FR 9471 then FR 8239 at Madrid
Pisa → Madrid → Porto
Timetable, Madrid time
12:25FR 9471 from Pisa at the gate
17:05FR 8239 to Porto leaves the gate
4 h 40 apart on the timetable
The last days
FR 9471 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.