UA 3998 then TK 8 at Dulles
Charlotte → Washington → Istanbul
Timetable, Washington time
21:25UA 3998 from Charlotte at the gate
21:20TK 8 to Istanbul leaves the gate
23 h 55 apart on the timetable, overnight
TK 8 leaves 23 h 55 after UA 3998 arrives on the timetable: more than half a day, so not a connection we count.