The submitted paper deals with the turboprop aircraft structure whirl flutter analysis. It gives a summary of the regulations requirements, the theoretical background, the aircraft certification relating issues and the ordinary analytical procedure by means of the NASTRAN SOL 145.

The main part deals with determination of critical engine suspension stiffness parameters considering the structure whirl flutter stability at the certification speed. The NASTRAN optimization solver (SOL 200) is employed. The analytical procedure is demonstrated on the two examples. Finally, the future exploitation of the method is outlined.