AA 1709 then UA 3998 at Charlotte
Myrtle Beach → Charlotte → Washington
Timetable, Charlotte time
06:14AA 1709 from Myrtle Beach at the gate
19:55UA 3998 to Washington leaves the gate
13 h 41 apart on the timetable
UA 3998 leaves 13 h 41 after AA 1709 arrives on the timetable: more than half a day, so not a connection we count.