Top of Descent / VNAV PTH Descent Behavior

[sniper228 2]

That in mind, I see what you're writing, but I can only go so far. When you're telling me that you're not flying STARs to the airport, you're highlighting that there's a lack of understanding in operating the aircraft (yes, I know the vast majority of airports in the world don't have SID/STAR procedures, but where the 744 flies, this is less of the case).

 

If a very simple navigational aspect of flying is being left out (STARs), it shows me that there's somewhat of a lack of learning the details of the way things work. With that, when you're saying you're reading the manual and so on, I can only put so much weight in that. The reason is that there's no lack of information - even at a simmer's level - all over these fora, on the interwebs, and it's all over YouTube (I'm presuming because the current generation hates reading). Of course, there's always the manuals (that even I find difficult to read). So, while I believe you're reading the manual and the tutorials, it seems as if there needs to be a more in-depth look.

 

Ok this post right here is so misleading I don't even know where to start....

 

Owen your original idea of what a STAR is, was CORRECT, it is mainly for ATC (or some cases obstacle clearances,) for expediting traffic into busy airspace. It is not used for descent planning, it means nothing for descent planning, the ONLY reason there are crossing restrictions and speed limits on most are because it is for ATC airspace and planning!!! In fact they are more in-efficient to airplanes to have them in there in the first place because they get them lower further out from the airport, thus burning more gas and taking more time. It has nothing to do with the operating of the aircraft....You do not need to fly a STAR every time you fly the 747...most airports the 747 goes into do have STARS because what do 747s do best?? hold a ton of people!! (or cargo) guess where those ton of people go to? Big airports that have a ton of traffic, you try and connect a false statement that the 747 needs a STAR to descend properly, how can someone say that?? You claim or like to talk to the fact that you think you know a lot of information about aviation....You might be very book/manual smart but you lack common sense and experience, so before you go blabbing on about ridiculous stuff I suggest you think more carefully before you post! It's people like you that create sim isms as you like to call it!!

 

Owen to your original question in this thread about VNAV descent planning that will actually help you and not make you more confused or simply tell you to watch more youtube videos or read manuals....here ya go!

 

After you load your approach into the FMS (doesn't matter if its ILS/GPS/VOR) the FMC off the AIRAC data will load most of the time crossing altitudes for fixes on the approach. Sometimes these altitudes are kinda weird....For example a ILS approach might have 5 waypoints on the localizer where each one is a at or above altitude. This is symbolized by something like this in the LEGS page...7000A could be the other way around too like 7000B. The A or B tell the FMS above or below respectfully...So check that out next time you load an approach in...

 

Also what helps too is you select your VREF speeds in the FMS also before you start your descent, I say this because if you are relying on the FMS to do ALL the descent planning down to the ground it will actually plan out your speed reductions on the approach. But it will have a really hard time doing this if you don't put your VREF speeds in there.

 

Some other tips i'm not sure if you know about is to just fly direct to the airport, put the airport in the scratchpad of the FMS ex. KLAX then type KLAX//40...this is what they call a Pilot defined waypoint. You just told the FMS to program a point 40NM out of KLAX on your current direct to heading. This to me is always nice because from my experience if you cross a 40DME mark outside your airport at 10,000ft you will have enough time to slow to 250kts and then descend down to pattern altitude or whatever approach your doing.

 

So while your original procedures was basically correct of putting an altitude into the FMS to cross, reset the MCP altitude and leave it in VNAV, sounds like you just need to pay attention to some details now. I would say try this out next time your flying the 747...

 

Good luck! have fun

[FSXReality 1]

Hello,

 

You seem genuinely interested in learning what is going wrong. If some people had their way, this forum would not exist and you would only have the book to rely on. Whilst useful, yes, forums are exceptionally useful for more in-depth and persnoalised help. Here is a further response to the great response by sniper2228 above.

 

"I am under the assumption that the FMC will automatically calculate the appropriate top of descent point based on altitude constraints, etc. and then automatically command a descent if the autopilot is left in VNAV mode and the MCP is reset to the altitude of the next waypoint prior to the top of descent point.".

