FDE issue with FBW system?

[MWR 36]

Good Afternoon all...

Since installing 1.20 I've found that many of the problems I had have been solved. However. I suspect there is a problem with the way the Autopilot trims the aircraft when the FBW system is operative. I've carried out a number of test flights as I was rather frustrated that the Airbus would operate when operated on all the autoflight systems but if I wanted to revert to manual control there was an immeadiate pitch up when uncoupling the autopilot. To illustrate what I mean here are the results...These flights are all at a representitive weight and whilst maintaing level flight at the following speeds and configurations.

250kts a/c clean.....on AP disengage....sharp pitch up to 2700 fpm climb with a gentle recovery to level flight.

220kts clean........................................pitch up to 1700 fpm with gentle recovery to level flight.

210kts Flap 1 pitch up to 2000 fpm with gentle recovery to level flight

190kts Flap 2 pitch up to 1700 fpm with gentle recovery to level flight

160 kts Flap 4 pitch up to 1300 fpm with gentle recovery to level flight

160 kts Flap 4 U/C down pitch up to 1500 fpm with recovery to 250 fpm descent.

If FBW is disabled this doesn't appear to occur and the aircraft seems trimmed when AP is disconnected. I chose a random add on aircraft from the 'hangar' and flew it under the same conditions, (it doesn't simulate FBW), when in the same configurations the aircraft was perfectly trimmed when the AP was disconnected.

Now. I suppose that if you fly the airbus under autoflight conditions at all times this is never going to bother you. However, if you like to hand fly if conditions permit for any period of time you have a problem. Particularly if you like to revert to manual flight in the latter stages of an ILS when the aircaft will immeadiatly pitch up on disconnection of the AP.

It would appear that the Airbus X has certain problems on certain systems and flies perfectly on others. Perhaps it's only me? Does anyone else notice this?

Regards.

MWR

[Paul Golding 159]

Good Afternoon all...

Since installing 1.20 I've found that many of the problems I had have been solved. However. I suspect there is a problem with the way the Autopilot trims the aircraft when the FBW system is operative. I've carried out a number of test flights as I was rather frustrated that the Airbus would operate when operated on all the autoflight systems but if I wanted to revert to manual control there was an immeadiate pitch up when uncoupling the autopilot. To illustrate what I mean here are the results...These flights are all at a representitive weight and whilst maintaing level flight at the following speeds and configurations.

250kts a/c clean.....on AP disengage....sharp pitch up to 2700 fpm climb with a gentle recovery to level flight.

220kts clean........................................pitch up to 1700 fpm with gentle recovery to level flight.

210kts Flap 1 pitch up to 2000 fpm with gentle recovery to level flight

190kts Flap 2 pitch up to 1700 fpm with gentle recovery to level flight

160 kts Flap 4 pitch up to 1300 fpm with gentle recovery to level flight

160 kts Flap 4 U/C down pitch up to 1500 fpm with recovery to 250 fpm descent.

If FBW is disabled this doesn't appear to occur and the aircraft seems trimmed when AP is disconnected. I chose a random add on aircraft from the 'hangar' and flew it under the same conditions, (it doesn't simulate FBW), when in the same configurations the aircraft was perfectly trimmed when the AP was disconnected.

Now. I suppose that if you fly the airbus under autoflight conditions at all times this is never going to bother you. However, if you like to hand fly if conditions permit for any period of time you have a problem. Particularly if you like to revert to manual flight in the latter stages of an ILS when the aircaft will immeadiatly pitch up on disconnection of the AP.

It would appear that the Airbus X has certain problems on certain systems and flies perfectly on others. Perhaps it's only me? Does anyone else notice this?

Regards.

MWR

Whenever I disengage the AP I get a mildly annoying pitch down afer a few seconds, no big drama and certainly no climb like you've described.

Not much use I know, but at least you know what you're seeing isn't normal.

