Autopilot disconnect sound in 1.024
I have been flying this wonderful aircraft since I first purchased the PILOT Editon for FSX back in January 2015. I am now flying the PRO Edition in P3Dv4.5.
I do not recall ever not hearing the autopilot disconnect sound. But, it appears that something has changed with the 1.024 version. I now find the autopilot disconnect sound to be intermittent; sometimes working and other times, not working (no sound upon disconnect).
I am wondering if this is a bug which may have been introduced in the 1.024 version, or correct behaviour in the real aicraft depending on how the autopilot is disconnected (ie, if you use the disconnect button on the yoke versus the AP push button on the aircraft's front panel)?
For reference, P3D is set up with the default "Z" key, under keyboard commands, for autopliot disconnect. I have also set, again within P3D, my joystick's fire button for a single press (no repeats) to disconnect the autopilot. I do not use FSUIPC for keyboard or joystick commands.
Pressing the fire button on my joystick has worked flawlessly for years, in all aircraft, to disconnect the autopilot ... as has pressing the "Z" key on my keyboard ... PMDG, Aerosoft, Flight1, A2A, FSLabs and Majestic. A disconnect sound has always played in each and every aircraft, including the Majestic Dash 8. But, since installing the 1.024 version, the disconnect sound now appears to be intermittent in the Dash 8.
I am also using the 125Hz controls, so I wondered if I should edit the ini file and add a joystick disconnect parameter in there. I previously had only the ailerons, elevators and rudder set to use 125Hz. So I did that, adding J2_b0=AFCS_->inputs.AP_disengage to the [JOYSTICK_INTERFACE_ASSIGNMENTS] of the ini file.
I thought that had fixed it. With testing, in flight, the autopilot disconnect sound did play when I pressed the fire button on my joystick. However, on the same flight, I also noticed that if I press the "Z" key on my keyboard, no disconnect sound played. Interesting. So I am wondering now if the autopilot disconnect button on the yoke (which would be activated in the sim by using the J2_b0=AFCS_->inputs.AP_disengage line in the ini file) causes the sound to be played in the real aircraft, but pushing/toggling the AP button on the front panel does not cause the sound to be played in the real aircraft?
However, on my last flight, despite thinking I may have solved it by adding J2_b0=AFCS_->inputs.AP_disengage to the ini file and the autopilot disconnect sound working during the cruise section of the flight, it suddenly did not work as expected. I was on final approach and wanted to hand fly the landing, I pressed my joystick's fire button, the autpilot disconnected, but the disconnect sound did not play. So why did it work in cruise, and not on finals? Is there perhaps some kind of wierd conflict occuring with my having three separate places set up for the sim to disconnect the autopilot ... the 125Hz J2_b0=AFCS_->inputs.AP_disengage in my ini file, the "Z" key within P3D's keyboard commands, and also my joystick's fire button within P3D?
I am sorry for the long explanation, but the playing or not playing of this sound does appear to be a bit intermittent for me and I think a full explanation of my setup, as well as my actions, will be helpful in possibly getting a good response to my question. There seems to be no "pattern" to when it works or not.
In short, does the autpilot disconnect sound always play for other users, every time ... or, has something perhaps changed in the 1.024 version to "correct" the behaviour of this sound as per the real aircraft (for example, in the real aircraft does the sound only play when the yoke button is pushed as opposed to when the AP push button on the front panel is pushed?) ... and/or, is there possibly a conflict with how I have three separate places in my sim configured as autopilot disconnect possibilities?
I am hoping Kroswynd or other users can shed some light on this for me.
Comments
We have "disabled" the "z" key for autopilot disconnection within FSX/P3D as it has the capability of causing issues with the MJC AP (this was done since v1.009). If you use the "z" key we can not guarantee that the AP will work as it is intended via the programmed logic for the add-on.
Since you are using the 125Hz controls for the PRO Edition it would be advisable to assign the AP disconnect via the mjc84.ini. There is already the syntax implemented so you just have to ensure that the intended joystick of use is correctly assigned.
