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pmillard
11-06-2019, 10:20 AM
Anyone successfully interfaced a TruTrak Vizion a/p with one of the new Garmin IFR navigators, e.g., GPS175, GNX375 or GNC355?

I recently spoke to the guys at TruTrak and they were not aware of anyone yet. The new navigators are not on their approved GPS list. But I?ve got to believe there are installs out there.

I?m hoping the new units output the same RS232 and AIRINC data as the 430 and 650 series. The TruTrak guy seemed to think so.

I?m ready to pull the trigger and order a 175 but want to make sure it?s compatible with my existing Vizion a/p. Can?t wait to fly those coupled LPV approaches!

wnplt
11-06-2019, 01:17 PM
I?m sure it will just use the standard ARINC A and B and the RS232 like a 430 or 650.

g3xpert
11-06-2019, 03:34 PM
Anyone successfully interfaced a TruTrak Vizion a/p with one of the new Garmin IFR navigators, e.g., GPS175, GNX375 or GNC355?

I recently spoke to the guys at TruTrak and they were not aware of anyone yet. The new navigators are not on their approved GPS list. But I?ve got to believe there are installs out there.

I?m hoping the new units output the same RS232 and AIRINC data as the 430 and 650 series. The TruTrak guy seemed to think so.

I?m ready to pull the trigger and order a 175 but want to make sure it?s compatible with my existing Vizion a/p. Can?t wait to fly those coupled LPV approaches!
Hello Peter,

We haven't tested this, but it appears that the Vizion 385 uses "Aviation Output 1" RS-232 format and "GAMA Format 1" low speed ARINC 429 format.

The Garmin GPS 175, GNC 355, and GNX 375 navigators all support these formats.

Let us know if we can help further.

Thanks,
Steve

pmillard
11-06-2019, 05:32 PM
Thanks Steve. That?s good to know.

As a Garmin tech can I ask you one more question? In the Procedures section of the GPS175 Pilot?s Guide under Feature Requirements it says that a ?baro-corrected altitude source? is recommended (which I don?t have) and therefore, altitude leg types require manual sequencing.

What does that mean?

Thanks...Peter

g3xpert
11-06-2019, 06:42 PM
Thanks Steve. That?s good to know.

As a Garmin tech can I ask you one more question? In the Procedures section of the GPS175 Pilot?s Guide under Feature Requirements it says that a ?baro-corrected altitude source? is recommended (which I don?t have) and therefore, altitude leg types require manual sequencing.

What does that mean?

Thanks...Peter
Hello Peter,

You are welcome.

The most common case where it is useful to have a baro corrected altitude source is for missed approaches such as KTOP RNAV (GPS) RWY 18.

The missed approach procedure is "Climb to 1500' then climbing right turn to 3600' direct GUKEC and hold".

When this missed approach procedure is flown with a GPS 175 receiving baro corrected altitude, all leg sequencing is continuous and automatic because the GPS 175 can "watch" you climb to 1500' and automatically transition to the right turn leg after you reach 1500'.

In the absence of this information, leg sequencing is suspended, and the pilot has to unsuspend to activate the right turn leg after the climb to 1500' is complete.

Thanks,
Steve

pmillard
11-07-2019, 07:12 AM
Understood. Thanks so much Steve. The 175 has been ordered!

Peter

pmillard
12-21-2019, 08:52 AM
Quick update. Got the GPS 175 installed and interfaced to the CDI and TruTrak a/p. Took it for a test flight and it works like a freaking dream! Makes beautiful curved intercepts and flys the RNAV LPV approach at my home airport like the plane was on rails. After the overshoot it navigates to the missed approach hold point and flys a perfect, wind corrected holding pattern. Totally cool!,,

Now I know this is old news for those flying the Garmin 430 and 650 navigators but it?s all new to me. I?ve got the RV grin but this time it?s the LPV grin!,

ALagonia
12-21-2019, 09:16 AM
I have the Vizion 385 connected to my Garmin 175 through an ARINC module communicating to my AFS 4500. It flies the LPV approach at my home and local airports like, as it has already been said, as if the airplane is on rails. It corrects for crosswinds in the hold and during the different legs of the approach perfectly.
I sync the altitude, as the Vizion 385 manual says to do before takeoff and the altitude captures are right on the money.

g3xpert
12-21-2019, 11:47 AM
Hello Peter and ALagonia,

Thanks for sharing your success stories on installing the GPS 175.

