Could be any number of factors here - weather, primarily, or unpredicted time spent at intermediate altitudes, the speed schedule in the descent, etc. However, in each case, the approach (starting at TOD and going until landing) took about 6000 more lbs of fuel than predicted by PFPX. I'm using the latest version of your 747-400 passenger GE performance file for PFPX, and the agreement was really excellent throughout the whole cruise portion. Normally I can't finish a full 15-hour flight but I was able to do this a time or two in the last few weeks, and I noticed that PSX and PFPX were basically in full agreement about the fuel consumption enroute. Steve, I have two quick questions for you.įirst, I had the pleasure of flying some full long-haul flights in PSX recently.