  We perform the stationary phase analysis of the vertex amplitude for the EPRL
spin foam model extended to include timelike tetrahedra. We analyse both,
tetrahedra of signature $---$ (standard EPRL), as well as of signature $+--$
(Hnybida-Conrady extension), in a unified fashion. However, we assume all faces
to be of signature $--$. The stationary points of the extended model are
described again by $4$-simplices and the phase of the amplitude is equal to the
Regge action. Interestingly, in addition to the Lorentzian and Euclidean
sectors there appear also split signature $4$-simplices.
