The electron-phonon interaction is a major factor influencing the competition between collective instabilities in correlated-electron materials, but its role in driving high-temperature superconductivity in the cuprates remains poorly understood. Recently phonon anomalies due to charge density wave formation were observed in YBa2Cu3O6.6 using inelastic x-ray scattering. Nevertheless, such anomalies are not seen using inelastic neutron scattering which opens up a question on the exact mechanism involved. In order to better understand the competition between the charge density wave phase and superconductivity, and the role of electron-phonon interaction in cuprates, as well as shed light on apparent discrepancy between two well established techniques; we propose to map out in detail the low lying phonon dispersion in YBa2Cu3O6.6 using neutron time-of-flight.