(2) Maintenance code. Maintenance codes
This manual lists repair parts and special tools required
are assigned to indicate the levels of maintenance
for performance of organizational maintenance of the
authorized to USE and REPAIR support items. The
MK-456/GRC and MK-456A/GRC.
maintenance codes are entered in the third and fourth
position of the Uniform SMR Code format as follows:
This Repair Parts and Special Tools List is divided into
(a) The maintenance code entered in
the following sections:
the third position will indicate the lowest maintenance
a. Section II. Repair Parts List. A list of repair
level authorized to remove, replace, and use the support
parts authorized for use in the performance of
item. The maintenance code entered in the third
maintenance. The list also includes parts which must be
position will indicate one of the following levels of
removed for replacement of the authorized parts. Parts
lists are composed of functional groups in ascending
numerical sequence, with the parts in each group listed
Support item is removed, replaced, used at
in figure and item number sequence.
the organizational level.
b. Section III. Special Tools List. Not applicable.
(b) The maintenance code entered in
the fourth position indicates whether the item is to be
c. Section IV. National Stock Number and Part
repaired and identifies the lowest maintenance level
Number Index. A list, in ascending National item
with the capability to perform complete repair (i.e., all
identification number (NIIN, last 9 digits) sequence, of
authorized maintenance functions). This position will
all National stock number appearing in the listings,
contain one of the following maintenance codes:
followed by a list, in alphameric sequence, of all part
number appearing in the listings. National stock number
and part numbers are cross referenced to each
The lowest maintenance level capable of
illustration figure and item number appearance.
complete repair of the support item is the
general support level.
3. Explanation of Columns
Nonreparable. No repair is authorized.
The following provides an explanation of columns found
(3) Recoverability code.
in the tabular listings:
codes are assigned to support items to indicate the
a. Illustration. This column is divided as follows:
disposition action on unserviceable items.
(1) Figure number.
Indicates the figure
recoverability code is entered in the fifth position of the
number of the illustration in which the item is shown.
Uniform SMR Code format as follows:
(2) Item number.
The number used to
identify each item called out in the illustration.
b. Source, Maintenance, and Recoverability Codes
Nonreparable item. When unserviceable,
condemn and dispose at the level indicated
(1) Source code. Source codes are assigned
in position 3.
to support items to indicate the manner of acquiring
Reparable item. When beyond lower level
support items for maintenance, repair, or overhaul of
repair capability, return to depot. Con-
end items. Source codes are entered in the first and
demnation and disposal not authorized
second positions of the Uniform SMR Code format as
below depot level.
c. National Stock Number. Indicates the National
stock number assigned to the item and will be used for
Item procured and stocked for anticipated or
d. Part Number. Indicates the primary number
A support item that is not stocked. When
used by the manufacturer (individual, company, firm,
required, item will be procured through
corporation, or Government activity), which controls the
normal supply channels.
design and characteristics of the item by means of its
engineering drawings, specifications standards, and
Cannibalization or salvage may be
inspection requirements, to identify an item or range of
used as a source of supply for any
items source coded above except
those coded XA, XD, and aircraft
When a stock numbered item is
support items as restricted by AR
received may have a different part
number than the part being replaced.