Thankyou for the reply, Kroswynd.
The "Z" key has been "disabled" in the Dash 8 for autopilot disconnection? And since v1.0.0.9? Wow. I wasn't aware of that. That is handy to know.
As per my original post, I have indeed already assigned autopilot disconnect via the mjc84.ini. I have added J2_b0=AFCS_->inputs.AP_disengage to that file. Tests have confirmed this is the correct joystick of use.
I believe that before I added J2_b0=AFCS_->inputs.AP_disengage in to the ini file, the autopilot disconnect sound did not play at all in the 1.024 version. But, since adding that line, the sound does now play. Interestingly, the sound always played in versions earlier than 1.024, without that line in the ini file.
You didn't mention whether the sound only plays in the real aircraft when the yoke button is pushed as opposed to when the AP push button on the front panel is pushed. I conclude from that that this is not the case and the sound does play in the real aircraft regardless of which button is pushed in the cockpit ... otherwise I would have read it in a manual somewhere, or you would have made mention of it in your reply.
I can only guess that I therefore have a conflict with my setup having both the J2_b0=AFCS_->inputs.AP_disengage parameter in the ini file and the same joystick button also assigned within the sim's internal settings. That "conclusion" makes some sense considering you said that you have "disabled" the "Z" key within FSX/P3D as it had the capability of causing issues with the Dash 8 autopilot. Perhaps the sim is actioning the setting from within P3D, instead of actioning the ini file parameter, and that action is behaving in a similar manner to what you said about the "Z" key. In other words, it has the capability of causing issues with the Dash 8 autopilot; revealing itself in this case by not playing the disconnect sound.
It looks like I need to run a few more tests.
I am perplexed that the autopilot disconnect sound always played in versions earlier than 1.024 and did so without me ever needing to change my setup, and without me needing to add the J2_b0=AFCS_->inputs.AP_disengage parameter in to the ini file. Logic says that if there has been no change to autopilot functionality, or, specifically, autopilot disconnect functionality, in 1.024, then the previous behaviour should remain; the sound should (always) play. But, strangely, in 1.024, that is not the currently the case for me.
Further testing has revealed that the parameter I have for AP_disengage in my ini file is, in fact, not working. (Yes, I have eaten a bit of humble pie here.)
I have J2_b0=AFCS_->inputs.AP_disengage in my ini file.
J2 is definitely the correct joystick of use. It's the same joystick that I have in my ini file for the elevators and ailerons. I know those are working because I can adjust the deflection values in the ini file and doing that does affect the amount of deflection for those surfaces.
So, I want to use the fire button on this joystick to disengage the autopilot. If I remove the autopilot keyboard commands out of P3D and assign J2_b1 in the ini file, then the autopilot disconnects when I press "button 2" on my joystick. I currently have that assigned to flaps, meaning that the flaps also deploy when the autopilot disengages. Along with the deflection test I mentioned above, this certainly confirms that J2 is the correct joystick of use.
I then assign J2_b2, as a test. The autopilot now disconnects when I press "button 3" on my joystick. Similarly, if I assign J2_b3 as an additional test, the autopilot disconnects when I press "button 4" on my joystick. I am using those buttons to retract flaps and operate the gear handle respectively, and those things also happen as well as the autopilot disconnecting. So, these tests coinfirm that J2 is definitely the correct joystick of use.
It's a four button joystick. The remaining button, the fire button, is the button I want to use to disconnect the autopilot. It's "button 1". So the line I need in the ini should be J2_b0=AFCS_->inputs.AP_disengage.
But, nope, this doesn't work.
In my previous posts where I thought this line was working, I was being mislead because the autopilot would indeed disconnect when I pressed the fire button. But that would have been due to me still having that button configured within P3D's internal settings for a single press (no repeats) to disconnect the autopilot. Removing that setting from P3D, and leaving the J2_b0=AFCS_->inputs.AP_disengage line inthe ini file should operate the autopilot disconnect. But it does not.
