TM  10-3930-638-24&P B-3 COLUMN ENTRIES USED IN THE MAC (cont) quality control time in addition to the time required to per. form the specific tasks identified for the maintenance func- tions authorized in the maintenance allocation chart. The  symbol  designations  for  the  various  maintenance  levels are: C . . . . . . . . . . . . . . . . . . . . . . . . . . .  Operator or crew O . . . . . . . . . . . . . . . . . . . . . . .Organizational  maintenance F . . . . . . . . . . . . . . . . . . . . .   Direct  support  maintenance H . . . . . . . . . . . . . . . . . . . . . .General  support  maintenance D . . . . . . . . . . . . . . . . . . . . . . . . . . . . Depot  maintenance e. Column 5, Tools and Equipment.  Column  5  specifies, by code, those common tool sets (not individual tools) and special tools, test, and support equipment required to per- form the designated function. f. Column 6, Remarks. This column shall contain a letter code in alphabetic order which shall be keyed to the re- marks contained in section IV. B-4. COLUMN ENTRIES USED IN THE TOOL AND TEST EQUIPMENT REQUIREMENTS a. Column 1, Tool or Test Equipment Reference Code. The tool and test equipment reference code correlates with a maintenance function on the identified end item or com- ponent. b. Column 2, Maintenance Catagory.  The lowest level of maintenance authorized to use the tool or test equipment. c. Column 3, Nomenclature.  Name or identification of the tool or test equipment. d. Column 4, National/NATO Stock Number. The Nation- al or NATO stock number of the tool or test equipment. e. Column 5, Tool Number. The manufacturer’s part number. B-5. EXPLANATION OF COLUMNS IN SECTION IV a. Reference Code.  The  code  scheme  recorded  in  column 6, section II. b. Remarks. This column lists information pertinent to the  maintenance  function  being  performed  as  indicated on the MAC section II. B - 2