Guys, as long as you are here,theoretical situation:I am performance lmited, thus packs off, but conditions require usage of antiice (wing and engine).my dispatcher says I can do that.How do I set up the air system?

Interesting quesion...In the PMDG and FSX, just forget Anti Ice, as you don't need it.. :)Seriously..Use the APU? I know one of the posts above had a Flow that said you couldn't turn on the AntiIce While the apu was pressurising the aircraft. Why is that? (Maybe because there wasn't enough Bleed to succsesfully use the apu for both systems?) And if so, goto oxygen and then use the APU for the Anti Ice?JB

Edited January 14, 201214 yr by Buzz313th

If your knoledge about the pneumatic/airconditioning is so sufficient, the difference between bleed off and packs off may be obvious.And, as JET 1 said, with bleeds off the pack switch position is like a light switch during a black out... completely useless.So, from the first page we are talking about the same things. I don't think there is something that has not already answered.The aircraft can take off with or without packsIf they are used it is better for structural reasonsApu can be used to supply pressure and let you use the engine at full power.You can use packs off (only packs) you will recover the 99,9% of the engine powerYou can use bleed off (and packs are obviously off as they work with pneumatic pressure) and you will have the 100% of itThe difference from only pack off and bleed off is the remaining of the pneumatic system as shown on the FCOM, including potable water tank pressurization, hydraulic reservoir pressurization, and eventually all the leakages.The schematic is sufficient to show all these things.

Daviersoft, why do you persist in being condescending? Please cease and desist! Read the post you objected to again. It should be obvious I know the difference between (engine) bleeds off and packs off if you actually read what I typed. You've suggested twice I don't know much about the NG's PACS, inferred that I'm a little slow and then proceeded twice to try and educate me on a bunch of issues I never raised. Why are you telling me the aircraft can take off with or without packs? Why not tell me that the aircraft can takeoff with or without the seatbelt sign on!I understand that English is not your first language but please try and give helpful answers and refrain from assuming others know less than you do. To make it clear to you again - I was simply trying to ascertain from the professional member(s) of the group whether in their opinion the only reason for turning the left and right packs switches off for takeoff in an NG was when performing an engine bleeds off takeoff with no APU. It was suggested that this was correct. If you do a quick google of 'packs off takeoff', look at the PPRUNE forums etc you'll see there's a wide range of procedures for the pneumatic system during takeoff. It varies between airline SOP's and aircraft. The other obvious scenario is an (engine) bleeds on/packs off takeoff. This is a common procedure with some aircraft/airlines in an attempt to somewhat increase takeoff thrust available eg short runway/heavy/high altitude/warm air. What I think I have learnt from the more helpful members of the group is that - with specific reference to the NG - whilst a bleeds off takeoff is clearly applicable to this situation, a bleeds on/packs off takeoff really doesn't have a role with this aircraft.Last point: remember there is no such thing as a stupid question.

Pack switch position when all bleeds are off makes as much difference as the light switch position in your house during a blackout - ain't gonna work anyway Anyone with deeper understanding of NG pneumatic workings please correct me if I'm wrong.

There's a lot of switches that don't do much if the 'upstream' switch is off, but they still have a correct position on the checklist flow. Otherwise I'd just shutdown by turning off the engines and battery and leave it at that! :)

I understand that English is not your first language...

This may be more of a translation thing....but to go off topic, how did you go with that cyclone last week? I see Qantas operates 717's into YPPD but have 737's ever flown in there? May have to try that one. And there's a thought, how about a PMDG 717? :(

Guys, as long as you are here,theoretical situation:I am performance lmited, thus packs off, but conditions require usage of antiice (wing and engine).my dispatcher says I can do that.How do I set up the air system?

If you have cold enough temperatures to require anti-ice, you usually have good enough performance to take-off without the BLEEDS OFF.You cannot use the APU to power the WING ANTI-ICE.If you really need the WING ANTI-ICE, then you should also be de-iced and sprayed with Type 4 anti-ice fluid. And if you were sprayed, then you shouldn't use WAI on the ground as the heat cooks the fluid. So, you really don't need WAI on the ground. If you can't take off with WAI until the power reduction, then you shouldn't takeoff.

Edited January 14, 201214 yr by Spin737

Maybe a little typo Andrea ?Fred.

Yes, OPEN :(

Interesting quesion...In the PMDG and FSX, just forget Anti Ice, as you don't need it.. :)Seriously..Use the APU? I know one of the posts above had a Flow that said you couldn't turn on the AntiIce While the apu was pressurising the aircraft. Why is that? (Maybe because there wasn't enough Bleed to succsesfully use the apu for both systems?) And if so, goto oxygen and then use the APU for the Anti Ice?JB

There is no problem for wing AI, it will shut off automatically when you advance throttles, you will be able to turn again on after lift off.Cowl AI thakes no part in the bleed discussion as it is before the bleed valve (so can be used either with bleed on or off).If you ave bad wheater, you can use wing and cowl just before take off, ten, turn them off and go. But pilots could help you better in the procedures.

