Simbrief says to descend to FL140 randomly during cruise, then climb back up again

Hey all!

I was just planning a flight from Dubai to London on a BA 777.
I have step climbs enabled.

Here’s two screenshots from the flight log.

As you can see, as I enter Bahrain’s FIR, it says to descend to FL140. Then, once I get into Jeddah, I climb back to FL340.
Any idea why? Is this realistic? Is there some kind of airspace restriction in Bahrain?


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Really good question I experienced the same for some regions all over the globe. Sometimes it affects speed as well. No idea why.
It makes absolutely no sense to me, why should a plane descent to such an alt while at cruise. That’s inefficient.

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Sometimes this happens because it charts you over an airway that has a low altitude restriction.

I just ignore them - just continue at FL340.


Okay thought it might have been something weird like that. Thanks!

Hello @InfiniteFlightDeck how are you? It’s happened to me too. When I reported it here I was told it was a bug. What would I suggest. Entering navigraph support it has a simbrief tab. Ask this question and I think they should know why. They are very considerate.
Ah! Come back here if you have any news about this 😉👍

i would suggest using Infinite Flight FPL Converter

Hello @InfiniteFlightDeck , how are you? I took the liberty of taking your example and asked in Navigraph and got this answer from the simbrief developer:

"Hi, it’s due to an airway restriction. Normally trying a different route will fix it.

In this particular case, L768 is restricted to FL145. but only on the default (outdated) AIRAC cycle. Cycle 2110 no longer has that restriction and would not have caused a step-down.

Best regards"

I’ll leave the dialogue link with him. I hope I helped you and I’m sorry for anything.

Greetings 👨‍✈️👩‍✈️🛫


With Infinite flight FPL converter, it tells me whenever I’m above China or Mongolia to be at an extra 100 feet in altitude for cruise, for example, 35,100. Is that the rules over there?

Hello @Skonert. 'm not sure, but I believe there is some restriction in this location you are referring to. An observation when you go to see the restriction, try to search within the airac cycle that you made the plan. I believe this helps.

Here is a flight from ZPPP-ZBAA as a reference.

I didn’t need the print 😁 . I had understood your reference. Air way search has some restriction. One way to search is using skyvector.


China uses metres, rather than feet, when issuing altitudes. The extra 100 feet you’re seeing is the conversion from the issued altitude in metres to feet.

I have attached a conversion chart for reference.

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Wow, awesome! This means that they actually do fly at that altitude then!


Yes, they do. :)

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Wow @Jai0114 imagem

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