No Pressure In Right Duct (Quick Quiz)

[Guest Ian_Riddell]

Hi, folks.Why is there no bleed air pressure in my Right Bleed Duct? (It's a Classic panel, but the NG is similar).http://members.ozemail.com.au/~b744er/737/...icECSPanel1.jpgCheers.Ian.

[Mats_J 2]

Hi Ian,Nice idea!APU bleed is ON. Engine bleed is ON. Isolation valve is in AUTO. Due to logic (IF BOTH ENG BLEED VLV ON THEN ISO VLV CLOSE?) the isolation valve will close. And pressumably at least the right engine is not running yet thus no pressure in right duct even if the APU is running. Am I right? ;-)Regards,

[Guest wkzzo]

APU running ,no engines , all bleed switches on, Dual bleed annunciation, isolation valve closed.

[Guest BrunoF]

Mats,Hi how are you?> Due to logic (IF BOTH ENG BLEED VLV ON THEN ISO VLV CLOSE?) the isolation valve will close. Isolates left and right pneumatic system.AUTO > Valve Opens automatically if any pack or engine bleed switch is placed in OFF Position.OPEN > Connects left and right pneumatic system.Istolation Valve: The isolation valve isolates the left and right sides of the pneumatic manifold during normal operations. The isolation valve is AC operated. With the isolation valve switch in AUTO and both Engine Bleed Air Switches ON and Both Air Conditioning Pack witches AUTO or HIGH the isolation valve is closed. The isolation valve opens if either Engine Bleed Air Switch or Air Conditioning Pack Switch is positioned OFF. Isolation valve position is not affected by the APU Bleed Air Switch. ***Later I will try to include some diagrams to make it easier.Cya,Bruno Francescoli.

[Guest BrunoF]

I agree.By the way, Very nice idea Ian !Bruno Francescoli.

[Guest Ray CYYZ]

APU & Engine must both be running to get the Dual Bleed annunciator.Engine 2 fail & APU started to compensate in flight? Since the annuciators beside the Dual Bleed are not lit, you must be in flight.Not sure why you have zero pressure in the right duct because I don't know the flow on a 737. Perhaps we are looking at a duct leak on the right side. Since the isolation switch does not look to be in the closed position, I don't know what causes it to trip? Right Pack blown? Lots of possibilities.Closest I can get:http://forums.avsim.net/user_files/33906.jpgRay

[Guest amerton]

Dr Spock, something's not working on the Enterprise !Please beam Ian up !Anthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com

[Guest]

>CLOSE > Isolates left and right pneumatic system.>>AUTO > Valve Opens automatically if any pack or engine bleed>switch is placed in OFF Position.>>OPEN > Connects left and right pneumatic system.I agree on that one, and because there is no ram door light, it must be in flight with flaps up.http://www.b737.org.uk/schemeaircon300small.gifbut i need to think a little more to get to the point what is wrong, hmmm might be a sensor fault :-)Dennis

[Mats_J 2]

ROFL! :-xxrotflmao:-spacecraft

[Mats_J 2]

Hi BrunoI'm fine thank you! How are you? :-)I will have to correct both you and myself: ;-)ISLN VLV in AUTO:- The ISLN VLV is switch sensitive not valve sensitive.- If both ENG BLEED are ON and both PACKS in AUTO or HIGH, ISLN is CLOSED- ISLN VLV looks at the four "corner" switches. If either of them are OFF, ISLN VLV will open- APU BLEED switch has no effect on ISLN VLV position. OPEN ISLN VLV!All this according to Cpt. Bulfer. But he has been wrong before apparently?So according to this. Either ENG 2 is out and the captain has something more important to take care of. Or there is a leak in the right air supply system.Here's another one for ya. If you are connected to ground air. Which pack would be pressurized if you had the ISLN VLV closed?TGIF

[Guest BrunoF]

Mats Johansson,Fine thanks.

[Guest]

>ISLN VLV in AUTO:>>- The ISLN VLV is switch sensitive not valve sensitive.>- If both ENG BLEED are ON and both PACKS in AUTO or HIGH,>ISLN is CLOSED>- ISLN VLV looks at the four "corner" switches. If either of>them are OFF, ISLN VLV will open>- APU BLEED switch has no effect on ISLN VLV position. OPEN>ISLN VLV!That is the right, it is switch sensitive, i allmost forgot that.So you are right, eng 2 must be off.About the ground pneumatic source, then it is the right duck.Dennis

[Guest Ian_Riddell]

"APU running ,no engines , all bleed switches on, Dual bleed annunciation, isolation valve closed."CORRECT.... Go to the top of the class, Wallace :-)No Engines are running. Nothing is broken.On the real aircraft, Isolation Valve operating logic is based on SWITCH position (not the availability of air from engines).In this situation, only the APU is running. It is providing bleed air to the Left duct, but the Isolation Valve is closed because of the positions of the Pack SWITCHES and the Engine Bleed SWITCHES.If ALL four Engines and Pack Switches are on, the Valve will close. If ANY are OFF, the Isolation Valve will OPEN.The DUAL BLEED is slightly different. It looks at Engine SWITCH position, but also at the ACTUAL position of the Isolation Valve (where applicable) and the APU Bleed Air VALVE. Unfortunately, they won't let me play with the engines just yet ;-)Cheers.Ian.P.S. Is there a real life option to have the APU Switch latched? I've noticed that in PMDG, the APU bleed Switch seems to do some things by itself (E.g. Can't switch it on if the APU is not running).

[Guest Ian_Riddell]

"Dr Spock, something's not working on the Enterprise !No, I believe Scottie fixed it up yesterday after the ion drive had a meltdown ;-)"Please beam Ian up !"Er.... Sunscreen factor 10, Mr Sulu.... There's a KliNGon on the Starboard bow.Silly season is definitely open ;-)Cheers.Ian.P.S. You canna change the laws of physics.... except in MSFS, perhaps :-lol

[Guest]

>CORRECT.... Go to the top of the class, Wallace :-)>>No Engines are running. Nothing is broken.I have to disagree, unless some CB