Announcement

Collapse

PMDG Forum Rules

1) SIGN YOUR POSTS. Since 1997, we have asked users to sign their real name, first and last, to all posts in the PMDG forum. We do this in order to keep conversations personal and familiar. You took the time to be here, we want to get to know you. This is one of the few rigid rules that we enforce regularly. We do so because we feel that forums in which users must engage one another personally are generally warmer, more collegial and friendly. Posts that are unsigned will be quietly removed without comment by the moderators, so to make your life easy- we recommend enabling your forum signature so that you never need to remember. Do this by clicking the username pull-down at the top right, then selecting "User Settings." You will find the signature editor on the ACCOUNT tab, about half way down the page. Look for "Edit Post Signature." Be sure to click the "Show Signatures" box.

2) BE NICE. We are all simmers here and no matter our differences of opinion, we share a common love of aviation, computing and simulation. Treat everyone else in the forum with respect even when you disagree. If someone frustrates you, walk away from the conversation or ask for a moderator to get involved. Speaking of Moderators, they prefer not to be treated as "The Thought Police" but if any behavior infringes on the enjoyment of another user or is otherwise considered to be unacceptable in the moderator's judgment, it will be addressed in keeping with our view of ensuring that this forum remains a healthy environment for all simmers.

3) BE LAWFUL: Any behavior that infringes upon the law, such as discussion or solicitation of piracy, threats, intimidation or abuse will be handled unsympathetically by the moderators. Threats and intimidation may, at the moderator's discretion, be provided to law enforcement for handling.

4) BE FACTUAL: When you post, always be factual. Moderators will remove posts that are determined not to be factually accurate.

5) RESPECT COPYRIGHTS: Posting of copyrighted material such as flight manuals owned by Boeing or various airlines is not allowed in this forum. If you have questions related to copyrighted material, please contact a forum moderator for clarification.

6) RESPECT PMDG: We love to hear what you like about our products. We also like to hear what you think can be improved, or what isn't working. Please do tell us and we will always treat your feedback with value. Just be sure to treat the team respectfully, as they do put a significant amount of effort into building and maintaining these great simulation products for you.

7) RESPECT PMDG DEVELOPERS: All of the developers will spend some time here. Given the ratio of developers-to-users, it simply isn't possible for us to answer every post and private message individually. Please know that we do try to read everything, but developer workload is simply too high to manage personal contact with tens-of-thousands of users simultaneously. In most cases, members of the development team will stick to conversations in the forum and will not answer private messages.

8) RESPECT OTHER DEVELOPERS: PMDG has always advocated for a strong development community and we have many friends within this community. Every developer offers something unique that helps to make the simming community larger and more vibrant. We insist that you treat our friends respectfully.

9) RESPECT MODERATORS: Moderators have a tough job, and none of them enjoy having to stomp out negativity. If a moderator has to weigh in to keep a thread peaceful, please respect that effort and refrain from giving the moderator any grief.

10) If you require official support for any of our products please open a support ticket through the support portal, https://support.precisionmanuals.com

11) This forum is designed primarily as a vehicle for the PMDG development team to interact with our customers, and for customers to interact with one another in a manner that is positive, supportive and assists in the general advancement of understanding the simulation and helping to make this and future simulations better. Any other use of this forum is not permitted, including but not limited to discussion of pricing policies, business practices, forum moderating policies, advertising of non-PMDG products, promotion of events, services or products that are not approved in advance by PMDG or any other topic deemed unacceptable by any forum administrator

12) HAVE FUN: This is the whole point of it all.
See more
See less

748 Autoland

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    748 Autoland

    I fly long haul, mostly in the 777F, which I love but occasionally I try the 748 and I love it as well but it sucks at auto land, I've looked at various threads on the topic and they always get shunted into talking about some technique issue, I don't want technique, I want "auto" land, in the 777F the performance ranges from under 100fpm to maybe 200 on the high end, but the 748 always seems to be in the high 300s. I just want someone at PMDG to tell me if this is the best I can expect, or if there is any way to "fix" this. I don't see why it shouldn't be able to perform as well as the 777.

    Thanks for the help!

    Jack Vogel
    Last edited by jfvogel; 27Apr2021, 18:06.

    #2
    Originally posted by jfvogel View Post
    I fly long haul, mostly in the 777F, which I love but occasionally I try the 748 and I love it as well but it sucks at auto land, I've looked at various threads on the topic and they always get shunted into talking about some technique issue, I don't want technique, I want "auto" land, in the 777F the performance ranges from under 100fpm to maybe 200 on the high end, but the 748 always seems to be in the high 300s. I just want someone at PMDG to tell me if this is the best I can expect, or if there is any way to "fix" this. I don't see why it shouldn't be able to perform as well as the 777.

    Thanks for the help!

    Jack Vogel
    There is nothing to fix. The vertical rate of descent at the beginning of the flare is going to be different for these two radically different aircraft. Just ensure that you're using A/T and your SPD is set to Vref+5. Honest, fixating on VSI during a landing is the last thing you should be focused on.

    One reason that these aircraft are different is in the main gears. The 777 has two trucks and the 747 has four and the rear ones are cantilevered to contact the ground first and provide an initial deceleration to the descent before the forward mains make contact. It's a relatively complex process that works very well.
    Dan Downs KCRP
    i7-10700K 32GB 3600MHz 2080Ti

    Comment


      #3
      Originally posted by DDowns View Post

      There is nothing to fix. The vertical rate of descent at the beginning of the flare is going to be different for these two radically different aircraft. Just ensure that you're using A/T and your SPD is set to Vref+5. Honest, fixating on VSI during a landing is the last thing you should be focused on.

