I think I froze all my passengers to death! :(

[nrcrate 40]

And now as I sat there and tried to surmise wether or not I had inadvertantly ended myself and my copilot, dooming the aircraft to continue on, controlled by the FMC to arrive in sunny Hawaii piloted by two dead crewman...SNIP...

This incident did not get that far, but it was pretty close... The pilots here were suffering from hypoxia. Luckily, it never got severe enough to kill them.

Very intersting story- I can admit that I have made the mistake a few times as well. :( Edited March 2, 2012 by FDX016 - Nick

[rsrandazzo 6,353]

David-Ah- yes it does appear that you tried to freeze your passengers- but worse you tried to starve them of O2 as well!I'm glad you posted about your experience. So many users of the NGX will only barely scratch the surface of what we have accomplished in terms of simulation value that it is always fun when someone discovers something interesting.Next time you are bored and have some free time- open the front door of the airplane while sitting on an extremely hot or cold ramp, and watch the impact it has on the zone temperatures.We have a long running joke around PMDG that we often use a back-hoe to plant seeds in a flowerpot. As a developer it is kind of fun to put far more functionality into the airplane than you would ever expect to find. It adds a nice dose of realism.On the subject of the horn: One interesting feature on the NG series airplanes that is a holdover from the 707 days is the aural warning system. Back in those days they didn't have software driven aural warning systems like we do now- so they used certain sounds to indicate certain problems. The sound you heard for the pressurization problem is the same one you would hear with a gear warning.You can see how the lack of immediate warning/message indication might cause a crew to believe they are dealing with a faulty gear indication. This is why some airlines have begin to retrofit their NGs with a visual pressurization indication in addition to the aural system. It isn't very common, however, and the airplane we based the NGX on did not have one.Thanks again for posting- I love seeing when you guys discover things you didn't expect!

[Nathos 0]

That happend to me, 3 times. It happens when i forgot to turn on the packs after start the engines.

[Wizz84 4]

i never forgot to turn on the packs, but everytime i have the aural warning i knew if forgot to turn on the engine bleed..

[Ken737 1]

Gotta use those checklists! It has saved my butt more then once.

[Guest dlrk]

This is why some airlines have begin to retrofit their NGs with a visual pressurization indication in addition to the aural system. It isn't very common, however, and the airplane we based the NGX on did not have one.

Any chance that could be added in an update?

[Spin737 102]

From the FCOM:The Cruise Mode is activated when the aircraft climbs to within 0.25 PSID of the selected FLT ALT. During cruise the controller maintains the cabin altitude slightly below the selected LAND ALT, if the differential pressure between the selected LAND ALT and FLT ALT is less than or equal to:- 8.35 PSID above 37,000 ft,- 7.80 PSID with the FLT ALT between 28,000 and 37,000 ft, and- 7.45 PSID with FLT ALT less than 28,000 ftIf the differential pressure between the selected LAND ALT and FLT ALT is greater than these values, the controller maintains a pressure differential of:- 8.35 PSID above 37,000 ft, - 7.80 PSID with the FLT ALT between 28,000 and 37,000 ft, and - 7.45 PSID with FLT ALT less than 28,000 ftDeviations from flight altitude can cause the pressure differential to vary as the controller modulates the Outflow Valve to maintain a constant cabin altitude.So, I'm still trying to figure out why the CABIN ALT would have gone over 10,000. It seems to me that the CRUISE MODE should have started as the plane approached the programmed 10,000 PSID. After that, the controller should have kept the cabin either a little below the LAND ALT or on the 7.45 PSID.

[hopskip 253]

I'm amazed Boeing, or some other aviation Saftey Authority didn't mandate a different pressurization warning system to be retrofitted to 737NG's at least which would make identifying a Pressurizatiion problem easier. Say a different warning sound that included a spoken "Pressure Altitude" or something similar. At least after Helios, and perhaps not manditory for 737-200's.But it is true that if you get those Packs/Airbleeds and Pressurization Auto switches in the right place after engine start. Even before taxi... then the only time you will come across this problem will be with equipment failure.... if.

• Trent Hopkinson

[Guest dlrk]

They did mandate a cabin altitude light, PMDG chose not to simulate it.

[Crankpin 16]

Maybe FS2Crew will cover that with appropriate bleating from the (freezing) cabin crew !