TM 55-4920-401-13&P
h. Replace. To replace unserviceable items with
serviceable assemblies, subassemblies or parts.
i. Repair. To restore an item to serviceable con-
dition through correction of a specific failure or un-
seviceable condition. This includes, but is not lim-
ited to, inspection, cleaning, preserving, adjusting,
replacing, welding, 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 tech-
nique of complete disassembly of the item, in-
spection of all parts or components, repair or re-
placement of worn or unserviceable elements
(items) using original manufacturing 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 Allo-
cation 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 main-
tenance 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 mainte-
nance indicated are authorized to perform the indi-
cated function.
B-6. Tools and Test Equipment (Section III).
Common tool sets (not individual tools), special
tools, test and support equipment required to per-
form maintenance functions are listed alphabet-
ically with a reference number to permit cross-ref-
erencing to column 5 in the MAC. In addition, the
maintenance category authorized to use the device
is listed along with the item National Stock Num-
ber (NSN) and, if applicable, the tool number to aid
in identifying the tool/device.
B-3
