A helicopter-borne 8-channel ranging scatterometer HUTSCAT (Helsinki University of Technology Scatterometer) was used to investigate the backscattering behaviour of low-salinity sea ice at 5-4GHz and 9-8 GHz. The measurements were conducted during the BEPERS-88 Sea Ice Campaign in the Gulf of Bothnia, 6-12 March 1988. The backscattering properties of several sea ice types were examined at the two frequencies, using HH, VV, HV, and VH polarization modes. An incidence angle of 23° off nadir was used in order to investigate the feasibility of the ESA ERS-I (launched in July 1991) SAR for sea ice mapping. The capability of the new scatterometer to identify sea ice types was examined using the following radar output products at 8 channels: (a) the backscattering coefficient and (b) the characteristics of the radar return versus range spectrum (range resolution 65 cm).