We expected these new 2" navigators to be very popular with homebuilts where size, weight and affordability are particularly important.

At a MAP price of $4,295 for the GPS 175, many no longer have to consider consider buying older used navigators to add unsurpassed IFR capabilites to their aircraft.

Thanks,
Steve

ALagonia
12-21-2019, 01:30 PM
After posting above about syncing the Vizion 385 to the altimeter prior to takeoff as per the Vizion manual I started questioning whether that was necessary if the autopilot is being commanded through an ARINC module and my AFS EFIS. So I went out today, just landed, and tried flying the airplane and shooting a coupled approach using the EFIS and the Garmin 175 without syncing the autopilot to the altimeter prior to takeoff. It appears that one does not need to sync the autopilot to the altimeter when using an ARINC module and controlling the autopilot with the EFIS.
One less step to make everything talk nice nice with each other.

stevehrv6a
12-21-2019, 05:12 PM
Quick update. Got the GPS 175 installed and interfaced to the CDI and TruTrak a/p. Took it for a test flight and it works like a freaking dream! Makes beautiful curved intercepts and flys the RNAV LPV approach at my home airport like the plane was on rails. After the overshoot it navigates to the missed approach hold point and flys a perfect, wind corrected holding pattern. Totally cool!,,

Now I know this is old news for those flying the Garmin 430 and 650 navigators but it?s all new to me. I?ve got the RV grin but this time it?s the LPV grin!,

Very happy to hear someone has done this and proven it works. I've actually been chasing this a little with Garmin & Trutrak and not had much success getting a solid answer. I'm trying to confirm (before I spend $7K) that I can hook a Garmin GPS175 directly to a Trutrak Vizion/Bendix King xCruze AP :rolleyes:
Could you please tell me if the AP you have is the Vizion (or is it one of the other Trutrak APs, like Gemini or Sorcerer?)?

I wasn't sure if other components were needed (like the Garmin GAD29 or a G5 or something along those lines, which I believe are all needed to hook a GPS175 to a Garmin GFC500 AP!). Seems hard to believe a direct connection between a Garmin product and a Trutrak/BK product is possible, when it's not even possible to do that while staying completely within the Garmin lineup? (i.e. GPF175->GAD29->G5->GFC500 ap)
Fingers crossed I'm understanding your post correctly, as it is a much simpler and less expensive setup! Thanks in advance... Steve

pmillard
12-24-2019, 02:52 PM
Hi Steve,

Yes, it's absolutely possible! I fly a C172 (not an RV) and installed a Vizion a/p last year and loved it. Interfaced it to my Aera 660 and it worked really well for VFR cross countries.

But I've always wanted to fly approaches since the Vizion is fully capable of doing that. However, the cost of a new 650 or even a used 430 was prohibitive so I held off until Garmin announced the GPS175 (and it's derivatives) earlier this year.

Ordered it last month from a local Garmin dealer. He made up the wiring harness and I did the install myself, under the supervision of my A&P (AME in Canada).

I found a good used GI106A for a CDI and that was all I needed. I followed Steve's advice and set up the 660 as a "repeater display" on a yoke mount.

The interface to the Vizion a/p was simple. One RS232 line and two AIRINC lines. That sends GPSS steering commands to the a/p which adds another whole level of capability to the aircraft.

As I said, it is freaking amazing. I go flying now just to watch it do it's thing.