I have searched Google and cannot find an easy way to determine the associated button number for my fire button. I did try 5 and 6, and even -1 ... but those did not work.
Pressing the fire button within FSUIPC shows it to be Joystick 0, button 0.
In summary, I would like to assign autopilot disconnect within the Majestic ini file, but I do not know what button number to assign. I am currently left with the internal P3D settings to disengage my autopilot, and, as per my previous posts, the disconnect sound is intermittent using that method.
FSUIPC reports/confirms my fire button as button 0, but, as using J2_b0 didn't work for me in the ini file. I am now wondering if Majestic's ini file doesnt accept "0" for button number?
Does anybody know of a utility or tool, apart from FSUIPC, that can confirm my joystick's fire button number? The joystick calibration utilities in Windows are no help, and neither is DXDIAG.
For a quick and easy way try this utility.
viaintercity.com/forums/bombardier-dash-8-q400-(dhc-8-402q)/
Thanks Jax.
That excellent utility/tool will give me joystick axis details ... X, Y and Z (ailerons, elevator and rudder) ... which I already have in my ini, and which are working fine.
However, it doesn't, unfortunately, give me details about joystick button numbers, which is what I am after. I need to find out what button number the fire button is on my joystick.
FSUIPC does give you the correct joystick and button numbers. IF using Windows (control Panel) you have to subtract 1 from the button number. You may want to check that you do not have a duplicate assignment for your controls. P3D will auto-assign functions to your controllers. These need to be deleted.
ps, It has been a while (couple years) since I have actually had to use that utility, and I didn't realize that it was for axis only. Sorry 'bout that!
Apologies all for the multiple, duplicated posts above. The forum didn't look like it was posting, and I kept hitting the "Post Comment" button. Admins, feel free to delete the duplicates.
Jax, yes, I have checked my P3D settings for duplicated assignments in P3D. I have fallen for that trap before.
I even double-checked them again when I could not get this to work -- there's no duplicates.
FSUIPC reports it as Joystick 0, button 0.
I am aware that when using Control Panel to view button numbers that I need to subtract 1. Control Panel reports the button I want to use as button 1. So I use "b0" in the ini file. And that is what is not working.
When I added "b1" in to the ini, as a test, pressing button 2 on the joystick (as reported by Control Panel) did disconnect the autopilot and a sound played ... so that confirms the knowledge that I need to subtract 1 and it confirms that I am indeed correctly assigning buttons (in the ini) to disconnect the autopilot. It also confirms that I have the correct "J" number ("J2") in the ini. But, I do not want to assign button 2 on my joystick as I am using that for other things (flaps down). I want to assign button 1 on my joystick. Control Panel reports the button as button 1 (ie, subtract 1 meaning "b0" in the ini) and FSUIPC shows the button is button 0. And that is what's not working for me. J2_b0 doesn't work.
Believe me, in my ini, I tried J0, J1, J2 and J3 as well as b0, b1, b2, b3 etc ... all the combinations.
Freddy I don't believe it's an "incorrect assignment" issue, as such. Your numbers match what the simulator is seeing, so something else is causing interference. Could you zip and post your ini file? I want to test it with my setup, if possible.
Jax,
Thanks for your help. Here is a link to my zipped up ini:
https://file.io/znfnXwXPDtUQ
I will be interested in your findings.
My suspicion is that having my joystick's button 1 set within P3D under "Autopilot master (On/Off)" is the thing which may be causing the interference you speak of. But, I have that setting in there for my other aircraft, and it gives me no grief at all with any of those.
I should add that I did remove the "Z" key and the Button 1 setting out of P3D, as one of the tests ... but the Dash 8's autopilot did not disconnect at all with those removed, despite the J2_b0 parameter being in the ini.
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Hi Freddy,
Removing the semi-colon (;) from in front of this line will enable the AP disconnect.
;J2_b1=AFCS_->inputs.AP_disengage
Do the same for the TCS line if you want to use that function as well.
