GI 275 and KFC150 - attitude source?

[elimansour]

I have been seriously looking at the GI 275 as a replacement to my old mechanical gyros (ki256/kcs55a) and was impressed in reading the manuals and documentation. I especially liked that it would allegedly interface with and drive the KFC150 as a complete replacement to the ki256/kcs55a.  I am now getting conflicting information on the GI275 and how compatible it is with legacy autopilots such as the KFC150. Specifically, my avionics shop got stumped with the following notation from the install manual:

[3] An attitude source must be provided to the autopilot in order for it to function properly. The KVG 350 gyro or the KI 255/256 ADI may be retained, or the KG 258 ADI may replace the KI 256 ADI to provide attitude information to the autopilot system.

They initially thought that the GI 257 ADAHRS+AP would interface completely and Garmin’s own materials and online compatibility chart would suggest this - but the install manual suggests otherwise so they are investigating further.

A call to Garmin tech support did not resolve this as they are still getting up to speed on this so they escalated to engineering and told us to expect a call back.

If it ends up not being to be capable to provide attitude to the autopilot then this would be very disappointing.  Will update when we hear back from Garmin.

 

[carusoam]

Eli,

You May want to contact Trek @ Garmin...  he can be found hanging out at BT...

Best regards,

-a-

[elimansour]

19 minutes ago, carusoam said:

Eli,

You May want to contact Trek @ Garmin...  he can be found hanging out at BT...

Best regards,

-a-

Thank you.  I left a similar message there. 

[Aerodon]

41 minutes ago, elimansour said:

I have been seriously looking at the GI 275 as a replacement to my old mechanical gyros (ki256/kcs55a) and was impressed in reading the manuals and documentation. I especially liked that it would allegedly interface with and drive the KFC150 as a complete replacement to the ki256/kcs55a.  I am now getting conflicting information on the GI275 and how compatible it is with legacy autopilots such as the KFC150. Specifically, my avionics shop got stumped with the following notation from the install manual:

[3] An attitude source must be provided to the autopilot in order for it to function properly. The KVG 350 gyro or the KI 255/256 ADI may be retained, or the KG 258 ADI may replace the KI 256 ADI to provide attitude information to the autopilot system.

They initially thought that the GI 257 ADAHRS+AP would interface completely and Garmin’s own materials and online compatibility chart would suggest this - but the install manual suggests otherwise so they are investigating further.

A call to Garmin tech support did not resolve this as they are still getting up to speed on this so they escalated to engineering and told us to expect a call back.

If it ends up not being to be capable to provide attitude to the autopilot then this would be very disappointing.  Will update when we hear back from Garmin.

 

What revision install manual are you using, my shop doesn't see that in Rev 3.    Or maybe he is looking at the wrong page?

 

Aerodon 

 

[elimansour]

Just now, Aerodon said:

What revision install manual are you using, my shop doesn't see that in Rev 3.    Or maybe he is looking at the wrong page?

 

Aerodon 

I’m not sure what version they have - it would be great if this ends up not being true.  Funny thing is that the Garmin tech noted it as well and I was told was unsure.  Maybe there are different versions of the manual it being so new...will report back as soon as we get the definitive answer.

[carusoam]

Expect some wackiness as the product is new and Garmin will be updating the install manual frequently...

A similar challenge happened last year with one of their other products...

Best regards,

-a-

[PTK]

On 1/23/2020 at 11:09 PM, elimansour said:

I am now getting conflicting information on the GI275 and how compatible it is with legacy autopilots such as the KFC150.

You’re getting incomplete and therefore  erroneous information. On the contrary one GI275 ADI with autopilot interface and a one 275 HSI completely interface with the KFC150! Including attitude reference, baro correction, yaw rate, gpss, vnav profile, alt preselect, etc. If you get only the ADI unit it does require standby instruments and I think therein lies the confusion. If you get one ADI with autopilot interface and one HSI version, replacing the KI256 and KCS55A as the KFC150 requires, the HSI can also be configured reversionary back up ADI! It doesn’t get any better then that! It seems Garmin designed the GI275 with the KFC150 in mind! 

”GI 275 system redundancy is satisfied by using a GI 275 MFD or HSI that is configured as a standby instrument, or by using a dedicated GI 275 ADI. When configured as a standby instrument the GI 275 MFD and HSI include an ADI Page which is displayed automatically when faults are detected or when selected by the pilot. Both the GI 275 primary and standby ADIs have their own integral ADAHRS and internal batteries for independence and redundancy.”

 

http://static.garmin.com/pumac/gi275_autopilot_compatibility2.pdf

http://static.garmin.com/pumac/190-02246-12_01.pdf

[tmo]

So in Garmin's world a PDF that essentially is a customer-oriented summary of marketing materials on a product web site trumps installation manual? ;-)

[BorealOne]

Hmm. I’m hoping the marketers have the inside over the manual writers on this one. As soon as someone has a definitive word, please advise!

[PTK]

16 hours ago, BorealOne said:

Hmm. I’m hoping the marketers have the inside over the manual writers on this one. As soon as someone has a definitive word, please advise!

