  Although the superconductivity in UPt_3 is one of the most well studied,
there are still lingering questions about the nodal directions in the B and C
phase in the presence of a magnetic field. Limiting ourselves to the low
temperature regime (T<<Delta(0)), we study the magnetothermal conductivity with
in semiclassical approximation using Volovik's approach. The angular dependence
of the magnetothermal conductivity for an arbitrary field direction should
clarify the nodal structure in UPt_3.
