  If a new massive vector boson with nonzero axial couplings to fermions will
be observed at LHC, then an upper limit on the scale of new physics could be
derived from unitarity of $\mathcal{S}$-matrix. The new physics will involve
either new massive fermions, or scalars, or even a strongly coupled sector. We
derive a model independent bound on the scale of new physics. If $M_{G}/ g_{A}
< 3$ TeV and the fermion is a top quark, the upper limit is 78 TeV.