It has to do with standby instruments requirement. In a VFR only installation it does not require standby instruments and a single GI275 AI is all that’s needed.
An IFR installation of a single GI275 needs back up. This can be satisfied by retaining aircraft’s original vacuum ADI. Another way to satisfy this requirement is to install two connected GI 275’s with independent ADHARS and backup batteries for the primary and standby instruments. Please see my post above. 

[flyboy0681]

Will the GI 275 provide altitude pre-select for the KAP/KFC 150?

[BorealOne]

That’s my question. This isn’t about standby - I get that - it’s about attitude source for the KFC150. 

from the install manual:

[3] An attitude source must be provided to the autopilot in order for it to function properly. The KVG 350 gyro or the KI 255/256 ADI may be retained, or the KG 258 ADI may replace the KI 256 ADI to provide attitude information to the autopilot system.

[carusoam]

Let’s see if Mr. @Baker Avionics is around today... (discussion regarding new Garmin avionics, what works with what...)  specifically, use of new GI 275 for attitude information for old KFC150...

Best regards,

-a-

[elimansour]

I just heard back from my avionics shop and Garmin engineering confirmed that the GI 275 can provide the attitude information directly to the KFC 150 - no additional box is needed.  With this confirmation the GI 275 is a very compelling offering.

 I am considering replacing the KI256/ KCS55A and ripping out the vacuum system and going with either a 2 x GI 275 install  or an Aspen EFD1000 + EA100 + Sandia 340A backup install, in either case to interface and drive the KFC 150.

The Aspen presentation is nicer and it has more features but the required install of the sensor module near the tail will require a lot more work on the Installation and the interior to be removed to run the wire. The GI 275 will not require taking out the interior as the GPS antenna sits on (possibly under) the dash.  The Aspen installation cost + required backup make it a more expensive install - so lots to think about...

[BorealOne]

15 hours ago, elimansour said:

I just heard back from my avionics shop and Garmin engineering confirmed that the GI 275 can provide the attitude information directly to the KFC 150 - no additional box is needed.  With this confirmation the GI 275 is a very compelling offering.

I've already got an Aspen PFD, but have maintained the Ki256 to drive the KFC150 and as an independent standby AI. Having a solid-state GI275 with battery backup configured as a secondary AI appears to meet the independent standby requirement for the Aspen install, and having it capable of driving the KFC150 in the event of the Aspen failure gives me the extra redundancy that I've been looking for. I don't need heading, SV or any of the other stuff, so hopefully I don't have to pay for those unlocks to get the autopilot functionality. If that's the case, buh bye vaccuum...Will investigate...

Edited January 28, 2020 by BorealOne

[SocataDan]

 I have a KAP150 Autopilot which says it's supported, with the exception of FD.  

What exactly does Gyro Attitude support with GI275 mean? 

1. Attitude information for when a GS is present? For a full coupled approach? 

2. Altitude pre-select?

3. Vertical speed control? 

 

 

Edited March 8, 2020 by SocataDan

[Steve W]

2 hours ago, SocataDan said:

 I have a KAP150 Autopilot which says it's supported, with the exception of FD.  

What exactly does Gyro Attitude support with GI275 mean? 

1. Attitude information for when a GS is present? For a full coupled approach? 

2. Altitude pre-select?

3. Vertical speed control? 

It means that you can replace the vacuum powered spinny Attitude-Indicator gyro(For the KAP 150 this is the KG 258) in your panel with a GI275. The existing gyro provides electrical signals to the autopilot to tell it the attitude of the plane. This was not possible with the G5 or G3x, but could be done with the G500+adapter or Aspen+adapter.

It won't add any new features(except maybe GPSS) so if you don't already have a preselect unit, you still won't have that. Similarly nothing will go away, so if you can fly a glideslope today you'll continue to be able to fly a glideslope.

[LANCECASPER]

21 hours ago, SocataDan said:

 I have a KAP150 Autopilot which says it's supported, with the exception of FD.  

What exactly does Gyro Attitude support with GI275 mean? 

1. Attitude information for when a GS is present? For a full coupled approach? 

2. Altitude pre-select?

3. Vertical speed control? 

 

 

The KAP 150 doesn’t have a Flight Director, the KFC 150 does - that’s the difference between the KAP & KFC 150.

The vertical speed and pre-select is still controlled by your KAS-297 and gets the grey code baro corrected altitude from your KEA-103A encoding altimeter (or equivalent).

[Mark89114]

Can a G5 be a legal backup to the GI 275?

[Aerodon]

Here's my layout with 2 x GI275's.  Also Sandel 3308 for #2 nav - gets heading from GI275, so real easy install.  Also EDM900 replaces all engine instruments.

Also considering 1 GI275 and a G3x or G500TXi, going around in circles with the options.

