Google on
rodgers "the impossible turn"
for the theory.
e.g.
here
Yes a turnback is clearly possible. It needs a steep bank, yoke back to the onset of stall, and no delay
A long runway and a strong wind can make it very easy, as does height.
A lot of people have been killed doing this; I wonder how many of them tried it in truly impossible conditions and how many were simply afraid to use a steep turn.