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Guest meirumeiru

retard in "white" autopilot mode

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Guest meirumeiru

I'm flying often with the FMS commanded speed during the whole flight (so, in the "magenta" mode, if you wan't to call it like that) ... in this mode, the AP is retarding at 35 feets over ground... an other solution is to disable ATS at about 100 feets and fly manually from there... now, want I don't understand is, if the AP commands the retard also, if it flyes in the what I call "white" mode... so, if you set the speed by pulling the speed selector knob... should/does it retard or not?

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I'm flying often with the FMS commanded speed during the whole flight (so, in the "magenta" mode, if you wan't to call it like that) ... in this mode, the AP is retarding at 35 feets over ground... an other solution is to disable ATS at about 100 feets and fly manually from there... now, want I don't understand is, if the AP commands the retard also, if it flyes in the what I call "white" mode... so, if you set the speed by pulling the speed selector knob... should/does it retard or not?
Rudolf,ATS will always retard the throttles if engaged during landing. And the RETARD label on the FMA will always be white, since the retard command is not coming from the FMS.Regards,Markus

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When I 1st read this topic I was wearing white sweats and a white T-shirt. So basically that you were making fun of me :(

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Guest meirumeiru
Rudolf,ATS will always retard the throttles if engaged during landing. And the RETARD label on the FMA will always be white, since the retard command is not coming from the FMS.Regards,Markus
Ok, I made a test. I took the MD-11 to LSZH (runway 16) and flew once around the airport. Then I laded again at runway 16. I entered LSZH/LSZH as the route, altitude of 100, ci of 50 then the whole infos for takeoff (to calculate the v1, vr and v2). Finally I had a good config (green bar). After takeoff I turned left (manually, then activated the AP by pressing the "autoflight" button). After, I selected the speed (250) and the heading (about north). The altitude was set to 6000.Then, north of the airport I turned left (manually, so, I pressed the yellow button on the yoke and turned left) ... I still had the ATS activated at this time... then I selected 156 for the speed and slowed down when I found the glideslope and started descending.I didn't extend the flaps fast enough, so the autopilot did set the speed to 172 and I corrected this by setting it to 156 again (this time with flaps and gear extended) ... so, everything seemed to be fine. (ATS on, rest manual). Then I waited what would happen... I expected, that the autopilot would command the retarding at 35 feet above ground... 100, 50, 40, 30 ... and so on... I started to flare, but the retarding never happened and so I ended flying along the whole runway at about 15-25 feets above ground... then, I disengaged the ATS manually and retarded manually to land the plane (of course, this was almost at the end of the runway and I had to go around) ... and, that's what I don't understand... shouldn't the autopilot command a retard in this situation? ... when I fly from one point to an other and let the FMS set the speed during the whole flight, I don't have that problem... I think, I also don't have it, if the FMS commanded the speed in the beginning and I switch to manual mode in the end (not always, but I can't say when it happens, that the retard isn't commanded) ... I think, the last time I had this problem was, when the FMS suddendly lost the "CRZ" entry and stopped commanding any speed...so... is this because of me? my pc? or... is this by design? ... a bug? ... would be nice to read more about thatRudolf

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As Markus wrote, regardless of whether you are in FMS mode or selected mode for speed, the ATS, when active, will retard the throttles on landing, around 35'RA...It is a good idea to move your controller's thrust lever to its idle position, to guarantee that the controller does not send a signal and interrupt the retard...You were flying an autopilot controlled approach or manually?If you perform an autoland with ATS in selected speed (the way I tend to land if I am in IFR/CATIII and cannot see the runway until decision height, otherwise, I throw off the AP at 1000'RA and fly in manually, sometimes with ATS active, sometimes not), then the ATS always retards the thrust at around 35RA... I cannot see what you may be doing wrong from your description. Perhaps you should take some screenshots to illustrate your problem and post them. If you do, make sure that the necessary elements on the displays are visible...A bug in this system would have been found by a number of users a long time ago, myself included. The MD11 is one of my personal FS hangar favourites, and I am sure I would have found a problem here if there was one...Andrew