[Kestrel 16]

I had similar problems too. I disengaged the A/P at 500ft and it felt like the trim wheel was trimming fully down (although I can't back this statement up because I didn't look at the trim wheel). Then at 100ft it felt like the control system was phasing into another type of control system thus making it fairly un-flyable. Auto-land is touchy, sometimes its fine and other times its not. Last night I did an auto-land and it didn't flare at all. - But maybe this is because the aircraft doesn't know the runway elevation?

[HenryD 39]

Good Afternoon all...

Since installing 1.20 I've found that many of the problems I had have been solved. However. I suspect there is a problem with the way the Autopilot trims the aircraft when the FBW system is operative. I've carried out a number of test flights as I was rather frustrated that the Airbus would operate when operated on all the autoflight systems but if I wanted to revert to manual control there was an immeadiate pitch up when uncoupling the autopilot. To illustrate what I mean here are the results...These flights are all at a representitive weight and whilst maintaing level flight at the following speeds and configurations.

250kts a/c clean.....on AP disengage....sharp pitch up to 2700 fpm climb with a gentle recovery to level flight.

220kts clean........................................pitch up to 1700 fpm with gentle recovery to level flight.

210kts Flap 1 pitch up to 2000 fpm with gentle recovery to level flight

190kts Flap 2 pitch up to 1700 fpm with gentle recovery to level flight

160 kts Flap 4 pitch up to 1300 fpm with gentle recovery to level flight

160 kts Flap 4 U/C down pitch up to 1500 fpm with recovery to 250 fpm descent.

If FBW is disabled this doesn't appear to occur and the aircraft seems trimmed when AP is disconnected. I chose a random add on aircraft from the 'hangar' and flew it under the same conditions, (it doesn't simulate FBW), when in the same configurations the aircraft was perfectly trimmed when the AP was disconnected.

Now. I suppose that if you fly the airbus under autoflight conditions at all times this is never going to bother you. However, if you like to hand fly if conditions permit for any period of time you have a problem. Particularly if you like to revert to manual flight in the latter stages of an ILS when the aircaft will immeadiatly pitch up on disconnection of the AP.

It would appear that the Airbus X has certain problems on certain systems and flies perfectly on others. Perhaps it's only me? Does anyone else notice this?

Regards.

MWR

You are not alone, I discovered this yesterday too (flight from LTBA to LTCG) while testing the ASFADEC.DLL Mathijs posted in the thread "Throttle issues", did just two hours ago a complete deinstall (with removing everything regarding to the AirbusX as mentioned now in several posts), I even restarted my computer after deinstallation, made a fresh install, but this issue remains. What did I do wrong? I have FSX SP2, not Accelleration, maybe another issue with the two different FSX versions?

Regards

Henry

[Kestrel 16]

I had similar problems too. I disengaged the A/P at 500ft and it felt like the trim wheel was trimming fully down (although I can't back this statement up because I didn't look at the trim wheel). Then at 100ft it felt like the control system was phasing into another type of control system thus making it fairly un-flyable. Auto-land is touchy, sometimes its fine and other times its not. Last night I did an auto-land and it didn't flare at all. - But maybe this is because the aircraft doesn't know the runway elevation?

Another auto-land tonight, no flare at all, in fact it was almost like there was a lot of drag somewhere, even when my reactions kicked in and I pulled back on the stick and the aircraft just hit the floor. Auto-land doesn't work with v1.2 for me now at all. I took the flight back and tried landing manually but with the flight control computers (FBW) turned off and it was fine, sensitive controls, no sudden change in pitch, perfect.

I think the best move would be to write a completely new FBW system, release it in the advance update and also include a patch for the basic one with the new FBW systems.

[MWR 36]

Very interesting! It would appear that a pitch DOWN is the more common experience. At least we're all experiencing an out of trim experience.

My system is also SP1/SP2 but no acceleration pack. I'm also willing to admit that my autoland experiences were not based on a number of tests at different weights and speeds but at very light landing weights and there was no problem on the few I carried out. Obviously from other reports there is a problem.

