Air Sys Failure--Help!

[HiFly 16]

This morning when I fired up FSX (I use the default tryke with engine off as my startup file) then loaded a model of MD-11.  After moving it to the gate of my departure airport, I noticed that everything was powered up so I loaded the "cold and dark" panel.  So far no problems.

 

I started battery and opened CDU to request EXT power and then activated EXT power on the overhead. I initiated ENG/APU fire test and then (according to the FCOM) then next item is the ANNUN LT TEST.  I tried the test but nothing was showing up on the SD as active (since I had no airflow).  I did notice, however, that the engines in the diagram showed over 110C which but they were off.  I next requested EXT air and heard the system come on.  I then ran the ANNUN LT TEST again and this time the test failed and the engine temps in the diagram were rising to well over 125C!  A few seconds into the test the air supply automatically shut itself off and though I did notice the "air system test" in cyan in the EAD, all my displays were over-marked with big X's and the same thing on the air SD window.  I went back to overhead, recycled the air system and I heard everything come back on.  I then checked the air SD window and sure enough it displayed the "air sys failure" notice and the engine symbols in the window were now showing 135C!

 

I rebooted my computer, opened FSX and selected a different model but had exactly the same results.  I did not notice this at all yesterday on my first flights and yet I am following the FCOM and the advanced tutorial protocol.  The only difference yesterday is that I had completed the FMC work including a long refueling before I got to the ANNUN test and everything proceeded without a glych.  I am stuck here and need some guidance and direction.

[xxJohnxx 21]

Hello Craig,

 

That seems very weird.

 

I am not sure what causes your problem, but I ask if it is possible to test it without that tryke with engine off as your startup file. I think the original one is that one, where the tryke is in the air.

Sometimes it is suggested that you first load a flight and shut everything down, and then load the aircraft you want to fly. However, at least for me, it works better if I just directly load the aircraft from the FSX freeflight menu screen.

 

Please also check that you don't have any failures active in the PMDG and FSX failure menu.

 

Additionally can you please post a screenshot of the air synoptic page with the red Xs on it?

 

Best regards,

 

Jonathan

[xxJohnxx 21]

Okay, I did a few tests on my system and that what you are writing is maybe not a bug.

 

That the engine bleed air temperature is rising, when the external air is connected, is normal. On a very short test they reached 125°C on my system too, and would probably even rise more over a longer period of time or diffrent climate conditions.

 

If you hold the ANNUN LT TEST button for a few seconds, you will perform the air system test. This is announced in cyan on your EAD. During this test the air system will shut down and several Level 2 and Level 1 allerts will apear.

 

This test should finish after maybe a minute, and the air system should return to normal operation, and all allerts should be removed again.

 

A screenshot would help to identify the problem if it remains.

 

Best regards,

 

Jonathan

[HiFly 16]

Thanks again, Jonathan.

 

 From your last post I gather that I am discontinuing the TEST too soon when the system goes off instead of waiting.  The FCOM stated that the test was completed when the EAD showed "Air Sys Test" in cyan and it does that within a couple of seconds.  I think the reason I was not having a problem yesterday is that once I activated the test it took me a while before I figured out how to get out of the overhead and into the AIR SD.  By that time the test had completed (?).   I have no problem with the test if I do it BEFORE I connect any air but I think that defeats the purpose doesn't it?

 

Still can't figure why I get temp rise in the engine nacelles when I use external air.  I thought "external" meant an "external" air source.  There should be nothing connected to the engines.  Even if bleed air were connected, why would it cause a temperature rise?  Nothing in the system manual that I can find directly addresses that.  Are you sure that is not a bug?

[xxJohnxx 21]

Hi Craig,

 

The FCOM stated that the test was completed when the EAD showed "Air Sys Test" in cyan and it does that within a couple of seconds.

 

I guess you are refering to this line in the FCOM:

 

NOTE: Air system preflight test is initiated by pushing and holding ANNUN LT TEST button until "AIR SYS TEST" alert is displayed.

