Prior to the construction of the Passenger Terminal Building. Circa 1960.
The first jet aircraft to perform night flying trials at Kai Tak was the BOAC Comet 4. China Mail 16 July 1959 refers.
Night flying commenced on 17 July 1959. A SCMP article on the subject here The aircraft that made the historic flight was a Cathay Pacific DC-3, registration VR-HDA.