EI-REH made an approach to Runway (RWY) 17 at EICK in gusting crosswinds and turbulent conditions. During the landing, initial contact with the runway surface was on the main landing gear wheels with a nose up pitch attitude. The aircraft bounced slightly and simultaneously pitched down sharply. The second contact with the runway was solely on the nose wheels. The Commander immediately initiated a go-around and thereafter a normal approach and landing was made on RWY 17. Subsequently, the nose landing gear was withdrawn from service since the certification basis and design criteria did not foresee such an occurrence.