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V Speeds V1,Vr,V2

Started by Daniel, Fri, 28 Jun 2019 14:49

Daniel

Dear Simulator pilots:

I have to ask again:

What do the V speed have to do with the first leg which has to be inserted in the FMS before they appear on the Takeoff Ref page as commented before?
As a real world pilot I calculate the V speeds (V1, VR, V2) by looking into the respective tables for flap condition, weather condition and I receive the required TO Distance for the specific values applied.
It has nothing to do with the first leg where I may fly to or NOT.

Kind regards
Daniel

Hardy Heinlin

Hi Daniel.

(By the way, on the forum there are sim pilots as well as real-world pilots, engineers, ATCs, dispatchers etc.)

The first leg is irrelevant to the FMC's V-speed calculation.

The first leg is only relevant to the route activation function.

The V-speed calculation needs a departure runway in the active route. This runway is also shown on the TAKEOFF REF page.

All legs may be deleted in an active route, and the V-speed calculation will still work -- as long as it contains a departure runway.

Before you activate an inactive route, the 744 FMC requires at least one leg. This activation logic has nothing to do with the V-speeds per se.

If you follow the normal 744 specific preflight steps, you will have an active route before you go to the TAKEOFF REF page, and the problem will never occur.


Regards,

|-|ardy

Daniel

Hello Hardy,

I have inserted an active runway 29 for Vienna,
however it does not calculate V speeds until at least one leg is inserted.
On the Learjet I can insert the values: mass, Flap setting, and other runway conditions and the V speeds will be calculated.
V speeds have correction values for slope, wind etc. but this is secondary.
Even the runway is unimportant for the calculations. I cannot attach a photo here but send it to u via email.

Regards
Daniel

Hardy Heinlin

#3
Quote from: Daniel on Fri, 28 Jun 2019 16:12
... it does not calculate V speeds until at least one leg is inserted.

This is actually impossible. Why can't you just tell me step by step what buttons you are pushing and what effects you are seeing after each push? You always just talk in "snapshots". A snapshot is not a history.

Please try this as an example:

1. Load the situation file "Basic 002 - On ground and doors closing.situ"

2. Press RTE key on CDU L

3. Press LSK 1L to downselect TNCC

4. Press LSK 1L to upselect TNCC.

5. All legs are now deleted.

6. Press EXEC.

7. Press CLR key to erase "TAKEOFF SPEEDS DELETED" message

8. Enter 11 in line 2L (runway 11)

9. Press EXEC.

10. Press NEXT PAGE key to see RTE page 2/2: VIA and TO are dashed. All legs deleted.

11. Press LSK 6R to go to the TAKEOFF REF page.

12. All V-speeds are computed and displayed in small font. As expected.



A leg is only required to activate an inactive route.
The V-speed calculation requires a departure runway in the active route -- regardless of the route being empty or not.



|-|



P.S.: You can't expect the 744 systems to behave like your Learjet systems. If you see an error, let me know. I'm working on improvements every day. But please refer to observations on the 744 flight deck, not to your Learjet. And even if it's a 744, the 744 systems are very much airline specific.

Daniel

Hello Hardy,

I always put a runway into the FMS before I "expect" to have V speeds calculated after I have inserted further values like the flap settings. There are no V speeds though. It requires one leg then V speeds appear.

It is very exhaustive to talk to you because you know always every thing better.

Kind regards
Daniel

Hardy Heinlin

Please try my example above -- exactly -- and tell me if it works.

If it doesn't work, tell me which step doesn't work. Don't just say "it doesn't work if I don't enter a leg". I need to know the exact situation and the exact step.

If you keep ignoring my answers, I will ignore your questions from now on.

Dirk Schepmann

Hi Hardy,

It took me a while to figure out what Daniel's problem is (he uses a workflow which is quite different from the typical Boeing procedure) and tried to reproduce it.

First of all, if I load the "Basic 002 - On ground and doors closing" situ file and follow your instructions step-by-step, everything works exactly as you described. The V-Speeds show up when a runway is selected AND executed.

But the procedure does not work when you start from scratch (load "Basic 001 - On Ground and IRS aligned" for example). The problem here is that you can't activate the route before at least 1 leg is inserted. And without route activation the "---PRE-FLT" reminder will be shown on the TAKEOFF REF page and at LSK 6R "ROUTE>" is displayed.

But once you have entered sufficient data to activate the route (1 leg) and have done this, everything works exactly as described for the "Basic 002" situ file. You can delete the route by overwriting the origin, select a runway and the V-speeds will be displayed with an empty flight plan (provided that all necessary data have been inserted on the PERF INIT and TAKEOFF REF page, of course).

So basically, it all depends whether the route has been activated or not. Overwriting the origin on 1L of the RTE page will delete a route (or at least all legs), but will not change the activation status of the route.

