Glideslope problems
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"Not holding the glideslope perfectly" is a gross understatement. It is absolutely terrible. It just kills the plane for me. I don't give a crap about potable water, boarding times, ambient music, etc. if the thing won't fly properly.
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At the moment the plane just can't hold an altitude or vertical speed below maybe 210 or 220 knots at all. It'll oscillate pitch wildly around a target, and in the long term I think it sort of hits a selected VS, but it's not great. For the glideslope it's useless and induces motion sickness.
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Although we have seen some oscillations introduced with the altitude hold mode in a recent sim update, we aren't able to reproduce any significant oscillation issues with the other autopilot modes.
It's worth considering that the IAS and VS modes are very literal as per their names and they just hold the indicated airspeed or vertical speed at the time of engagement. Unlike more modern airliners which have an autothrottle linked to the autopilot modes, the 146 doesn't have that, so any adjustments to the throttle should be made smoothly to avoid any sudden pitch movements.
One thing that may be worth trying in the simulator is going to MSFS Options > Assistance Options and setting turbulence to LOW or MEDIUM. The feedback we have received from real-world pilots on our beta testing teams across multiple products is that the default REALISTIC option is a bit too strong and can generate excessive wind speeds and up/down drafts which could cause oscillation issues like you're describing.
If you're still having issues after considering the above, please open a ticket with Just Flight Support via the following link providing steps to reproduce then we can get this logged and investigated: https://www.justflight.com/support
Mark - Just Flight
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@Mark my experience on the last few flights has been that as soon as the plane goes below some "magic" speed, it reliably becomes unable to fly straight. Due to normal flight profiles, that has hit me mostly in the arrival descent (VS and ALT modes) and then on the GS. Flying into EGGP via the ELVO1L arrival, holding and descending at KEGUN and then ILS to rwy 09 via the 003° radial to WAL, the plane was effectively oscillating all the way from NANTI.
I do have turbulence set to medium.
I'll try to get a video of that and send it to support. I assume a Youtube link would work?
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Unfortunately, I have to confirm that the autopilot glideslope following is not actually usable. I have the additional problem that it can't really cope with extending the flaps. This leads not only to oscillations but sometimes it just ends up leveling out or at around 200 FPM or so - in the middle of the final approach - so it loses the glideslope completely and then no longer corrects the path at all. Sometimes it works. All in all, not comprehensible. I have not yet observed this kind of behavior with other addons and I have to agree that this really dampens the enjoyment of an otherwise excellent add-on.
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Must be a weird combination from weight, balance, weather, trim and perhaps timing (gear down, flaps, speed). Sometimes, at slow speeds the aircraft indeed feels a bit sensitive around the elevators but manageable.
Yesterday I had the worst case, where the autopilot corrected to around 0-200 FPM and stopped further corrections during approach. That was in EGLL, not much wind, no gusts, perfect configuration, turbulence even set to low… it was simply not able to hold the glideslope. -
What's truly bizarre to me is that the JF F-28 is perfect every time. Subject to the same variables as the 146, including the MSFS turbulence and weather settings. Never a problem. But the 146 is absolutely terrible on the glideslope with the autopilot. Exasperating!
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That is a good idea. I use always Simbrief and import the weights. Perhaps I should try some flights with standard-weight-settings.
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I have now tested this and have not changed the loading of the 146-100 (apart from the fuel). I can therefore rule out the influence of the "simbrief conditions".
My tests were carried out exclusively with the BAE146-100.I can definitely say that the autopilot has a problem with
a) the transition from climb/descent to level flight at slower speeds
b) holding the glidesloperegarding a): at slower speeds (I tested in the range between 220-180 knots) when reaching an armed altitude and transitioning to level flight, the autopilot regularly start oscillating up and down. After a while (a few minutes), it recovers. At higher speeds, for example climb to cruise alt and transitioning to level flight it worked well.
regarding b): when following the glideslope, the autopilot either oscillates regularly up / down or it deviates upwards or downwards from the path and then no longer corrects this. For me, in 9 out of 10 cases it is not usable.
I have now made many flights with the BAE146-100 because it is otherwise a very nice airplane. At least one of the above problems has occurred in every single one of these flights. These were flights in all kinds of weather, with or without wind. I am therefore of the opinion that this is a permanent and reproducible problem that does not have to be proven by any records.
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FWIW, I've been running into those issues some more, but going into SYNC and quickly trimming out the aircraft fairly reliably "fixes" autopilot behaviour down the road (and the glideslope). Basically it starts happening when slowing down during arrival or approach, I trim the plane once, and it'll keep working the rest of the way.
I hope the RJ received some better logic there and we see it ported back soon :-)
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L Laurreth referenced this topic
