FB 851 then BA 742 at Heathrow
Sofia → London → Geneva
Timetable, London time
12:10FB 851 from Sofia at the gate
15:05BA 742 to Geneva leaves the gate
2 h 55 apart on the timetable
The last days
FB 851 and BA 742 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.