VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 11-20-2020, 08:51 AM
bill.hutchison bill.hutchison is offline
 
Join Date: May 2020
Location: Northern VA
Posts: 109
Default EFIS, A/P and GPS: who's driving?

I really have been searching on this...

In a scenario where one would have a Dynon EFIS (which doesn't seem to be compatible with a Trio EZ-Pilot) a Trio EZ-Pilot, and a certified IFR Navigator (Garmin or Avidyne)....

....which component is sending steering cues to the A/P when navigating/flying an approach? It seems the Trios ARE compatible with IFR navigators, but I'm trying to figure out where an EFIS would fit into the mix. Does the EFIS send commands to the GPS and it feeds the A/P?

Or will the GPS send steering to the AP and the EFIS simply displays everything happening? I know I'm not understanding all of this correctly.

Last edited by bill.hutchison : 11-20-2020 at 09:01 AM.
Reply With Quote
  #2  
Old 11-20-2020, 01:20 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 7,070
Default

It can be complicated.
I have a GRT HX, which does interface with a Trio Pro autopilot. There is a Garmin 420W. And an SL30 for vor/ILS. The data lines (one RS232, one ARINC A/B pair) from the Trio run thru a toggle switch, so they can be connected to either the 420W or the HX, but never both at the same time.
With the switch set to send the data directly from the 420W: the autopilot is controlled by its own controls. It can track a ground course heading, it can hold altitude, or climb/descend to altitude, with the altitudes entered into the Trio; it can track the gps info including a gps-LPV approach. All this with the Hx out of the loop, e.g., you can fly the plane without the efis. This is the advantage (and the duplication cost) of a stand-alone autopilot.
With the switch set for the Trio to get data from the efis: the autopilot can now do magnetic heading track (e.g., radar vector). It can now track a vor or ils (the efis will process that data and send it out in a format the Trio can read). It can still follow a gps ground track and follow a gps LPV approach (in the case of the Hx, it does some processing of the gps data, it is not a straight pass thru). Almost forgot, either mode will follow a hold or procedure turn if it’s in the gps database. For this the Hx must be in GNav mode, where the gps is controlling navigation.
Personally, I always control the Trio thru the Hx. Not only are there ‘extras’, like ILS or heading modes, I just find the interface easier to use. In fact, I need to go practice ‘stand alone’ operation. If you don’t exercise these skills they slowly fade away.
Reply With Quote
  #3  
Old 11-20-2020, 02:29 PM
MacCool's Avatar
MacCool MacCool is offline
 
Join Date: Aug 2020
Location: central Minnesota
Posts: 293
Default

I have an AFS EFIS, a TruTrak A/P, and a 430W. I have a little switch on the panel to change the input to the autopilot from either the EFIS or the 430W. I usually have it set to the EFIS so I can avail myself of the heading and altitude bugs. I've noodled around with flying a flight plan from the 430W, but I don't really need to fly coupled approaches, and I don't completely understand, yet, how to set those up.
Attached Thumbnails
Click image for larger version

Name:	IMG_8196.jpg
Views:	36
Size:	123.9 KB
ID:	4898  
Reply With Quote
  #4  
Old 11-20-2020, 03:00 PM
bill.hutchison bill.hutchison is offline
 
Join Date: May 2020
Location: Northern VA
Posts: 109
Default

I guess the real problem I'm trying to solve is to figure out if I go to an EFIS-based system with an IFR Navigator, can I keep my Trio EZ Pilot (and servos) or do I need to replace?

Like, I know a Dynon HDX can't use my Trio/Servos but I'm not sure that has to happen if I have the right GPS, and I'm still not understanding how all the interop works.
Reply With Quote
  #5  
Old 11-20-2020, 03:24 PM
Finley Atherton Finley Atherton is offline
 
Join Date: Nov 2005
Location: AUSTRALIA
Posts: 753
Default

Quote:
Originally Posted by bill.hutchison View Post
I really have been searching on this...

In a scenario where one would have a Dynon EFIS (which doesn't seem to be compatible with a Trio EZ-Pilot) a Trio EZ-Pilot, and a certified IFR Navigator (Garmin or Avidyne)....
You also mentioned approaches so you would need the Trio Pro Pilot with it’s ability to fly coupled approaches rather than the more basic Trio Ez-Pilot.

This is my experience with a Dynon SKyview, GTN 650 and Trio Pro Pilot combination.
For redundancy I have a switch to select GPS input to the autopilot from either the Skyview or the GTN. For normal operations including approaches the GTN is selected and flight plans/procedures are loaded on the GTN. The Skyview is along for the ride and simply displays (via the Skyview ARINC module) what the IFR GPS is telling the Pro Pilot to do. Note there is one exception to this: with the GTN in OBS mode the Course knob on the Skyview (via the ARINC module and GTN) will control the Pro Pilot.

Fin. 9A
Reply With Quote
  #6  
Old 11-20-2020, 04:00 PM
Finley Atherton Finley Atherton is offline
 
Join Date: Nov 2005
Location: AUSTRALIA
Posts: 753
Default

You could replace the Ez-Pilot with a Pro Pilot and keep the Trio servos. Might be more practical to go with the Skyview autopilot???

Fin 9A
Reply With Quote
  #7  
Old 11-20-2020, 04:04 PM
bill.hutchison bill.hutchison is offline
 
Join Date: May 2020
Location: Northern VA
Posts: 109
Default

Quote:
Originally Posted by Finley Atherton View Post
You could replace the Ez-Pilot with a Pro Pilot and keep the Trio servos. Might be more practical to go with the Skyview autopilot???

Fin 9A
Yeah, I'm thinking that as well, I just wanted to see if I could retain mine to cut down some of the cost.

I suppose I can sell to offset, though.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 12:48 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.