South Carolina Code of Laws — Title 12 (Taxation)
S.C. Code Ann. § 12-37-2420 — Required tax returns
All airline companies operating in the State shall make an annual property tax return on or before the thirtieth day of April in each year for the preceding calendar or fiscal year of their flight equipment to the department. Each type and model of flight equipment shall be separately returned, valued and apportioned as herein provided.
Source: official text