Cant Maintain Cruise Altitude

[Allan Burek 3]

Hello All,Im having a recurring issue the past few days and I was wondering if anyone could help. I am attempting to depart VTBS enroute to YSSY and for some reason my PMDG 744 struggles to make FL310. After going through moderate turbulence, I noted that the aircraft struggles to maintain altitude and speed, and unless I select CON from the thrust limit page, I cant help but almost stall. By the way, this is with and without using VATSIM weather selected, and with a flight plan entered into AS.Now for the usual stuff:FSUIPC-registeredA/C-not overweight and correctly trimmedFS9.1Win XP Pro with SP3Plenty of RAM, HDD space, etc.Thanks in advance for any help.

[markadeane 272]

Allan, are you running Activesky? Great application though it is, there are occasions when it sets temperatures at extreme values for that 30-40,000 feet band we operate in. The flight model reacts to these values with adverse performance, your description is certainly similar to what I've experienced.

[Allan Burek 3]

Affirm on Active Sky. I posted in their forum as well and am still waiting for some responses.

[veldthui 0]

>Allan, are you running Activesky? Great application though it>is, there are occasions when it sets temperatures at extreme>values for that 30-40,000 feet band we operate in. The flight>model reacts to these values with adverse performance, your>description is certainly similar to what I've experienced.I have seen that with FSInn but never ActiveskyJohn Veldthuishttp://www.virtualpilots.org/signatures/vpa475.png

[midcon385 1]

>I have seen that with FSInn but never Activesky>>John VeldthuisI've seen this with running ActiveSky too, though can't be certain that it is the culprit, of course. I don't have FSInn so that can't be the cause for me.Tim

[markadeane 272]

One thing to check next time you encounter the issue is to go to your PROG page (number 2/3 I think?) and determine the Static Air Temp reported on the right hand side of the CDU screen.Static Temp is the one we are most interested in as it represents the ambient temperature of the air you're moving through, rather than the warmer total air temperature.Depending on what it reads and what altitude you're at, this will allow you to determine if the temperature aloft is realistic for that altitude and thus if the adverse performance impact is due to ActiveSky.Knowing a little of your background from the AS forums Allan, I'll assume you can do this without help but don't hesitate to bring the figures back here for analysis if you're unsure.