      One reason that these aircraft are different is in the main gears. The 777 has two trucks and the 747 has four and the rear ones are cantilevered to contact the ground first and provide an initial deceleration to the descent before the forward mains make contact. It's a relatively complex process that works very well.
      I'm not "fixating", i've heard this response before When you're in a VA that tracks stats like this they matter, it effects points on the flight. It's not like I'm losing sleep over it however... I just wanted to know if there was anything that could be done to improve it.

      Thanks for the response!

      Jack

      Comment


        #4
        Jack, the real plane is absolutely capable of doing butter smooth autolandings while the PMDG never will do that. I actually got tired of pointing to this issue because almost nobody seems to be willing to acknowledge that there is an issue. Again and again when the discussion comes to ground effect you will be told "look at your technique" which is extremely frustrating when the autoland issue shows quite clearly that there is something not OK. You can only fix it by editing the ground effect yourself.

        best regards
        Manolo Ruiz Carrió

        Comment


        #5
        Landing on B744 (I presume B748 is similar to this) with a rate of 200 - 250 fpm is desired. As I understand it, at this rate met all requirements for a good landing. Lower fpm may result in a long landing. Smooth / "butter" landing - as popularized by many - is not always proper and desired landing technique. Landings at 300 fpm are more than acceptable (even at 400 fpm). Hence if autopilot lands at such figure (350+), I would say all is well and as works as planned.
        Andrej Lippay

        Comment


          #6
          And here we go again. Instead of giving any explanation why the PMDG 747 wont ever touch down softly on autoland while the real plane can do that, you will be told that a firm landing is safer than a soft landing. Nobody doubts that this is true, but it is just not the topic.
          Manolo Ruiz Carrió

          Comment


          • DDowns
            DDowns commented
            Editing a comment
            The topic is I want a soft landing. The response is no you don't, you want a safe landing.

          • Sekkha
            Sekkha commented
            Editing a comment
            No, its NOT the topic

          #7
          Some examples of how the real thing (the 744 in this case) is doing autolands if somebody is interested (and yes, I know, it wont always be this smooth depending on conditions). But you wont ever see this on your PMDG even in best possible conditions, and despite the fact, that the PMDG autothrottle is ALWAYS giving an extra boost of thrust before closing throttles, something I highly doubt the real autothrottle is doing under any condition. Before PMDG added this boost autolandings on the PMDG 744 were as "safe" as 400-600 fpm....So, might the ground effect perhaps not be spot on ?

          https://www.youtube.com/watch?v=vCP7vVn0Nes
          https://www.youtube.com/watch?v=HxsIlBI7gwc
          Last edited by Sekkha; 27Apr2021, 21:44.
          Manolo Ruiz Carrió

          Comment


            #8
            Originally posted by Sekkha View Post
            Some examples of how the real thing (the 744 in this case) is doing autolands if somebody is interested (and yes, I know, it wont always be this smooth depending on conditions). But you wont ever see this on your PMDG even in best possible conditions:

            https://www.youtube.com/watch?v=vCP7vVn0Nes
            https://www.youtube.com/watch?v=HxsIlBI7gwc
            I didn't see any indication the first one was an autoland. It looked like most of my hand flown landings.
            The second one had the VSI partially obscured by the yoke horn but I noticed at touch down the need jumped up from the first mark below zero to zero and a look in the book reveals that mark to be the -500 fpm mark.

            Regardless.... in the first video pay attention to the landing. Note how the rear mains are swiveled such that the aft most tires make first contact and then there is mechanical dampening of the remainder of the landing as the full rear and then the from center gear make contact. This allows the landing to almost always feel "smooth" because of the this mechanical dampening during the landing. In a PC simulator you can never feel the landing so you are using clues such as the VSI, which is patently wrong because you notice how it instantly swings to zero but the landing is still in progress. The VSI is driven in part by the IRS to give such instantaneous indications.

            You will not find evidence that the PMDG 748 autoland lands "too hard." If you do I'd like to see it.
            Dan Downs KCRP
            i7-10700K 32GB 3600MHz 2080Ti

            Comment


              #9
              The autor of the first video is saying that he was hearing it on the ATC. And if you listen well you can hear the crew saying that they are on autoland. On the second video the captain makes this statement: "The Autopilot was flying this amazing soft Landing, I was just sitting in my pilot seat watching the beauty of the BOEING automatic landing system".
              All the evidence is there,no need to feel anything. Just measure the time the PMDG needs between 10ft and touch down.
              Last edited by Sekkha; 27Apr2021, 21:56.
              Manolo Ruiz Carrió

              Comment


                #10
                Originally posted by Sekkha View Post
                The autor of the first video is saying that he was hearing it on the ATC. And if you listen well you can hear the crew saying that they are on autoland. On the second video the captain makes this statement: "The Autopilot was flying this amazing soft Landing, I was just sitting in my pilot seat watching the beauty of the BOEING automatic landing system".
                All the evidence is there,no need to feel anything. Just measure the time the PMDG needs between 10ft and touch down.
                Good lord man..... the first video didn't give you any sense of the VSI at beginning of touchdown.
                In the second, I can clearly see the VSI instantly change from -500 fpm to zero.... and the last 10 feet are already quite a way into the gears touching down. Gear touchdown is not an instant event.

