GRT HXr autopilot and the GPS approach: Need button-pushing help

[BobTurner]

Originally Posted by BobTurner

While inbound for the approach, have LNAV set to GNAV (so it will do turn anticipation). Once on final, the HXr will automatically switch to ENAV. If you push "missed" it will go back to GNAV.
I have the newest software and that's how mine works. Arm the approach anytime, it switches when on final.

Edit: I should go check wrt the holding pattern behavior, I fly so few, you may be right there. It must be in GNAV to do the holding pattern, as you say.

Okay, I went out and checked. (Why is this easier when flying than when typing?)
My setup: HX with V6 software (latest), G420W, Trio Pro with GPSS/GPSV, but I suspect HXr and HS and other GPSS autopilots will all be the same.

Starting Point: G420W has an LPV gps approach loaded and activated. GRT has the 420 gps selected as the nav source.
Case 1: If using the gps to navigate along a NoPT route to final, set GRT to GNAV; Set "GPSV Arm" anytime, before or after final course intercept. GRT goes from GNAV to ENAV at intercept if set before, otherwise when you select ARM. (Set it before glide slope intercept or the autopilot will dive the airplane to try to catch it!)
Case 2: If being vectored to final, set GRT autopilot control to "Heading". Use heading bug to set in vectors. Select "GPSV ARM" PRIOR to final course intercept. GRT will automatically go from Heading to Enav at intercept
Case 3: If using gps to navigate to a holding pattern course reversal: Select "GNAV" on GRT. Do NOT select "GPSV ARM" until inbound for the approach. If you need more than the course reversal, e.g., you need to actually hold, do not select ARM until inbound the last time (and you will need to push OBS on the 420W to keep it from sequencing during the hold).

[Bavafa]

Originally Posted by BobTurner

Okay, I went out and checked. (Why is this easier when flying than when typing?)
My setup: HX with V6 software (latest), G420W, Trio Pro with GPSS/GPSV, but I suspect HXr and HS and other GPSS autopilots will all be the same.

Starting Point: G420W has an LPV gps approach loaded and activated. GRT has the 420 gps selected as the nav source.
Case 1: If using the gps to navigate along a NoPT route to final, set GRT to GNAV; Set "GPSV Arm" anytime, before or after final course intercept. GRT goes from GNAV to ENAV at intercept if set before, otherwise when you select ARM. (Set it before glide slope intercept or the autopilot will dive the airplane to try to catch it!)
Case 2: If being vectored to final, set GRT autopilot control to "Heading". Use heading bug to set in vectors. Select "GPSV ARM" PRIOR to final course intercept. GRT will automatically go from Heading to Enav at intercept
Case 3: If using gps to navigate to a holding pattern course reversal: Select "GNAV" on GRT. Do NOT select "GPSV ARM" until inbound for the approach. If you need more than the course reversal, e.g., you need to actually hold, do not select ARM until inbound the last time (and you will need to push OBS on the 420W to keep it from sequencing during the hold).

Bob,
You are correct on all three scenarios and the case #2 will also apply for ILS approaches which are far more likely to be vectored than a typical GPS approach. This method makes flying ILS approach easier than a-walk-in-the-park. What I have learned, NOT to arm it until you have been cleared for the approach. There has been times that I have vectored cross the localizer and if you arm it too soon, the system will sees that an intercept and will try to follow the course.

On other notes, thanks for sharing that the new SW version has been released. Do you know what or how much would be the subscription for the IFR charts and plates?
Looks like one of the new features in the new version is ?Add georeferenced plates, diagrams, sectionals, enroute low, and enroute high charts?

[RV8iator]

On the HXr I always ARM all the modes well before flying the approach and then push EXECUTE once cleared for the approach and inside the normal intercept parameters. This way, I'm briefed and setup early on the terminal phase and usually before top of descent.

Are you guys using the EXECUTE function?

[BobTurner]

Originally Posted by RV8iator

On the HXr I always ARM all the modes well before flying the approach and then push EXECUTE once cleared for the approach and inside the normal intercept parameters. This way, I'm briefed and setup early on the terminal phase and usually before top of descent.

Are you guys using the EXECUTE function?

That sounds like the way to go. Since this is a relatively new feature I had been pushing it as soon as I armed, out of fear I would forget! Not sure how, with it right in front of you. Latest software lets you turn it on or off.

Charts will come from Seattle Avionics. i can only guess that they will set the price.

[Radomir]

Bob, thanks for testing it out.. I guess the behavior is still the same.. I first remember running into it 2+ years ago and have reported it to GRT back then, but I guess no changes have been made... Technically that's fine, but just something to be aware of (so it doesnt' catch you by surprise when you least need surprises )

[BobTurner]

I think I'll adopt Jerry's method of setting it up early, but holding off of the execute button until just before intercept.

[Bavafa]

Originally Posted by BobTurner

I think I'll adopt Jerry's method of setting it up early, but holding off of the execute button until just before intercept.

This is how I have been doing it since the change was made. It is really great to stay ahead of the game and only one push instead of going thru the menu.