 Due to problems with the ASh-82M engines, the powerplant was changed to ASh-82FN making 1,380 kW (1,850 hp), but while reliable, the less-powerful engines caused the Su-12 to miss its top speed and service ceiling specifications.The Su-12 successfully completed government testing in September 1949 and was recommended for production.Due to lack of production capacity in the USSR, in October 1949 it was proposed to build the airplane in Czechoslovakia.