Section 23.2245 - Aeroelasticity(a) The airplane must be free from flutter, control reversal, and divergence-(1) At all speeds within and sufficiently beyond the structural design envelope;(2) For any configuration and condition of operation;(3) Accounting for critical degrees of freedom; and(4) Accounting for any critical failures or malfunctions.(b) The applicant must establish tolerances for all quantities that affect flutter.