New bleed air SimVars

Questions & Community Discussions Aircraft
1

Hello, In the SDK v0.20.1 release notes, we can see the following:

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However, the SimVars are absent
from the documentation. What are their effects and how to use them? On a
similar topic, the following SimVar is listed in the documentation, and I can
see its value changing but what is the logic behind the value it takes?
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Is it related to bleed air fed to
the engine for start, or bleed air control from the indexed engine? Thank you.

2

Hello @boufogre The pages describing the effects of those variables wasn’t
ready when the flighting (beta) version of the documentation was released, it
will be explained in the official documentation when SU11 will go out but
here’s the state of the page from our side. For the BLEED AIR SOURCE CONTROL
simVar, the value change the source of the bleed air used by the plane, if you
want to set up the bleed air fed to the engine for start you need to use
APU_BLEED_PRESSURE_RECEIVED_BY_ENGINE Best regards, Yohan

3

@Yoanito, Thank you for the explanations. I am still having doubts on how the
BLEED AIR SOURCE CONTROL SimVar value changes. For example, on the default
747, when all the engine bleed air switches are ON, and the APU bleed air
switch is ON too, it will return 0, which is min according to the doc (not
sure what min means though).

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But if switch the APU bleed air switch to OFF, then the BLEED AIR SOURCE
CONTROL SimVar returns 3, which is APU according to the doc. That does not
make sense, or am I missing something?
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I have to say I understand the
idea with the TURB ENG N1 LOSS SimVar, but IRL if you increase bleed air
demand, ie switch on EAI or WAI, the N1 for a given throttle position will
increase, while the maximum rated N1 will decrease to respect engine limits.
After testing the TURB ENG N1 LOSS SimVar, it appears it will only reduce N1
for a given throttle position.

4

I think I found something. It would seem the SimVar doc is outdated, and the
correct information is given in the Event IDs section.

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Could you confirm? Thank you.

5

Hello @boufogre After a quick look in the code we realise that the
documentation was false, 0 stand for AUTO so it will be returned when you have
the engine and APU active, if you disable the APU you will go to Engine so 3,
the documentation will be updated at the release of SU11 to display the
following : Best Regards, Yohan