The Hawker-Siddeley HS.121 Trident followed the Caravelle with a (CAT IIIA) and to CAT IIIB during 1975. Published 16/01/2022 at 1024 × 653 in The Hawker-Siddeley HS.121 Trident followed the Caravelle with a (CAT IIIA) and to CAT IIIB during 1975. The Hawker-Siddeley HS.121 Trident followed the Caravelle with a (CAT IIIA) and to CAT IIIB during 1975. The Hawker-Siddeley HS.121 Trident followed the Caravelle with a (CAT IIIA) and to CAT IIIB during 1975.