Just for the attention of any Aerosoft people reading this. I'd just like to state that my knowledge of how FDE files are written is pretty minimal! I just decided to post this info to illustrate my findings in the hope that it may produce a constructive conclusion that may assist the Airbus X project. I think it's pretty obvious that if the FBW system doesn't trim the aircraft properly but, just looking at my results, the system then attempts to , very slowly, trim itself to level flight. As I'm currently stuck in the house awaiting a delivery i might have to have a think about this so sorry in advance to those of you are bored already. (lights imaginary pipe in the manner of Sherlock Holmes).

Right....Back from some heavier wieght autolands with FBW operating. I see what you mean..my rate of descent on the worst one was 700 fpm down with no discernable flare at all.....Oouch! I also noticed that the autopilot isn't very neat at capturing an altitude. It develops a mild phugoid, (pich up pitch down), which gently dampens out. The trim wheel can be seen chasing the correct attitude. This begs the question.....

IF the elevator trim with FBW is lacking sensitivity and IF the elevator trim initiates the flare in the autoland? Are these problems then linked? Any experts?

Mike

[KAPTEJNLN 237]

about the nose down that is easy to explane what happens. have some one watched the trim wheel 2 sec or so after ap is turned off it retrims to 0 as when ap is off it returns to the locked trim wheel ( you cant use trim before you get down to 100 ft) as it seems the autopilot control of trim works the same way as under 100 ft. so fly an full automatic flight works best it seems there are some small isues whit touchdown. but my faver is manual landing

[MWR 36]

about the nose down that is easy to explane what happens. have some one watched the trim wheel 2 sec or so after ap is turned off it retrims to 0 as when ap is off it returns to the locked trim wheel ( you cant use trim before you get down to 100 ft) as it seems the autopilot control of trim works the same way as under 100 ft. so fly an full automatic flight works best it seems there are some small isues whit touchdown.

Hi KAPTEJNLN.

If you are flying an aircraft which is on autopilot, wether it is operating on a FBW system or 'analogue' you wouldn't expect to find the aircraft out of trim when disengaging the autopilot would you? Secondly, if you operate entirely on automatic systems there are still many people who are experiencing very heavy landings. (See my experience above, no flare with 700 fpm sink rate). Thirdly. If the only way to operate Airbus X was entirely on automatic systems then it isn't simulating the aircraft as it should. Don't you agree? I have every respect for Aerosoft, but feel there's still a way to go with this one and am trying to help in my own small way.

Mike

[KAPTEJNLN 237]

Hi Mike,

updatet

but the problem is it jump from ap trim setting to 0 trim after 2 sek or so, and then locked trim wheel down to 100 ft for manual flight. best way to get over this at this stage is as other say turn off flight by wire on the overhead and set the response for control as low as posible, then fly whit out FBW. found out it in some way works best whit slow control.

About the flare and autoland i dont know why it dosent do as real plane. also in some way it works like it isent acurate enough as it makes to small corrctions on approch as it starts good 2 red and white papi light, then it wents to 4 white also whit constand speed and lands after touch down zone whit out flare.

Update 29/9 18:26 local. Full autolanding

well about why it dosent seem to follow the path and touch down point must be an fs thing as i was checking the visual glide path and the airbus followed right after the book at EKCH default airport

[Francisco S 4]

So you are saying by disabling FBW this bus is not going to dive anymore??

[KAPTEJNLN 237]

So you are saying by disabling FBW this bus is not going to dive anymore??

well don´t realy know if it would happen as tested it in another way as now trim wheel is working faster to retrim then whit FBW as trim wheel locked. But 1 thing is sure it works better then whit FBW on i think from other tests

UPDATE now tryeid to disconect on final and only a verry litel corection on the yoke to maintain it seems wery well when used whit autoland then disconect it works best posible i think.

it seems in some way the hole problem is the trim wheel. if it should work right the trim wheel should stop when ap disconect and then when flyeing manual it should read the vaulve from ap at disconect or some thing els like kil the interface it gets when switching to manual again. but that is programing. as i dont know what it reads right now but it sets it to 2.5 on the trim wheel and whit FBW it would after 2 sec go to trim 0. Have a look at the trim wheel at disconect and see what happens then you understand why you have had an nose down problem.

