I never minded why the air conditoning light was coming on just about at the point of decent as I was changing my computer. Have reinstalled everything again and strangely enough I still get this message. I have tried many switch settings - but obviously not the correct ones. Can anyone shed some light on this. Kind regardsNigel Thomas-Smith

Probably you don't set the correct cruise altitude in the digital dial in the overhead panel (lower-right)?

I never used to set it or at least not very often and it never dislapyed this warning so I dont think thats the answer. It is appearing after tod so if that was it it would have come on earlier before toc possibly.Any other answers on a postcard please to . . . >Probably you don't set the correct cruise altitude in the>digital dial in the overhead panel (lower-right)?Kind regardsNigel Thomas-Smithhttp://www.precisionmanuals.com/images/forum/800driver.jpg

Nigel,Claudio is right. If you descent before reaching what is set on the cabin pressurization panel you'll get this warning. Default value is 35000ft so if your cruise altitude was lower than that it will definitely trip. DOn't know what happens if you go higher.Hope it helps,

Mats,Once you go above the crz alt set on pressurization panel the "off sched desc" warning will be diabled (I have occasionally forgotten to adjust it after requesting a higher FL as per FMX suggestion)It will only activate if you never reach the ALT set.Best RegardsMax (Bern, LSZB)http://www.hifisim.com/images/as2004betateam.jpg http://www.precisionmanuals.com/images/forum/800driver.jpg

Just this morning, I read an accident report of a Greek 737 (Helios Airlines) in which all aboard died due to lack of cabin pressurization. The report said that as the airplane increased in altitude, the pilots were aware there was a problem, but didn't know what the cockpit indications were trying to tell them. The pilots even had time to contact their maintenance department to discuss the indications. By the time they reached 28,900 feet however, all communications from the aircraft stopped. The airplane flew on autopilot until it ran out of fuel & crashed. All 121 persons onboard were killed.I have to admit that when I started flying the 737, I received the "Air Cond" messages and posted a message in these forums to ask why I was getting it. Someone who replied told me it related to the pressurization settings. I scratched my head and figured the person responding to my query simply didn't understand my question. After all, the indicating message was about AIR CONDITIONING. But in the end, I came to understand that this cryptic message (about "Air Cond") had everything to do with aircaft cabin altitude. Go figure.I gotta say I think Boeing goofed on the indicator messaging with regard to cabin altitudes on the 737. Granted, the real world Helios pilots should have had better training so that they could understand just what the indicator messages were telling them. But I find it amazing that the airplane didn't simply tell the pilots in a clear way that the aircraft was not pressurized.Why display an "Air Cond" indication when the cabin alt controls are not set right???? I'm thinking "Cabin Pressurization" is better. My thought is: "Don't simply engineer something that can be understood; Engineer something that can't be mis-understood."

>I never minded why the air conditoning light was coming on>just about at the point of decent as I was changing my>computer. Have reinstalled everything again and strangely>enough I still get this message. I have tried many switch>settings - but obviously not the correct ones. Can anyone shed>some light on this.The PMDG-737 air temp indicator (overhead panel) is active (modelled), so you can read the actual air temp in the cabin.If the warning light pops up is due to high or low temperature (check it)There are two rotary knobs below the air temp indicator. Turn both left to lower the temperature or turn both right to rise the temp.This has worked ok for me.Jose Luis

Together with the "air cond" master warning light you have an "OFF SCHED DESCENT" light on the overhead panel. In the real plane you should see that, and on the virtual aircraft you should anyway scan all your panel for warning lights :) Luca