Anyone can land a GV, it's the taking off part which is difficult.
I am getting a ditch on pavement on an air field to include the rearm pad. I lost more perk points since this last patch than I do in a year of GVing because of this ditch bug.
There's at least one (minor?) omission on this chart: Under certain circumstances you can get a "death" result when in enemy country, being damaged and no enemy is within 6k - when the player that had damaged you is not around, but still in sortie.