  The common envelope interaction is thought to be the gateway to all evolved
compact binaries and mergers. Hydrodynamic simulations of the common envelope
interaction between giant stars and their companions are restricted to the
dynamical, fast, in-spiral phase. They find that the giant envelope is lifted
during this phase, but remains mostly bound to the system. At the same time,
the orbital separation is greatly reduced, but in most simulations it levels
off? at values larger than measured from observations. We conjectured that
during the post-in-spiral phase the bound envelope gas will return to the
system. Using hydrodynamic simulations, we generate initial conditions for our
simulation that result in a fall-back disk with total mass and angular momentum
in line with quantities from the simulations of Passy et al. We find that the
simulated fall-back event reduces the orbital separation efficiently, but fails
to unbind the gas before the separation levels off once again. We also find
that more massive fall-back disks reduce the orbital separation more
efficiently, but the efficiency of unbinding remains invariably very low. From
these results we deduce that unless a further energy source contributes to
unbinding the envelope (such as was recently tested by Nandez et al.), all
common envelope interactions would result in mergers. On the other hand,
additional energy sources are unlikely to help, on their own, to reduce the
orbital separation. We conclude by discussing our dynamical fall-back event in
the context of a thermally-regulated post-common envelope phase.