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Guest meirumeiru
As Markus wrote, regardless of whether you are in FMS mode or selected mode for speed, the ATS, when active, will retard the throttles on landing, around 35'RA...
that's what I understood now... but it didn't retard... now I'd like to find out why
It is a good idea to move your controller's thrust lever to its idle position, to guarantee that the controller does not send a signal and interrupt the retard...
I had the same idea and did that.
You were flying an autopilot controlled approach or manually?
At about 5000 feet i pressed the yellow button on the steering wheel to disengage the autopilot. But the ATS remained active. From then I flew manually. I never was in the "auto-land" mode or something...
If you perform an autoland with ATS in selected speed (the way I tend to land if I am in IFR/CATIII and cannot see the runway until decision height, otherwise, I throw off the AP at 1000'RA and fly in manually, sometimes with ATS active, sometimes not), then the ATS always retards the thrust at around 35RA... I cannot see what you may be doing wrong from your description. Perhaps you should take some screenshots to illustrate your problem and post them. If you do, make sure that the necessary elements on the displays are visible...
Ok, what are those necessary elements? The PFD?
A bug in this system would have been found by a number of users a long time ago, myself included. The MD11 is one of my personal FS hangar favourites, and I am sure I would have found a problem here if there was one...
Well, the MD-11 is also my favorite... that's clear. But what you say about the bug... you know, I'm software engineer and one thing I learned is, that I always find bugs in software, even if thousands say, that there are none. Strangely they always show up, when I use the software... or, maybe I'm the only one to remark that there is a bug?? ... anyway... this time, I'm able to reproduce the behaviour... again and again and again... so, I can easily make those screenshots ...so... what should I do? post the PFD? ... do you need other things? ... or, should I note every single point (every click I did) so that someone can try to reproduce it on an other computer?

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Guest meirumeiru

you can say what you want... but the retard never happens, if I don't fly from x to y (and enter that in the FMS) ... I flew an other two times around the airport... this time I activated the autoland and waited, until it went into the "dual land" mode... then I disengaged it (ATS still working) and landed... nothing... no retard...and, other problem... because the system started shifting the CG out of limmits (drained tank 2 and filled 1 and 3), I switched to the manual mode and wanted to open the fill valve 2... no chance... it didn't open... when I clicked on the button (virtual cockpit), it opened, and when I let the left mouse button go, it closed again... but, when I had the "mouse down" over the button and the "mouse up" outside, it remained active...I wouldn't say, that this is because of the MD-11 ... could also be because of the FSX, that this happens... but these little bugs don't make me happy... I don't want to work around problems... I want to play... :)Isn't there a debug version, to analyse this behaviour?

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When I 1st read this topic I was wearing white sweats and a white T-shirt. So basically that you were making fun of me :(
Thats what you get for wearing white after labor day....:(....:(

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What is it that you are trying to acheive? For the ATS to engage retard automatically, a number of conditions must all be met but it sounds like you are not attempting to meet them. Why not just post a screen shot of the 2D panel from just before and just after you expect retard to be engaged and then we can see if you are suffering a PEBKAC episode.

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Guest meirumeiru
What is it that you are trying to acheive? For the ATS to engage retard automatically, a number of conditions must all be met but it sounds like you are not attempting to meet them. Why not just post a screen shot of the 2D panel from just before and just after you expect retard to be engaged and then we can see if you are suffering a PEBKAC episode.
ok, I'll do that... you will get the screenshot tomorrow...

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Have you done any preflight whatsoever?With no preflight of weights and so on, you will have no programmed landing weight, and so no programmed landing speed...Guessing, as I haven't been in the MD11 for a few days...Andrew

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Have you done any preflight whatsoever?With no preflight of weights and so on, you will have no programmed landing weight, and so no programmed landing speed...Guessing, as I haven't been in the MD11 for a few days...Andrew
Andrew, he has pointed out many times that he uses managed speed without problems so it's safe to say his preflight is correct.

