When HX (now HXr) is driving TT AP it constantly wing rocks
Posted: Sun May 19, 2019 12:21 pm
(This is a new summary post of a thread in the HX forum with new information added. It seems more appropriate under autopilot)
At some point in the first 1,000 hours on this installation of (3) HX systems, a G430w, and a TruTrak AP in an RV10 this wing rocking began. I don't recall this being a problem in the first 500 hours. It's a constant problem in calm air.
After 1,100 hours and an upgrade of (1) of the (3) HX systems to an HXr, the problem continues.
When the HX, or now the HXr, is driving the TT AP it constantly rocks the wings left and right. It seems to be hunting for the exact track and ends up deviating a degree or 2 left and right for the duration of the flilght in calm air. This occurs whenever the TT is in LS or NAV mode. To mitigate the problem, I allow the HX to get the AP on course and at the right altitude, then switch the AP into 'native mode' where it navigates using its internal guidance. The immediately stops the banking.
I've played with some of the HX settings (e.g. steering gain) but with no noticeable change in the problem.
Regarding the various modes:
There is 'full function 2 axis HX driven mode' where the TT AP displays "EXT LS GS". It is ARINC driven and it is full GPSS steering mode. A G430w supplies the GRT with the GPSS data.
There is 'steering-only mode' where the TT AP displayd "NAV". The HX is still driving it but only lateral steering and not GPSS steering mode. That is, it flies to and over waypoints rather than anticipaing them. I'm guessing that it is a serial feed.
In both of the above modes, I get the wing rocking.
There is 'TT native mode" where the AP flies whatever track and climb/descent rate I select. No wing wagging here.
I had to step away from this issue due to some other electrical issues but the problem persists despite a recent HXr upgrade.
There is one more data point to be considered: I have a switch that changes the ARINC input between the HX/HXr and direct input from the G430w. When connected to the HXr, the wing rocks. When getting the GPSS signal directly from the G430w, steady as a rock. Obviously in that mode I lose the vertical navigation function and the ability to control the Trutrak with the EFIS.
Next flight, I will document this behaviour with a video camera where it is very easily viewed. I can do a demo recording as well. The question is what else can I do to document my installation and the behavior?
- Is there a way to view or printout the settings from a backup file?
- How can I return all relevant settings to the defaults without effecting other settings?
And does anyone have a TruTrak - HX/HXr - G400/G500 installation where there is no wing rocking in GPSS mode? If so, can you share the settings.
Any and all advice welcomed.
1100 hours and flying...
At some point in the first 1,000 hours on this installation of (3) HX systems, a G430w, and a TruTrak AP in an RV10 this wing rocking began. I don't recall this being a problem in the first 500 hours. It's a constant problem in calm air.
After 1,100 hours and an upgrade of (1) of the (3) HX systems to an HXr, the problem continues.
When the HX, or now the HXr, is driving the TT AP it constantly rocks the wings left and right. It seems to be hunting for the exact track and ends up deviating a degree or 2 left and right for the duration of the flilght in calm air. This occurs whenever the TT is in LS or NAV mode. To mitigate the problem, I allow the HX to get the AP on course and at the right altitude, then switch the AP into 'native mode' where it navigates using its internal guidance. The immediately stops the banking.
I've played with some of the HX settings (e.g. steering gain) but with no noticeable change in the problem.
Regarding the various modes:
There is 'full function 2 axis HX driven mode' where the TT AP displays "EXT LS GS". It is ARINC driven and it is full GPSS steering mode. A G430w supplies the GRT with the GPSS data.
There is 'steering-only mode' where the TT AP displayd "NAV". The HX is still driving it but only lateral steering and not GPSS steering mode. That is, it flies to and over waypoints rather than anticipaing them. I'm guessing that it is a serial feed.
In both of the above modes, I get the wing rocking.
There is 'TT native mode" where the AP flies whatever track and climb/descent rate I select. No wing wagging here.
I had to step away from this issue due to some other electrical issues but the problem persists despite a recent HXr upgrade.
There is one more data point to be considered: I have a switch that changes the ARINC input between the HX/HXr and direct input from the G430w. When connected to the HXr, the wing rocks. When getting the GPSS signal directly from the G430w, steady as a rock. Obviously in that mode I lose the vertical navigation function and the ability to control the Trutrak with the EFIS.
Next flight, I will document this behaviour with a video camera where it is very easily viewed. I can do a demo recording as well. The question is what else can I do to document my installation and the behavior?
- Is there a way to view or printout the settings from a backup file?
- How can I return all relevant settings to the defaults without effecting other settings?
And does anyone have a TruTrak - HX/HXr - G400/G500 installation where there is no wing rocking in GPSS mode? If so, can you share the settings.
Any and all advice welcomed.
1100 hours and flying...