The existence of super-cooled liquid water (SLW) in clouds is of concern to the general aviation community since it can freeze on contact with aircraft, increase drag, decrease lift and even cause control problems. The degree with which SLW will freeze and affect an aircraft's performance depends on several factors including the type and weight of the aircraft, the duration of exposure to SLW and the accretion rate of ice on the airframe. The severity of ice accretion is sensitive to temperature, the liquid water content and the drop size distribution. Recent advances in geostationary satellite sensors now permit us to derive cloud optical depth, particle size, phase and water path in near real-time. Therefore, satellite data can be used to detect SLW directly since SLW is often found to accumulate in the top several hundred meters of cloud layers. A technique to derive the cloud optical properties of SLW clouds from geostationary (GOES) satellite data will be presented. The satellite retrievals of icing conditions compared favorably to positive Pilot reports in a previous study. In this paper, the satellite retrievals are co-located and compared with in-situ aircraft measurements of cloud microphysical properties made over a three month period from the NASA Glenn Twin Otter. This work is being done in an effort to further validate the satellite retrievals and to explore the potential for determining icing severity from real-time operational satellite data.