AI 131 then BA 426 at Heathrow
Mumbai → London → Luxembourg
Timetable, London time
18:55AI 131 from Mumbai at the gate
18:45BA 426 to Luxembourg leaves the gate
23 h 50 apart on the timetable, overnight
BA 426 leaves 23 h 50 after AI 131 arrives on the timetable: more than half a day, so not a connection we count.