This may be more of a translation thing....but to go off topic, how did you go with that cyclone last week? I see Qantas operates 717's into YPPD but have 737's ever flown in there? May have to try that one. And there's a thought, how about a PMDG 717? :(

It might be more of a translation thing as you say, and now I've had my morning coffee I'm not annoyed anymore :). Hey Andrea, it's OK, I see you posted some interesting stuff after shooting down my packs off/bleeds off/APU post, so it's cool.Direct hit from Cyclone Heidi, if you watched the ABC news last night and saw some live footage of the cyclone well I shot that. Got the camera a little wet (it wasn't working yesterday). Actually not too much death and destruction, we've had the TV crew from Perth staying at our house and have been trying to find them something actually worth shooting!As for YPPD and aviation: the most common plane I fly on is in fact the NG, did a Virgin Blue YPPD-YPPH and a Qantas YPPH-YPPD last week. The 717 replaced the Bae146 for some of the routes a couple of years ago. For FSX, the Pilbara scenery is not great, I've been brewing a bit of home-made photoscenery for the region over the past few days and some of the inland desert is pretty amazing. A part of the world very few real or virtual pilots will ever fly over.Anyway, back on to the NG's PACS/packs...

Interesting quesion...In the PMDG and FSX, just forget Anti Ice, as you don't need it.. :)Seriously..Use the APU? I know one of the posts above had a Flow that said you couldn't turn on the AntiIce While the apu was pressurising the aircraft. Why is that? (Maybe because there wasn't enough Bleed to succsesfully use the apu for both systems?) And if so, goto oxygen and then use the APU for the Anti Ice?JB

Daviersoft, why do you persist in being condescending? Please cease and desist! Read the post you objected to again. It should be obvious I know the difference between (engine) bleeds off and packs off if you actually read what I typed. You've suggested twice I don't know much about the NG's PACS, inferred that I'm a little slow and then proceeded twice to try and educate me on a bunch of issues I never raised. Why are you telling me the aircraft can take off with or without packs? Why not tell me that the aircraft can takeoff with or without the seatbelt sign on!I understand that English is not your first language but please try and give helpful answers and refrain from assuming others know less than you do.To make it clear to you again - I was simply trying to ascertain from the professional member(s) of the group whether in their opinion the only reason for turning the left and right packs switches off for takeoff in an NG was when performing an engine bleeds off takeoff with no APU. It was suggested that this was correct. If you do a quick google of 'packs off takeoff', look at the PPRUNE forums etc you'll see there's a wide range of procedures for the pneumatic system during takeoff. It varies between airline SOP's and aircraft.The other obvious scenario is an (engine) bleeds on/packs off takeoff. This is a common procedure with some aircraft/airlines in an attempt to somewhat increase takeoff thrust available eg short runway/heavy/high altitude/warm air. What I think I have learnt from the more helpful members of the group is that - with specific reference to the NG - whilst a bleeds off takeoff is clearly applicable to this situation, a bleeds on/packs off takeoff really doesn't have a role with this aircraft.Last point: remember there is no such thing as a stupid question.

Ok, as you wish,... I'll stop to answer...That's simple to do, wasting time with people like you.

And, years after years, probably with few take off without packs, ard landings and more, in that area it is possible to find cracks, and they must be repaired as you can see here:

Andrea, this is a really interesting photo but please could you explain what's actually going on here. I see what looks like a crack (or fracture?) above the (studs?). Is this taken during the repair procedure? My background is ship design (many eons ago) so I'm a little bit curious about the mechanicalstress aspects of aircraft design, which of course I know zero about.

Ok, as you wish,... I'll stop to answer...That's simple to do, wasting time with people like you.

What do you mean by 'people like me'? Keen flight simulation enthusiasts who like learning from forums without being told they're confused when it's actually the responder (you) who doesn't understand the question? Look, I've read your other posts and you clearly have some expertise in this area. I appreciate the useful posts you've put up above. I'm taking a deep breath and figuring the apparent sarcasm in your posts is more of a language thing. And I looked back and there is a typo in my first post (wrote 'on' instead of 'off') so perhaps you just read that and figured I really do have no idea what the difference is between a mixing manifold and a pack valve.Anyway, you possibly missed the 'olive branch' post I put up just before you posted. If you feel your time is being wasted, well that's your call. Have a fun day doing whatever!I'm going back to flying my NG, reading the forums and trying to learn a bit more about this awesome aircraft whilst I'm at cruise at FL390!

Ok, I will do a "reset", maybe there are faults on my side, and english maybe one of them.Using this forum let me learn also on this side.I think that sometimes my attitudes are misunderstood due to language limitations, and I've not read your previous post.Ok, for me it's all ok!Whiteknuckle:The picture shows the parts already during repair, the cracks are not visible as they were already removed and the 2 holes are the resulting.What it is visible inside the holes is a stringer, part of the structure of the plane.The crack started from a rivet, joined to another, and then started again. This kind of damage is the resulting of fatigue that is high in that area, we had these kind of damages 2 or 3 times on +10 years old aircrafts.The part unpainted is the one where a new sheet of aluminium will be installed to close the holes. As you can see, for a tiny hole, a big patch must be installed.Fatigue cracks caused also the Aloha airlines accident (737-200). After that episode boeing increased checks on the sensible parts (lap joints) by adding periodical visual inspections between each deep inspections.

Ha, reset here too. :)Flight 243 had some pretty decent cracks, pax claimed they could see them when boarding.

Ha, reset here too. :)Flight 243 had some pretty decent cracks, pax claimed they could see them when boarding.

And they were more visible at landing.

Ok, I will do a "reset", maybe there are faults on my side, and english maybe one of them.The picture shows the parts already during repair....

Ok I'm going to have a another look at the photo tomorrow. I'm assuming your mother tongue is German? The Germans, and most other mainland Europeans seem to manage English (spoken and written) to varying degrees of competency, yet how many of the British can claim to speak (or write for that matter) a foreign language? Not many, I can assure you, having grown up in the UK myself.