ROL mode defect G3X Touch

[Cactus Charlie]

Two months after I submitted my report Garmin has acknowledged that there is a defect in AFCS ROL mode in G3X Touch experimental software ver 9.52.

AP should hold the roll attitude that existed at mode engagement but, instead, it always rolls wings level. See Pilot Guide "ROLL HOLD MODE (ROL)" for intended operation.

There is currently no scheduled release date for a fix.

 

[ve6yeq]

When I use the AFCS, I generally use NAV + ALT (from a flight plan), TRK + ALT (without a flight plan but following a coastline, etc.), or HDG + ALT (for ATC re-routes), and very rarely the blue LVL key if I get behind ATC too far and forget "A" "N" "C". I have tried VS (descents) and IAS (climbs), but since I normally cruise below 3000 ft AGL, I just climb and descend by hand or manually adjust the ALT hold level. As I have a GNC 355, not a GTN 650, VNAV is only for approaches, not en route, so I see much use for it VFR.

I am not sure that I have ever attempted to use ROL + PIT modes. Why would someone use ROL + PIT modes? A steep turn?

 

[Cactus Charlie]

ROL and PIT are the basic AFCS modes. They become active on AP engagement and remain active until another mode is selected.

I used to use ROL mode to hold a constant bank angle for air to ground photography. It no longer works.

ROL mode cannot be used for a steep turn because, if it worked as described, it is limited to max 20 deg roll.

It doesn't really matter what ROL is used for. The defect is that it does not work as described in the pilot guide.

 

[ve6yeq]

Do you know if it is possible to get the AFCS functionality to fall back from the G3X Touch PFD to the G5 BFD without completely powering off the G3X Touch display? From what I can read, the G5 should be able to manage the AFCS, but the fallback will require manual re-engagement.

 

[Cactus Charlie]

Do you know if it is possible to get the AFCS functionality to fall back from the G3X Touch PFD to the G5 BFD without completely powering off the G3X Touch display? From what I can read, the G5 should be able to manage the AFCS, but the fallback will require manual re-engagement.

I'm not clear what configuration you area asking about. If G5 is configured as a backup instrument then changes made on the G5 will drive the same changes on the GDU. They cannot have independent settings. E.g. I use G5 knob to adjust baro setting for both G5 and PFD. Similarly a HDG bug slew on G5 will drive the PFD beading bug.

I have verified that AP remains available with PFD CB pulled but I saw some anomalies when PFD CB was restored. I wrote up a procedure to investigate this but have not run it.

My notes from that PFD CB test say - "Ground test showed AP engages and follows G5 heading bug with GDU CB pulled. AP showed failed after GDU CB restored. Was AP still engaged when GDU CB pushed? Cycling Servo CB switch did not force PFT. Had to kill MAIN and IBBS while engine running to restore normal operation. Needs data review."

(for "GDU CB" read "PFD CB")