I have done it on more than one occasion during testing.
Guys,
No. Sorry ... let me explain.
I am very aware that the semi-colon "comments out" the line.
I did orginally have that semi-colon removed ... and the autopilot disconnect didn't work, thus starting this series of posts. After running a plethora of tests, as per my posts above, and it still didn;'t work, I then put the semi-colon back in place.
As I wrote in one of my earlier posts, I am currently left with the internal P3D settings to disengage my autopilot (see the screenshot) ... and, hence, that is why that semi-colon is currently there in the ini file I uploaded. (I simply didn't think to mention that fact when I uploaded it.)
You will also notice that the line with the semi-colon is J2_b1, instead of J2_b0. J2_b1 is just a left over from the testing. As explained earlier, J2_b1 does work, but that button (button 2 on my joystick) is assigned to lower my flaps (so the flaps lower and the autopilot disconnects, with sound). I want J2_b0 to work, which does not.
Bottom line, with the semi-colon removed, and J2_b0 as the line, it does not work for me. And that is what we're trying to figure out.
You're welcome, Kroswynd. I am always happy to help, and I enjoy a good "puzzle". And yes I have made the same mistake many times.
Jax,
I see you have replied to Kroswynd. Our posts were pretty much at the same time, so you may have missed my explanation above.
Sorry Freddy I did miss your post. Is there a software for your joystick? Anything that may be locking the ability for assigning that button? I had an older logitech joystick software that did that for the trigger switch. It was a PITA to figure out.
No. No software. It's a USB joystick and is using the Windows built-in drivers. So there should be nothing (that I know of) locking the ability of assigning that button.
(I haven't mentioned this yet, because I don't want to come across as being "arrogant" ... but it may be handy for you to know that I actually work in IT customer support and I actually solve these exact kinds of issues for customers of the company that I work for. I've been doing it for more than 20 years. I am not suggesting that I am an expert, by any means ... one is always learning ... but I mention it here to give you an idea of my "skill level". That said, I haven't figured this one out, so it is certainly possible that I could have missed something obvious (it happens) and a fresh set of eyes and suggestions in forum posts might reveal that.)
I tried to d/l your .ini again but it seems to be deleted
Yes, the file sharing page I used deletes the file when somebody downloads it.
I have uploaded it again for you:
https://file.io/y7wXhCIO8N6C
I also re-added the line "J2_b0=AFCS_->inputs.AP_disengage" back in to the ini (and not commented out with a semi-colon this time
) for your benefit.
Thanks, so the syntax is correct. Just out of curiosity. can you swap the AP disengage with the TCS and see if you get any response from the TCS when engaged in flight plz.
Do you use any 3rd party add-on that can any access to the AP functions. back in the early days ran into a similar issue with Flight Sim Commander (FSC) where by a user was explaining oddities being exhibited by the Q400 but it so happened that the AP interface for FSX was preventing certain functions of the Q400 (just an off the wall thought).
Hmmm. A question. I have just noticed that if I click the AP button on the front panel, with my mouse, the autopilot disconnects, and no disconnect sound plays. The same thing happens if I press the fire button (button 1) on my joystick. A subsequent click of that button again, with my mouse ... or a press of my joystick's fire button ... will re-engage the autopilot. Note that this behaviour is being observed without the J2_b0 line in my ini file.
Is that correct behaviour? Is that how it works in the real aircraft? Because, if it is, then I really have no issue here ...my Dash 8 would be behaving exactly as per the real aircraft. However, if a disconnect sound is supposed to play, then, well, that's the issue, it isn't.
Intriguingly, if I click the A/P DIS button on the yoke, with my mouse, the autopilot disconnects, and the disconnect sound plays. This action also invokes "AP INHIBIT" on the display, as well as the "AP DISENG" advice on the front panel push button. Pressing my joystick fire button after these actions does not re-engage the autopilot. That is, not until the "AP DISENG" button is pressed first (with the mouse). Again, this behaviour is being observed without the J2_b0 line in my ini file.