 

You are under the correct assumption. Clearly something is being overlooked for your aircraft to not begin its descent at the T/D. However, the fact you even have a T/D means you are doing something right, so don't be too disheartened! Before arriving at your T/D, in VNAV mode (and with no speed intervene active - by this, I mean you have not pushed the speed knob to intervene VNAV speed with your own manual speed - if you have, repush it to re-enable VNAV speed, otherwise it will mess up your FMC descent profile because the speed will not be what it needs to achieve its own programmations), verify you have no route discontinuities in the legs page (you may well have selected an ILS/VOR approach to fly after the STAR, but its not necessary to connect the last leg of the STAR with the first leg of the ILS/VOR approach because usually that would be vectored by ATC and by that time, arrival fuel/time and other important things re. descent planning/FMC intervention are worthless since you'll be on the ground in under 10 minutes and either be hand flying or using basic A/P functions (HDG/ALT/SPD) rather than LNAV/VNAV). Having closed any route discons, make sure you are actually currently flying at the correct cruise altitude for the VNAV cruise. Perhaps you're not flying at the entered cruise flight level, hence why the aircraft is confuzzled a little bit at T/D. So verify alt/speed are being flown exactly as entered in the FMC and no speed intervene is being used. At T/D, the speed bug (purple marker on speed tape on left of PFD) will drop back to descent IAS so, do your throttles close on passing T/D? The aircraft won't necessarily descend immediately; it will hold the nose relatively level while the throttle reduction brings back the speed, then it will slowly lower the nose. VNAV page will automatically change from VNAV Cruise to Descent... of course. Does that happen? If so, great. You may be interested in intervening with the speed knob by pressing it and selecting a higher descent speed, but I'd allow it to descend at the Mach then IAS as they come together).

 

"is it normal that the B747 is slow to rotate during takeoff? Using the proper FMC-calculated speeds and trim setting, I am never able to reach an altitude of 35 feet at V2 (as recommended in the manual). Usually, I do not even make it off the ground when V2 is reached."

 

2-3 degrees a second is common practice. Maybe you're hesitating because you fear a tail-strike? Maybe your trim is not set exactly? Maybe you're simply not following through with control column pressure? You need to be quite 'firm' (but not violent) when rotating. In real life, if you pull back on the control column for a few seconds and then release, the nose wheel, if up, will come down again. If you pull it to 'one position' and don't move, the aircraft will stop pitching up and your speed will go so far above limits, it will be your last flight on the line - think about obstacle clearance, engine failure, mechanical problem... the list is endless. You must apply firm but controlled pressure during rotation and just get that nose to 15 degrees ish. The F/D does not becmoe reliable until about 400+ feet, so don't use that as a target pitch below that altitude, by which you will be climbing and at a good speed anyway so it's not a problem.

 

Anything else, I'd be happy to help. Screenshots also greatly aid in understanding for resolution.

 

Best,

Dan

[scandinavian13 5,192]

Owen your original idea of what a STAR is, was CORRECT, it is mainly for ATC (or some cases obstacle clearances,) for expediting traffic into busy airspace. It is not used for descent planning, it means nothing for descent planning, the ONLY reason there are crossing restrictions and speed limits on most are because it is for ATC airspace and planning!!! In fact they are more in-efficient to airplanes to have them in there in the first place because they get them lower further out from the airport, thus burning more gas and taking more time. It has nothing to do with the operating of the aircraft....You do not need to fly a STAR every time you fly the 747...most airports the 747 goes into do have STARS because what do 747s do best?? hold a ton of people!! (or cargo) guess where those ton of people go to? Big airports that have a ton of traffic, you try and connect a false statement that the 747 needs a STAR to descend properly, how can someone say that?? You claim or like to talk to the fact that you think you know a lot of information about aviation....You might be very book/manual smart but you lack common sense and experience, so before you go blabbing on about ridiculous stuff I suggest you think more carefully before you post! It's people like you that create sim isms as you like to call it!!

 

Had you bothered to read my posts before, you'd see you're making assumptions of what you think I said instead of what I actually said in that post in addition to what I said in the posts before. First, and foremost, I'd already explained that STARs bring you from altitude to the approach (though I didn't exactly state the why, as you did). Second, I didn't say that you needed a STAR in order for it to descend properly. I said (and I quote):

Without the STAR, you're mostly on your own for your descent. If there are no altitudes set into the FMC, what is prompting the computer that it needs to descend? [...] If you don't provide it with the information it needs to know when to descend, it's not going to do it for you.

 

While it is true, I could have been more detailed in my explanation, STARs most often include some type of altitude constraint, which helps the computer do its whiz work behind the scenes to descend in a more realistic manner. If there are no altitudes, the only thing the plane has to go on is a direct path between the last fix and the airport, and that you have to be a airport elev at the end of that last (inaccurate) leg. Since most STARs have at least one altitude (even if only "expected"), it assists the descent calculation.

