...everything.

EXCEPT the controls and status of your KAP 150.  But all you have to do there is keep the existing KAP150 control head and if you have it, the altitude preselector, and the annunciator. those all do what they've always done and you look at them for what you've always looked at them for.

later, when your KAP150 dies, you can replace it with the GFC500 and you have a setup that looks like mine, except your GI275 instead of the G5 and if you do EIS instead of my EDM 900.

If you're looking for unsolicited advice I'd say that if budget isn't an issue, do the G3X and get "big glass" all at once to replace the 6 pack instead of going halfway with GI275s.  And if you don't have something specific you want the 275 to do once you get the G3X (I can't think of what that'd be, but don't have one so I may be missig something)  the G5 is an outstanding instrument, has a bigger display, has its own 4-hour backup battery, is probbly a few $k cheaper, and is totally integrated with the G3X. I do all altimeter settings with the G5 knob and it changes them both at once, so they always agree. no vacuum required anymore (unless like me your speedbrakes are vacuum, but that's all my engine mounted pump now powers). Lots of weight savings.

that's my $.02...but from someone who's done it.

 

[Steve Dawson]

Thanks PJ,

The main goal presently is to only have one 275 with the G3X and from what the avionics shop suggested was to install the Garmin EIS with the G3X and save $4-6K over the price/installation of the JPI 900. I'm keeping the storm-scope so with the Bravo panel having the KFC controls kept in the panel, it still won't crowd any available surface and be much better then the legacy. I have vacuum speed brakes so I'll have to keep one of the two pumps.  

 

BTW very nice panel. 

 

[PJClark]

Wx500 also displays on G3x 

Sounds sweet and you'll love it 

[jetdriven]

9 hours ago, Mooney Dog said:

My understanding of the G3x is that it cant drive the rate based autopilots such as the KFC150. Thats where the 275 would come in, as its able to drive rate based autopilots. In theory it shouldnt make a difference to you if the 275 or the g3x is feeding the unit, so long as both of the units are linked inside the aircraft. It would more be that if the 275 where to fail, so would the AP at that point. That would be something you'd have to discus more with the shop it sounds like. Im only guessing here though. I dont know a whole lot about the G3X. 

 

As for EIS. Absolutely. Its a great, almost needed, upgrade to have in modern airplanes. 

the KFC150 is an attitude-based autopilot.

[jetdriven]

4 hours ago, PJClark said:

Wx500 also displays on G3x 

Sound sweet and you'll love it 

i serched and searched and coulndt find that.  where does it say it will?

[Mooney Dog]

6 minutes ago, jetdriven said:

the KFC150 is an attitude-based autopilot.

doh. You're correct. I should have paid more attention. I was mixing up the 140 and the 150. Totally my error there. 

[PJClark]

29 minutes ago, jetdriven said:

i serched and searched and coulndt find that.  where does it say it will?

IDK where it says it will, but mine does so I reckon it works!

Actually it says so in the pilot handbook.

[Warren]

9 hours ago, PJClark said:

The G3X CAN drive legacy autopilots.  You just won't get the annunciation on the G3X, and no FD,  and you must still make autopilot selections on the legacy control cranium.

The G3X CAN provide course and heading information.

The G3X CANNOT provide attitude reference.

[PT20J]

3 hours ago, jetdriven said:

i serched and searched and coulndt find that.  where does it say it will?

Byron, 

Not much info in the Pilot’s Guide. There are more details in the secret Installation Manual.

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