1 23 CEAS Aeronautical Journal An Official Journal of the Council of European Aerospace Societies ISSN 1869-5582 CEAS Aeronaut J DOI 10.1007/s13272-013-0082-z Rotorcraft aeroelastic stability using robust analysis Giuseppe Quaranta, Aykut Tamer, Vincenzo Muscarello, Pierangelo Masarati, Massimo Gennaretti, Jacopo Serafini & Marco Molica Colella