Aviation meicine, also called flight medicine or aerospace medicine, is a branch of preventive or occupational medicine in which the patients/subjects are pilots and aircrews. The specialty strives to treat or prevent conditions to which aircrews are particularly susceptible, applies medical knowledge to the human factors in aviation and is thus a critical component of aviation safety. A military practitioner of aviation medicine may be called a flight surgeon and a civilian practitioner is an aviation medical examiner.