The Grad-Shafranov approach to the problem of the structure of the black-ho
le magnetosphere is discussed. For the double transonic flow, the number of
boundary conditions in the pair creation region is shown to be sufficient
to determine not only the longitudinal electric current, but also the angul
ar velocity of a flow as a solution to a problem. As a result, the energy l
oss is determined by the physical parameters at the particle creation regio
n rather than the "boundary conditions" at the event horizon.