maintenance and operations of embarked aircraft. It is tailored  for  each  carrier,  and  the  items  listed  are selected from all allowance requirement registers and allowance lists (ARRs and ALs) from each type of aircraft embarked. The allowance quantities are based on  the  ships’  demand  records.  The  AVCAL  is comprised of seven basic parts; they are titled as follows: Part I. AVCAL Index List Part II. ARR Gross Item List Part III. AVCAL Net List Part IV. Part Number to NSN Cross-Reference Part V. Requirements List Part VI. Excess Material List Part VII. Stock Rotatable List For more detailed information on the AVCAL and the specific parts, refer to Afloat Supply Procedures, NAVSUP  PUB-485,  and  FASOINST  4441.15 CODED NATIONAL STOCK NUMBER Each   Navy   item   stocked   under   centralized inventory control has assigned an NSN. The NSN is used for all supply management functions and in all supply   publications. The NSN is a 13-digit number that identifies an item of material in the supply system. It consists of the  four-digit  federal  supply  classification  (FSC) plus a nine-digit national item identification number (NIIN). The NIIN consists of a two-digit National Codification Bureau (NCB) code and seven digits that uniquely identify each NSN item in the Federal Supply Distribution  System.  Additionally,  within  the  Navy supply  system,  code  prefixes  and  suffixes  are  used. These prefixes and suffixes are used only within the Navy  and  not  in  interservice  transactions.  So,  when you requisition an item from supply in the Navy, you use the coded NSN for that item. Figure 3-8 shows you a complete coded NSN. The parts of this number are discussed in the following text. Cognizance  Symbol.  The  cognizance  symbol  is  a two-character  prefix.  It  identifies  the  systems command, office, agency, or Navy inventory manager that controls the category of material. The cognizance symbol 7R, shown in figure 3-8, tells you that the item of supply is under the control of the Aviation Supply Office (ASO). Material  Control  Codes.  Material  Control  codes divide inventories into segments that show similar demand or repairability. Look at figure 3-8 again. Here, Material Control code H tells you that the item is a depot-level repairable. Since the item cannot be repaired locally, it must be shipped to a naval aviation depot  (NADEP)  or  commercial  concern  for  repair. Material Condition Codes. Material Condition codes classify material in terms of readiness for issue and use. They also identify action under way to change the  status  of  material.  Condition  codes  A  through  S (less I and O) are assigned to Navy material. The Material Condition code F, shown in figure 3-8, tells you that the item of supply is fast moving, in high demand, and used quite often. Figure 3-8.—Breakdown of a coded national stock number. 3-13