I will run that test for you and report back here.
No, I do not run any 3rd party add-ons that can access the AP functions.
I would be interested to read any comments you may have to my question(s) in my previous post.
Pressing the AP button on the glareshield will not play the AP disconnect aural tone or provide an indication on the PFD.
Using the mouse to disengage the AP via the disconnect button on the yoke will play the disconnect aural tone and provide the AP Inhibit message on the PFD (this is the incorrect message and will be addressed in a later update). Pressing the joystick button should never in the MJC Q400 re-engage the AP. The AP button the is provided is for disconnection only as in the real aircraft it can not be engaged via a button.
The "z" key is not supposed to have control of the MJC Q400 AP - BUT I was able to engage and disengage the AP with its use. I will have to discuss this with the Boss to see if the logic may have been altered intentionally or not. That being said, if your b0 button is still mapped via P3D for the AP function there could very likely be a conflict
Hi,
As I can't see your INI file one question: How is AFCS_FSX_SYNC set in your INI file?
majesticsoftware.com/forums/discussion/comment/582#Comment_582
Rgds
Reinhard
Yes, I get a response from the TCS when in flight. I see TCS indicated on the PFD and the aircraft responds to pitch and roll movements accordingly.
.
FSX sync is set to "disabled". ie, in the ini file, it is set to "disableFDEtoFSXSync=1"
.
Interesting. In my aircraft, when the autopilot is connected, there is an "AP" indication on the PFD. When the autopilot is disconnected, the "AP" indication on the PFD dissappears.
Without having the J2_b0 entry in my ini file, manually pressing the AP button on the glareshield, using my mouse, will alternate between those two modes ... ie, if the autopilot is currently disconnected, then it will connect, "AP" will display on the PFD and the AP button on the glareshield will illuminate ... if the autopilot is currently connected, then it will disconnect, no aural tone will play, "AP" will dissappear from the PFD and the AP button on the glareshield will go dark. I can toggle from one to the other, connected, disconnected, connected, disconnected, and each time the "AP" indication on the PFD toggles accordingly as does the AP button illumination. No aural tone is heard at any time using this method.
The same is true if I use button 0 on my joystick (the fire button). Without having the J2_b0 entry in my ini file, I can use the fire button to toggle from one to the other, connected, disconnected, connected, disconnected, and each time the "AP" indication on the PFD toggles accordingly as does the AP button illumination. No aural tone is heard at any time using this method.
I am a little confused by "The AP button the is provided is for disconnection only as in the real aircraft it can not be engaged via a button." But I think you mean that pressing this button on the yoke does not engage the autopilot. That does makes sense considering the button is labelled "A/P DIS".
.
The "Z" key on my PC does the same as what you describe. If it is not supposed to do that, then, yes, check with the boss.
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OK ... It didn't seem logical to me that manual disconnection of the autopilot, by pressing the AP button on the glareshield, would not play an aural tone. I went to the "Smart Cockpit" web page and did some reading on the Q400 autopilot. The following screenshot seems to imply that an aural tone is supposed to play for 1.5 seconds when the autopilot is manually disconnected (and a longer, repeating tone if the autopilot is automatically disconnected). And this is why I am expecting to hear a disconnect tone when I use the glareshield AP button. You have advised that pressing the glareshield AP button will not play the AP disconnect aural tone or provide an indication on the PFD ... so that seems to go against what I am reading here. Can you confirm?
https://www.smartcockpit.com/docs/Q400-Autoflight.pdf
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Oops. You asked about AFCS_FSX_SYNC.
In my ini file, that is set as follows: AFCS_FSX_SYNC=1
It has always been set to "1" in my in file ... for all previous versions of the Dash 8, and now this version too. I've never changed that parameter.
