In this paper, the Dirac, twistor and Killing equations on Weyl manifolds
with CSpin structures are investigated. A conformal Schr"odinger-Lichnerowicz
formula is presented and used to show integrability conditions for these
equations. By introducing the Killing equation for spinors of arbitrary weight,
the result of Andrei Moroianu in [9] is generalized in the following sense. The
only non-closed Weyl manifolds of dimension greater than 3 that admit solutions
of the real Killing equation are 4-dimensional and non-compact. Any Weyl
manifold of these dimensions admitting a real Killing spinor has to be
Einstein-Weyl.Comment: Latex2.09, 11 page