As part of an "around the world" series of flights I've been undertaking, I recently flew from Sappora Japan (RJCC) to Shemya Island in the Aleutians (PASY). Since the FS flight planner couldn't generate a route using airways, I plotted it as Direct GPS - a "straight line" distance of just over 1400 miles. The problem of course is that a direct east-west (more or less) route of that length at that latitude is nowhere near a straight line.The problem began right after take off as the controller vectored me to 085 degrees (instead of the correct 67 deg.) Once released to "resume own navigation" I turned to the correct course and was soone being berated by the controller for being off course and told to fly heading 085 - a heading that would soon run me out of gas somewhere over the North Pacific and get me nowhere near Shemya. I had to shut down RC and finish the flight under FS ATC control. I couldn't figure out where RC was coming up with 085.As I neared Shemya following the great circle route plotted by my GPS, I noticed my course had curved around and I was now flying 085 degrees. Obviously RC had been looking at the course INTO Shemya and erroneously assumed that the course OUT of Sapporo was the same.This is obviously an extreme case with a leg of this length this far north, but the Great Circle effect is noticable on east-west legs of only a couple hundred miles at high latitudes. I've seen several mentions in this forum of controllers issueing (or auto-pilot flying) incorrect headings and wonder if this doesn't account for at least some of them.

i don't know how realistic direct gps flight plan in this case would be. i'm sure fsnavigator or nav would plot a course using intersections, and be a little more realistic.surely there are some reporting points required for this type of flight.

Doug,It is very unrealistic to have 1400 mile legs. Realistically, you need to add fixes if there are none. You don't need to stick to airways, but you do need to have waypoints at most 650 miles apart - and 500-600 is best. It is a misconception that you are required to fly the airways only.RC also does not follow the Great Circle route very well over long distances, so 500-600 mile legs will keep you in RC's heading deviation range.Find waypoints, or just add them, at 600 mile intervals.I routinely fly 8000 miles in the 777-200LR on a Great Circle route without problem as long as I keep the leg distances to this limit.Don't forget, you also need to calculate for winds aloft, go-arounds, holds, deviation to alternates, and aircraft loading in general. If you don't have enough fuel for a 45-minute reserve when you arrive, you need to put down somewhere, refuel, then complete the flight. If you're flying East to West, then count on 120-200 knot headwinds. This is why even 747-400's from LAX/SFO to YSSY may need to put down in Fiji.