Osrodek Konstrukcji Lotniczych, aircraft construction centre, set up at WSK Warsaw-Okecie 12 October 1957 to take over all Polish aircraft design (previously handled by IL). Main projects MD-12 20-passenger airliner (4 x 330-hp WN-3, 21 July 1959) and TS-11 Iskra jet trainer, plus many light aircraft, but excluding designs by WSK Mielec and Swidnik.