GI-275 impressions

[RobertGary1]

8 hours ago, Rmag said:

The one nice thing about the GI 275 is you can get the PFD and HSI with reversionary and you don’t need anything else.  

What’s amazing is that can be your whole panel. It’s legal not just for attitude and hsi/dq and back up attitude but also all your pitot / static and your heads for vor/ ILS/gps. So your entire pilots side Ifr panel can be two gi-275’s

 

-Robert 

[PTK]

On 6/7/2020 at 4:43 PM, Rmag said:

The one nice thing about the GI 275 is you can get the PFD and HSI with reversionary and you don’t need anything else. 

Does the GI275 provide TAS and air data? I know the G5 (with the GAD13) was updated to provide wind speed and direction in the HSI and TAS in the pfd version. Does the 275? Thanks.

[RobertGary1]

1 hour ago, PTK said:

Does the GI275 provide TAS and air data? I know the G5 (with the GAD13) was updated to provide wind speed and direction in the HSI and TAS in the pfd version. Does the 275? Thanks.

Yes. Each unit has an Air Data Computer and either display will use either ADC. However, unlike the G-5 it is certified as a primary instrument so you could legally fly with your factory pitot static displays inop.

Also, if the pitot system fails the 275 has logic to provide GPS based IAS (I assume it uses GPS speed and takes out wind correction based on known wind conditions)?

Flying the HSI on the 275 is trivial. You just put the track diamond on top of the HSI arrow and you'll hit the runway numbers.

-Robert

[RobertGary1]

One thing that I'd like to see (and my dealer says he's heard it may happen) is for the GI-275 to share databases with Garmin navigators. Since I have mine set up as PFD/HSI I don't use the navigation, terrain , etc databases much in the GI-275 although its nice to have when the HSI is in MFD mode. But I don't see paying for the separate databases based on my use.  As a result I get a warning on start up that the databases are out of date.

 

-Robert

[PTK]

1 hour ago, RobertGary1 said:

Yes. Each unit has an Air Data Computer and either display will use either ADC.

I’m aware of the ADC in the units but was asking about displaying the info. The units configured as HSI or ADI cannot actually display TAS and wind speed/direction. This info can only be displayed on MFD configured units. This is a small limitation but a limitation nevertheless. 

[Rmag]

1 hour ago, PTK said:

I’m aware of the ADC in the units but was asking about displaying the info. The units configured as HSI or ADI cannot actually display TAS and wind speed/direction. This info can only be displayed on MFD configured units. This is a small limitation but a limitation nevertheless. 

I believe you are correct.  I have not flown with it in MFD config, but with ADI & HSI, there is no wind vector or TAS.

[Rmag]

2 hours ago, RobertGary1 said:

its nice to have when the HSI is in MFD mode.

So you have a GI 275 as a standby instrument configuration?

[RobertGary1]

Just now, Rmag said:

I believe you are correct.  I have not flown with it in MFD config, but with ADI & HSI, there is no wind vector or TAS.

You may be right. There is an extensive menu on the hsi when you select the map page. I though I saw it there but I also show that on my gnx 375 so maybe I saw it there. 
 

-Robert 

[RobertGary1]

Just now, Rmag said:

So you have a GI 275 as a standby instrument configuration?

I have one set up as attitude and one as hsi. The hsi one has three pages, map, hsi and attitude. It will auto switch to attitude if it loses connection to the top one. I also have a many failover switch external. 
 

-Robert 

[RobertGary1]

The map page on the hsi has a ton of info on it. But I find for approaches it gets distracting so I put it in hsi mode. 
 

-Robert 

[PTK]

3 hours ago, Rmag said:

I believe you are correct.  I have not flown with it in MFD config, but with ADI & HSI, there is no wind vector or TAS.

This info will not even be sent to a GTN if connected!  The GI275 will send this info to a D2 watch if bt connected to the watch.
Not sure what Garmin’s logic is here. If there's a good reason I’d love to know what it is! Surely they can display this info just as they do on the G5. 

[Rmag]

23 minutes ago, PTK said:

This info will not even be sent to a GTN if connected!  The GI275 will send this info to a D2 watch if bt connected to the watch.
Not sure what Garmin’s logic is here. If there's a good reason I’d love to know what it is! Surely they can display this info just as they do on the G5. 

The GI 275 does provide Baro corrected altitude sensor data to the GTN and will do VNAV.  I am pretty sure in the Utilities/"DALT / TAS / Winds page if you click "Use Sensor Data" it will provide the TAS and Wind direction and components.  My brother said he was flying it and when he went to that page it was all there and he "didn't have to do anything".

I will have to confirm myself...

I wouldn't be shocked if Garmin added this functionality to the GI 275s in a future firmware update.  Seems logical.

[bradp]

I’d be impressed if you could use a GI 275 as a stand-alone backup for G5’s - you could potentially get rid of ASI, VSI, alt etc. 

[RobertGary1]

5 hours ago, bradp said:

I’d be impressed if you could use a GI 275 as a stand-alone backup for G5’s - you could potentially get rid of ASI, VSI, alt etc. 