                I'm done here unless you got something better than that. Got too many rated B744/748 pilots hanging out here to not believe them and instead try to follow your path.
                Dan Downs KCRP
                i7-10700K 32GB 3600MHz 2080Ti

                Comment


                  #11
                  Originally posted by DDowns View Post

                  Good lord man..... the first video didn't give you any sense of the VSI at beginning of touchdown.
                  In the second, I can clearly see the VSI instantly change from -500 fpm to zero.... and the last 10 feet are already quite a way into the gears touching down. Gear touchdown is not an instant event.

                  I'm done here unless you got something better than that. Got too many rated B744/748 pilots hanging out here to not believe them and instead try to follow your path.

                  That is perfectly Ok for me. Perhaps I am just wrong and the first video is showing a rather firm landing , and the captain in the second one was just amazed by a 300-500 fpm landing. Who knows..
                  Manolo Ruiz Carrió

                  Comment


                    #12
                    You're probably better off submitting a ticket to get a developer's attention if you believe it to be that big of a deal, you won't really get anywhere with an issue like this in the forum unless you can provide hard evidence that cannot be disputed, sadly sometimes a video is not enough. You might get a more final answer to this matter. Be prepared to provide evidence of your claims though. Pmdg team prefers facts, and unless you're a real 747 pilot, it may be a bit difficult to convince them, especially since the auto land isn't OBVIOUSLY broken, like slamming into the runway at 800fpm or something obvious like that.

                    Also keep in mind, maybe, just maybe they can't simulate things exactly like the real aircraft because of whatever arrangement they have with Boeing.
                    Bryan Richards

                    Comment


                      #13
                      In all fairness this is a computer simulation, a few (sry RSR) lines of code calculating things in an environment of a few different lines of code. The outcome is a visual simulation of an incredibly complex machine that automatically calculates a touchdown difference of not even 50 meters per minute. At school I ran those 50m in 10 seconds or so, no idea anymore. And I didn‘t have any hydraulic shock absorbers.

                      The real 747 costs a few bucks more than PMDG has ever earned with their addon, the development time exceeds the simulation a bit too and the big advantage is the real air outside that flows over the wings and build the real ground effect. This stupid VSI in front of us shows a code-based rate of descent while the whole physics of this instrument (basically a can with a hole in it, yes I know that the 747 has a more sophisticated version but the principle is still the same) doesn’t even allow a direct reading right at this time in a flare/ground effect that flattens the whole curve. It always lags a moment. What the logging software if this genius VA does is read the output of some code of FSUIPC when it reads a touch down from the sim. Use two loggers at the same time, get two values.

                      100 feet per minute difference between a computer calculated hobby simulation that even has to bother with some weather engine injected variables that shall shake the airplane and a 300 Million Dollar aircraft is good enough for me.

                      The fuel flow isn‘t 100% correct either by the way. Nor the fuel shake. And the chemtrails are too short.
                      Last edited by Ephedrin; 28Apr2021, 02:16.
                      i7-6700k, GTX 1080TI, 32GB DDR4 RAM @2666MHz, 4k
                      Marc Ehnle

                      Comment


                        #14
                        Bryan and Marc, you are both absolutely right with what you are saying. But it takes only a little tiny bit of tweaking of the ground effect to make the plane autoland/land a bit softer, not a technical big deal at all, no platform limitation is being in the way here. And if I remember correctly , you also have been wondering about this issue Marc, didnt you? And among the many users who complain about it there have been some RW 747-pilots,too. For sure there are other RW pilots which wont agree and they seem to have PMDGs ear, but so is life, and especially with issues like this, which are not so easily defineable as saying, "this switch does this and that". Have you ever had a medical problem and went for a second opinion which was then the opposite to the first one. Hmm...

                        In one thing however I need to rectify or rather clarify. I am only speaking about the PMDG 744, not the 748 which the OP was speaking about. I dont know how the 748 behaves as I am noy flying her

                        best regards
                        Manolo Ruiz Carrió

                        Comment


                          #15
                          Originally posted by Sekkha View Post
                          Bryan and Marc, you are both absolutely right with what you are saying. But it takes only a little tiny bit of tweaking of the ground effect to make the plane autoland/land a bit softer, not a technical big deal at all, no platform limitation is being in the way here. And if I remember correctly , you also have been wondering about this issue Marc, didnt you? And among the many users who complain about it there have been some RW 747-pilots,too. For sure there are other RW pilots which wont agree and they seem to have PMDGs ear, but so is life, and especially with issues like this, which are not so easily defineable as saying, "this switch does this and that". Have you ever had a medical problem and went for a second opinion which was then the opposite to the first one. Hmm...

                          In one thing however I need to rectify or rather clarify. I am only speaking about the PMDG 744, not the 748 which the OP was speaking about. I dont know how the 748 behaves as I am noy flying her

                          best regards
                          No I was wondering about the nosewheel slamming down which was indeed a problem, but on my side. I almost never do autolands, the sim and Active Sky simply hardly generate the conditions that would require it. I wouldn't even have noticed it. It's a bit like the frequency of the strobes, nothing I would ever notice or compare to videos. 300fpm is a perfectly save touchdown, nothing to ever worry about. And all above it's just a value read from the sim. My VA has the same habit of making competitions about the landing rate and I always smirk when I get positive values. And a couple of weeks ago I did a "greaser" with the Kingair just to get a readout of -300 or so too. Well, it was a falling runway. This value is just too pointless to scratch our heads about, autoland or manual.

