Hey fallows,I know how to operate the ngx perfectly and any other plane, but sometimes people are doing things without really know how they're doing.so i have wanted to ask if some one can explain to me what's the isolation valve is doing, i know on the checklist they call it pressurisation,so i know before engine start and when shutting down its need to be open, but when it needs to be closed and what is he really doing?also my i ask how to calculate thrust for takeoff? if there any program that calculate it for free? how i need to calculate it now? i am just guessing, and its really does not realistic, so if some one can help with that it will be nice, thanks andcheers, Daniel

I know your answer for the thrust. I'm using a programm called TOPCAT which is payware. Simply enter the T/O weight of your aircraft, your departure runway, and click Compute, it will then give you the correct thrust tempature to enter in the N1 Limit page. For example today I was departing Budapest LHBP, and it gave me a FLEX TEMP of 44C, which was 91.7% of thrust.

is there no freeware program? thanks any way

Isolation Valve is closed for engine fires and smoke problems, configuring for no-bleed go-around, and other pressurization problems. Search the QRH for it, and you can find when checklists call for it.Day to day, my company uses it in the closed position to provide heat or cooling by the #2 engine to the Right Pack after #2 engine start and before #1 engine start.The valve switch is normally in the AUTO position and the valve itself is normally closed in flight.

Isolation Valve is closed for engine fires and smoke problems, configuring for no-bleed go-around, and other pressurization problems. Search the QRH for it, and you can find when checklists call for it.Day to day, my company uses it in the closed position to provide heat or cooling by the #2 engine to the Right Pack after #2 engine start and before #1 engine start.The valve switch is normally in the AUTO position and the valve itself is normally closed in flight.

Hey , thanks for the answer, do you say that as a real pilot?

I believe Spin 737 is a real 737 pilot indeed. The FCOMs might have more information on what the isolation valve actually does, but I haven't delved into those yet.As for take-off thrust. Basically you want to find the minimum thrust that will allow you to take off from a certain runway, given the current configuration of the aircraft and atmospheric conditions, (temperature, pressure and wind) and that will give you sufficient safety margin in terms of runway distance required. You could perform that calculation by hand, but it would make a good question for a university level aircraft performance exam. Unless you like doing maths for half and hour before each flight I would recommend against it.In real life dispatchers use software written by Boeing to do those calculations. Assuming you don't have access to such software (and few people would have) Topcat seems to be well regarded (I don't have it, so won't offer an opinion). I don't know of any good freeware alternatives.

The FCOMs do, and they're searchable.CTRL + F, type, enter, read, answer. Staples button: That was easy!

Edited January 4, 201214 yr by scandinavian13

The function of the isolation valve can be easily seen on the air conditioning panel itself, there are some "lines" that goes from bleeds to packs, from left to right. And at the center there is this valve.The function is logic, join the left to the right.The purpose of the pneumatic system is to provide pressure to the users.The sources are the bleeds and the ground cart, the users are wing antiice, left and right pack and other things.The panel says all.You must connect the red sources you turned on to the blu user you want to use following the yellow line.To connect a right user with a left source you need to open the valve.If all is working, left and right bleeds on, it is better for some reason to mantain the 2 systems isolated.

For a second there, I was wondering why it was complaining about dual bleed, since the APU bleed was off, but then I realized all the lights were illuminated for a test.

For a second there, I was wondering why it was complaining about dual bleed, since the APU bleed was off, but then I realized all the lights were illuminated for a test.

Yes, as soon as I found the picture I thinked the same :)

Hey , thanks for the answer, do you say that as a real pilot?

I am. I've flown the 737 in the U.S. and Asia. Most of my time is in other aircraft, but I've flown the 737 since 2007.

is there no freeware program? thanks any way

There is. Search Avsim for 'Utopia'. Being free it doesn't have as many features, but it's better than nothing.

About TO thrust settings:there is a small program called UTOPIA, but I have NO idea how dependable it is.

i use TOPCAT, and for at least the 800 it is very accurate, it doesn't however have performance data for the 900, but it does for the 700, although that isn't as accurate as the 800 because the engine variant TOPCAT has for the 700 is a different thrust rating than the one PMDG has on it's 700, but i use it anyway and so far it has gotten me out of short runway'd airports without much panic.

thanks guys for all of your great answers.!