You need a Density Altitude caculator... ???? I have one of those on a Jeppesen Flight calculator I have, but I'm not sure how you will corrolate thrust values... ??? I know what you are trying to do... I'm gonna have to backwards think on this !!!! I'll get back to you if I get a brainstorm... It seems if you know what the thrust value is at 29.92 , 59F at sea level, the you should be able to calculate precentage of performance lost due to Density Altitude increase, but converting that to lbs of thrust is what I'm not sure how to do... It's not going to be a linear scale I would think... All Performance charts I have seen and used have a curve that becomes more aggresive as the altitude increases... .... I think all the BS I have been saying is somewhat true... Keep me posted !!!!

Danno, Intrested and Confused !!!!