Genghis - A turnback (in the RAF anyway) is a manoeuvre to return to the airfield because the landing area options ahead are unsuitable. It is not soley focussed on a downwind landing on the runway. The airfield is a known environment, flat, with limited obstacles etc.. where you have better options for a forced landing than the terrain ahead. The subsequent landing could be anywhere on the airfield, it may be downwind on the runway but that would depend on a host of factors on the day. Most of the real SEP turnbacks I have known have resulted in a landing on the grass outside of the runway surface.