  We consider a thin film of superfluid ${}^3$He under conditions that
stabilize the A-phase. We show that in the presence of a uniform superflow and
an external magnetic field perpendicular to the film, the spin degrees of
freedom develop a nonuniform, helical texture. Our prediction is robust and
relies solely on Galilei invariance and other symmetries of ${}^3$He, which
induce a coupling of the orbital and spin degrees of freedom. The length scale
of the helical order can be tuned by varying the velocity of the superflow and
the magnetic field, and may be in reach of near-future experiments.