                          If the tweak is so simple then just go ahead. However I personally wouldn't risk it, changing cfg files can easily mess up other parts of the addon. I'm not here to defend PMDG, this won't earn me a washing mashine. But I sometimes don't understand the motivation of complaining so passionately about these things. I see that there might be discrepancies between the simulation and the real airplane (regardless of the developer) but I don't expect it to be 100%. I know the real C172 and the A2A version is great but not a perfect match. It's normal. The NGX has lagged the pitch-power-momentum for 10 years, the NGXu has other inaccuracies and so does the 777 and 747. They are not perfect and are never going to be and a search about these topics display PMDG's attitude towards improving these parts: If it's feasable they do it. But they have never changed a single value because it looks better then, as simple as this modification might be.

                          Out of curiosity: what tweak do you speak about?
                          i7-6700k, GTX 1080TI, 32GB DDR4 RAM @2666MHz, 4k
                          Marc Ehnle

                          Comment


                            #16
                            Originally posted by Ephedrin View Post

                            No I was wondering about the nosewheel slamming down which was indeed a problem, but on my side. I almost never do autolands, the sim and Active Sky simply hardly generate the conditions that would require it. I wouldn't even have noticed it. It's a bit like the frequency of the strobes, nothing I would ever notice or compare to videos. 300fpm is a perfectly save touchdown, nothing to ever worry about. And all above it's just a value read from the sim. My VA has the same habit of making competitions about the landing rate and I always smirk when I get positive values. And a couple of weeks ago I did a "greaser" with the Kingair just to get a readout of -300 or so too. Well, it was a falling runway. This value is just too pointless to scratch our heads about, autoland or manual.

                            If the tweak is so simple then just go ahead. However I personally wouldn't risk it, changing cfg files can easily mess up other parts of the addon. I'm not here to defend PMDG, this won't earn me a washing mashine. But I sometimes don't understand the motivation of complaining so passionately about these things. I see that there might be discrepancies between the simulation and the real airplane (regardless of the developer) but I don't expect it to be 100%. I know the real C172 and the A2A version is great but not a perfect match. It's normal. The NGX has lagged the pitch-power-momentum for 10 years, the NGXu has other inaccuracies and so does the 777 and 747. They are not perfect and are never going to be and a search about these topics display PMDG's attitude towards improving these parts: If it's feasable they do it. But they have never changed a single value because it looks better then, as simple as this modification might be.

                            Out of curiosity: what tweak do you speak about?
                            Marc, the issue is actually not the autoland itself, I almost dont use it either. The real topic is the ground effect and the autoland ist just useful to see what the plane does without having to talk about landing techniques.

                            And I am actually almost not complaining about this issue anymore. I found my way to live with it perfectly.
                            The thing is that every few weeks sombody else brings up this ground effect thing because he finds out that the commonly recomended landing technique (or the autolanding) is not working very well but leading to quite hard landings in the sim. I normally dont chime in anymore but sometimes I do, this depends on my mood.. Yesterday I was in the mood to argue a bit,sorry But I actually do that to show people who are complaining or wondering that hey are not allone with their findings. Nothing else.

                            There have been endless discussions about landing techniques. The FCTM and many people here in the forum including real world pilots say that flare should be initiated at around 30ft. But many others (including you by the way: https://forum.pmdg.com/forum/main-fo...latest-version) found that this is not really working in the sim.
                            The PMDG autopilot initiates flare at around 40ft and always gives that extra boost of thrust just prior to flaring regardless of conditions, and even then the landings it achieves -unlike its real world counterpart as it seems- are everything else than smooth.

                            So, given this situation: Is there anything unreasonable or surprising that one comes to the conlusion that the ground effect might perhaps be a little bit too weak? This has nothing to do with being obsessed with greasers at all, an allegation we ignorant armchair pilots are so many times confronted with. And there is also no need to explain that a sim never ever will be 100% accurate in everything, of course not. But what else if not these type of things are understandable to be discussed here in this forum? Landing is the culminative point of every flight , at least for me, and if the landing is not fully satisfying, the whole flight leaves an unsatisfying feeling. I am sure you know what I am talking about. So do you really find it more understandable that people are endlessly and passionately discussing the hypothetic future of the MSFS flight model or other stuff alike instead ?

                            To your last question: Ground effect in P3D is coded in form of a x/y-graph in the -.air file. It is easily editable with any freeware air file editor.

                            best regards
                            Manolo Ruiz Carrió

                            Comment


                              #17
                              Originally posted by Sekkha View Post

                              Marc, the issue is actually not the autoland itself, I almost dont use it either. The real topic is the ground effect and the autoland ist just useful to see what the plane does without having to talk about landing techniques.

                              And I am actually almost not complaining about this issue anymore. I found my way to live with it perfectly.
                              The thing is that every few weeks sombody else brings up this ground effect thing because he finds out that the commonly recomended landing technique (or the autolanding) is not working very well but leading to quite hard landings in the sim. I normally dont chime in anymore but sometimes I do, this depends on my mood.. Yesterday I was in the mood to argue a bit,sorry But I actually do that to show people who are complaining or wondering that hey are not allone with their findings. Nothing else.

                              There have been endless discussions about landing techniques. The FCTM and many people here in the forum including real world pilots say that flare should be initiated at around 30ft. But many others (including you by the way: https://forum.pmdg.com/forum/main-fo...latest-version) found that this is not really working in the sim.
                              The PMDG autopilot initiates flare at around 40ft and always gives that extra boost of thrust just prior to flaring regardless of conditions, and even then the landings it achieves -unlike its real world counterpart as it seems- are everything else than smooth.

