Izvestia has an article on the modifications made to the MiG-31K so that it can operate the Kinzhal air-launched ballistic missile.
Photo: Russian Ministry of Defense
The plane’s radar was removed and the fuel capacity increased. The cockpit was redesigned and new targeting system is installed.
The crew had to be retrained as the centre of gravity has shifted with the missile on board.
The jet’s aerodynamics qualities was improved and the engines are modernized as well.