In his words, the engine lacks gas-dynamic stability. The general said it was not accidental that for a short period of the aircraft's tests there were 52 cases of engine failure in the air. Besides, the engine does not meet ICAO requirements by noise level, Mr. Mikhailov said.
The commander-in-chief said he was actively trying to help his Ukrainian colleagues to remove the engine defects. However, at a recent joint conference, Russian and Ukrainian engineers and designers "failed to agree that all defects have been removed," the general said.