BA 1347 then BA 173 at Heathrow
Saint Helier → London → New York JFK
Timetable, London time
11:45BA 1347 from Saint Helier at the gate
11:20BA 173 to New York JFK leaves the gate
23 h 35 apart on the timetable, overnight
BA 173 leaves 23 h 35 after BA 1347 arrives on the timetable: more than half a day, so not a connection we count.