Actually thats what I thought, and I set the code up to work that way, but I seem to have run into a snag. When I irst read FSUIPC, the calculations are all correct and the proper result is displayed. However fresh reads of FSUIPC continue to produce the same result even as fuel is burned. Also I found that if I adjust the fuel qty from inside FS the result will always be 0 from that point on. Infact I have to do a restart on FS to get the result back to a correct reading. At first I suspected an error in my code and thought that it simply wasn't refreshing the reads, But I noticed that my Lat and Long were changing properly and they are in the same string of code. I am stumped.... any ideas...?