BA 393 then AY 1338 at Heathrow
Brussels → London → Helsinki
Timetable, London time
18:20BA 393 from Brussels at the gate
18:10AY 1338 to Helsinki leaves the gate
23 h 50 apart on the timetable, overnight
AY 1338 leaves 23 h 50 after BA 393 arrives on the timetable: more than half a day, so not a connection we count.