Physical properties of a quasi-Kinnersley tetrad

Without fixing tetrad freedom, the physical interpretation of components of curvature tensors such as the Newman-Penrose $\Psi_4$ is ambiguous. Expanding on earlier literature on quasi-Kinnersley tetrads, we suggest a particular tetrad fixing procedure based on the characteristic structure of the Weyl tensor. This talk focuses on the physical properties of the resulting tetrad.