  The evolution of the five largest satellites of Uranus during the crossing of
the 5/3 mean motion resonance between Ariel and Umbriel is strongly affected by
chaotic motion. Studies with numerical integrations of the equations of motion
and analysis of Poincar\'e surface sections provided helpful insights to the
role of chaos on the system. However, they lack of a quantification of this
chaos in the phase-space. Here, we construct stability maps using the frequency
analysis method. We determine that for low energies (small eccentricity and/or
inclinations), the phase-space is mainly stable. As the energy increases, the
chaotic regions replace the stable motion, until only small, localized
libration regions remain stable.
