 Meanwhile, Sukhoi was busy with the T10M (later renamed Su-35 in 1993) program, which was a comprehensive upgrade over the Su-27. The T10M would incorporate aerodynamic modifications, improved avionics and armament, and have a better propulsion system, designed to give it greatly enhanced agility. The first Su-27M prototype (T-10S-70) made its maiden flight on 28 June 1988. Changes from the Su-27 include canards, upgraded engines, new radar, and a digital fly-by-wire flight-control system. Later Su-35 prototypes featured glass cockpits and modified vertical stabilizers. The Su-35's construction made significant use of composites, including aluminium-lithium (Al-Li) alloy. The aircraft, like the Su-27, could perform the previously unattainable "Pugachev's Cobra" and tailslide, but during these low-speed maneuvers, active controls could not be achieved because the flight control surfaces were ineffective.
