BA 491 then UA 15 at Heathrow
Gibraltar → London → Newark
Timetable, London time
16:15BA 491 from Gibraltar at the gate
15:10UA 15 to Newark leaves the gate
22 h 55 apart on the timetable, overnight
UA 15 leaves 22 h 55 after BA 491 arrives on the timetable: more than half a day, so not a connection we count.