Check-ins on the fly is a term used by many NCS to indicate they will take check-ins outside of the normal pause in the worklist. These are typically called for on AIM and are allowed at the discretion of the NCS. However, no call for a check-in on AIM can be added to the official worklist until they are heard, on the air, by NCS or a designated relay. NCS will typically pause and call the station with a request for a “Roger Roger”. If this is repeated back, and heard by an NCS or designated relay, it is enough to add them to the worklist.