BA 873 then AC 861 at Heathrow
Krakow → London → Vancouver
Timetable, London time
18:05BA 873 from Krakow at the gate
14:30AC 861 to Vancouver leaves the gate
20 h 25 apart on the timetable, overnight
AC 861 leaves 20 h 25 after BA 873 arrives on the timetable: more than half a day, so not a connection we count.