Yea you can. 

[RobertGary1]

5 hours ago, Rmag said:

The GI 275 does provide Baro corrected altitude sensor data to the GTN and will do VNAV.  I am pretty sure in the Utilities/"DALT / TAS / Winds page if you click "Use Sensor Data" it will provide the TAS and Wind direction and components.  My brother said he was flying it and when he went to that page it was all there and he "didn't have to do anything".

I will have to confirm myself...

I wouldn't be shocked if Garmin added this functionality to the GI 275s in a future firmware update.  Seems logical.

Yes I show wind on the gnx-375 which requires it to get air data from the 275. I also show ground speed. Never looked to see if tas was an option although I guess I don’t care about tas 
 

-Robert 

[RobertGary1]

Found another oddity. When flying an LPV approach my GNX375 sets the course in the GI-275 HSI. But when I select an ILS in the 375 it does not. So if you have the course set wrong on the HSI it points you in the wrong direction. My GNC-255A is driving the nav signal.

 

-Robert

[Ragsf15e]

On 6/15/2020 at 7:31 PM, RobertGary1 said:

Yes I show wind on the gnx-375 which requires it to get air data from the 275. I also show ground speed. Never looked to see if tas was an option although I guess I don’t care about tas 
 

-Robert 

You don’t care about TAS?!  You’re gonna be kicked off MS!  Where’s Anthony?  We need a moderator!

[Austin305Rocket]

On 6/15/2020 at 8:32 AM, PTK said:

Does the GI275 provide TAS and air data? I know the G5 (with the GAD13) was updated to provide wind speed and direction in the HSI and TAS in the pfd version. Does the 275? Thanks.

yes, with gdt 59 oat probe.  We installed 2 x 275s and we're able to replace the entire six pack.  We left the altimeter and airspeed indicator in just because... Side benefit is that we now get winds aloft info displayed on the map screen of the 430w.

We have a century 31 AP.  The 275s send attitude info to the AP where the g5s do not.

Edited June 21, 2020 by Austin305Rocket

[Rmag]

On 6/15/2020 at 4:55 PM, Rmag said:

The GI 275 does provide Baro corrected altitude sensor data to the GTN and will do VNAV.  I am pretty sure in the Utilities/"DALT / TAS / Winds page if you click "Use Sensor Data" it will provide the TAS and Wind direction and components.  My brother said he was flying it and when he went to that page it was all there and he "didn't have to do anything".

I will have to confirm myself...

I wouldn't be shocked if Garmin added this functionality to the GI 275s in a future firmware update.  Seems logical.

I confirmed it...

[Rmag]

On 6/5/2020 at 6:38 PM, flyboy0681 said:

When interfaced to an autopilot such as King KAP 150, can the I-275 drive an altitude preselect mode similar to the KAS 297?

 

No.

[carusoam]

Great follow-up Rmag!

Thanks for sharing the details...

Best regards,

-a-

[bradp]

On 6/19/2020 at 1:11 PM, RobertGary1 said:

Found another oddity. When flying an LPV approach my GNX375 sets the course in the GI-275 HSI. But when I select an ILS in the 375 it does not. So if you have the course set wrong on the HSI it points you in the wrong direction. My GNC-255A is driving the nav signal.

 

-Robert

I think what you’re referring to is the auto slew function.  For an LPV approach this is contained in the (presuming rs-232 or AIRINC) data stream to the GI-275.  For units like the 4xx/5xx there’s a menu item called ILS CDI CAPTURE that allows you to have the unit use GPS to navigate to a final ILS approach course, and then the box automatically switches to VLOC and sends the new course information to the HSI.  But this is for Nav/GPS boxes. You can see this here on a G5 display at 2:50  

 

 

For the GNC-255, there is no way for the unit to know what your desired course is without you entering it*. The GNC255 database includes names and frequencies but no other info.  The OBS resolver is usually connected from the pictorial display (CDI or HSI) to the navigator.  It’s user selectable ie you have to put in the information.  This can be done by resolver or serial information on the GNC 255.   

The gnc 375 allows you to Select a GPS overlay for an ILS for monitoring purposes only.  Anyway this would presumable be on NAV1 as the displayed data on the HSI and the GNC255 would be on NAV2 on the HSI or vice versa. So those data displays would be separate and not be taking to each other.  

Only garmin dealers have access to the GI 275 IM, but my guess is there is an AIRINC 429 from 255 to the 275. The 255 and 375 won’t be talking to each other, however.  

*with one caveat that it can accept RS-232 NMEA commands including obs selection. 

[SantosDumont]

Can a single unit replace a AI?  Thinking about getting rid of my vacuum AI when the pump dies and needs replacing.

[Ragsf15e]

9 minutes ago, SantosDumont said:

Can a single unit replace a AI?  Thinking about getting rid of my vacuum AI when the pump dies and needs replacing.

Yes.  Same as G5 can.  You lose the automatic backup of having a second one, but it does have battery backup.