  We study out of time ordered correlators (OTOC) in a free fermionic model
with a quasi-periodic potential. This model is equivalent to the Aubry-Andr\'e
model and features a phase transition from an extended phase to a localized
phase at a non-zero value of the strength of the quasi-periodic potential. We
investigate five different time-regimes of interest for out of time ordered
correlators; early, wavefront, $x=v_Bt$, late time equilibration and infinite
time. For the early time regime we observe a power law for all potential
strengths. For the time regime preceding the wavefront we confirm a recently
proposed universal form and use it to extract the characteristic velocity of
the wavefront for the present model. A Gaussian waveform is observed to work
well in the time regime surrounding $x=v_Bt$. Our main result is for the late
time equilibration regime where we derive a finite time equilibration bound for
the OTOC, bounding the correlator's distance from its late time value. The
bound impose strict limits on equilibration of the OTOC in the extended regime
ans is valid not only for the Aubry-Andr\'e model but for any quadratic model
model. Finally, momentum out of time ordered correlators for the Aubry-Andr\'e
model are studied where large values of the OTOC are observed at late times at
the critical point.

Statistical Mechanics;Disordered Systems and Neural Networks;Quantum Physics