FSX KEY_AP_PANEL_HEADING_HOLD vs KEY_AP_HDG_HOLD

#1
KEY_AP_PANEL_HEADING_HOLD is described as: Toggles heading hold mode on/off
and
KEY_AP_HDG_HOLD is described as: Toggles heading hold mode

I assume there is some subtle difference between how these these two events are used, but I don't understand what that is. I would appreciate is someone could explain what the difference is.

I have a similar question regarding KEY_AP_PANEL_ALTITUDE_HOLD and KEY_AP_ALT_HOLD which again appear to me as having essentially the same description.

Thanks,
Al
 

rcbarend

Resource contributor
#2
KEY_AP_PANEL_HEADING_HOLD is described as: Toggles heading hold mode on/off
and
KEY_AP_HDG_HOLD is described as: Toggles heading hold mode

I assume there is some subtle difference between how these these two events are used, but I don't understand what that is. I would appreciate is someone could explain what the difference is.

I have a similar question regarding KEY_AP_PANEL_ALTITUDE_HOLD and KEY_AP_ALT_HOLD which again appear to me as having essentially the same description.

Thanks,
Al
When OFF, the *_PANEL*_ events sets the HOLD function ON, using the current values in the Heading/Altitude selectors.
So they hold the values previously set/dialled into the Heading/Altitude selectors.

The other two events, when OFF, implicitely sets the Heading/Altitude selectors to the CURRENT Heading/Altitude and then sets the Hold ON.
So these hold the current Heading/Altitude.

For Airspeed/Mach Hold; the same.

Rob
 
#3
Rob, thanks very much for the help; I think I understand it now.

Generally speaking, the word 'panel' is used to imply there is some kind of selector involved (supposedly panel mounted), such as a speed selector or heading bug, that has been preset to a value. So, for example, if the intent is to capture and hold the current a/c heading, KEY_AP_HDG_HOLD would be used. On the other hand, if the intent is to capture and hold a previously set heading bug value, then KEY_AP_PANEL_HEADING_HOLD would be used.

Al
 
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#6
There may be a misunderstanding here. I never use the AP_PANEL_HEADING_HOLD which i am sure this toggles the mode but does not capture. I use the AP_HDG_HOLD and this one toggles the mode and captures.;) Both capture the bug not the current heading. And if you want something to hold the aircraft's current heading you have to write code that sets the bug to the aircraft's current heading.
 
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#7
There may be a misunderstanding here. I never use the AP_PANEL_HEADING_HOLD which i am sure this toggles the mode but does not capture. I use the AP_HDG_HOLD and this one toggles the mode and captures.;) Both capture the bug not the current heading.
That is true..and here is where things gets messy with the current SDK. I really hope we wont see these things back again in whatever new SDK FS2020 might give us..
 
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