I love flying the CubCrafter XCub with the WT x-v0.1.0 dev5 mod - the autopilot and navigation seems to work better than any other GA aircraft I've flown.

However, today on my approach to KFHR (Friday Harbor, San Juan Island, Washington State, USA) RWY 34 it performed several tricks I've not seen before and do not understand.  I have the Garmin G3X manual and study it at times but I cannot find this stuff yet.

I had not loaded or activated a Flight Plan but there was an "old" flight plan in the G3X from a prior flight.  I did not activate it and had the G3X set to a Direct To KFHR from KBLI where I took off on RWY 16.  

Enroute I changed the D-> to DFUCA, which is a waypoint in the RNAV(GPS) RWY 34 approach to KFHR.  I had setup the HDG bug to the runway heading of 341° and when I approached DFUCA, at 2000',  I changed the AP control from NAV to HDG.  The plane then rolled onto the 341 heading.

NOTE: Jeppesen shows a RNAV(GPS) RWY 34 approach for KFHR but there is no such approach in the G3X, G1000, or G3000 databases.  I am current with Navigraph and AIRC. 

As I approached KFHR with VS set to -400fpm with a target Altitude of 0' and still on HDG - the autopilot suddenly switched to V ALT GP, which really confused me because there is NO ILS at KFHR and I was using HDG not NAV as the AP input and I had no active procedure  But, the AP suddenly stopped descending and flew over RWY 34 at 1000' still showing a VS of -400fpm.

I then changed to NAV mode with DFUCA as the waypoint and 2,000' as the altitude target.  The AP did as told.  

But, when I was 0.5 NM from DFUCA the G3X changed the Waypoint to USER and send me flying off to the SE and a waypoint 6 NM away.  

Again, I changed the waypoint back to DFUCA @ 2,000'.  As I flew thru DFUCA on the RWY 34 heading with target altitude of 0' and a VS of -400fpm everything seemed OK.  But once past MUNVE at 720', the last waypoint in the RNAV approach, which was NOT activated and there was NO active Flight Plan, the AP again switched to V ALT GP and refused to descend.

I switched off the AP and landed OK.

How is the G3X deciding to use a procedure when I have not activated one and there is NO such procedure shown in the G3X?

I cannot find any way to DELETE the "old" flight plan.  The G3X manual describes the procedure but it uses the G3X joystick to select options, such as individual or all flight plans, and I cannot find a joystick on the G3X as implemented in the XCub.  How do I delete a flight plan in the XCub?

Edited February 3, 20215 yr by TacomaSailor

The Asobo Garmins in the sim are like some ACME Wiley Coyote clones, with the Garmin name stuck on them.  

Working Title has made some big improvements but there is still a ton missing.

So I have found real world videos very hit or miss. 

Also there was a Garmin G3X (non-touch) and then a G3X Touch which don't operate the same way.

It sounds like you got the AP confused somehow, which is not really surprising unfortunately.

I think GP is Glide Path, used for RNAV, as opposed to GS, Glide Slope, used with ILS, so it sounds like the RNAV(GPS) approach was somehow activated. That approach is in Navigraph, so it must be picking it up from there. The ISLND waypoint, SE of the airport is in the missed approach procedure. If that's the waypoint you mentioned maybe it was flying a missed approach.

None of the existing Garmin Gxxx units work reliably...even with the WT mods.  WT created a new flight plan system for their Pro Line 21 in tht CJ.  This would have to be done for all the Garmin units to make them functional.