 

Aerodon

 

 

[jlunseth]

On 1/26/2020 at 8:36 AM, PTK said:

It has to do with standby instruments requirement. In a VFR only installation it does not require standby instruments and a single GI275 AI is all that’s needed.
An IFR installation of a single GI275 needs back up. This can be satisfied by retaining aircraft’s original vacuum ADI. Another way to satisfy this requirement is to install two connected GI 275’s with independent ADHARS and backup batteries for the primary and standby instruments. Please see my post above. 

I am looking at a 275 as strictly a standby instrument for the AI to go in place of the Turn Coordinator.  Turns out there are many subspecies of 275's, and I am not talking about just, for example, the ADI version v. the ESI version.  You and your shop need to be careful about what instruments you are taking out, and whether the 275 is certified as primary for all the removed instruments.  In my case, a standby 275 could take the place of the Turn Coordinator according to AC 90-75, but the electric TC in my 231 includes a slid/skid (ball), and the 275 can only act as primary for the ball if you get the correct version of the 275 , and also install a GTP59 temp. probe ($500 for the part).  That probe is part of a kit of sensors used to drive the G3, there may be other parts of that kit that need to be installed for other installations where the 275 is going to act as primary for some instrument, I don't know, I just know what I need to do. 

One major difference between the G500TXi and the G3 is that with the exception of third-party autopilots, the G3 works almost entirely only with other Garmin devices while the G500 was designed to work with many third-party devices. The G3 works with a number of third-party AP's.

I may be more conservative than most, but I am not hot to replace the vacuum instruments in my 231 with all electric, the electric system is just not robust enough and a backup battery has limited value if you have to get down from the flight levels and then fly an approach in IMC.  My experience with backups is that they have an actual life that is about half that of the rated life when the time comes that you need it.

Edited March 16, 2020 by jlunseth

[louisut]

Another data point: we have a plane in the shop now getting its ADI and HSI replaced with dual GI 275s. One is the ADAHRS variant and the other is the ADAHRS+AP, which will be the primary attitude source for the Century 31 autopilot.

This was the main consideration over the G5. The GI should talk directly to the autopilot. The G5 could send heading data to the autopilot (via the GAD43), but could not act as the attitude source, and so we would have needed to keep the vacuum system--a non-starter. Replacing the working autopilot with the GFC-500 wasn't in the budget; it would have been about $35k for the dual G5 + GFC-500 vs $15k for the two GIs.

One GI will be configured as the primary ADI and the other an HSI and standby ADI. With the GTP 59 OAT probe, the ADI will also display a mark for standard rate turns. This means these two instruments will replace the steam ADI, HSI, airspeed, altitude, and turn coordinator. Pretty capable little instrument it seems.

Edited March 24, 2020 by louisut

[LANCECASPER]

7 hours ago, louisut said:

Another data point: we have a plane in the shop now getting its ADI and HSI replaced with dual GI 275s. One is the ADAHRS variant and the other is the ADAHRS+AP, which will be the primary attitude source for the Century 31 autopilot.

This was the main consideration over the G5. The GI should talk directly to the autopilot. The G5 could send heading data to the autopilot (via the GAD43), but could not act as the attitude source, and so we would have needed to keep the vacuum system--a non-starter. Replacing the working autopilot with the GFC-500 wasn't in the budget; it would have been about $35k for the dual G5 + GFC-500 vs $15k for the two GIs.

One GI will be configured as the primary ADI and the other an HSI and standby ADI. With the GTP 59 OAT probe, the ADI will also display a mark for standard rate turns. This means these two instruments will replace the steam ADI, HSI, airspeed, altitude, and turn coordinator. Pretty capable little instrument it seems.

I hope.

https://www.beechtalk.com/forums/viewtopic.php?f=21&t=179194

[OZMOONEYMAN]

On 1/24/2020 at 7:40 AM, PTK said:

You’re getting incomplete and therefore  erroneous information. On the contrary one GI275 ADI with autopilot interface and a one 275 HSI completely interface with the KFC150! Including attitude reference, baro correction, yaw rate, gpss, vnav profile, alt preselect, etc. If you get only the ADI unit it does require standby instruments and I think therein lies the confusion. If you get one ADI with autopilot interface and one HSI version, replacing the KI256 and KCS55A as the KFC150 requires, the HSI can also be configured reversionary back up ADI! It doesn’t get any better then that! It seems Garmin designed the GI275 with the KFC150 in mind! 

”GI 275 system redundancy is satisfied by using a GI 275 MFD or HSI that is configured as a standby instrument, or by using a dedicated GI 275 ADI. When configured as a standby instrument the GI 275 MFD and HSI include an ADI Page which is displayed automatically when faults are detected or when selected by the pilot. Both the GI 275 primary and standby ADIs have their own integral ADAHRS and internal batteries for independence and redundancy.”

 

http://static.garmin.com/pumac/gi275_autopilot_compatibility2.pdf

http://static.garmin.com/pumac/190-02246-12_01.pdf

Hi PTK,

Reading this thread.  Q) would the GI275 output altitude info to KFC150 autopilot to allow altitude capture / alt preselect ?  I assume G5 most will not.  Thanks

[carusoam]

@PTK Peter was around earlier today... (question for you above)

Best regards,

-a-