[1] The design featured numerous improvements including a redesigned wing with a new low drag section, a larger fuselage and bonded rather than riveted construction.

This was designated the Y-12 (II), which featured more powerful engines and removal of leading edge slats, first flying on 16 August 1984 and receiving Chinese certification in December of the following year.

Harbin Aircraft Manufacturing Corporation (HAMC) and the Civil Aviation Administration of China (CAAC) applied for Part 23 certification of the Y-12 in September 1992.

Modifications are made to the Y-12 (II) to meet US requirements, including a larger, reshaped, wing with wing-lets and landing gear reinforced with stronger struts.

[2] The latest development is the Y-12F, which is almost a new design with many improvements: new wings, landing gear, fuselage, more powerful engines, and extended payload and range.