[mike81 7]

I also suffered the sudden drop in fpm on Autoland into LFPG.

Yes ILS settings were correctly inserted as well as the correct LOC Course.

Everything was going fine until the last 400ft when she suddenly dropped. Ended up giving me a touchdown of 650fpm.

I also agree with what someone said earlier maybe the aircraft isnt recognising the airport elevation even if it is inserted into the PERF page.

Im going to test it again with some other airports and see what comes of it.

If anyone would like to test their Autoland at LFPG , it was Runway 26R using RENS4P STAR RW26R Transistion.

Freq: 109.1

Ident: GAU

Loc Course: 266

GS Angle : 3 Degrees.

[HenryD 39]

You are not alone, I discovered this yesterday too (flight from LTBA to LTCG) while testing the ASFADEC.DLL Mathijs posted in the thread "Throttle issues", did just two hours ago a complete deinstall (with removing everything regarding to the AirbusX as mentioned now in several posts), I even restarted my computer after deinstallation, made a fresh install, but this issue remains. What did I do wrong? I have FSX SP2, not Accelleration, maybe another issue with the two different FSX versions?

Regards

Henry

Is this issue with the annoying heavy pitch up while disconnecting the autopilot in cruise flight be looked into by Aerosoft? Answer to my question above posted two days ago also not yet given?

Regards

Henry

[MWR 36]

Is this issue with the annoying heavy pitch up while disconnecting the autopilot in cruise flight be looked into by Aerosoft? Answer to my question above posted two days ago also not yet given?

Regards

Henry

HenryD.

I'd like to know an answer to that question too. That was why I started the thread as an attempt to indicate that I thought the FBW pitch/trim issue might be behind a couple of the issues posted by other AirbusX users. Unfortunately, it doesn't appear to have attracted any Aerosoft interest at all! I don't pretend to be an expert on simulation software but I'd have thought that the fact that the aircraft FBW system has a trim incompatibility problem would affect a number of phases of flight?

Mike

[KAPTEJNLN 237]

Is this issue with the annoying heavy pitch up while disconnecting the autopilot in cruise flight be looked into by Aerosoft? Answer to my question above posted two days ago also not yet given?

Regards

Henry

well first of all i use the Accelleration pack so you see it is not just therefor. and yes i also noticed the pitch up in flight which seems to happen when you have used vertical speed that is what i have seen.

Mike about "it doesn't appear to have attracted any Aerosoft interest at all!" well i think it does but there are many factors, people creates to many posts, makes it harder also for other users to find the awensers. sec i think in some way it would be to recreate it all to fix. or the plane is pushed to the limits to include all the feautures fbw and all that as it is a bit when this is in use this should not work and other parts should work. it seems to be complications be tween 2 systems comunication.

But i agree it is not that fun when things are so.

And to mike81 well dident fly the hole route but made the landing whit full autoland and it works nearly like at EKCH. it is hard to find problems as even if you do the same every time it in some way it flyes diferent, flare stil gets at "RETARD" but at 100 ft it nose down a bit to corect and then flare but not as much as at ekch now but for just a few days ago at ekch it was the same not much flare like here at LFPG.

but 1 thing to be sure of set the same qnh in to the app page on the MCDU as the local qnh

[Paul Golding 159]

HenryD.

I'd like to know an answer to that question too. That was why I started the thread as an attempt to indicate that I thought the FBW pitch/trim issue might be behind a couple of the issues posted by other AirbusX users. Unfortunately, it doesn't appear to have attracted any Aerosoft interest at all! I don't pretend to be an expert on simulation software but I'd have thought that the fact that the aircraft FBW system has a trim incompatibility problem would affect a number of phases of flight?

Mike

Can you give me a scenario with the fully AP settings you're using that can repeatedly result in this pitch up on AP disconnect please.

