  We investigate whether flavor changing neutrino interactions (FCNIs) can be
sufficiently large to provide a viable solution to the atmospheric neutrino
problem. Effective operators induced by heavy boson exchange that allow for
flavor changing neutrino scattering off quarks or electrons are related by an
$SU(2)_L$ rotation to operators that induce anomalous tau decays. Since
$SU(2)_L$ violation is small for New Physics at or above the weak scale, one
can use the upper bounds on lepton flavor violating tau decays or on lepton
universality violation to put severe, model-independent bounds on the relevant
non-standard neutrino interactions. Also $Z$-induced flavor changing neutral
currents, due to heavy singlet neutrinos, are too small to be relevant for the
atmospheric neutrino anomaly. We conclude that the FCNI solution to the
atmospheric neutrino problem is ruled out.
