S.C. Code Ann. § 25-1-1150

Whenever a vacancy occurs in the position of chief of staff, headquarters South Carolina Air National Guard it must be filled by promoting the fully qualified rated officer who has a minimum of five years commissioned service in the South Carolina Air National Guard and who is, in the opinion of the Adjutant General of South Carolina, considered to be the best qualified to fill the vacancy. Officers considered for this assignment must have served in a state status the next two years preceding the date the vacancy occurred. Active duty tours or schools of one year's duration or less shall count toward accrual of the two-year period specified in this section. In the event of federal mobilization of the majority of the South Carolina Air National Guard, the two-year requirement does not apply. The chief of staff shall supervise preparation of plans, policies, and programs for the Air National Guard units assigned to the State and advise and assist the Adjutant General in the execution of such of these plans, policies, and programs as he approves. If he is the senior Air National Guard officer in the State, he may be vested with the authority to command all Air National Guard units assigned to the State.