CRM is the "effective use of all available resources by individuals and crews to safely and effectively accomplish a mission or task, as well as identifying and managing the conditions that lead to error." CRM training has been integrated and mandatory for most pilot training programs, and has been the accepted standard for developing human factors skills for air crews and airlines. Although there is no universal CRM program, airlines usually customize their training to best suit the needs of the organization. The principles of each program are usually closely aligned. According to the U.S. Navy, there are seven critical CRM skills: