PU 502 then W4 3172 at Madrid
Buenos Aires → Madrid → Bucharest
Timetable, Madrid time
15:45PU 502 from Buenos Aires at the gate
10:40W4 3172 to Bucharest leaves the gate
18 h 55 apart on the timetable, overnight
W4 3172 leaves 18 h 55 after PU 502 arrives on the timetable: more than half a day, so not a connection we count.