The first-stage LE-7A and second-stage LE-5B engines of the H-IIA launch vehicle started being developed in 1994, with the LE-5B development completed in 2000, the LE-7A development is still under way to improve the engine further. Failures occurred in the H-II Flight No.5 launch in 1998 where the second-stage engine, the LE-5A, failed and in the H-II Flight No.8 launch in 1999 where the first-stage engine, the LE-7, failed. Development of these engines was continued improving the development plan reflecting the cause of these launch failures. Both engines operated satisfactory in 2001 during the maiden flight of the H-IIA.