I have to say that all through the beta this has never been an issue, and with 1.20, still isn't............for me. In fact, I have the opposite issue in that the nose will momentarily dip after AP disconnect - annoying, yes; a problem for me, no. But, this is the complete opposite of what some users are experiencing!

[HenryD 39]

well first of all i use the Accelleration pack so you see it is not just therefor. and yes i also noticed the pitch up in flight which seems to happen when you have used vertical speed that is what i have seen.

Mike about "it doesn't appear to have attracted any Aerosoft interest at all!" well i think it does but there are many factors, people creates to many posts, makes it harder also for other users to find the awensers. sec i think in some way it would be to recreate it all to fix. or the plane is pushed to the limits to include all the feautures fbw and all that as it is a bit when this is in use this should not work and other parts should work. it seems to be complications be tween 2 systems comunication.

But i agree it is not that fun when things are so.

And to mike81 well dident fly the hole route but made the landing whit full autoland and it works nearly like at EKCH. it is hard to find problems as even if you do the same every time it in some way it flyes diferent, flare stil gets at "RETARD" but at 100 ft it nose down a bit to corect and then flare but not as much as at ekch now but for just a few days ago at ekch it was the same not much flare like here at LFPG.

but 1 thing to be sure of set the same qnh in to the app page on the MCDU as the local qnh

Thanks for your answer trying to assume the position of Aerosoft. But indeed I would like to have an official statement from anyone from Aerosoft in charge of support for this product. I also see the problem that there are many threads now, which makes it difficult to search for answers or already posted issues, but as Aerosoft says, support is only done via this forum, then they should at least react to, I think, severe issues like this one here by saying: "thanks for reporting, we will look after that", and get a structure into support here by combining threads referring to the same issue, simply now for three days saying nothing only leads to more confusion if not frustration. Please don't argue now with the popular excuse "They have a wife, familiy and so on...", since Aerosoft is a professional company.

Regards

Henry

[HenryD 39]

Can you give me a scenario with the fully AP settings you're using that can repeatedly result in this pitch up on AP disconnect please.

I have to say that all through the beta this has never been an issue, and with 1.20, still isn't............for me. In fact, I have the opposite issue in that the nose will momentarily dip after AP disconnect - annoying, yes; a problem for me, no. But, this is the complete opposite of what some users are experiencing!

What more than MWR posted in the first, very detailed post here would you like to know?

I can add here: flying with a flightplan entered in MCDU, in cruise, speed managed (~ mach .78), lateral navigation managed, altitude FL370 managed too (dash-ball-dash-ball-37000-ball-dash-ball), A/T engaged (green light on), "mach" "Alt crz" and "nav" showing on PFD, AP1 engaged (green light on), now disconnecting AP1 with right click on AP1 button, green light goes out and aircraft pitches up more than 2.500 ft vertical speed, of course loosing speed rapidly, without pitch input by myself, aircraft manages to recover after some seconds (I think 15 to 30 seconds) in level flight (before nose down with negative vertical speed now), because of resulting speed loss now spooling up thrust until now two or three minutes later again in stable cruise with mach .78. All on FSX SP2 not Acceleration.

Regards

Henry

[MWR 36]

Paul.

I haven't had a chance to do any test flights at a number of weights but my suspicion, and it's no more than that, is that the pitch up/pitch down may be an aircraft weight phenomenon but the main cause is the aircraft being out of trim when operatig with FBW system engaged. My test flights are at lower altitudes because the problem first manifested itself to me when reverting to a manual ILS approach and getting an immeadiate pitch up. However, the description HenryD gives appears to be exactly what I experienced just that he was in the cruise at the time. The auto trim when the FBW system is engaged appears to be very 'low sensitivity' and the aircraft does recover, (as described by HenryD), but only slowly. I also think this manifests itself in the altitude capture performance of the autopilot when the aircraft tends to react slowly to the altitude capture with a slight fly through to about +250ft or so. It then attempts to level at the selected altitude/Flight level but develops a gentle phugoid until settling spot on the selected altitude/Flight Level. I hope this helps?

