jns278

I did not find any pack failures options there...

hi, one more question about the ngx: do you know if there are PACK failures avaiable for the 737? The fms only shows bleed air related programmable failures...?

TY for you reply!!! "modulating valve" is not my term found in in several manuals from boeing... and this valve is referring to beoing "pressure operated" maybe same principle like on a governor. yep thx again... that what I assumed, too.^^ But it's hard to find definite answer on the inet for that

OK!, thank you for answering! do you know why it could stall? on takeoff the highstage should be closed anyways since 5th stage should be sufficient on take off... PS: I did not expect a level-d, i just wanted to ask how deep they simulated and what is "behind the panel"...that would have been my next question then: why would someone simulate systems even a advanced simmer would never come across... My PC and I are happy that it's not a maintenance trainer (for pilots?!), too. :wink:

Hi, I need help/answer for these questions. 1) FCOM says(concerning APU vlave&dual bleed) (2.20.02):'there is a possibility of APU bleed air backpressuring the 9th stage modulating and shutoff valve. This would cause the 9th stage valve to close.' ok and? whats the problem when it's closed? 2)is it possible to damage something(valve, ducts etc.) on the ngx by pilot missbehaviour? e.g.: when I'm in a dual bleed configuration and set thrust to more than idle will it damage the APU as it is mentioned in the respective FCOM section? I tried it with 100% N1 on ground an nothing happened.. APU + valve were fine... 3)PMDG general simulation depth: did PMDG simulate everything?, e.g. in the maintenance manual of the 737 the bleed air schematics are far more complex as those of the FCOM.. there are more bleed trip temp sensors and other components (like precooler) shown that work independently of pilot input. so are all of these valves and sensors physically simulated? is the bleed air temperature really simulated because I don't think there's a need for that since you can't read the actual bleed air temp by any gauge and there are only two failures in the FMC programmable(+ may pilot errors) that cause an overtemperature in the bleed air system. so it could be programmed like this:"If left bleed air overtemp failure is activated, shutoff left eng bleed valve and indicate 'BLEED TRIP OFF'" or is it like: when temp failure is activated via FMC each air atom gets more thermodynamic energy which causes the bleed trip sensors to interpretate the temp as too high and send an electrical signal with 0,1 AMPS in 0,12 sec to the respective computer(or controller as on the MD-11) whose CPU then needs more electrical power to give the comment to shutoff the DC bleed air valve with 0,53 AMPS? the latter seems very visionary to me since if it was like that there should be like 10^10^10 possible failures available in the FMC. (BTW i already found out that bleed air valves can't adopt continuous positions.. when you turn on eng bleed air and let the respective valve fail simultaneously it will be either closed or fully opened, not half or 3/4...=> they are not simualted as real modulating valves(?)!).. would be happy if anyone knows answers to these let's say specific questions!! thx in advance!!