MAE Professor Richard Wirz was quoted in the November 8, 2017, Los Angeles Times article “SpaceX says rocket engine test failure won’t affect its launch schedule” on the use of qualification tests for rocket engines:
Qualification tests are generally used to test new designs, changes in operating conditions or even slight modifications to a part, said Richard Wirz, director of the plasma and space propulsion laboratory at UCLA and a professor in the university’s mechanical and aerospace engineering department.