 

I think that means that the air system test will be started/is started once the "AIR SYS TEST" alert comes up. The test is then performed as long as the "Air Sys Test" is displayed in cyan, and is finished once it extinguishes.

If you just push, and not hold the ANNUN LT TEST button, the air system test won't be performed.

 

I am sorry, but I think I am missunderstanding you here:

 

I have no problem with the test if I do it BEFORE I connect any air but I think that defeats the purpose doesn't it?

 

Do you have a problem when you do the test AFTER you connect any air source, or does it work?

 

Still can't figure why I get temp rise in the engine nacelles when I use external air.  I thought "external" meant an "external" air source.  There should be nothing connected to the engines.  Even if bleed air were connected, why would it cause a temperature rise?  Nothing in the system manual that I can find directly addresses that.  Are you sure that is not a bug?

 

Do you mean the readout on the AIR synoptics page, or do you mean the NAC readout on the ENG synoptics page?

Because the readout on the AIR synoptics page shows the engine bleed air temperature. As the crossbleed valves are open and ground air is connected to the engine number 2 bleed air system, all 3 bleed air systems will heat up to that 125 - 135°C.

 

Best regards,

 

Jonathan

[HiFly 16]

Thanks a lot, Johnathan.  That puts it all together for me.  I just was not keeping the test on until it completed.  And what I meant about running test before I activated EXT air but only had EXT power connected.  But that is irrelevant because I was misunderstanding the FCOM as you so astutely pointed out.  Thank you.  I also didn't study the system manual too closely and didn't remember that the external air was connected thru the #2 engine.  That explains why the temperature was rising first in that engine symbol.  BTW, the temperature rises I was alluding to were indeed the ones appearing in the AIR synoptics not the ENGINE synoptics.  I think you have cleared it all up for me.   I am going to restart the flight from cold and dark again so I can run the test properly.  Thank you again.  Have a great rest of the day.

[xxJohnxx 21]

You are welcome! Enjoy your flight! :good:

[mburkhard 23]

Craig,

quote from my MD-11 manual:

 

CAUTION: During the Manifold Fail Detect System Preflight Check, switching the AIR SYSTEM P/B will result in the shut down of all three pneumatic systems or interfere with the test. Maintenance action is required to restore air system operation.

 

 

So I suggest you do not interrupt the test

 

Cheers,

Markus

[RichBowman 1]

Hmmm - I've for this same problem - but I can't seem to clear it. It results in no temp control of the fwd or aft cargo, and if ignored seems to result in a Pack 2 failure.

 

I've even tried a re-install (of the MD-11) to clear it, but must have missed a file...

 

Is there a way to get shot of it? I've tried letting the test run (for a couple of minutes) and clearing the failures on the menu option... Bit it's still not working...

 

Any suggestions?

 

Thanks in advance,

 

Rich

[HiFly 16]

@ Rich:

 

     What I finally discovered is that I was interpreting the FCOM wrongly.  When you press the ANNUN TEST it is going to go through an entire long procedure that may last a couple of minutes.  You can view it on the Air Synoptic but do not turn off the test or you get that unrecoverable failure.  Once you get "air sys failure" you may as well shut down because it seems it can no longer be cleared. You have broken one of the manifolds.

 

    Procedure is to activate the test then go to the SD AIR and just let it continue to announce "overspeed" as it works through the 3 pages.  I have been clicking the "air" button on the SD each time the diagnostic says to press to continue and it then goes to the next page.  The air supply WILL shut off for about a minute during the second part of the test.  Do not interrupt it.  When the test is finished you will hear it all come back on and much of the diagnostic diagram will clear.  I know when it is done when 1) I hear the air come back on; and 2) when the synoptic no longer prompts me to continue to the next page (it has 3 pages of display).  I then deactivate the test on the overhead.  

 

    Try it that way and see if it works successfully for you.

[RichBowman 1]

Ace - that's sorted it! Thanks for that!

 

Cheers,

 

Rich

[HiFly 16]

Glad to hear it, Rich.