The past couple of days I have noticed massive fluxuations of SAT while at turbojet cruise altitudes. Most recently at 1625Z today 11MAR about 100NM west of Flint Mich at FL390. For a 2-3 minute period the temp spiked from -52C to +15C before returning to normal temps. Obviously this disrupted the flight path of the aircraft in both instances. I use Build 355.

Hi Ryan,Sorry for the issue.We are continuing to work on aloft temperature issues such as this one and we are internally testing our next SP. This could have been an issue with the data. Also, the weather has been pretty crazy here in Michigan the last few days. What I would suggest is to watch this and report back if it keeps happening.Thanks,

Hi Ryan,Sorry for the issue.We are continuing to work on aloft temperature issues such as this one and we are internally testing our next SP. This could have been an issue with the data. Also, the weather has been pretty crazy here in Michigan the last few days. What I would suggest is to watch this and report back if it keeps happening.Thanks,

Thanks as always Jim. Not to beat on a dead horse, but this is a pretty serious issue that can have catastrophic consequences to flight, similar to the severe wind shift issue. Regarding the possibility of flawed temp data, how about implementing a filtering algorithm into ASA that allows the user to specify a maximum ISA DEV value above say FL180? As ISA devs beyond +/- 15C (a nice default figure) are extremely rare above this altitude, this would address the issue nicely.

Hi Ryan,Thanks for that. We are getting closer to a new SP release and I would like you to see how the new SP handles this for you.Thanks,