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  #1  
Old 11-07-2018, 06:22 AM
Ezburton Ezburton is offline
 
Join Date: May 2017
Location: MD
Posts: 39
Default G3X Pathways

I installed a dual G3X Touch in my plane recently and finally got around to entering a flight plan and letting the autopilot fly the route in Nav & Alt Hold modes. This is the first time I have seen the Pathway boxes appear on the PFD. It was about a 30 kt crosswind at 3500' and I was surprised to see that the Pathway Boxes were significantly skewed to the left side of the display, with the velocity vector going through them and the HSI centered.

I was expecting that I would see the boxes in the center of the display since I was on course albeit with a significant crab angle. If the wind had been higher, I wouldn't have seen the Pathways at all. Seems strange if I were IFR. Is there a setting which changes this or comments about the use of or experience with Pathways?

Thanks,
Don
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  #2  
Old 11-07-2018, 07:50 AM
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g3xpert g3xpert is offline
 
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Quote:
Originally Posted by Ezburton View Post
I installed a dual G3X Touch in my plane recently and finally got around to entering a flight plan and letting the autopilot fly the route in Nav & Alt Hold modes. This is the first time I have seen the Pathway boxes appear on the PFD. It was about a 30 kt crosswind at 3500' and I was surprised to see that the Pathway Boxes were significantly skewed to the left side of the display, with the velocity vector going through them and the HSI centered.

I was expecting that I would see the boxes in the center of the display since I was on course albeit with a significant crab angle. If the wind had been higher, I wouldn't have seen the Pathways at all. Seems strange if I were IFR. Is there a setting which changes this or comments about the use of or experience with Pathways?

Thanks,
Don
Hello Don,

Don't forget that synthetic vision is heading based (aligned with the nose of the aircraft) since it is meant to give you the same picture that you see out the front window of the aircraft.

When you are flying with a crosswind, the nose of the aircraft can be significantly misaligned with the flight path marker which is showing you "where the aircraft is going".

Since the track of the aircraft is aligned with the course line, not the nose of the aircraft, you will frequently see the flight path marker and pathway boxes (if you use them) off the center of the display when the CDI is centered.

Let us know if you have additional questions.

Thanks,
Steve
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  #3  
Old 11-07-2018, 11:20 AM
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Dbro172 Dbro172 is offline
 
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Default Another Question

I see the pathways when I use "direct to" navigation and also during the "approach" but I do not see the pathways while on a leg of a flightplan. Is that right?
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  #4  
Old 11-07-2018, 06:13 PM
Ezburton Ezburton is offline
 
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Location: MD
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I have a GTN650 with the flight plan loaded. I also have the AP Panel which I used to set the target altitude. After takeoff when I turned toward the first leg of the flight plan, I noticed the Pathway boxes sitting up at altitude (and when I change target altitude, they immediately move with the changing knob... they don't wait until I command the VS or IAS climb mode).

I connected the AP and it flew right to them (once I put in a VS at which to climb). In the (somewhat acute) corners the boxes disappeared due to the rounding of the corner, then came back into view as the turn completed and the second leg became active.

Thanks G3Xpert.... That's what I understood. The flight director was spot on in front of me as it should have been. I guess I hadn't thought that the Pathways were heading based and not track based. I was wondering if they were slaved to the DG, which I think has two different settings.

Don
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  #5  
Old 11-07-2018, 06:48 PM
Scott Hersha Scott Hersha is offline
 
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Location: Cincinnati, OH
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Remember, the G3X/latest Garmin EFIS info is a ‘path’ based flight display. The boxes (active route) indicate your path. Where the nose is pointed is indicated by the circle with the bulls eye in it - both laterally and vertically. If you takeoff when there’s a substantial crosswind, the bulls eye (heading) will be straight ahead, but after takeoff when you climb into a crosswind and correct your heading to maintain track, the flight path indicator will slew to the downwind side of your heading whenever you are using an active route. The flight path (boxes) indicate where you are going, not where your nose is pointed. When you don’t have a route programmed, the heading/bulls eye will still show crab angle between heading and track based on GPS track information.
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  #6  
Old 11-08-2018, 07:27 AM
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kbalch kbalch is offline
 
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So, simply put, flight path (as presented by the G3X) equals ground track? Such that they'll only coincide in a no-wind condition?
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  #7  
Old 11-08-2018, 02:04 PM
Ezburton Ezburton is offline
 
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Correct. Its the desired track.

The green pip is your velocity vector and should be going through the center of the windows. Following the flight director should keep you on the ground track and at the selected altitude.

I need to go out and play with this again.
db
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  #8  
Old 11-09-2018, 07:04 AM
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Walt Walt is offline
 
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For me, I prefer flying with the flight director only, all the other 'toys' are turned off.
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  #9  
Old 11-09-2018, 07:36 AM
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AlexPeterson AlexPeterson is offline
 
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A 430w drives my G3X Touch. What I observe is that the Garmin autopilot will only settle in with the airplane in the center of the HITS boxes when the ball is centered (coordinated flight), when the navigation was driven by the 430w. This is unrelated to winds aloft. I can choose which side of the boxes by simply holding in a little rudder (it takes a moment for the a/p to settle into an offset). Hold in enough rudder and the boxes will almost disappear off to the side. If the ball is slightly off center, it will move the boxes noticeably. Half ball will put the plane outside the boxes.

However, if the navigation is driven by the G3X, the autopilot will always settle in with the center the plane in the boxes regardless of the lack of coordination.

I corresponded with the Garmin G3X guys about this. The explanation was that the course information from the 430w is more sensitive than the G3X's internal one. I cannot imagine how this would cause the observed behavior. Somehow the G3X's algorithms are coupling the degree of un-coordination into the track information, which makes no sense to me.

I don't fly IFR, so for me it was a curiosity. I don't display the boxes anymore.
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  #10  
Old 11-09-2018, 09:00 AM
Robert Anglin Robert Anglin is offline
 
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Location: houston, texas
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Default OK

I kind of do what Walt has said. Every now and then when the weather is good and bumpy, with a strong cross wind, if we are on a cross country I will turn off the AP and only hand fly with the flight director up and running. It will challenge you to be a better pilot trying to stay on track and not get to over worked. I think flying in the green is a good idea, so I don't get too dependent on all the easy automation. We don't have Sim's for our RV's so I have to train as I go kind of thing. 2 pennies worth, Yours, R.E.A. III # 80888
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