My question to you...what are you waiting for?!!

Thanks...Peter

stevehrv6a
12-26-2019, 05:42 PM
Thanks so much Peter for the reply... I really appreciate it!
The BendixKings folks sent me an email just today saying I needed to install a GAD29 interface box for the 175 to talk to the AP. But I get the feeling from the responses I'm getting from both Trutrak & Garmin that the people answering my questions are not so confident of their answers.
If you have done this with a direct connection, then I guess it must work!! And that is the confirmation I was waiting for! :-)
I'm going to get the Vizion and the 175 and that's it... no G5 and no GAD29. That's a couple'a grand savings!
Thanks again for your help with this!!!
Steve

propizza
03-31-2020, 07:10 AM
Hello Peter,

You are welcome.

The most common case where it is useful to have a baro corrected altitude source is for missed approaches such as KTOP RNAV (GPS) RWY 18.

The missed approach procedure is "Climb to 1500' then climbing right turn to 3600' direct GUKEC and hold".

When this missed approach procedure is flown with a GPS 175 receiving baro corrected altitude, all leg sequencing is continuous and automatic because the GPS 175 can "watch" you climb to 1500' and automatically transition to the right turn leg after you reach 1500'.

In the absence of this information, leg sequencing is suspended, and the pilot has to unsuspend to activate the right turn leg after the climb to 1500' is complete.

Thanks,
Steve

Steve can you tell me where to source the baro corrected altitude. Not seeing any encoder connection in the harness diagram.

Canadian_JOY
03-31-2020, 09:57 PM
Thanks so much Peter for the reply... I really appreciate it!
The BendixKings folks sent me an email just today saying I needed to install a GAD29 interface box for the 175 to talk to the AP. But I get the feeling from the responses I'm getting from both Trutrak & Garmin that the people answering my questions are not so confident of their answers.
If you have done this with a direct connection, then I guess it must work!! And that is the confirmation I was waiting for! :-)
I'm going to get the Vizion and the 175 and that's it... no G5 and no GAD29. That's a couple'a grand savings!
Thanks again for your help with this!!!
Steve

No GAD29 required... The 175 outputs the necessary RS232 and ARINC429 signals which can be connected directly to their corresponding inputs on the Vizion 385 autopilot. For those of us with something like a GRT or similar EFIS system, we install a switch that allows us to feed ARINC429 to the autopilot from either the navigator or the EFIS.

Ya, flying coupled approaches is kinda cool.

uk_figs
06-01-2020, 12:31 PM
It looks like the connections for the Vision and the Gemini are the same which suggests the Gemini would work with the 175/371 also which appears to be the easiest way for me to add vertical guidance without ripping out my entire panel.

Next question then is whether the 175/375 arinc 429 can be daisy chained to drive my D100 HSI/CDI via the HS34 control panel as well as the Gemini AP.

The 375 could also replace my GTX 327, GDL 82, and GDL 39 for a clean upgrade. Could maybe even reuse the 327 antenna and the GDL 82 GPS puck so I would only have to install the ADSB In antenna.

Moving the 327, 82, and 39 to my Champ project for ADSB would save a couple of grand so the net upgrade if this all worked would be around $5K additional cost, not too shabby:cool:

It also appears that I can leave my 796 rs232 connected to the Gemini for quick DirectTo control and the autopilot will ignore the 232 input if a 429 input is present (i.e. the 175 overrules the 796). More to study but looking promising.

BobTurner
06-01-2020, 04:30 PM
One less step to make everything talk nice nice with each other.

I presume you have an autopilot source switch, to switch between your GPS and the EFIS? I have a Trio Pro and GRT EFIS, but I think they both work the same way: The (only) reason to sync the autopilot altitude to the altimeter is in case the EFIS fails, and you want to throw that switch and fly the autopilot directly off the GPS. If you didn?t set the autopilot?s altimeter prior to takeoff, it will now fly at the wrong altitude. So, just in case, I would continue to sync the autopilot?s altitude to the altimeter prior to takeoff, just in case...

