General Aviationhttp://www.jets.dk/cs/forums/15/ShowForum.aspxQuestions about General Aviationen-USCommunityServer 2.0 (Build: 60526.2668)Aeronautical chart questionhttp://www.jets.dk/cs/forums/thread/1571.aspxThu, 22 Nov 2001 21:32:00 GMTa23efcf1-9e75-4ff9-be18-cd9cb68b9485:1571Anonymous0http://www.jets.dk/cs/forums/thread/1571.aspxhttp://www.jets.dk/cs/forums/commentrss.aspx?SectionID=15&PostID=1571*** Posted by Eric T *** <br />I'm pre-studying to get my private pilot's license. I have some confusion <br />about some terminology on the Aeronautical chart: <br /> <br />Some airports with a tower have a C symbol next to the CT frequency, <br />indicating that the frequency is a CTAF when the tower is closed. <br />But some of these airports also have a different UNICOM frequency. <br /> <br />Why do they have both? Are they used for different things? How do <br />you know which one to use, and when?