During these 40 minutes, the aircraft made successive passes through wave clouds with temperatures -15 to -18C (RED, bottom panel). Liquid water contents as high as 0.7 g m-3 were measured (BLUE, bottom panel).
Although the inlet tip is heated, and its temperature is controlled (RED, top panel), flow through the air sample inlet decreased (BLUE, top panel). This decrease in flow may have been due to rime ice accumulating and blocking the inlet. After being blocked for about 20 minutes, the flow was restored (ice plug melted or was blown off the inlet tip).
Further information-
http://raf.atd.ucar.edu/~dcrogers/Wavecloud/inlet/InletFlow.html