The project received final approval on 18 January 1986. The model's codename was changed to P729 as it moved into the production phase, under head of program Toshihiko Hirai. The task of constructing five engineering "mules" (more developed prototypes) was again allocated to IAD, which also conducted the first front and rear crash tests on the P729. While Tom Matano, Mark Jordan, Wu-huang Chin (, also on the RX-7 team), Norman Garrett, and worked on the final design, the project was moved to Japan for engineering and production details.