 

Third, on your criticism of my point about 744s will always use STARs, you're putting words in my mouth. I did not say you need to, I said (again, quoting my post):

When you're telling me that you're not flying STARs to the airport, you're highlighting that there's a lack of understanding in operating the aircraft (yes, I know the vast majority of airports in the world don't have SID/STAR procedures, but where the 744 flies, this is less of the case).

My point there was not that it's a requirement, it was that it's not simply an optional ATC-assigned aid. It's a way of life in 744 operation. You can by all means skip it, but if you're not on top of the automation it's not going to behave like a real 744 because that 744 you're seeing on YouTube, or FlightAware, or whatever else is in one of a few cases:

it's on a STAR; or it's being controlled by a pilot through the use of alternate methods (likely not VNAV) for it to descend properly, because of the lack of altitude information that would otherwise be there in the STAR.

 

This isn't a 744, but it certainly doesn't have a STAR, and it's into a Class B:

http://flightaware.com/live/flight/SWA3847/history/20120803/1130Z/KLGA/KBWI

There's a BAW flight that comes in on a route very similar (at least the segment at the end), and it's occasionally a 744. I know they exist, but note I said "but where the 744 flies, this is less of the case," not "this is never the case."

 

The difference between that flight and someone who doesn't have a grasp for the 744 yet is that the pilot of the real plane fully understands when and how to best use the different modes on the MCP to get the plane to do what it wants.

 

 

 

 

In the end, my overall message holds true:

If you don't give the computer the realistic level of information it needs, it's not going to give you the realistic descent you're looking for.

 

 

 

...and John. I don't know who you are, where you came from, or what your issue is, but I've done nothing to you, so I don't know why you're so critical of me. Just because you're reading more into my posts than what I'm actually saying doesn't mean that I don't know what I'm talking about or lack common sense. I'll gladly take you up on any opportunity to prove that to you, and if you're in the Northern Virginia area, you can meet me at Leesburg Airport and we'll take a flight somewhere. By the way, how the [heck] do you know how much experience I have?

 

This isn't a prison. Coming in here and taking a shot at a more public member of the forum isn't going to get you street cred. It just makes you come off like a jerk. I already apparently have that role covered pretty well.

[sniper228 2]

...and John. I don't know who you are, where you came from, or what your issue is, but I've done nothing to you, so I don't know why you're so critical of me. Just because you're reading more into my posts than what I'm actually saying doesn't mean that I don't know what I'm talking about or lack common sense. I'll gladly take you up on any opportunity to prove that to you, and if you're in the Northern Virginia area, you can meet me at Leesburg Airport and we'll take a flight somewhere. By the way, how the [heck] do you know how much experience I have?

 

This isn't a prison. Coming in here and taking a shot at a more public member of the forum isn't going to get you street cred. It just makes you come off like a jerk. I already apparently have that role covered pretty well.

 

Well your correct, I don't know your experience, however by the posts that you make, and you do make a lot of them, I would bet that you do not have that much experience in aviation.

 

Without fighting out the extreme details of posts...the main reason for me coming into here is what you are doing to new people to flightsim or PMDG products...You come across as "hey no your wrong you NEED TO DO IT THIS WAY" which is not the case at all. I mean look at Owens post a few ones up where he says this:

 

Okay. I will use STARs. For some reason, it just did not seem obvious that they were necessary to the standard operating procedures of the aircraft (I thought that STARs were only optional ATC aids to help coordinate traffic efficiently). Thank you for the clarification.

 

From his response he will now think he has to use STARs all the time when flying the 747. You come across as it is very black and white and specific which is not true at all!!!

 

And for the record I am not looking for "street cred" especially in a forum, that is just retarded. Your posts have been standing out to me because you post often, and from what I read it is a lot of misleading information. I wouldn't say incorrect information, just totally misleading to the pertinent post.

[scandinavian13 5,192]

Well your correct, I don't know your experience, however by the posts that you make, and you do make a lot of them, I would bet that you do not have that much experience in aviation.

 

I guess I should re-evaluate how I write my posts, because if I come across as inexperienced, then there's a problem. What exactly is causing you to think that? That's a 100% honest question. As much as I come here to share information, I also get a lot back from these fora.

