UA 217 then TP 4392 at San Francisco
Arcata → San Francisco → Boston
Timetable, San Francisco time
09:13UA 217 from Arcata at the gate
22:10TP 4392 to Boston leaves the gate
12 h 57 apart on the timetable
TP 4392 leaves 12 h 57 after UA 217 arrives on the timetable: more than half a day, so not a connection we count.