BA 339 then BA 285 at Heathrow
Nice → London → San Francisco
Timetable, London time
12:15BA 339 from Nice at the gate
11:45BA 285 to San Francisco leaves the gate
23 h 30 apart on the timetable, overnight
BA 285 leaves 23 h 30 after BA 339 arrives on the timetable: more than half a day, so not a connection we count.