Development of a version for the Soviet Navy called the "Su-27K" (Russian for "Korabyelny" - "Shipborne", NATO designation 'Flanker-D') commenced not long after the development of the main land-based type. Some of the T10 demonstrators were modified to test features of navalized variants for carrier operations. These modified demonstrators led to specific prototypes for the Soviet Navy, designated ""T10K"" (Korabyelny). The "T10K"s had canards, an arresting hook and carrier landing avionics as well as a retractable inflight re-fueling probe. They did not have the landing gear required for carrier landings or folding wings. The first "T10K" flew in August 1987 flown by the famous Soviet test pilot Viktor Pugachev (who first demonstrated the cobra manoeuvre using an Su-27 in 1989), performing test take-offs from a land-based ski-jump carrier deck on the Black Sea coast at Saky in the Ukrainian SSR. The aircraft was lost in an accident in 1988.