 This one also crashed on 23 December 1981 during a high-speed test, killing the pilot.Eventually the T-10-15 demonstrator, "T-10S-3", evolved into the definitive Su-27 configuration.The "T-10S-3" was modified and officially designated the "P-42", setting a number of world records for time-to-height, beating those set in 1975 by a similarly modified F-15 called "The Streak Eagle".