Autopilot Issue

[Ch.Cole]

Hi, I've got the following issue:

When I want do decend from ALT, I turn in the next alt and hit ARM.
I then push the DN button for my desired vertical speed, and the plane starts decending, but the annunciated mode is still ALT.
Shouldn't it say VS?

Cheers,

Chris

[Coop]

14 hours ago, Ch.Cole said:

Hi, I've got the following issue:

When I want do decend from ALT, I turn in the next alt and hit ARM.
I then push the DN button for my desired vertical speed, and the plane starts decending, but the annunciated mode is still ALT.
Shouldn't it say VS?

Cheers,

Chris

Clicking the "VS" button after setting the VS desired should enter VS mode.

[Ch.Cole]

6 hours ago, Coop said:

Clicking the "VS" button after setting the VS desired should enter VS mode.

Sorry, I think I didn't write the the issue clearly enough. The mode itself does change after I hit DN (the aircraft decends), but the mode annunciation is still ALT. So actual mode and annunciated mode do not match.

Setting the VS automatically enters VS mode without changing the mode annunciation.

[Coop]

42 minutes ago, Ch.Cole said:

Sorry, I think I didn't write the the issue clearly enough. The mode itself does change after I hit DN (the aircraft decends), but the mode annunciation is still ALT. So actual mode and annunciated mode do not match.

Setting the VS automatically enters VS mode without changing the mode annunciation.

I did some testing to see if I could replicate. It seems that X-Plane decides to enter some sort of a semi-pitch change mode when those buttons are hit, but without adjusting the autopilot status datarefs (so we have no way to know!) I will gather some more data and file a bug with LR on this. 

[Ch.Cole]

@Coop Thanks for the feedback!

I noticed that the dataref sim/aircraft/autopilot/preconfigured_ap_type is 6, which is "KAP-140 dual axis". Shouldn't it be 7 (KAP-140 dual axis with altitude preselect)

from https://developer.x-plane.com/datarefs/ :
0=X-Plane custom, 1=Airliner, 2=GFC-700, 3=S-Tec 55, 4=S-Tec 55 with altitude preselect, 5=KAP-140 single axis, 6=KAP-140 dual axis, 7=KAP-140 dual axis with altitude preselect, 8=Piper Autocontrol, 9=Rockwell/Collins FCS-65

Although I'm not sure how that would be the problem at hand.

Additionally, researching the KFC 225, I noticed that the VS and ARM buttons have switched places. (see https://www.bendixking.com/en/~/media/bendixking/files/006-18035-0000_1-kfc-225-ki-525a-pilot-s-guide.pdf for example )

From the above mentioned guide, I also found that UP/DN doesn't actually change the altitude mode

Quote

If ALT mode is active, successive button presses will move the altitude hold reference altitude either up or down by 20 feet per press, or if held continuously will command the airplane up or down at the rate of 500 ft/min, synchronizing the altitude hold reference to the actual airplane altitude upon button release. (Note that neither the pitch attitude nor the altitude hold reference is displayed. The display will continue to show the altitude alerter reference.)

 

[Coop]

We will see what we can do. The non-preselect mode is because the "Arm" button needs to be manually selected, where the KAP-140 with altitude preselect will always arm the AP.