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ghutcheon

Exceptionally high TAT

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I Googled this problem and I see a few posts on various websites relating to a similar problem (PDMG is the common factor) so I am guessing it is not just my configuration.Occasionally (not everytime) when I start up the PDMG 747X (FSX) I notice a crazy TAT in the FMS and on the upper EICAS screen - in the region of 50 - 60 degrees celcius. If this goes unnoticed, I would find out on the taxi where nearly full power would need to be applied just to get moving. Needless to say, one cannot get airborne, even with a very low take off weight. This can happen regardless on whether I start the sim with the aircraft ready to roll or "cold and dark". It can also affect a saved (good) flight and a completely new flight.I went into the FS menu and changed the weather, going to advanced weather options and setting a temp of 15 deg celcius. Going back into the sim, the TAT simply started to rise again at 2-3 degrees per second. Whay does it do this on occasion. Best thing for me to do is shut the sim down and start again, hoping the issue will go away (which is usually does). It then never reappears in flight, even flights lasting up to 11 hours.I have full licensed FSUIPC running. Can this be interfering with FSX? I am running this on Windows & Home Premium (32bit) . I also had this issue when I was using Vista.Please help... :(

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FSUIPC is part of the solution. The problem is the MSFS wx engine, the solution is to use temp/press smoothing in FSUIPC (I set mine to half the default value). Also, if you are using default downloaded weather and you are in an area of few reporting stations this is going to be a problem. You might look at ASX or REX as a weather add-on.

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Thanks Dan,When this first happened I was using the basic weather setting, and not real world download WX. Off to Google ASX and REX then...Greg

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Probably not the cause, but have you pressurized your bleed air manifolds? Without bleed air, there is no venturi effect created in the TAT (sensing) probes (just below the pilots' windshields). With no airflow, the TAT probes record a higher than normal reading (especially in direct sunlight).I was working on a customer airline a few months ago and they had a problem with high TAT readings at the gate, intermittently, for 6 months! The aircraft had had this problem since it had been converted to a freighter.... Reason: The mechanics had forgotton to hook up the bleed line to the TAT probes :( Fortunately, when the aircraft is barrelling down the runway at high speed, the venturi is not required.Cheers.Q>

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Thanks Dan,When this first happened I was using the basic weather setting, and not real world download WX. Off to Google ASX and REX then...Greg
Hi Greg, A lot of ASA users have been reporting TAT issues as well, but their problems are that the TAT changes enormus amounts basically knocking them out of the sky and unable to maintain altitude. Here is their post. I too have experienced this on long hauls with default FSX weather but seems they are on a witch hunt for ASA and don't want to believe me haha.

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