In the present work, the freezing behaviour, for droplets colliding at terminal free fall speed with an ice substrate, is studied. The study of the crystal structure of singular frozen droplets was carried out using spectra, having 135 and 75 μm mean volume diameter. The results show that the transition temperature T∗, corresponding to a value P = 0.5 of the probability of nucleation of new orientations in the droplets, decreases with the droplet diameter, varying from -18 to -29°C on a prism (112̄0) substrate, and from -11 to -13°C on a basal substrate. This behaviour is discussed on the basis of the nucleation theory. Small accretions were also grown in a cold room without ventilation, using droplets having 85 μm mean volume diameter. It is shown that, for air and substrate temperatures T a = -7 and T s = -3° C respectively, these accretions mostly followed the substrate orientation, although a few crystals with new orientations were formed. The difference existing between these accretions structures and those obtained in icing wind tunnels, at about the same values of T a and T s, is pointed out.