DL 541 then UA 4473 at Dulles
Seattle → Washington → Richmond
Timetable, Washington time
00:20DL 541 from Seattle at the gate
22:10UA 4473 to Richmond leaves the gate
21 h 50 apart on the timetable
UA 4473 leaves 21 h 50 after DL 541 arrives on the timetable: more than half a day, so not a connection we count.