BA 712 then FB 492 at Zurich
London Heathrow → Zurich → Sofia
Timetable, Zurich time
12:10BA 712 from London Heathrow at the gate
10:00FB 492 to Sofia leaves the gate
21 h 50 apart on the timetable, overnight
FB 492 leaves 21 h 50 after BA 712 arrives on the timetable: more than half a day, so not a connection we count.