The AC3 was designed at NASA Langley inspired by a previous Straub and Collett (2004) version. The probe samples in-situ cloud water by separating droplets from the main airflow.  This is accomplished by imparting swirl on an axial flow following an in-line stator, and collecting droplets that have impacted on the probes outer walls. Cloud-water is then transferred into the aircraft cabin using teflon tubing and manually collected into vials. Cloud-water can then be analyzed by a number of laboratory analytical techniques including ion-chromatography, pH electrodes, or total organic content. The probe utilizes a shutter to inhibit sample contamination by aerosols.