                              So, given this situation: Is there anything unreasonable or surprising that one comes to the conlusion that the ground effect might perhaps be a little bit too weak? This has nothing to do with being obsessed with greasers at all, an allegation we ignorant armchair pilots are so many times confronted with. And there is also no need to explain that a sim never ever will be 100% accurate in everything, of course not. But what else if not these type of things are understandable to be discussed here in this forum? Landing is the culminative point of every flight , at least for me, and if the landing is not fully satisfying, the whole flight leaves an unsatisfying feeling. I am sure you know what I am talking about. So do you really find it more understandable that people are endlessly and passionately discussing the hypothetic future of the MSFS flight model or other stuff alike instead ?

                              To your last question: Ground effect in P3D is coded in form of a x/y-graph in the -.air file. It is easily editable with any freeware air file editor.

                              best regards
                              Please, don‘t excuse yourself if there is a heated discussion, I like them actually lol, as long as they remain civil and based on truth. I also like to provoke a bit at times and I can certainly take some headwind

                              yeah I remember now, I haven‘t flown the 747 much this year. I can obviously not tell why PMDG seems so reluctant to change or improve the ground effect / flare behaviour but I suppose two things: Every change to the flight model would have the potential to mess up something else and I think that they have tweaked it to the best they could in the P3D version they had available when the 747 was updated. I don‘t know if P3D changed this behaviour in the meantime but I cannot exclude it. Second point is that as soon as PMDG update something like this it will require a new build number which means another official update cycle that has to be paid. Even if RSR does it himself it has to be accounted and given the problems with Covid, MSFS and Boeing (Max) all at once I wouldn‘t be surprised if a new update cycle simply wasn‘t justifiable at the moment. Maybe we‘ll see another big update for the 747 once the pressure reduces a bit. Fingers crossed
                              i7-6700k, GTX 1080TI, 32GB DDR4 RAM @2666MHz, 4k
                              Marc Ehnle

                              Comment


                                #18
                                Originally posted by Ephedrin View Post

                                Please, don‘t excuse yourself if there is a heated discussion, I like them actually lol, as long as they remain civil and based on truth. I also like to provoke a bit at times and I can certainly take some headwind
                                LOL, I think I can say the same about me. I enjoy them as well, but as I said, it depends on my mood...

                                Regarding your thoughts about the reasons, yea, I have no real idea either. The flight model thing could be, but I just realized that I seem to have no idea about how software business works: What do you mean with "a new built / an official update cycle has to be paid" ? Has that to do with taxes or something? Completely confused now LOL
                                Last edited by Sekkha; 28Apr2021, 20:57.
                                Manolo Ruiz Carrió

                                Comment


                                • Ephedrin
                                  Ephedrin commented
                                  Editing a comment
                                  I have no idea about the US tax system in Germany you‘d have to do the whole accounting as a self-employed as well.. but it works completely different here. And nobody doesn‘t want to work for free 🤷🏻‍♂️ But I think that‘s another topic.

                                • Sekkha
                                  Sekkha commented
                                  Editing a comment
                                  Ok, yes, that is indeed another topic

                                #19
                                Originally posted by jfvogel View Post
                                I fly long haul, mostly in the 777F, which I love but occasionally I try the 748 and I love it as well but it sucks at auto land, I've looked at various threads on the topic and they always get shunted into talking about some technique issue, I don't want technique, I want "auto" land, in the 777F the performance ranges from under 100fpm to maybe 200 on the high end, but the 748 always seems to be in the high 300s. I just want someone at PMDG to tell me if this is the best I can expect, or if there is any way to "fix" this. I don't see why it shouldn't be able to perform as well as the 777.

                                Thanks for the help!
                                Jack Vogel
                                Jack,
                                Getting back to your original post, there are too many unknown variables in your post for any user to say for certain whether or not the 300ft/min ROD you are seeing in your PMDG B748 at touchdown is an issue - or not. For starters, Boeing have said in the past that it is possible for the real aircraft to autoland without flaring. Although this is very unlikely to happen, it could result in an 800ft/min ROD at touchdown on a 3 deg glideslope; in which case your 300ft/min seems perfectly reasonable to me .

                                Unfortunately, you do not say anything about the aircraft livery you were using; for example what version was it, what was its landing weight, what were the landing flap setting and approach speed etc. There was also no mention of the P3D version you are using and where you were attempting to autoland. Are you using any addon scenery or weather and what were the conditions?. Is the airfield runway's ILS correctly modelled and approved for (CAT IIIB) autolands? If you decide to submit a suppor ticket these are the sort of details PMDG will need to know about in order to replicate your flight and presumably have any chance of giving you a definitive answer.

                                All PC simulators are a compromise and P3D is no different, so maybe we are all expecting too much from our PMDG aircraft - and others? P3D cannot possibly reproduce the performance or handling characteristics of this one aircraft type as closely as a dedicated full-size B744/-8 simulator does and even they are not 100% realistic. Marc Ehnle mentioned the NGX and said it "has lagged the pitch-power-momentum for 10 years, the NGXu has other inaccuracies and so does the 777 and 747". Even RW B737 pilots converting onto a B744 or A380 can get caught out by their larger size during their initial conversion training, because they do not appreciate at first how much extra inertia they have. It is therefore hardly surprising their "pitch-power-momentuim" lags when compared to a Cessna 172, because they are slow to respond to thrust changes and even the engines are slow to spool up from flight idle.

