the design had to incorporate other political desires as well; there was a great value placed upon powering the type with the first all-japanese production turbofan engine, the ishikawajima-harima f3-ihi-30. reportedly, the selection of a twin-engine configuration for the trainer was one of the easiest decisions taken, being made not just for engine power but from a high priority being placed upon safety. a robust, damage-tolerant and long-lived structure was also specified for the trainer; in order to achieve this, it was decided to make limited use of composite materials in the form of carbon fiber and kevlar in areas such as the radome and elements of the rear wing, tail unit, and undercarriage. extensive use of computer-aided design (cad) and computer-aided manufacturing (cam) techniques was also applied. these advances contributed to the design being certified for a total lifespan of 7,500 flight hours.