TM 55-920-399-13&P
B-4. Functional Groups. Standard functional
and adjust any discrepancy in the accuracy of the
groupings are not considered feasible for aviation
instrument or test equipment being compared
ground support equipment due to variation and
with the certified standard.
complexity. Therefore, variations to functional
g. Install. To set up for use in an operational en-
groupings may occur.
vironment such as an emplacement, site or vehicle.
h. Replace. To replace unserviceable items with
B-5. Maintenance C a t e g o r i e s a n d W o r k
serviceable assemblies, subassemblies or parts.
T i m e s . The maintenance categories (levels)
AVUM, AVIM, and DEPOT are listed on the
i. Repair. To restore an item to serviceable con-
Maintenance Allocation Chart with individual col-
dition through correction of a specific failure or
umns that indicate the work times for maintenance
unserviceable condition. This includes, but is not
functions at each maintenance level. Work time
limited to, inspection, cleaning, preserving, ad-
presentations such as 0.1 indicate the average time
j u s t i n g , r e p l a c i n g , welding, riveting, and
it requires a maintenance level to perform a
strengthening.
specified maintenance function. If a work time has
j. Overhaul. To restore an item to a completely
not been established, the columnar presentation
serviceable condition as prescribed by
s h a l l indicate "-Z-". Maintenance levels higher
maintenance serviceability standards prepared
t h a n the level of maintenance indicated are
and published for the specific item to be over-
authorized to perform the indicated function.
hauled.
k. Rebuild. To restore an item to a standard as
B-6. Tools and Test Equipment (Section
nearly as possible to the original or new condition
III). Common tool sets (not individual tools),
in appearance, performance, and life expectancy.
special tools, test and support equipment required
This is accomplished through the maintenance
t o perform maintenance functions are listed
technique of complete disassembly of the item, in-
alphabetically with a reference number to permit
spection of all parts or components, repair or
cross-referencing to column 5 in the MAC. In addi-
replacement of worn or unserviceable elements
tion, the maintenance category authorized to use
(items) using original manufacturing tolerances
the device is listed along with the item National
and specifications, and subsequent reassembly of
Stock Number (NSN) and, if applicable, the tool
the item.
number to aid in identifying the tool/device.
B-3