I'll leave it to the experts to discuss if the deletion of an active route will require a new activation of the route.

But I think this might explain Daniel's confusion.

@Daniel:
Please keep in mind that Boeing has a very straightforward FMC preflight procedure. First you enter and activate a route. After doing is, the ACTIVATE prompt at LSK 6R is replaced by the PERF INIT prompt which allows you to enter the weights, cost index, cruising altitude etc. Next, follow 6R to the THRUST LIM page and from there 6R will direct you to the TAKEOFF REF page.

However, what you are apparently doing is that you fill in some data here and some data there and expect the thing to show you similar results as in your Learjet. If you want to enjoy the 747-400 and get the most out of it, you should really familiarize yourself with the Boeing procedures. If you do this, you'll have lots of fun with the aircraft.

And by the way: even a Boeing is not a Boeing. The FMCs of the 737NG, 777, 767 and 747-400 show lots of similarities but also a lot of differences. So if you fly different types and find something which is not logical or appears to be wrong, you'll often find out that it is not a mistake of the respective simulation. It is more likely that Boeing designed it that way. And what might be illogical to some people, might be logical for others.  ;)

Best regards,
Dirk







Avi

Quote from: Dirk Schepmann on Sat, 29 Jun 2019 01:45
The problem here is that you can't activate the route before at least 1 leg is inserted.

This is not a (or the) problem since this is how the B744 FMC works.
He doesn't want to get it.
Avi Adin
LLBG

Daniel

Hi Dirk,

it looks like extremism and rassism takes place also in this forum.
Very sad that Nazis get their way every where in our daily life.

The information I have inserted into the FMS is enough to calculate V speeds. A first or whatever waypoint has nothing to do with V speed calculations.

I know what I am talking about because I have also flown airplanes with Honeywell FMS.

I also know what I am talking about because I can think logically independent what I have flown before or not.

I will talk to my friends which fly the 777 and the 744 and I will ask them to replicate my questions in the actual airplane.

Then we will see who is getting something or not!

Have a nice day ahead and stop to be rude to me!

Best wishes!

Daniel

Daniel

Hi all,

yesterday I wanted to depart from EDDM.
I just tried to insert the waypoint MIQ (NDB) into the CDU as my "first" waypoint and not an SID.
This did not work.
Then I tried to insert SNU VOR as a waypoint into the CDU as the first waypoint.
It worked.
Then I inserted MIQ as the second waypoint. It worked.
Then I deleted SNU waypoint an voala the MIQ waypoint was now the first waypoint suddenly accepted by the FMS.

I flew last time to LHBP with a STAR inserted into the FMS.
I flew with 240 kts and this was to fast for the FMS to calculate turns so the ND has shown strange bows instead of the continuous waypoints along the STAR rout.
This is not normal. The FMS shall not calculate turns and deleting STAR waypoints on its own and showing strange "turning" bows instead.
A STAR stays a STAR independent of what speed is flown.

Yesterday I flew to EDDM for an ILS.
The APP was armed.
I maintained 5000 feet to capture the GS. However suddenly the CDI horizontal needle showed a climb towards a higher altitude.
This is not normal. When a altitude is maintained and the glide is to be captured the CDI horizonal needle stays at the altitude which it is currently flown thus showing a level flight until the glide diamond goes through the center position of the vertical CDI scale and afterwards the CDI shows a descent following the what ever glide angle and associated aircraft ground speed requires to maintain the center of the GS.

Kind regards
Daniel

John H Watson

#10
Quoteyesterday I wanted to depart from EDDM.
I just tried to insert the waypoint MIQ (NDB) into the CDU as my "first" waypoint and not an SID.
This did not work.

What did not work?  It wasn't selected? It wasn't accepted as a first waypoint?

I went to the Route page, entered EDDM as a departure airport. I then went to the LEGS page and entered MIQ (NDB) as a single/first waypoint in a route. A choice of VOR or NDB was offered to me. I selected the NDB. It was accepted. I executed it.

Can you explain further?

QuoteI flew with 240 kts and this was to fast for the FMS to calculate turns so the ND has shown strange bows instead of the continuous waypoints along the STAR rout.
This is not normal. The FMS shall not calculate turns and deleting STAR waypoints on its own and showing strange "turning" bows instead.

I've seen plenty of strange turning bows on the real 744. If you need us to properly analyse what you are seeing, you will need to provide us with a .situ file. Are the waypoints disappearing as you pass them?

Here's a previous discussion on some strange turning bows with photographs of the real aircraft Navigation Display:

http://aerowinx.com/board/index.php?topic=3800.msg39832#msg39832

This software has been tested by dozens of real world 744 pilots. I don't know why you're having so many problems.

