AY 1333 then BA 720 at Heathrow
Helsinki → London → Zurich
Timetable, London time
12:35AY 1333 from Helsinki at the gate
15:35BA 720 to Zurich leaves the gate
3 h apart on the timetable
The last days
AY 1333 and BA 720 weren’t both flown 15 min to 12 h apart in the last 21 days.
Statistics from past flights, not live flight information. Always check times and your connection with your airline, and don’t base travel or booking decisions on these numbers.