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Guest meirumeiru

well, you mentioned, that the LW has to be calculated... when you only enter something like WMKK/WMKK, you don't get a real route, and then the FMS does not calculate the LW (but since I've been told, that the FMS has nothing to do with the retard function of the ATS, I thougt, that I don't have to look at this)... anyway, I tryed it... I flew the first flight without LW, and the second with LW (I entered a route around a waypoint and returned to the airport, so that the FMS did calculate a trip time and also a LW) ... but... it still does not retard. You can see this on both screenshots... I'm flying below 35 feets (this was some kind of "controlled flight into terrain" what I tryed here) and it's still in the "thrust" mode...

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My first thought is that you are not landing, you are just flying into the ground. Looking at the FCOM "before landing procedure", you should slow to Vref + 5 while still above 50ft AGL, you still have 152 dialed into the FMS. Try the same landing again, but this time dial in 142 instead of 152 and see what happens.

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My first thought is that you are not landing, you are just flying into the ground. Looking at the FCOM "before landing procedure", you should slow to Vref + 5 while still above 50ft AGL, you still have 152 dialed into the FMS. Try the same landing again, but this time dial in 142 instead of 152 and see what happens.
Been a few months since I've flown the MD11 but something doesn't look right on the FMA, it does look like he's flying the aircraft into the ground rather then landing. Also the Vapp shouldn't matter even in selected, High elevation & Heavy you can be landing at 170+ knots

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Guest meirumeiru

ok, tried that... I did touch down with 142, 142 selected and, it remained in the "thrust" mode... LW was correct... everything ok... the spoilers deployed, and it still didn't retard ... but, what I saw now is, that the "magenta circle" on the speed-bar is at 180 ... so, for some reason, the FMS thinks, that this is the best speed for the current situation... don't ask me why... and don't ask me, why the ATS is doing what the FMS is telling, if those systems have no relation with each other (as some sayed)...

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I don't see the green box. Have you armed the spoilers etc.?@David Harrision: While your pictures are very pretty, they are quite a bit larger then forum rules allow for.

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I don't see the green box. Have you armed the spoilers etc.?@David Harrision: While your pictures are very pretty, they are quite a bit larger then forum rules allow for.
Yeah David, I was thinking the same thing, I thought you were posting sceenshots :) Nice shots! I think they are too big :) Paul, the whole thing just looks wrong after flying many approaches myself, as you said it looks like he is flying into the ground rather then landing. Wish I had access to my sim so I could confirm this. If your at home maybe you could get screenshots of a correct managed/selected approach?

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I don't see the green box. Have you armed the spoilers etc.?@David Harrision: While your pictures are very pretty, they are quite a bit larger then forum rules allow for.
You're right... I don't have the green box... but I don't remember, if I had it in the FMS mode... the spoilers are armed (alltough, is that needed on landing? ... for touch and go for example?) and I set the auto break to someting between min and max... flaps 35 or 50, gear out... I don't know what's missing? ... lights? are on... correctly trimmed flying in without problems... ILS activated and... still no green box... I agree, that something must be wrong... but I've no idea what it could be...next thing I try is to fly a very short flight... maybe I'll be able to remark something... or... isn't it enough to disable the autopilot, should I also select an altitued of 0 first? ...

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You're right... I don't have the green box... but I don't remember, if I had it in the FMS mode... the spoilers are armed (alltough, is that needed on landing? ... for touch and go for example?) and I set the auto break to someting between min and max... flaps 35 or 50, gear out... I don't know what's missing? ... lights? are on... correctly trimmed flying in without problems... ILS activated and... still no green box... I agree, that something must be wrong... but I've no idea what it could be...next thing I try is to fly a very short flight... maybe I'll be able to remark something... or... isn't it enough to disable the autopilot, should I also select an altitued of 0 first? ...
No, altitude should be set to Go-Around altitude after G/S intercept