Regards.

Mike

Oh! By the way. I meant to add that my system appears to be identical to HenryD. FSX Sp1/2 No Acceleration pack.

[KAPTEJNLN 237]

Well think i found why FBW cause up or down as it is the default FBW fault or what ever you would call it, after a flight in the default plane by microsoft i do the same approch at EKCH where FBW was on and it does like airbus X (nose down) but if FBW is turned off it dosen`t corect the trim wheel, and therefore no nose dive. so there is an difference as Airbus X did the same nosedive when FBW was off, thats the awenser of why it keeps nose dive.

It was becaus i have seen thay say the default FBW was good enough i thinked why not try it in the default plane and seee what happens.

So for Airbus X it would be an re-create of FBW and if it is turned off as told before it changes between the systems. There for when FBW is off it also need to be re-done to get over the problems between the systems i think.

[Bizzy 20]

Well think i found why FBW cause up or down as it is the default FBW fault or what ever you would call it, after a flight in the default plane by microsoft i do the same approch at EKCH where FBW was on and it does like airbus X (nose down) but if FBW is turned off it dosen`t corect the trim wheel, and therefore no nose dive. so there is an difference as Airbus X did the same when FBW was off, thats the awenser of why it keeps nose dive.

It was becaus i have seen thay say the default FBW was good enough i thinked why not try it in the default plane and seee what happens.

So for Airbus X it would be an re-create of FBW and if it is turned off as told before it changes between the systems. There for when FBW is off it also need to be re-done to get over the problems between the systems i think.

so if i want no nosedive on my autolanding i turn Off FBW ? so after maybe a smooth landing?

[KAPTEJNLN 237]

so if i want no nosedive on my autolanding i turn Off FBW ? so after maybe a smooth landing?

well it depends on if you mean as in here both full autoland and fly by manual at the last part have been talked about. It would still do an nosedive as told before it looks like an bug even if you turn off the 3 butons on the over head only on pilot side found at FLT CTL (FBW) it would dive but faster to get back if use trim or just smal push back on the joystick. also in some way it works better whit full autoland if FBW is off better flare. but i cant give you an fix that stop the nosedive as that is programing stuff. so if you like FBW start whit it on and before AP disconect at approch turn the 3 buttons of and FBW is off, then it is easyer to land manual.

It is only the default airbus that dosent nosedive when FBW is off. Sorry if i wasent clear enough in the last post.

[Bizzy 20]

well it depends on if you mean as in here both full autoland and fly by manual at the last part have been talked about. It would still do an nosedive as told before it looks like an bug even if you turn off the 3 butons on the over head only on pilot side found at FLT CTL (FBW) it would dive but faster to get back if use trim or just smal push back on the joystick. also in some way it works better whit full autoland if FBW is off better flare. but i cant give you an fix that stop the nosedive as that is programing stuff. so if you like FBW start whit it on and before AP disconect at approch turn the 3 buttons of and FBW is off, then it is easyer to land manual.

It is only the default airbus that dosent nosedive when FBW is off. Sorry if i wasent clear enough in the last post.

thanks

and do you think it's possible to incoporate the fbw of wilco airbus or microsoft airbus into Aerosoft airbus?

[KAPTEJNLN 237]

thanks

and do you think it's possible to incoporate the fbw of wilco airbus or microsoft airbus into Aerosoft airbus?

well im not much into how to building aircraft add-ons more into airports. but as told before they say Airbus X use default microsoft airbus FBW. so it is an bug in microsoft Airbus. the only diference is that in some way Airbus X use same bug when FWB is off, as microsoft dident made that bug when FBW is off only when FBW is on. therefor if it worked like default plane you would notice any nosedive if FBW was off

[Todd_F 38]

Go to avsim and download "trimgauge.zip". It is meant for the default airbus but it fixed my 100ft. nosedive quite nicely. I can't say what it might do to the autoland though. I would suspect it shouldn't effect it negatively.

-Todd