Compared to the T-4, it was an evolutionary design, and thus its appeal laid in its simplicity and low cost. The Soviet government was skeptical about the need to approve the development of a replacement aircraft so soon after the Tu-22 had just entered service. The Air Force and Tupolev, in order to save face with regards to the Tu-22's operational deficiencies and to stave off criticisms from the ICBM lobby, agreed to pass off the design as an update of the Tu-22 in their discussions with the government. The aircraft was designated Tu-22M, given the OKB code "Aircraft 45", and an internal designation of "AM". Their effort was successful as the government approved the design on 28 November 1967, and decreed the development of the aircraft's main weapon, the Kh-22. The T-4 itself would make its first flight in 1972, but was later cancelled.