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T/C appearing ahead of T/D

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Hi,

I was having a flight today and as I got closer to T/D I noticed T/C appeared ahead of it on the F-PLN page.This prevented me from descending with the FMC and I then had to descend manually, not a big deal.

Does anybody know why this appeared or how I could have deleted it? I tried but couldn't get rid of it.

I was flying at FL360, it stated FL 365 in the FMC. I would guess it was some sort of set climb.

 

Can anybody shed any light on this. So I can prevent this in the future.

Thanks

 

http://s1363.photobucket.com/user/Aeroset/media/2013-8-12_23-29-42-889_zps4c4fad28.png.html

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I wonder if you were below the cruise level set on the INIT page. Sometimes if you enter a cruise level that is above your max flight level you can get a funky flight level set. I see the T/C is for FL365. This is an atypical cruise level and think that may have been the issue.

 

Kevin

 

Sent from my Nexus 7 using Tapatalk 4

 

 


Kevin Sullivan

800driver.jpg

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  • Just to be clear at no point did I fly at FL365 or enter that value into the FMS. It appeared there by itself somehow.

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Just to be clear at no point did I fly at FL365 or enter that value into the FMS. It appeared there by itself somehow.

 

No offense, but I highly doubt that.  Computers, while powerful, are really quite dumb and rarely ever do anything without being prompted to do so.

 

I'm with Kevin.  I would've liked to see the INIT page, or perhaps the MCP.  Sounds like it was just an unintentional action on your part.  Then again, looking at it, it's not in large print, which means the system calculated that and added that in there (it's not a hard altitude that you, or the navdata set).

 

Try flying the same route and see if you can reproduce it.  Take as many shots of the route and MCP while you do so.


Kyle Rodgers

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When you set FL360 on the init page and during the flight you've dialed on the MCP FL 370 or 380 for example and just later turned it back to 360 the chance is pretty big that on the init page it changed to 365. (You will also see 360 in white instead of magenta colour on the PFD). It will chase 365 instead of 360 even when passing TOD. Same as Kevin and Kyle said.

 

I've had it multple times too, just set 360 in the init page again when it happend. I'm sure if you do this it won't happen again.

 

John

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Thanks for the help, I won't re-fly it because it was a 3 hour flight. I'll keep an eye out for it in the future. In the meantime I flew a shorter route without it reappearing.

So it seems that I must have set the MCP Alt too high, although I don't remember doing so.

Thanks again.

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When you set FL360 on the init page and during the flight you've dialed on the MCP FL 370 or 380 for example and just later turned it back to 360 the chance is pretty big that on the init page it changed to 365.

If you dialed in FL380 the MCDU cruise level would remain at FL380 when you set it back to 360.  A more likely explanation is that when setting FL360 during the climb if you accidentally overshoot by one click it will read FL365.  The FMC interprets this as a selected increase in cruise flight level.  It's not a question of chance, it always does it.  In the aircraft such a selection overshoot is probably less likely, but in the sim it's really easy to do. 

 

In a Boeing if you dial in a higher flight level than the flight plan you have to confirm such a new cruise level in the FMC, but apparently in the MD-11 you don't.  It's one of the things that makes this sim less user friendly in the VC because the MCP clickspots are so small and mistakes are so easy to make.


ki9cAAb.jpg

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PROF TO 34000

PERF 6000

 

Means that you selected 34000 on the MCP, but there is an FMS hard altitude constraint before then that it needs to meet.

 

 

 

PERF 6500

 

Means PERFormance mode is active, but that you selected an altitude that is neither a hard altitude constraint, nor a cruise altitude as set in the INIT page. In this case, the MCP is the altitude constraint. FMS will not climb above this altitude until you select a higher altitude.

 

 

 

HOLD 6500

 

Means MCP altitude constraint resulted in level off (PROF mode ACTIVE) at altitude other than FMS hard altitude constraint or cruise altitude.

 

 

HOLD 6500

 

MCP altitude constraint (PROF mode INACTIVE).

 

 

Once you get used to it, it is very intuitive.

 

Best regards,

Robin.

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Perhaps if the route is shorter than the climb and descent distances combined for that altitude leaving no level flight confuses the toc/tod?


Steve Waite: Engineer at codelegend.com

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If that happens, a CTD is usually the result.

 

I suspect that it took the cruise altitude from the INIT page, whilst the aircraft was below it. There was no CTD because the FMS was in CRZ phase (if it is in CLB and tries to go directly to DES it causes a CTD).

 

Best regards,

Robin.

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