 

Without fighting out the extreme details of posts...the main reason for me coming into here is what you are doing to new people to flightsim or PMDG products...You come across as "hey no your wrong you NEED TO DO IT THIS WAY" which is not the case at all.

 

I can see how you think that. My true end goal is to encourage (although, admittedly, I tend to bludgeon in certain cases) the idea that one should learn concepts instead of avoiding them. That was the angle I was taking earlier, though in retrospect I can see how that is not fully clear.

 

From his response he will now think he has to use STARs all the time when flying the 747. You come across as it is very black and white and specific which is not true at all!!!

 

Again, if anyone with a brain read my post properly, I'm sure they'd see that I meant "use them where available." I do agree that it could use more clarification, however.

 

And for the record I am not looking for "street cred" especially in a forum, that is just retarded. Your posts have been standing out to me because you post often, and from what I read it is a lot of misleading information. I wouldn't say incorrect information, just totally misleading to the pertinent post.

 

Then come in and address me like you're here to help someone, not attack me. Telling me I lack experience and I'm book smart without any common sense isn't exactly the way to approach someone if you're not looking to ruffle feathers. I know I can be very blunt, but when I help people, I avoid labeling them.

 

If I say something that's wrong, tell me it's wrong. If I'm outright wrong, I'll admit it. I agree that I could have phrased things more clearly, but it doesn't mean I don't know what I'm talking about. Furthermore, what I said wasn't technically wrong, or intentionally misleading. I left out my involved NAS/ATC discussion for simplicity's sake. If I was intentionally misleading, I understand some of the flame, but I wasn't, and I think my posts make that clear.

 

If you're going to correct me, great, but if you're not looking to take me down, why add in all the extra "you're inexperienced, don't know what you're talking about, and you're just bluffing about everything you claim to know?" My method of sharing information doesn't come with CareBears and rainbows, but that doesn't mean I think I know everything there is to know about aviation. I'm also willing to admit that I get frustrated by what I perceive (meaning, I'm willing to accept that I'm wrong in this assumption) as a dismissal knowledge before fully attempting to understand it. In this case, it ended up clouding my speech as I took a more hard-line stance that STARs should be used, partly on the account he said he doesn't use them, but didn't really specify why. Still, I don't think I deserve the labels you've pinned on me.

[WyattN 4]

I guess I should re-evaluate how I write my posts, because if I come across as inexperienced, then there's a problem. What exactly is causing you to think that? That's a 100% honest question. As much as I come here to share information, I also get a lot back from these fora.

 

 

Constantly packing every post on this forum full non-sense and bad information for one. Completely holding onto arguments that have no basis in fact or reality. I just read another post of yours where you jumped in and made a guess on an aircraft system response that was totally wrong (albeit you stood corrected but of all people you should know to RTFM before spouting off at the mouth). For every post someone had to correct you in there are more that no one bothered.

 

Secondly there's plenty of bad info on flightsim forums in fact I don't think I could find a more concentrated source generally speaking but that's ok it's flightsim.

 

It's guys like you that obviously have a limited spectrum as far as hands on real life experience that really need to leave their 'expert' opinion to the experts. I have to call you out when I see you mislead new guys in such a matter of fact, condescending, and arrogant tone especially when directed towards the more humble hobbyist found here.

 

Here's some advice next time you feel the need to weigh in on someones troubles or a technical discussion. Just stick to the facts in particular something you have a current working knowledge of. If you choose to weigh in on something based on amateur interpretations or hear say leave the matter of fact and condescending tone out because you may not be as right as you think you are.

[sniper228 2]

Again, if anyone with a brain read my post properly, I'm sure they'd see that I meant "use them where available." I do agree that it could use more clarification, however.

 

Stop staying stuff like this and maybe responses like mine will stop...

 

If you want a more clear message of what my point is, take a look at FSXReality's post above. This is a very well laid out, technical post about procedures in properly using the VNAV. Not talking about regulations, different ways of doing things, how real 747s do it, etc....You constantly try to bring up relevances to the OP probably in your mind to help him get a bigger picture of things, but you dig yourself deep in a hole with lots of assumptions which you really do not know much about.

 

 

...and John. I don't know who you are, where you came from, or what your issue is, but I've done nothing to you, so I don't know why you're so critical of me. Just because you're reading more into my posts than what I'm actually saying doesn't mean that I don't know what I'm talking about or lack common sense. I'll gladly take you up on any opportunity to prove that to you, and if you're in the Northern Virginia area, you can meet me at Leesburg Airport and we'll take a flight somewhere. By the way, how the [heck] do you know how much experience I have?

