AP disconnect on ILS finals
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I made 2 flights since latest update. One with F70 and one with F100. On both I used an ILS approach, and on both approaches the AP suddenly disconnected while on final. I have checked for any key binding issues but didnt find anything. Both disconnects occurred more or less at the same stage of the approach I believe, around the time the flaps 42 callout came and I was selecting full flaps.
Anybody else had this? Is there any particular limitation for AP use om approach? Or is that a bug or what could have triggered that? Any advise would be appreciated, many thanks !
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I'm not aware of any bugs, new or old, that'd be causing this. The only thing that comes to mind is the trim disconnect if sustained stab/elevator trim inputs by the pilot are detected, but presumably you aren't making any trim inputs?
Martyn - Development Manager
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I'm not aware of any bugs, new or old, that'd be causing this. The only thing that comes to mind is the trim disconnect if sustained stab/elevator trim inputs by the pilot are detected, but presumably you aren't making any trim inputs?
I was flying the RNP Y approach for RWY 06 into Vitória (SBVT) today. Right in the middle of the procedure, the autopilot suddenly disconnected completely on its own, without any input from my end. Immediately following this uncommanded disconnect, the aircraft aggressively pitched down into a severe nose dive.
We are already aware of the pitch-down tendency when manually disconnecting the AP for landing, but having the autopilot drop out uncommanded and instantly throw the nose down during an RNP procedure is a critical failure...
I caught this specific behavior on video, and you may watch it here: https://www.youtube.com/watch?v=UhpcDVPt8Ak
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I had similar on my flight earlier to Manchester ILS 05R approach. Sudden disconnect of the autopilot.
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Hi all. As we aren't guaranteed to be able to reproduce the issue here, and didn't encounter it during our v1.2 pre-release testing, it'd be great if some of you could try this updated WASM gauge to see if it helps: WASM Download
The WASM, which has MSFS 2020 and 2024 versions, needs to replace the existing one that is found in: \justflight-aircraft-f100\SimObjects\Airplanes\Just Flight Fokker F100 Airstairs Small\panel
\justflight-aircraft-f70\SimObjects\Airplanes\Just Flight Fokker F70\panel\Thanks for your feedback and assistance, and apologies for the inconvenience.
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Note this reverts a couple of recent changes - AP auto-trim, aimed at addressing the out of trim condition when disconnecting the AP, and the introduction of the 1.5 second manual trim input AP disconnect. Those are the most likely causes of this new issue. If the issue no longer occurs with these reversions then we can work to reintroduce those improvements without causing the issue.
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Hey Martyn, many thanks. I´ll give it a try and report back
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Martyn, just did an ILS into LOWW 34 and AP did not disconnect (as expected due to the mentioned reversion - when disconnecting manually close to minimums out of trim was severe)
Another item which I was wondering if with this wasm file has also reverted is the AT speed under- and overshooting - on final it overshoot App speed by at least 40kt....so quite an unstable approach altogether, but AP did hold LOL -
Martyn, just did an ILS into LOWW 34 and AP did not disconnect (as expected due to the mentioned reversion - when disconnecting manually close to minimums out of trim was severe)
Another item which I was wondering if with this wasm file has also reverted is the AT speed under- and overshooting - on final it overshoot App speed by at least 40kt....so quite an unstable approach altogether, but AP did hold LOLThanks both for confirming that fixed the issue.
I can confirm that no other changes were reverted, including the ATS logic. I've not encountered such a significant speed overshoot so hopefully that was a one off. If not, please get in touch with our support team so they can investigate.
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I can confirm the abovementioned observations: MSFS 2024, unaltered version 0.1.2, F100 (OE-LVI from the livery installer), ILS 08L into LROP. Flaps 42, AP and AT on until the AT undershoots the V_App (138 kts in this case) by about 10 (?) knots. AP disconnects with aural alert, AT stays engaged, aircraft pitches down (probably due to the thrust increasing significantly at that moment). Looks to me like the AP disconnect was triggered by an underspeed (V_MA) protection.
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I also experienced all the reported issues with the AP disconnecting in the app.
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Not sure if it's related, but I was watching British Avgeek on YouTube and I think he experienced this AP disconnect during his live stream:
https://www.youtube.com/live/cfEko8yc6sY?si=wnz1XKJzGQKfjJfO&t=8027ATS was not keeping the proper airspeed and dipped well below the target speed.
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Not sure if it's related, but I was watching British Avgeek on YouTube and I think he experienced this AP disconnect during his live stream:
https://www.youtube.com/live/cfEko8yc6sY?si=wnz1XKJzGQKfjJfO&t=8027ATS was not keeping the proper airspeed and dipped well below the target speed.
@neinnunb It looks like this is separate from the auto-trim related issues, from the video the AT looks hesitant to increase thrust to counter the drag from lowering gear. We'll look at improving the AT response during this flight phase as a priority.
John Hodgson - Development Assistant
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@neinnunb It looks like this is separate from the auto-trim related issues, from the video the AT looks hesitant to increase thrust to counter the drag from lowering gear. We'll look at improving the AT response during this flight phase as a priority.
Hi everyone, Martyn and John
Just wanted to drop some quick feedback after testing the newly released hotfix.
The good news is that, despite the hotfix rolling back some of the improvements introduced in V1.2, I was successfully able to fly an ILS approach all the way down to the minimums without any of the erratic behaviors I had reported previously. It is definitely a relief to have that baseline stability back for instrument approaches.
However, I must point out a critical detail regarding the autopilot disconnect. I understand that this temporary fix reverted the modifications made to the F100's trim logic. Even so, the aggressive pitch-down tendency upon disconnecting the autopilot remains exactly the same as I experienced across my multiple flights on the initial V1.2 build.
While we can now reliably get down to the minimums on the ILS, you still have to be extremely prepared for that uncommanded nose dive the second you press the AP disconnect button.
I'm glad the lateral/vertical tracking is temporarily stable again, but I really look forward to a definitive fix for the trim/pitch logic in the next full update.
Best,
João -
Would it be worth it to update the hotfix or just take it out of ATS and manually apply thrust? I’ve noticed this on approach into RWY18 @ YPXM with flaps 42° and did troubleshooting with flaps 25° and noticed a slight improvement but after a multiple attempts I ended up just taking the plane out of ATS altogether and at MDA, I then took out the AP as well and got the results I wanted.
