I see the winds die off at FL 520 exactly in several planes, so is not plane specific. I checked FSUIPC and somehow discovered the " smooth winds " box was checked on the WINDS tab of the settings. I unclicked it, and voila i now have winds above FL 520 that is what causes this. Apparently wind smoothing = killing completely at and above FL 520 in FSUIPC lol I have tested and tested this, and confirmed that this is in fact true in all flight modes and aircraft. Can this please be fixed so that wind smoothing can be used above FL 520 ? That would be so helpful when flying the Concord at up to FL 600 and the SR71 at up to FL 850 Thank you and have a great day. Love FSUPC Pete, please do not get me wrong, this would just make it better is all :) Gary