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Guest meirumeiru
No, altitude should be set to Go-Around altitude after G/S intercept
That's what I thought ... well, I tryed to fly from WMKK to WMSA (very short flight) ... and, I was able to get the green bar on final... and... this was after pushing the auto-land button, but then I disabled it again and flew it manually... so, I can't say why it worked this time, because I did to many things, but it seems, that the retarding works, when I'm able to get this green bar... but I don't know why I don't get it always... I don't think, that I did something different (of course, I did, since otherwise it would behave the same way round... it's just software, I know that)... this time I also had the first officer anouncing "glide slope is alive" and "localizer is alive" ... I never heart that before...well, it remains interesting... I'll try to figure out, what makes this green bar showing up and why sometimes the systems seems to hang on the 180s in the middle of the descend (this is the descend speed, because otherwise it would be 250 below 10'000 feets).

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Thats what the manual says about the retard autothrottle mode:"The RETARD mode is a form of thrust control. The throttles are driven to the idle stop when the AP goes into FLARE mode or when RA is less than 50 feet, flaps are greater than 31.5 degrees and ATS is engaged. Exit from retard mode is by setting throttles to reverse thrust or initiation of go-around mode."For my understanding, this converts to the following "logical" expression (that's not C or C++ or so):if (AP.Mode == flare) or (Flaps.Setting >= 31.5 and RA.Alt <= 50) then Throttle.Mode = retardSo, when ground sensors put the plane into flight mode (i.e. no weight on the main gear), throttles should go to retard whenever the plane is below 50 ft RA and flaps are extended in landing configuration.There's no indication that any other requirement is needed to get the throttles retardes (FMC entries etc.). I'd conclude that if in the described landing situation throttles don't retard, this must be either a bug in the MD-11 add-on or the throttle logic has additional properties that aren't in the manuals.

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Guest meirumeiru
For my understanding, this converts to the following "logical" expression (that's not C or C++ or so):if (AP.Mode == flare) or (Flaps.Setting >= 31.5 and RA.Alt <= 50) then Throttle.Mode = retardSo, when ground sensors put the plane into flight mode (i.e. no weight on the main gear), throttles should go to retard whenever the plane is below 50 ft RA and flaps are extended in landing configuration.There's no indication that any other requirement is needed to get the throttles retardes (FMC entries etc.). I'd conclude that if in the described landing situation throttles don't retard, this must be either a bug in the MD-11 add-on or the throttle logic has additional properties that aren't in the manuals.
thanks a lot... that's exactely what I think too... but I have the strong feeling, that the FMS (at least in the PMDG MD-11 addon) has an influence on the ATS... and, I'd say, that this is a bug (either in the addon or in the documentation).

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Maybe you could go through the 1st tutorial flight (again). I think it's a classical PEBKAC.

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Maybe you could go through the 1st tutorial flight (again). I think it's a classical PEBKAC.
Matthew (nothing against you personally, your posting is taken only as an example), I don't think this helps in finding a solution for the original problem :( . The original poster describes a situation that's not in the tutorials. I guess that if the tutorials are followed, everything would be ok. But in this case, the autopilot is switched off and autothrottles are on intentionally.Though I don't know if such a landing ("1/2 on automatics") is performed in real life, it's legitimate to ask such a question since the system logic should act accordingly. Which, to my understanding when reading through all the stuff in this thread, it doesn't. So, it's either a bug, or someone needs to come up with an explanation what exactly is missing in the landing configuration to make the autothrottles work as expected. The aircraft manuals don't say much more than what I posted.I absolutely don't agree that this is "a classical PEBKAC"! Forum threads like this one, where a poster asks for help for a relatively simple problem setup, get this long because many repliers make the classical error of not thoroughly trying to understand and analyze what the problem really is.When one reads through this thread with an appropriate degree of attention, I think the problem is visible and can be understood. I'm missing some serious statements here other than assumptions or suggestions which are irrelevant for a solution. What I'd expect to read here are facts that can be backed with references, or simple "don't know" statements.I'm interested in this thread because I too want to know what goes wrong here. Maybe someone can enlighten us :(

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