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carlan2uk

Flight Level.

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I set up a flight with    FL 34000. Before Take off I checked the legs page and found that by page  2 or 3 the FL had gone up to 38000!

I left the MCP at 34000 as planned. when top of descent appeared on the nav. display I set the MCP to 3000. At the TD the vertical path deviation

showed no deviation but  the plane did not start to descend for a long time. when it did descend, all went well to landing.

I repeated the flight after re-booting and the same thing happened again.This time I set the MCP to 38000.When into cruise at 38000 I had

to go out, so I saved the flight.. When I re-loaded,  the panel was hopeless as usual so I re-loaded the panel state. This was then ok but I had

lost a lot of height so it started to climb. BUT- the legs page now showed 34000 as it should. I quickly changed the MCP to  34000 and all went well to the end.

How is the FMC incorrect when first loading and how is it correct when  re-loading? A puzzle, an ideas?

David

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The higher flight levels you noticed later in the flight are due to the FMC planning step climbs for you as fuel is used and the 777 can fly higher. Perfectly normal, but you don't have to climb above the initial flight level if you don't want to. Just keep the MCP altitude as required.

 

I can't explain what happened after you reloaded a saved flight. The FMC simulation might behave differently in such circumstances.

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Mmmm, I'd have thought this is simply the ACARS "PERF INIT UPLOAD" ....... in other words, "flight dispatch" are deciding your FL, not you. :wink:

If you accpept the "PERF INIT" UPLOAD, it will enter the flight level, so you perhaps chose FL340, but then accepted the ACARS PERF INIT Upload, which entered FL 380 ?

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I set up the FMC exactly as in the tutorial apart from change of  start and destination.

I started from Gatwick using a long turnround. I used the information at the end of the tutorial

regarding a cold and dark startup. After a few items it then says-At this point continue with FMC setup used in the tutorial.

I did all this putting in (in my case) 34000ft. In the tutorial 38000 is inserted and all the legs showed this.

Later a choice for a step climb came but was not used.So the TD went without problem.

In my case there is no step climb as it goes straight up to 38000.

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YOu may want to contact Houston Space center if you are at FL34000, that's 3,400,000 feet.  That is barely within the atmosphere... Poor GE90s...  :lol:

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On the Perf Init page in the FMC next to the bottom right line select key the default input there is RVSM or something near that (not by FSX computer at the moment) If you leave RVSM there the FMC will work out when it expects your gross weight to be low enough to climb 4,000ft and will therefore at the appropriate waypoint show the increased flight level. If you replace RVSIM with a zero the FMC will not increase your flight level. You can also type in say 2,000 and then the FMC will when you are light enough indicate a flight level 2,000ft above your initial cruise level.

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Thank you Nixon- That did the trick.

I suppose that it is somewhere in the 2000 pages but I am not up to  that yet!¬

David

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If you leave RVSM there the FMC will work out when it expects your gross weight to be low enough to climb 4,000ft and will therefore at the appropriate waypoint show the increased flight level. If you replace RVSIM with a zero the FMC will not increase your flight level. You can also type in say 2,000 and then the FMC will when you are light enough indicate a flight level 2,000ft above your initial cruise level.

 

Almost...

 

RVSM will actually have the FMC calculate 2000' steps in RVSM airspace, and 4000' steps outside of it.  Forcing 2000' will use 2000' steps in and outside of RVSM, and 0 overrides all steps and tells the plane that you intend on remaining at your CRZ ALT on the PERF INIT page for the duration of the flight.

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Thank you Nixon- That did the trick.

I suppose that it is somewhere in the 2000 pages but I am not up to  that yet!¬

David

I am glad it helped David

Almost...

 

RVSM will actually have the FMC calculate 2000' steps in RVSM airspace, and 4000' steps outside of it.  Forcing 2000' will use 2000' steps in and outside of RVSM, and 0 overrides all steps and tells the plane that you intend on remaining at your CRZ ALT on the PERF INIT page for the duration of the flight.

Kyle why "almost"?

I was answering the specific query of the topic starter where he refers to 4,000ft. I was not defining RVSM airspace.  I don't wish to be awkward but am at a loss as why you also felt it necessary to repeat what I had written especially as the topic starter had said that the issue was now sorted.

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Kyle why "almost"?
I was answering the specific query of the topic starter where he refers to 4,000ft. I was not defining RVSM airspace.  I don't wish to be awkward but am at a loss as why you also felt it necessary to repeat what I had written especially as the topic starter had said that the issue was now sorted.

 

...why would I dare question your post?  Because it's wrong.

 

You said RVSM will make the FMC calculate when it's okay to climb 4000 feet:

 

 


If you leave RVSM there the FMC will work out when it expects your gross weight to be low enough to climb 4,000ft

^ Your words.  They essentially say "RVSM climbs are 4000."

