FSX Flight Planner - Technical questions

Good day,We all know that the Flight Planner included with FSX is a rudimentary tool at best, and likely a direct carryover from FS9. There are more sophisticated planning tools available, but I would like to know the details of how the one included works.After having selected a route from origin to destination and an appropriate flight level, the Planner produces a Navigation Log. At the top of this log are estimated values for fuel burn and time en route.Can anyone tell me how the Flight Planner derives these values?It knows the aircraft type and distance. I've looked through the SDK and any other potential sources to try and find the method used, but no luck. The Planner must access values somewhere to perform the calculations ---- I would really like to know what it works with and where it finds the information for calculation.My apologies if this has been answered elsewhere. If so, just point me to the relevant post(s).Thank youWayne