BobTurner
06-01-2020, 04:41 PM
Steve can you tell me where to source the baro corrected altitude. Not seeing any encoder connection in the harness diagram.

?Baro corrected altitude? means what your altimeter, with a proper barometer (Kollsman window) setting, reads. That?s what you?re expected to fly if ATC or a procedure says ?maintain 5000?. The encoder is for the transponder and ADSB, and sends pressure altitude. Your EFIS should have an RS232 output format that includes baro corrected altitude. That?s what you?re looking for. You need to find a format that includes this data, and both boxes understand.

Acenels
07-04-2020, 11:25 PM
No GAD29 required... The 175 outputs the necessary RS232 and ARINC429 signals which can be connected directly to their corresponding inputs on the Vizion 385 autopilot. For those of us with something like a GRT or similar EFIS system, we install a switch that allows us to feed ARINC429 to the autopilot from either the navigator or the EFIS.

Ya, flying coupled approaches is kinda cool.

Maybe a silly question, but what?s the advantage of having both options? Does one have functionality the other doesn?t?

catmandu
07-05-2020, 06:47 AM
Maybe a silly question, but what?s the advantage of having both options? Does one have functionality the other doesn?t?

If my GRT box lets the smoke out, I move the autopilot control switch from EFIS to GPS and I will still have lateral commands sent to the autopilot, particularly nice if I have to fly an approach using my backup instruments.

ALagonia
07-05-2020, 07:35 AM
I presume you have an autopilot source switch, to switch between your GPS and the EFIS? I have a Trio Pro and GRT EFIS, but I think they both work the same way: The (only) reason to sync the autopilot altitude to the altimeter is in case the EFIS fails, and you want to throw that switch and fly the autopilot directly off the GPS. If you didn?t set the autopilot?s altimeter prior to takeoff, it will now fly at the wrong altitude. So, just in case, I would continue to sync the autopilot?s altitude to the altimeter prior to takeoff, just in case...

Yes I have an autopilot source switch. And I came to the same conclusion about syncing the autopilot altitude to the altimeter.

Acenels
07-06-2020, 09:26 PM
If my GRT box lets the smoke out, I move the autopilot control switch from EFIS to GPS and I will still have lateral commands sent to the autopilot, particularly nice if I have to fly an approach using my backup instruments.

Ahhh?gotchya. Thanks. May be hard to see with the tears that smoke causes. Not from the smoke itself, but sadness from the box failing and thinking about the replacement 🤣

Canadian_JOY
07-07-2020, 08:00 AM
If my GRT box lets the smoke out, I move the autopilot control switch from EFIS to GPS and I will still have lateral commands sent to the autopilot, particularly nice if I have to fly an approach using my backup instruments.

Ummm just a refinement of this response... Both lateral and vertical commands can be sent to the a/p. The switch acts as a source selector for that lat/vert data - either getting it directly from the GPS navigator, or from the EFIS.

The EFIS (in my case it's GRT equipment) is capable of providing navigation functionality very much like that of a GPS navigator, including to places like a waypoint defined by the pilot (think flying into your back yard airstrip). The EFIS provides additional refinements that the autopilot can use, refinements like setting a specified climb speed rather than a climb rate. (In our installation, when coupled directly to the GPS navigator, the Vizion 385 only supports the setting of climb and descent rates.)

The source selector switch is a handy tool to have. I leave mine set in "GPS" most of the time since it provides most of the functionality that I need while preserving a simple user interface. I have flown with both lateral and vertical guidance into a private airstrip that is not featured in the GPS navigator's nav database, using the EFIS to provide guidance. Works like a charm (but one has to understand this is not an approved, surveyed approach with guaranteed obstruction/obstacle clearance, especially in the vertical guidance.)