 

I think this is the main reason right here why you are so arrogant in these forums....You are part of the 10 percent I would say (total guess figure) of the FS community that has at least their private pilot or above. This proves to me without knowing anything about how much flying experience you have is that by most your a private pilot. That is fine and I congratulate you on having that license many can't get one and much more wish they could get one especially in the FS community. However with dealing with complex addons like PMDG you try and take your knowledge of flying as a private pilot, general aviation, and FS to answer peoples questions with a knowledge of someone who actually flys an airliner of any type, not just a 737 or 747. You simply do not have the experience and you end up saying more false stuff then you think. Most are not regulatory as you always like to point out, but its just simply the way things are done.

 

You probably will question my experience...I will just tell you this, I do not fly a 737 or 747 but I am professional Part 121 airline pilot in the US and my knowledge of the 737/747 is just as good as yours (from yes FS haha). But please please watch what you say about flying procedures whether it be STARS, approaches, ATC, etc....

[scandinavian13 5,192]

Constantly packing every post on this forum full non-sense and bad information for one. Completely holding onto arguments that have no basis in fact or reality. I just read another post of yours where you jumped in and made a guess on an aircraft system response that was totally wrong (albeit you stood corrected but of all people you should know to RTFM before spouting off at the mouth). For every post someone had to correct you in there are more that no one bothered.

First, the vast majority of the threads around here don't have even a hint of me in there, so while I know you're just trying to make a point, the hyperbole really isn't necessary. From the NGX subforum alone, you'll note I'm absent from threads where I'd add absolutely no value. Most of the time someone asks a question about specific details and procedures I have no value to add to that. I don't fly a 73, and I've never been on a ramp that's had to service them, so I couldn't even tell you what happens on turns. I will say, though, that in certain posts, I'll add in a "this is how we did it at company X" if it's relevant.

 

I will say thanks for acknowledging that I admit I'm wrong when I am.

 

It's guys like you that obviously have a limited spectrum as far as hands on real life experience that really need to leave their 'expert' opinion to the experts. I have to call you out when I see you mislead new guys in such a matter of fact, condescending, and arrogant tone especially when directed towards the more humble hobbyist found here.

Where did I say I was an expert? The misleading, the condescension and the arrogance are read into what I've written. Granted, the latter two come out whenever someone decides to be the same with me. I'm not going to claim to be a saint around here. If the level is brought down a notch, I'll jump down to that level.

 

Here's some advice next time you feel the need to weigh in on someones troubles or a technical discussion. Just stick to the facts in particular something you have a current working knowledge of. If you choose to weigh in on something based on amateur interpretations or hear say leave the matter of fact and condescending tone out because you may not be as right as you think you are.

Where in my posts here did I not do just that?

 

I think this is the main reason right here why you are so arrogant in these forums....You are part of the 10 percent I would say (total guess figure) of the FS community that has at least their private pilot or above. This proves to me without knowing anything about how much flying experience you have is that by most your a private pilot. That is fine and I congratulate you on having that license many can't get one and much more wish they could get one especially in the FS community. However with dealing with complex addons like PMDG you try and take your knowledge of flying as a private pilot, general aviation, and FS to answer peoples questions with a knowledge of someone who actually flys an airliner of any type, not just a 737 or 747. You simply do not have the experience and you end up saying more false stuff then you think. Most are not regulatory as you always like to point out, but its just simply the way things are done.

When you find all that false stuff, let me know. I know there's some out there, but I really don't think I'm as much of a black mark on the forums as you are trying to put across.

 

...and in reference to that other thread, I was really only trying to open up the idea that just because "that's how it's done" doesn't mean that's how it's required to be done in all cases (which I also stated over there). I wasn't saying it would be smart to do it any other way (again, I also stated that over there).

 

You probably will question my experience...I will just tell you this, I do not fly a 737 or 747 but I am professional Part 121 airline pilot in the US and my knowledge of the 737/747 is just as good as yours (from yes FS haha). But please please watch what you say about flying procedures whether it be STARS, approaches, ATC, etc....

Please, let's have a discussion on that "higher" order, shall we? You're making some pretty broad assumptions about my knowledge and experience and I feel that you're underestimating what I know and what I can do simply because I don't fly 121 or 135.

