TM 10-3930-653-14&P The symbol designations for various maintenance categories remain as follows. C - Operator/Crew O - Organizational Maintenance. F - Direct Support Maintenance H - General Support Maintenance D - Depot Maintenance e. Column  5  -  Tools  and  Equipment:  Column  Five  (5)  specifies  by  code,  those  common  tool  sets  (not  individual tools), test and support equipment required to perform the designated functions. B-13