Hmmm. That thread you referenced does suggest it should probably be set to "0". I haven't run a test on it, but I assume if it is set to "0" then the Q400 will not respond to autopilot commands from FSX/P3D? In other words, the "Z" key and, in my case, the fire button on my joystick (which is set to toggle Autopilot Master in my P3D settings) will be ignored? Considering I do want to use my joystick fire button to disable the autopilot, by "pressing" the AP button on the glareshield, then that may not be what I want.
I think what I want is to assign the AP button on the glareshield to my joystick fire button and to have the aural disconnect tone sound whenever that button is used to disconnect the autopilot, as the documentation I referenced above refers to. Right now, without needing to assign my fire button in the ini file, my joystick fire button does toggle the autopilot via the P3D settings ... so it seems to only be a matter of not hearing the aural tone, when the documentation suggests that I should; and which did occur in previous versions of the Dash prior to v1.024 (or else I would have raised this question previously).
I don't currently use the A/P DIS button on the yoke to disconnect the autopliot, so there really is no need for me to have that assigned in the ini file. I agree with Kroswynd that there is probably a conflict there with having that assigned in the ini to my fire button and also having that same button assigned within P3D itself. The TCS test Kroswynd asked me to perform confirms that I can link that button successfully in the ini file ... so having it in the ini file and in P3D will indeed be a conflict and has probably been the cause of my confusion around this matter. I just want to hear the aural disconnect sound when I disconnect the autopilot. Currently, I can disconnect the autopilot using my joystick fire button ... that's working fine using internal P3D settings ... however, I am not hearing an aural tone when I do that and I am not so sure that is correct as per the real aircraft.
As per aua686's question, I ran a test on the AFCS_FSX_SYNC parameter.
I changed it from AFCS_FSX_SYNC=1 to AFCS_FSX_SYNC=0
As I guessed, the Q400 no longer responded to autopilot commands from FSX/P3D. In other words, the "Z" key and, in my case, the fire button on my joystick (which is set to toggle Autopilot Master in my P3D settings) were ignored.
I then re-added the J2_b0=AFCS_->inputs.AP_disengage line in to my ini file, and tested again.
This time, the Dash 8 behaves exactly as Kroswynd described. The AP is connected by me having to manually press, using the mouse, the "AP" button on the glare shield. The autopilot can be disconnected using the fire button on my joystick (in other words, the "A/P DIS" button on the yoke is being pressed, by way of the ini file parameter). When this is done, the autopilot disconnects, the aural tone is heard and "AP DISENG" appears on the front glareshield push button. This sequence seems to match the Q400 documentation from Smart Cockpit. Further, the autopilot cannot be reconnected until the "AP DISENG" is first cleared by manually pressing that button with the mouse, and reconnection of the autopilot can only be achieved by manually pressing the "AP" button on the glare shield again. This all seems to match what the Smart Cockpit documentation says.
However, where this doesn't match the Smart Cockpit documention is when manual connection and disconnection of the autopilot is done via the AP button on the glareshield. According to the documentation, if I am reading it correctly, using that button on the glareshield to manually disengage the autopilot (ie, using the mouse in our Q400) should invoke the aural disconnect tone ... but, it does not.
Now, having the AFCS_FSX_SYNC parameter in my ini file set to "0" is all well and good. But, this means I cannot operate the Dash 8 autopilot as I would like to. I want to be able to manually use the AP button on the glareshield, with my joystick's fire button, and have the autopilot toggle on and off. I cannot do that with this parameter set to "0". Yes, I can map this button in the ini file to my joystick ... sure, that would probably work ... but the problem remains ... when I toggle the autopilot to off (ie, disconnecting it) via this button, I expect to hear an aural disconnect tone as per the Smart Cockpit documentation; but I do not.
Therefore, having the AFCS_FSX_SYNC parameter in my ini file set to "0" in my ini file does give me the aural disconnect tone, but it doesn't allow me to operate/toggle the autopilot on and off in my Dash 8 as I want. Having it set to "1" does allow me to operate/toggle it how I want, but there is no aural disconnect tone.
