Islander - I wasn't saying that losing speed in a turnback wasn't important! My grasp of the physics behind the whole inertial airspeed/groundspeed issue may need some work, but I have flown many simulated turnbacks (luckily no real ones, yet), and am very well aware of the vital need to maintain suficient airspeed for the turn. I was saying that I'm not sure the inertia issue is really key in the consideration of turnbacks. You might be well advised to do people the justice of reading what they actually write before you are so keen to rubbish what they say!