LOU wrote on Jul 22^nd, 2011 at 6:36pm:

No, not as you are describing. But in the older planes such as the 727 & 707 I do not use a GPS, only VOR's. Yet, as you can see the VOR and the GPS are lined up. Maybe Mark can shed some light since I think he uses GPS in the old birds. Lou

That's nice to know Lou. When boeing247 first brought the subject up a while ago, I had the exact same problem as he did. I was offtrack by up to 2 miles and increasing. The VOR showed that it was following the track, but even when I tried it with no winds (Clear skies), you could see it wasn't going to go over the VOR. It was definitely going to miss. By more that two miles!

Mark