@kroswynd ... I would suggest that the "Z" key working for you in your own tests is possibly due to your ini file having AFCS_FSX_SYNC=1, just as I have it. And, if that is the case, then it also explains why you mentioned to me that no aural tone is heard when the AP button on the glare shield is pressed. Because that is exactly the same behaviour that I am seeing with the AFCS_FSX_SYNC=1 parameter in my ini file. However, having no aural tone sound when the AP button on the glareshield is pressed does not seem to match the Smart Cockpit documentation. Therefore, I am thinking that this means there is either a bug in our v1.024 Q400, or that I am perhaps misunderstanding that documentation? That said, you did also say that the "Z" key is not supposed to have control of the MJC Q400 autopilot and perhaps that is why the AFCS_FSX_SYNC parameter is in the ini file; but I will still suggest that hearing no aural disconnect tone when the user makes use of this parameter and subsequently disconnects the autopilot manually (via the "AP" button on the glareshield using their mouse or via a mapped joystick button), is a bug or an oversight?
I do apologise for such longs posts. But a few people are/were helping and following along and I want(ed) to try to convey a full understanding of my thought processes, the steps, and the theories/conclusions.
Hi,
You have to implement this via the XML interface. You can either program this via LUA scripts or you could use the method, which I described here:
majesticsoftware.com/forums/discussion/1098/assigning-buttons-via-fsuipc-directly-to-xml-interface-controls#latest
Then you can leave AFCS_FSX_SYNC at 0. You have to look for the right commands and add them according to the examples already in the files. But be aware: it's a little bit technical and I am not able to provide support.
Rgds
Reinhard
Hi,
I have checked my Q400 configuration and identified these three codes, which must be added in the sample file:
XMLIF_write.xml:
Q400BUT.MCRO:
50=AFCSAP=C69686
55=APDisOn=C69691
56=APDisOff=C69692
Adding these three lines to the files mentioned in the post should allow you to toggle either the AP button or to switch the disconnect button to on or off.
Rgds
Reinhard
@aua668 Thanks! I am not all that unfamiliar with scripting or XML, although I am no expert. I will definitely look in to this. However, with my AFCS_FSX_SYNC parameter set at 0, my joystick's fire button does already toggle the autopilot ... so it is just the disconnect sound that I need. I need to map a sound to the event. I have read a thread on the Internet somewhere about how to do that, so I'll have to do a search. Although, until I investigate that more, I am not sure that is even going to work as the sound may fire in other aircraft when I press my joystick's fire button. Of course, if I could map the sound to a Q400 variable such as APDisOff, then that could work. Hmmm.
I have made an attempt at some scripting, and also at mapping the aural autopilot disconnect tone sound to pulling the fire button on my joystick to disengage the Q400 autopilot. I struggled a bit and had limited success. I'll spare the details here.
I think my best course of action is to leave the AFCS_FSX_SYNC parameter set at 0 in my ini file (thankyou @aua668 for that suggestion) along with J2_b0=AFCS_->inputs.AP_disengage. This means my joystick's fire button will disconnect the autopilot and I will hear the aural tone. And, it also means there is no possible conflict with my setup having autopilot disconnect commands mapped within P3D itself.
Whilst I am happy that, according to what I have read, this works as per the real aircraft, I am disappointed that it means I'm unable to operate the autopilot as I would like. This setup means my joystick's fire button is mimicking a press of the A/P DIS button on the yoke to disconnect the autopilot, as opposed to using the AP button on the glareshield, and that means I am unable to toggle the autopilot on and off at will, which is what I would prefer. But, at least I am now hearing an aural tone when I disconnect the autopilot. I suppose I will get used to this setup over time, and I can at least justify it in my mind as "a quirk of this unique aircraft".
Whilst I have achieved an end result, I am still left wondering if the lack of an aural tone when the autopilot is disconnected via the AP button on the glareshield is how it actually is in the real aircraft, or whether it is possibly a bug or an oversight in the 1.024 version of the Q400.