FB 851 then BA 482 at Heathrow
Sofia → London → Barcelona
Timetable, London time
07:50FB 851 from Sofia at the gate
11:25BA 482 to Barcelona leaves the gate
3 h 35 apart on the timetable
The last days
FB 851 and BA 482 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.