TM 55-4920-414-13&P
h. Replace. To replace unserviceable items with
serviceable assemblies, subassemblies or parts.
i. Repair. To restore an item to serviceable condition
through correction of a specific failure or unserviceable
condition. This includes, but is not limited to, inspec-
tion, cleaning, preserving, adjusting, replacing, weld-
ing, riveting, and strengthening.
j. Overhaul. To restore an item to a completely
serviceable condition as prescribed by maintenance
serviceability standards prepared and published for the
specific item to be overhauled.
k. Rebuild. To restore an item to a standard as
nearly as possible to the original or new condition in
appearance, performance, and life expectancy. This is
accomplished through the maintenance technique of
complete disassembly of the item, inspection of all
parts or components, repair or replacement of worn or
unserviceable elements (items ) using original manu-
facturing tolerances and specifications, and subsequent
reassembly of the item.
B-4. FUNCTIONAL GROUPS.
Standard functional groupings are not considered
feasible for aviation ground support equipment due to
variation and complexity. Therefore, variations to
functional groupings may occur.
B-5. MAINTENANCE CATEGORIES AND WORK
TIMES.
The maintenance categories (levels) AVUM, AVIM,
and DEPOT are listed on the Maintenance Allocation
Chart with individual columns that indicate the work
times for maintenance functions at each maintenance
level. Work time presentations such as 0.1 indicate the
average time it requires a maintenance level to perform
a specified maintenance function. If a work time has
not been established, the columnar presentation shall
indicate “-.-”. Maintenance levels higher than the
level of maintenance indicated are authorized to per-
form the indicated function.
B-6. TOOLS AND TEST EQUIPMENT (Section Ill).
Common tool sets (not individual tools ), special
tools, test and support equipment required to perform
maintenance functions are listed alphabetically with a
reference number to permit cross-referencing to col-
umn 5 in the MAC. In addition, the maintenance
category authorized to use the device is listed along
with the item National stock Number (NSN) and, if
applicable, the tool number to aid in identifying the
tool/device.
B-3