                                If I were you, I would not worry too much about a 300ft/min ROD during an autoland unless your PMDG B744/-8 visibly bounces, or it makes a complete mess of the touchdown and rollout.. Whenever I have watched my PMDG B747/-8 from the outside during an autoland the aircraft has not bounced (with or without the momentary addition of a small amount of extra autothrottle thrust). Three important things to watch out for during autolands are for the aircraft to start to flare at approximately 50ft RA depending on the ROD, the thrust levers retard to idle at 25ft RA and Rollout mode engages at 5ft RA. Oh - and just make sure you are using typical CAT III weather as well - i.e. light winds and thick fog - then you won't see a thing outside uintil after nosewheel touchdown and end up worrying yourself unnecessarily about your 300ft/min ROD !
                                Last edited by Michael Codd; 28Apr2021, 22:53.
                                Michael Codd

                                Comment


                                  #20
                                  The thing that bugs me the most about the latest and greatest 747 and 777 iterations from PMDG is that the ground effect, thrust timing, or whatever has been adjusted, causes such consistently hard landings despite following FCTMs to the T... whereas previous iterations for 32bit P3D performed just splendidly.

                                  Something in recent updates (the last year or two) have broken these airplanes' ability to perform as their real-world counterparts do in the landing sequence (auto or manual)
                                  - Kevin Boydston
                                  Flickr, Airliners, Repaints Dropbox

                                  Comment


                                    #21
                                    Originally posted by N800AN View Post
                                    The thing that bugs me the most about the latest and greatest 747 and 777 iterations from PMDG is that the ground effect, thrust timing, or whatever has been adjusted, causes such consistently hard landings despite following FCTMs to the T... whereas previous iterations for 32bit P3D performed just splendidly.

                                    Something in recent updates (the last year or two) have broken these airplanes' ability to perform as their real-world counterparts do in the landing sequence (auto or manual)
                                    I can not agree Kevin. What has changed is that you need to reduce the thrust more slowly, in accordance with the FCTM, which states that your thrust levers should reach IDLE by the moment you touch down.
                                    If you do this in the simulation both the 777 as well as the 747 land perfectly fine on my side.
                                    This was indeed a change from previous versions where the thrust had no effect and you could just slam the thrust levers to the close position at 50ft without any noticable consequences.

                                    Comment


                                      #22
                                      It’s just that hard for PMDG to admit that something is their problem right? And there is always someone jump out saying it’s OP’s problem and not PMDG in no time and sometimes providing faulty informations.

                                      To the OP’s question, I think current autoland system indeed has some problem, both in 744 and 748. And hopefully the coming AFDS update will fix this issue.

                                      To Sekkha, I think PMDG did a nice job on Ground effect now. Although there are still some difference between PMDG and the real thing, but at least the pitch attitude at landing is more or less match the manual states.
                                      Chi-cheng Liu (Volleyball)

                                      Comment


                                        #23
                                        You guys have to be kidding me. I never. NEVER look at my VSI during landing. Nor does the PM or the relief. Because in the end it doesn’t matter. Soft landings are NOT desirable. They might be bragging rights but you can damage tires on a smooth landing. The friction coefficient between the runway surface and tire might not be enough to spin the tires up and you can shave layers of rubber from the tires. Seen it done. Now you have a flat spot and at 170kts at rotation those flat spots shake the aircraft quite violently. High 200s is actually a decent landing and these VVI indicators in the sim from my understanding are incredibly inaccurate. If you’re part of a VA that seriously grades you in them I might suggest going elsewhere.
                                        Last edited by thibodba57; 01May2021, 06:13.
                                        Brian Thibodeaux
                                        ‘Giant’ B747-400/8 Captain
                                        Typed MD-80, BE1900
                                        ATP, CFI, MEI
                                        My Liveries

                                        Comment


                                          #24
                                          Originally posted by thibodba57 View Post
                                          You guys have to be kidding me. I never. NEVER look at my VSI during landing. Nor does the PM or the relief. Because I’m the end it doesn’t matter. Soft landings are NOT desirable. They might be bragging rights but you can damage tires on a smooth landing. The friction coefficient between the runway surface and tire might not be enough to spin the tires up and you can shave layers of rubber from the tires. Seen it done. Now you have a flat spot and at 170kts at rotation those flat spots shake the aircraft quite violently. High 200s is actually a decent landing and these VVI indicators in the sim from my understanding are incredibly inaccurate. If you’re part of a VA that seriously grades you in them I might suggest going elsewhere.
                                          Nobody is kidding you.
                                          But is it really so hard to understand what the topic is and what not ?

                                          The topic is -for example- NONE of the following questions:

                                          Should I look at the VSI during landing?
                                          Should I not look at the VSI during landing?
                                          Where should I look during landing?
                                          Is a hard landing a good landing?
                                          Is a soft landing a good landing?
                                          What is a good landing?
                                          What is a bad landing?
                                          Will the airframe suffer by a hard landing?
                                          Will the airframe suffer by a soft landing?
                                          Is a soft landing a safe landing?
                                          Is a hard landing a safe landing?
                                          etc etc etc...

                                          No doubt, these are interesting questions and must have their place in this froum as well.

                                          But The ONLY relevant question here is the following:
                                          Is the virtual replica of the real plane in ALL aspects as close to the real airplane as it can be in a PC-simulation ?

