It was followed by trainer SK 37 and reconnaisance version SF 37. JA 37 was modified in 1977. 1xVolvo RM8, 127.50 kN of afterburner thrust Max. 6000 kg Max. The fuselage is rectangular with large clear canopy and a wide, swept tail fin.
Rectangular tailplane is set near the tip of the tail fin.
Landing gear with nose wheel is not retractable. Originally based on MBB Bo 208, first MFI 15 was flown on July 11, 1968. First production version was flown on Februaury 26, 1971. First MFI 17 was flown on July 6, 1972. The aircraft went in production in 1973.