 

And no. I wasn't going to question your experience, just for the record.

[Rations 102]

Thank you all for continuing to provide suggestions. First, I (unfortunately) do not currently have access to my flight simulation equipment, due to a recent international move. Sorry for the poor timing.

 

Now, regarding the numerous points everyone has made so far:

 

John: I will pay attention to the above/below altitude restrictions, although I do not remember observing them around the beginning of the descent (only later, during the actual approach).

When you mention VREF speeds, you mean selecting the landing flaps and speed on the POS INIT page, right? I'll set them before descent next time, as I used to select them a little into approach (so there would be less of a chance that they would be affected by the changing aircraft weight).

 

Dan: I know I was flying at the cruising altitude as inputted in the FMC and duplicated in the MCP altitude window. I used to use SPD intervention in order to smooth the descent, but now I do not. While the aircraft does take a few seconds to reduce thrust to idle, the descent rate that follows is too excessive, and idle thrust is always unable to prevent an overspeed situation.

Regarding the takeoff situation, I always set the trim using the 2-D panel in order to achieve high accuracy. Are you able to lift off before V2? Again, screenshots will follow once I receive the equipment (if the issues are not solved by then). Also, thanks for your video recommendations.

 

Kyle: I guess I misunderstood you. Then again, your first line in reply to my original post stated "Yes - [it is] very incorrect [not to use STARs]." Again, I thought that providing the FMC with at fewest one hard restriction (i.e., GUAVA at 220/8000) after cruise would be enough for the computer to compute a descent path properly. If it is possible for a human to calculate a descent path based on the information inputted, why can't the FMC do it, given that it has the same information? The reason why I did not use STARs was that I received the impression from videos and other resources that STARs were simply not necessary. Are the restrictions provided in STARs not conceptually the same as the restrictions I specify?

 

A few more points. I just read the thread involving the same issue (TOD) except with the B737, which mentioned cost indexes. I currently use a cost index of 500, but I do not think there is anything severely incorrect about doing so. Another thing that could be the issue: I do not forcast the weather for cruise and descent. Could this lack be severe enough to mess up the entire descent path? If all else fails, I will try to reinstall/update (if there are any), but I did do several reinstalls over the course of my ownership of the B747.

 

Lastly, while I do find bluntness and intimidation in Kyle's writing, there is no need to attack and challenge his experience personally. After all, we shouldn't stray off topic and start discussing teaching philosophies on every thread.

 

Thank you again and I'm sorry about the timing issues.

[scandinavian13 5,192]

Owen,

 

First, I have to say I apologize for not being more clear, and for being intimidating. I honestly don't know why I do it. I know some of it is inherent in my writing style, but the rest is just me not being mindful of how my writing could be interpreted.

 

Kyle: I guess I misunderstood you. Then again, your first line in reply to my original post stated "Yes - [it is] very incorrect [not to use STARs]." Again, I thought that providing the FMC with at fewest one hard restriction (i.e., GUAVA at 220/8000) after cruise would be enough for the computer to compute a descent path properly.

 

My understanding is that as long as the plane knows it needs to be at a lower altitude than cruise by some fixed point (destination airport, or some type of crossing restriction), it will be able to calculate a descent point.

 

The reason why I did not use STARs was that I received the impression from videos and other resources that STARs were simply not necessary. Are the restrictions provided in STARs not conceptually the same as the restrictions I specify?

 

Again, I apologize for speaking in such black and white terms. STARs are not necessary for the proper operation of the aircraft. What I meant was that in normal operations, they are a normal occurrence. You are correct in that they are not necessary. The flight from EGLL to KBWI has no STAR and there are no problems there. In their case, the pilots could use a pseudo-waypoint of 25nm after MXE (along V378), with a crossing restriction of 12,000' and they'd be just fine.

 

Hand entered, or loading via a stored procedure on the DEP/ARR page is conceptually the same.

 

A few more points. I just read the thread involving the same issue (TOD) except with the B737, which mentioned cost indexes. I currently use a cost index of 500, but I do not think there is anything severely incorrect about doing so. Another thing that could be the issue: I do not forcast the weather for cruise and descent. Could this lack be severe enough to mess up the entire descent path? If all else fails, I will try to reinstall/update (if there are any), but I did do several reinstalls over the course of my ownership of the B747.