                                          I think one of the reason for this missunderstanding might be that the motivation for being a virtual pilot can be very diverse among users and can thus be completely different from the motivation of being a real word pilot. And therefore the perspective and interest on flying and the aircraft itself and what the virtual flying is used for, can be completely different as well. I am sure that many many users are by no means wannabe real world pilots. But some real world pilots possibly think exactly this about them. So,If I am a real world pilot I would not look at the VSI or the strobes timing in the real airplane either, why the hell should I ? But if I am just a pedantic model builder I will look at strobe times of course.

                                          My feeling is that PMDG is open for and interested in many different views, and this is good. Why would they have adjusted the strobes timings for example if only flight training was in their interest ?

                                          But one thing you said makes me curious: How do you measure the accuracy of a VSI indicator in a closed virtual world? Against which objective reality?

                                          best regards
                                          Last edited by Sekkha; 30Apr2021, 20:46.
                                          Manolo Ruiz Carrió

                                          Comment


                                          • Kevin Hall
                                            Kevin Hall commented
                                            Editing a comment
                                            I could be wrong, but I think Brian probably meant the touchdown rate of descent that is calculated by FSUIPC, not the VSI. The FSUIPC number that most VAs record isn't reliable. You can easily verify the VSI accuracy by setting a vertical speed and seeing how much altitude changes in one minute.
                                            Last edited by Kevin Hall; 30Apr2021, 20:47.

                                          • Sekkha
                                            Sekkha commented
                                            Editing a comment
                                            Ah ok, probably he meant the FSUIPC . I never used that so no idea..
                                            But is the altitude indication always reliable in this closed virtual world? Can its accuracy be measured ?

                                          #25
                                          Originally posted by Sekkha View Post

                                          Nobody is kidding you.
                                          But is it really so hard to understand what the topic is and what not ?

                                          The topic is -for example- NONE of the following questions:

                                          Should I look at the VSI during landing?
                                          Should I not look at the VSI during landing?
                                          Where should I look during landing?
                                          Is a hard landing a good landing?
                                          Is a soft landing a good landing?
                                          What is a good landing?
                                          What is a bad landing?
                                          Will the airframe suffer by a hard landing?
                                          Will the airframe suffer by a soft landing?
                                          Is a soft landing a safe landing?
                                          Is a hard landing a safe landing?
                                          etc etc etc...

                                          No doubt, these are interesting questions and must have their place in this froum as well.

                                          But The ONLY relevant question here is the following:
                                          Is the virtual replica of the real plane in ALL aspects as close to the real airplane as it can be in a PC-simulation ?

                                          I think one of the reason for this missunderstanding might be that the motivation for being a virtual pilot can be very diverse among users and can thus be completely different from the motivation of being a real word pilot. And therefore the perspective and interest on flying and the aircraft itself and what the virtual flying is used for, can be completely different as well. I am sure that many many users are by no means wannabe real world pilots. But some real world pilots possibly think exactly this about them. So,If I am a real world pilot I would not look at the VSI or the strobes timing in the real airplane either, why the hell should I ? But if I am just a pedantic model builder I will look at strobe times of course.

                                          My feeling is that PMDG is open for and interested in many different views, and this is good. Why would they have adjusted the strobes timings for example if only flight training was in their interest ?

                                          But one thing you said makes me curious: How do you measure the accuracy of a VSI indicator in a closed virtual world? Against which objective reality?

                                          best regards
                                          I think the big "problem" is that PMDG interpretes the whole VS at touchdown topic with another approach of reasoning than the people who "complain" about it.

                                          What people say is basically "The real 747 (and 777) can land at -100fpm, we want a simulation that is as close to those airplanes that fly around and land themselves out there in reality as possible so please correct the landing VS to those real airplanes.

                                          PMDG says (in my humble understanding): "We have original technical documentation, we know exactly what the airplanes are supposed to do by design and what not and how their systems calculate what they do. We know there are videos of 747s that land at -100fpm but that is not what the documentation says"

                                          And nearly every pilot in this forum, GA or commercial/airline has commented with statements like "a greaser is not a safe landing" Even I as a 15 years old sailplane pilot and later with engine was always tought not to aim for soft landings but make sure that the plane stays on the ground firmly once it's down. In the Skyvan an intentional greaser is even forbidden to prevent any sideslip of the main gear as the wheel rims can't stand them. I don't understand why it's so important to make PMDG force a touchdown that is not willed by design.
                                          i7-6700k, GTX 1080TI, 32GB DDR4 RAM @2666MHz, 4k
                                          Marc Ehnle

                                          Comment


                                            #26
                                            Originally posted by Ephedrin View Post

                                            I think the big "problem" is that PMDG interpretes the whole VS at touchdown topic with another approach of reasoning than the people who "complain" about it.

                                            What people say is basically "The real 747 (and 777) can land at -100fpm, we want a simulation that is as close to those airplanes that fly around and land themselves out there in reality as possible so please correct the landing VS to those real airplanes.

                                            PMDG says (in my humble understanding): "We have original technical documentation, we know exactly what the airplanes are supposed to do by design and what not and how their systems calculate what they do. We know there are videos of 747s that land at -100fpm but that is not what the documentation says"

                                            And nearly every pilot in this forum, GA or commercial/airline has commented with statements like "a greaser is not a safe landing" Even I as a 15 years old sailplane pilot and later with engine was always tought not to aim for soft landings but make sure that the plane stays on the ground firmly once it's down. In the Skyvan an intentional greaser is even forbidden to prevent any sideslip of the main gear as the wheel rims can't stand them. I don't understand why it's so important to make PMDG force a touchdown that is not willed by design.
                                            I pretty much agree with what your are saying. And that is basically what I am saying, too. It has to do with different approaches and motivations to model building and simming in general. And of course it is PMDGs choice to do what they want. But there is no need to treat people who have other approaches as ignorant wannabe pilots which are obsessed by greasers and give them possibly unwanted flying lessons. They have the same "right" to request things as anybody else. So why shouldnt they do it?
                                            And then there is this original technical documentation which says "flare should be initiated at around 30ft" and this "..the flare maneuver brings the airplane to a smooth automatic landing touchdown..."

