TK 1847 then BA 637 at Athens
Istanbul → Athens → London Heathrow
Timetable, Athens time
06:05TK 1847 from Istanbul at the gate
19:40BA 637 to London Heathrow leaves the gate
13 h 35 apart on the timetable
BA 637 leaves 13 h 35 after TK 1847 arrives on the timetable: more than half a day, so not a connection we count.