pressurization? mine 707-300 works. 727 not, but 707 good with it.

You mean the oxygen panel lights, near seatbelt sign switch? Thats not a pressure warning lights. That lights says that oxygen system is charged, so it can be used if necessary.
They should illuminate above 14 000 ft, system works automatically.

There is no pressure warning light in CS 707-300.

As for pressurization:
1 - set airfield elevation.
2 - load pax n cargo
3 - close doors
4 - takeoff
5 - clear flaps
6 - do after takeoff checklist, and there is item air cond & press.
At that moment you set pressure altitude for cabin. 6 000- 8 000 ft, and then monitor differential pressure. it should not reach limits of 9.5 or so.

For landing you operate it so your cabin pressure alt be lower then altitude you flying. pressure inside cabin must be greater than outside pressure, so doors be pushed outwards for more sealing.

Thats how i doing it, but its good to know real thing from real pilots!

I have to correct windplayer on, what I think, some items and their understanding.
Quote:


That 14.000ft value is important. What is missing is the fact that it reflects the cabin altitude, not the one of the plane. You are in serious trouble when your cabin reaches that altitude and, therefore, the oxygen masks will automatically deploy ('rubber jungle!') and the system will pressurize to allow a flow of oxygen to the masks.
The overhead lights are an indicator that this has happened, so imagine some upset and 'masked' passengers in your back while you should take care of that situation and descend well below 14.000ft if the terrain allows. Some 10.000ft would be nice. Also talking about a fast descent, no easy vertical speed, but the max. safe value.

That old 707 does not use chemical oxygen generators but cylinders instead. You can read their (remaining) pressure on the FE's panel. That pressure reading will come up when being over 14.000ft cabin altitude which, unfortunately, happens a lot in the current 1.3 707.   The pressurization system is flawed and you will for example read 20.000ft and more on the cabin altitude gauge when the plane is flying high. This happens regardless of how you set up the FE's panel. I think Lou has tried to trick the flaw once, but wasn't successful.

However, you can stick to windplayer's list of course. For the sake of realism and to keep the checklist flow in shape. Just don't expect the warnings to stay away. Your cabin will always go well beyond 14.000ft and the overhead lights will illuminate. They shouldn't with a working pressurization. Lets hope 1.4 gives us one. There's hope since the current 757 and 767 updates ruled out that error and therefore stay away from warning levels.

That item is on our 1.3 bug list. http://www.captainsim.org/yabb2/YaBB.pl?num=1299594859


In rw terms, the problems when having the cabin that high mainly come down to only few conscious seconds without wearing a mask or with empty oxygen tanks. Hence the need to make a decision as long as your consciousness allows for valid ones.

If you're up for a very sad but in a way very informing story, look up the 'Helios Flight' here. http://en.wikipedia.org/wiki/Helios_Airways_Flight_522 When reading about the initial cause, you will look like this.   Remember, there always is a chain of events to be considered though and learning about such a chain is a win coming with a high cost.  

LOU wrote on Jun 25^th, 2012 at 5:50pm:

While the FE only has that escape rope to defend himself. What a fight.  

To add, for the 727, there's a user mod for the pressurization available. Unfortunately not for the 707 so far.

The 707 pressurization panel she's a no work!  



In the above screen capture I am asking for full increase pressure using the manual controller.
All three turbos are on and the wing valves are open. The cabin is at airplane altitude.



In this photo, I even opened the bleed valves - something we never had on our 707's - along with the turbos.
The plane is level at FL310 and the cabin shows the same FL310.
The cabin differential in the second picture shows 2,2 p.s.i. when it should show zero if the cabin is at the same altitude as the plane.

I found the problem similar to the 727 and guess the code is bad for both.

Since I love to just fly the plane - both the 707 & 727 - I just don't let the F/E panel bother me since I don't feel the pressure bump in my ear and I'm still breathing without the mask...so far!  

Lou


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ok. i got it. member Dutch, who partially fixed 727 press, said that he can't go far because cs used microsoft default press code, which is broken. Or sort of that kind of things.

Now another question long awaiting:

There is a two gauges below Packs - high press and low press.

What does they show, and why high press gauge comes alive only by opening engine bleed valve?

Just a few thoughts on the 707 F/E panel.



1. High pressure duct gauge. Used for high pressure bottle start only.
2. Not a clue! Did not have anything like this on TWA 707's
3. Another switch that goes nowhere. In the manual it says it controls the outflow valves, but how? Never saw this either on 707's. It could be a later option that some operators installed, but where is the control switch to move the outflow valve?
4. Some sort of controls for ACM (air cycle machine). TWA had Freon packs on the -300's no ACM's. The ACM's in the 727 were much more advanced. This looks like some after thought to me.
5. Engine bleed air switches? Never had anything like this. Seems like overkill. Why have bleed air and turbo compressors? Again some sort of hybrid add-on. Why would you carry around three turbos when you can bleed the engines with a switch? Remember, in an earlier post I wrote about why the 707 had turbo compressors instead of using bleed air. The reason was the evolution of the engine bleed air valve was thought to be too risky for getting clean air into the cabin. By the time the 727 came along that problem was solved. This plane could have been built later and hence the dual system. Still seems silly to carry around all the turbo stuff when you can just use engine bleed air.

It would be interesting to know what real aircraft this CS plane was modeled after.

Lou


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