                                            have a nice weekend everybody
                                            Last edited by Sekkha; 01May2021, 08:47.
                                            Manolo Ruiz Carrió

                                            Comment


                                              #27
                                              Originally posted by jfvogel View Post
                                              When you're in a VA that tracks stats like this they matter, it effects points on the flight.
                                              Serious question. Suppose you're flying into Fort Lauderdale for runway 28L. This runway has a significant slope, as the start of the runway is at an elevation of 65 feet, and the end of the runway is at an elevation of only 10 feet. If you end up touching down on the slope, you will end up with a fairly high vertical speed, not because of technique, but simply because you're going down the hill to try to get to the runway. If you end up over the slop and you aim for 100-200 feet per minute, you won't touch down until you end up on the other side of the runway. Do you shoot for a higher vertical speed to try to land on this runway or would you be better off just going off the end of the runway just for a low vertical speed.
                                              Captain Kevin

                                              Kevin Yang

                                              Comment


                                              • Ephedrin
                                                Ephedrin commented
                                                Editing a comment
                                                The whole VA landing points are useless anyway. In a slow airplane a 3degree angle has a lower neg VS than a faster airplane so even if you had no idea what you do and let a C172 fly on approach mode until it hits the ground you wouldn’t exceed the -300fpm much xD Doing autolands you‘d even cheat the system as it rates the autopilot, not the pilot. 😜

                                              • Captain Kevin
                                                Captain Kevin commented
                                                Editing a comment
                                                That's my point.

                                              #28
                                              Originally posted by DDowns View Post

                                              There is nothing to fix. The vertical rate of descent at the beginning of the flare is going to be different for these two radically different aircraft. Just ensure that you're using A/T and your SPD is set to Vref+5. Honest, fixating on VSI during a landing is the last thing you should be focused on.

                                              One reason that these aircraft are different is in the main gears. The 777 has two trucks and the 747 has four and the rear ones are cantilevered to contact the ground first and provide an initial deceleration to the descent before the forward mains make contact. It's a relatively complex process that works very well.
                                              Dan, are you even a pilot? I'm sorry, but you have absolutely no idea of what you're talking about here. The real 747-8 makes ultra-smooth autolands. The PMDG autoland is broken and has been from the very beginning.

                                              Comment


                                                #29
                                                Originally posted by Julian Speer View Post
                                                Dan, are you even a pilot? I'm sorry, but you have absolutely no idea of what you're talking about here. The real 747-8 makes ultra-smooth autolands. The PMDG autoland is broken and has been from the very beginning.
                                                Julian,
                                                I’m sorry to say you are mistaken when you say Dan has absolutely no idea what he is talking about. He probably knows more about Flight Simulation and how your PMDG aircraft interacts with P3D than you and I have had sliced bread. With the greatest respect, it is therefore unhelpful to turn an issue raised in these forums into a personal one by questioning his qualification when it is the facts of the matter we should be dealing with.

                                                I know of many flight simulator engineers and software programmers who can ‘fly’ an ILS in a B744 simulator far better than any qualified pilot can, simply because it is a fact that they understand exactly how the damn things work! Please read my #19 post and Brian’s at #23 above for our own thoughts on this original topic, because in the real world it would be wrong to assume that the real B747-8 will always make ultra-smooth autolands.
                                                Michael Codd

                                                Comment


                                                • DDowns
                                                  DDowns commented
                                                  Editing a comment
                                                  Thanks Michael but it's best to ignore him. He'll go away with a lack of attention. You know I have four decades of flying, just happen to take the Air Force engineer route as opposed to air transport. Damn engineers.

                                                • thibodba57
                                                  thibodba57 commented
                                                  Editing a comment
                                                  DDowns Hey a fellow Eng?!?! 2000Hrs on the Herk here!
                                                  Michael Codd I’ll add the two worst Autolands I witnessed were in the -8 and the Dreamlifter. Actually I’ve personally never witnessed a good Autoland in that Lifter....

                                                • Michael Codd
                                                  Michael Codd commented
                                                  Editing a comment
                                                  There is a reference I have seen which states that the ROD at touchdown during an autoland in the B744/-8 should not exceed 300ft/min. I have heard that if this touchdown ROD was exceeded whilst carrying out a manual landing in the original B747/100 series it was not uncommon for the Flight Engineer to produce a watering can from underneath his table!

                                                #30
                                                And here I am regularly doing "carrier landings" in both the 747 and 737. If the VSI needle is North of the little tickmark for -500fpm when I plant the mains, then I have done my job lol.

                                                My virtual passengers and bean counters can suck it, I'm catching the 3-wire.
                                                Matt Smith

                                                Comment


                                                • Ephedrin
                                                  Ephedrin commented
                                                  Editing a comment
                                                  LOL! There is a hot discussion in the MSFS forum going on about brakes and „rollout distances“ as someone confused it with „landing distance“ in some books ^^ Now a tail hook on a 747 would probably confuse them even more
                                              Working...
                                              X