  Using a weak limit for the hopping integral in one direction in the
Hofstadter model, we show that the fermion states in the gaps of the spectrum
are determined within the Kitaev chain. The proposed approach allows us to
study the behavior of Chern insulators (CI) in different classes of symmetry.
We consider the Hofstadter model on the square and honeycomb lattices in the
case of rational and irrational magnetic fluxes $\phi$, and discuss the
behavior of the Hall conductance at a weak magnetic field in a sample of finite
size. We show that in the semiclassical limit at the center of the fermion
spectrum, the Bloch states of fermions turn into chiral Majorana fermion liquid
when the magnetic scale $ \frac{1}{ \phi} $ is equal to the sample size N. We
are talking about the dielectric-metal phase transition, which is determined by
the behavior of the Landau levels in 2D fermion systems in a transverse
magnetic field. When a magnetic scale, which determines the wave function of
fermions, exceeds the size of the sample, a jump in the longitudinal
conductance occurs. The wave function describes non-localized states of
fermions, the sample becomes a conductor, the system changes from the
dielectric state to the metallic one. It is shown, that at $1/\phi>$N the
quantum Hall effect and the Landau levels are not realized, which makes
possibility to study the behavior of CI in irrational magnetic fluxes.