 

Cost index will affect how the system calculates your target descent speed. If the value is too high, you could see steeper descents, I believe. The forecast shouldn't cause huge issues either way, provided the winds aren't drastically different as you descend (going from a large tailwind at altitude to a large headwind lower down could cause problems, unless you told it to expect it via the FORECAST page).

 

I wouldn't reinstall until you've ruled out all other possibilities. As Dan mentioned, you're clearly getting things right. There just might be a few things you're missing. Sometimes even the smaller things can cause more visible results.

 

 

Again, sorry for the assumptions and intimidation.

[Rations 102]

Hello all,

 

I have finally received my flight simulation equipment again.

 

I tried the flight from Taipei to Hong Kong again, this time using a cost index of 90 and using a STAR. This time, the TOD was passed normally, after which the aircraft commenced a descent rate of −2500 to −3500 ft/m. While I still feel the descent rate was slightly on the high side, this was a huge improvement over the previous descent conditions. I believe this current performance is realistic. I do not know whether it was the updated NAVDATA or the use of the STAR that helped. I also followed tips that Dan and John recommended.

 

As for the rotation issues, I am still having trouble lifting off before V2, but honestly, that is a small issue that can be remedied through personal research.

 

I have purchased the flight crew operation manuals (which are actually significantly different and more professional compared to the ones provided free-of-charge with the aircraft). I will do some investigating as to what the original error was. If it is worthy of being shared, I will report back.

 

Thanks again guys for all of your assistance!

 

Owen

[fstulm 4]

Hello all,

 

Owen, regarding the V2 problem allow me to say that some operational common sense should be used. All these numbers are there to add as indicators and should not be taken as stone carved make you or break you. The more "relaxed" (lesser limiting) is the takeoff the closer theV numbers can be.

 

From an operational point of view think about the physics of it. We have a behemoth rushing down the runway at an incredible speed and still accelerating fast; the smaller the distance between the V speeds the lesser the time you have to reach correct pitch attitude at the rate of 3 degs/second. So, by the time you reach 9 degs of pith you may be well passed V2 and that is fine. The important thing here is to reach and mentain a healthy departure from mother Earth.

 

If you are not more than V2 + 20 by the time you are established on your initial ascent THAT IS PERFECT! The worst thing you can do is to chase the numbers at this point. Hold what you have and you will be fine. Trying to agressively recapture V2 might get you in a very dangerous situation in which, given the moment of rotational inertia, you may fall way to low below V2 and that will mean that you have just busted your check ride or worse, stall the aircraft!

 

I hope this helps,

 

Ionut G. Micu

Romania

[Rations 102]

Thanks Ionut. I was merely trying to adhere to the procedures depicted in real-world videos and described in the type rating courses. But as I said, the V2 issue was just a minor concern that I thought I would discuss along with the top-of-descent issue, the latter of which was my primary concern. I understand your reasoning and will only try to rotate at the specified three-degree-per-second rate instead of the "off-the-ground-by-V2" technique.

[kevinh 409]

The tilt of the gear (i.e., during lowering of the gear) should be independent from the pitch of the aircraft.

No one mentioned this point raised by the OP, but it's not correct. When not in contact with the ground, the gear tilt is relative to the gear strut, and therefore does vary with aircraft pitch. This is important as the gear will not fit in the landing gear bays unless the angle of tilt relative to the strut is correct. Gear tilt is controlled by a hydraulic actuator, the bogie is not freely swinging like a see-saw.

[Rations 102]

I can see that my original statement was ambiguous. By lowering of the gear, I meant when the main gear untilts to accommodate the lowering of the nose gear after touchdown. I believe the PMDG B747 gear untilts with a change in aircraft pitch (e.g., when the nose is "un-flared") regardless of the vertical speed on touchdown. If you observe most real-world manual B747 landings, the gear "collapses" quickly after touchdown, even if the nose is held at the same pitch. If you try a hard landing with the PMDG B747, you can still float on the last set of rear wheels for a while (this would more accurately resemble a real-world A330's gear tilt behavior during touchdown). The POSKY B747 simulates gear tilt more realistically during touchdown.

 

For example:

(a smooth landing)

(a hard landing)

In both instances, the gear completely untilts even though the pitch of the aircraft increases / remains constant. I cannot reasonable simulate this behavior with the PMDG B747.

 

Again, my main issues were with the top of descent, and I am not trying to insult the quality of PMDG products. I just hope that this animation is refined in the upcoming second version, as it just does not really seem realistic compared to real-world videos.