British Airways Boeing 747-436 G-BYGF operated BA177 London Heathrow – New York JFK today, however it was unable to operate the return BA174 due to a flaps problem. Sister G-CIVI, which operated BA183 London Heathrow – New York JFK and would normally have overnighted at JFK prior to operating BA178 New York JFK – London Heathrow tomorrow morning, was instead turned around to operate the delayed BA174.