 

This is incorrect.  The FMC will calculate when it's okay to climb 2000 feet (going along with the whole entire point of RVSM airspace - 1000 foot separation between opposite direction traffic).  Seeing that RVSM ends at FL410, and the 777's max certified ceiling is about that high, there's no real way you could argue that RVSM would regularly calculate 4000 foot steps (which it will, if you're above RVSM, but you rarely are in the bird, and you normally take a 2000 foot final step to get there).

 

Why would I feel it necessary to correct you even though the thread was "resolved?"  Because people still read posts regardless of the solution or answer being posted.  This community is already stuffed full of bad information (US 250/10 rule anyone?), so I felt it necessary to correct what you'd written.

 

The rest of it (overriding the step value) is true, but you do not need to override RVSM to get a 2000 foot step.

 

If you don't want me correcting your posts of incorrect information, either post correct information or don't post.

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Jeez Kyle, and you wonder why some people always get on your back?

 

Don't you realize your condescending tone?

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Almost...

 

RVSM will actually have the FMC calculate 2000' steps in RVSM airspace, and 4000' steps outside of it.  Forcing 2000' will use 2000' steps in and outside of RVSM, and 0 overrides all steps and tells the plane that you intend on remaining at your CRZ ALT on the PERF INIT page for the duration of the flight.

Almost...

 

Manual entered STEP climbs on the LEGs page are still taken into account for by the ETA and FUEL performance calculations even when 0 is entered.

 

Sorry Kyle.....I could not stop myself ;-)

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I set up a flight with    FL 34000. Before Take off I checked the legs page and found that by page  2 or 3 the FL had gone up to 38000!

Kyle my post was in answer to the above quote and that is why I wrote 4,000ft. As I clearly said in my last post I was not defining RVSM. Therefore I haven't posted incorrect information but instead I have answered the topic starters query and he has kindly thanked me for doing so. 

I of course don't need your permission to post. Whilst I think you posts in this thread are rude and unhelpful I certainly wouldn't tell you not to post, because I believe in the freedom of speech and the exchange of ideas.

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Therefore I haven't posted incorrect information but instead I have answered the topic starters query and he has kindly thanked me for doing so.

 

With respect Nixon, you posted:

 

 

If you leave RVSM there the FMC will work out when it expects your gross weight to be low enough to climb 4,000ft and will therefore at the appropriate waypoint show the increased flight level. If you replace RVSIM with a zero the FMC will not increase your flight level. You can also type in say 2,000 and then the FMC will when you are light enough indicate a flight level 2,000ft above your initial cruise level.

 

That implies RVSM looks for 4000 ft steps. You also said entering 2000 would give 2000 ft steps, which reinforces that impression. So even though you fixed the OP's problem, Kyle is right. The OP, and anyone else reading it, may get the idea RVSM means 4000 ft steps.

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With respect Nixon, you posted:

 

 

That implies RVSM looks for 4000 ft steps. You also said entering 2000 would give 2000 ft steps, which reinforces that impression. So even though you fixed the OP's problem, Kyle is right. The OP, and anyone else reading it, may get the idea RVSM means 4000 ft steps.

 

Kevin I presume you have read all of this thread and will have seen that I have stated twice that I was not defining RVSM. My first post said this

On the Perf Init page in the FMC next to the bottom right line select key the default input there is RVSM or something near that (not by FSX computer at the moment) If you leave RVSM there the FMC will work out when it expects your gross weight to be low enough to climb 4,000ft and will therefore at the appropriate waypoint show the increased flight level. If you replace RVSIM with a zero the FMC will not increase your flight level. You can also type in say 2,000 and then the FMC will when you are light enough indicate a flight level 2,000ft above your initial cruise level.

 

I mention RVSM solely because it is the default setting and therefore replacing it with a zero will solve the original posters query. I mentioned 2,000ft to show that the pilot can input whatever step he wishes. If I had been defining the term RVSM I would have clearly stated so and I did not. In fact I actually said "RVSM or something near that (not by my FSX computer at the moment)". I think you would agree it would be nonsensical to try and define a term when I wasn't 100% certain of the how the term is written. I would be grateful if you or Kyle could actually point to where I say am defining RVSM rather than assuming that I have defined it. 

 

I answered the original query to the satisfaction of the person who made it only for Kyle to then jump in with his "almost" remark. I then politely asked him exactly what he meant by that and also why he felt the need to virtually repeat the rest of the post.

 

His reply was in my opinion rude. Especially his last paragraph

 

.

 

If you don't want me correcting your posts of incorrect information, either post correct information or don't post.

 

Thanks to Kyle's input this thread has gone on far too long and I will therefore close with this Kyle quote which is a rather sweeping statement especially as he repeated most of my "wrong" post in his reply.

...why would I dare question your post?  Because it's wrong.

 

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