Aircraft Loads Assessment for Windmilling Sustained Engine Imbalance

The failure of an aircraft engine fan blade produces an unbalanced rotor condition. Even after the engine is shutdown the aerodynamic forces may keep the rotors running during the remainder of the flight. This condition can induce significant vibratory loads throughout the airframe that may damage the airframe structure and critical equipments and also affect the crew’s ability to sustain a safe flight. This work intends to present a numerical methodology to assess dynamic vibratory loads in a commercial aircraft under windmilling sustained engine imbalance condition necessary to demonstrate compliance with the current aeronautical design rules. Case study results are also included.