FR 3813 then FR 8239 at Madrid
Bologna → Madrid → Porto
Timetable, Madrid time
13:05FR 3813 from Bologna at the gate
17:05FR 8239 to Porto leaves the gate
4 h apart on the timetable
The last days
FR 3813 and FR 8239 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.