Numbers of vibratory phenomena occur on a turbomachinery fan. Among the various challenges to take into account in conception, this report focuses on an aero-elastic instability called flutter that can reduce engine operating range. It’s caused by a lot of factors and so, its origin can be different from case to case (for instance aerodynamic, acoustic origin). It needs to focus on the cause of this phenomenon: from certain prediction criteria, the aim of this report is to present the improvements made on the evaluation of the flutter criticality during design phase. A first bibliographic study has allowed to increase the knowledge of criteria used for verifying the flutter influence on the fan performances and operability.