QuoteYesterday I flew to EDDM for an ILS.
The APP was armed.
I maintained 5000 feet to capture the GS. However suddenly the CDI horizontal needle showed a climb towards a higher altitude.
This is not normal. When a altitude is maintained and the glide is to be captured the CDI horizonal needle stays at the altitude which it is currently flown thus showing a level flight until the glide diamond goes through the center position of the vertical CDI scale and afterwards the CDI shows a descent following the what ever glide angle and associated aircraft ground speed requires to maintain the center of the GS.

What APFD mode were you in prior to capture? Had you captured the MCP altitude prior to this?

Daniel

Dear John,

I will try to replicate all scenarios and will send you a SITU file.

Kind regards

Daniel

Britjet

Daniel...
'the CDI horizontal needle"

And what, exactly, is that?
If you want help here you may wish to be more informative with your rants, and less abusive. Some of your recent comments have crossed the line on what would be considered reasonable forum conversation. Or are you just another attention-seeking troll?
Peter.

emerydc8

QuoteOr are you just another attention-seeking troll?

That was my thought too.

Jon

Daniel

How can I send you a picture attachment here?

Jeroen Hoppenbrouwers


Dirk Schepmann

I spent at least 30 minutes in front of PSX to find out under which conditions the V-speeds might not be shown in small font.

And if my friendly reminder to stick to Boeing procedures (with the rationale in mind to get the most of the aircraft) is interpreted as racism and behavior of a Nazi, I'm deeply shocked. It makes me feel sad, actually.

These words don't belong on any forum, and especially not here in this friendly community.

Hardy Heinlin

Quote from: Dirk Schepmann on Sat, 29 Jun 2019 01:45
The problem here is that you can't activate the route before at least 1 leg is inserted.

Hi Dirk, this is what I and others have been trying to explain Daniel for several days now.


|-|ardy


P.S.: And ... Daniel ... one more insult with "nazi" etc. and you're off.

Avi

Quote from: Dirk Schepmann on Sat, 29 Jun 2019 11:47
And if my friendly reminder to stick to Boeing procedures ... is interpreted as racism and behavior of a Nazi, I'm deeply shocked. It makes me feel sad, actually.

I'm not sure if this (few next words self-censored) remark meant for you, Hardy, me or anyone else here (not that it is even close to be relevant).

Anyway, I'm done with him.
Avi Adin
LLBG

skelsey

#19
Quote from: Daniel on Sat, 29 Jun 2019 04:11The information I have inserted into the FMS is enough to calculate V speeds. A first or whatever waypoint has nothing to do with V speed calculations.

Daniel,

As others have already mentioned and I will emphasise again: a B747 is not a Learjet. Just because you can do something in the Learjet does not mean it will work in the B747. There are many things that you can do in other Boeing FMCs that will not work in the B747, or vice versa, let alone trying to compare it to a completely different type altogether.

I agree with you that, from a technical point of view, all that is required to come up with a basic V speed calculation is aircraft weight and runway. However, that is immaterial because, once again:

- The B747 FMC will not calculate the speeds unless there is an active route.
- To activate a route the B747 FMC requires that there there must be at least one leg in it.

That is the beginning and end of it. The fact that technically this information is not required to calculate the speeds is irrelevant. Before the FMC willl even start thinking about calculating the speeds, it needs an active route.

QuoteWhen a altitude is maintained and the glide is to be captured the CDI horizonal needle stays at the altitude which it is currently flown thus showing a level flight until the glide diamond goes through the center position of the vertical CDI scale and afterwards the CDI shows a descent following the what ever glide angle and associated aircraft ground speed requires to maintain the center of the GS.

Like Peter, I'm not really sure what you are referring to here but I assume you mean the VNAV path pointer and deviation scale shown on the ND.

If so, you seem very confident about what you expect to see happen. Have you got a reference for that?

If you operate the PSX B747 simulation as Boeing intended -- that is to say, using the B747 FCOM Normal (and other) Procedures -- then you will find that everything works properly. If you deviate from the Boeing procedures at any point, then just like the real aeroplane, all bets are off as to what might happen. I am sure that your Learjet is no different. The B747 will fly a go-around with two engines failed very happily. I wouldn't, however, expect a Learjet to do the same ;)

As others have said, you need to seriously adjust your attitude and approach to the others in this friendly community. I don't know what your level of experience is but as Hardy mentioned earlier: there are very many people here (including in this thread) with, I suspect, more time in the bunk in the real B747-400 than many pilots have total flying hours, not to mention extremely experienced engineers like John who have a near-encyclopeadic knowledge of the systems on the aircraft. I can tell you from personal experience that they are all extremely forthcoming and helpful so if you want to learn how to operate the B744 then I suggest you stop giving it the big I-am about your Learjet experience, open up your mind to the fact that the B744 is operated in a very different way, and start listening to what people are trying to tell you.