Maintenance Categories and Work Times

TM 55-4920-424-13&P

and adjust any discrepancy in the accuracy of the

Standard functional

B-4.

Functional Groups.

instrument or test equipment being compared with the

groupings are not considered feasible for aviation

certified standard.

ground support equipment due to variation and

complexity. Therefore, variations to functional groupings

g. Install. To set up for use in an operational

may occur.

environment such as an emplacement, site or vehicle.

B-5. Maintenance Categories and Work Times. The

h. Replace. To replace unserviceable items with

maintenance categories (levels) AVUM, AVIM, and

serviceable assemblies, subassemblies or parts.

DEPOT are listed on the Maintenance Allocation Chart

with individual columns that indicate the work times for

i. Repair.

To restore an item to serviceable

maintenance functions at each maintenance level. Work

condition through correction of a specific failure or

time presentations such as 0.1 indicate the average time

unserviceable condition. This includes, but is not limited

it requires a maintenance level to perform a specified

to, inspection, cleaning, preserving, adjusting, replacing,

maintenance function. If a work time has not been

welding, riveting, and strengthening.

established, the columnar presentation shall indicate

"----". Maintenance levels higher than the level of

j. Overhaul. To restore an item to a completely

maintenance indicated are authorized to perform the

serviceable condition as prescribed by maintenance

indicated function.

serviceability standards prepared and published for the

specific item to be overhauled.

B-6.

Tools and Test Equipment (Section III).

Common tool sets (not individual tools), special tools,

k. Rebuild. To restore an item to a standard as

test and support equipment required to perform

nearly as possible to the original or new condition in

maintenance functions are listed alphabetically with a

appearance, performance, and life expectancy. This is

reference number to permit cross-referencing to column

accomplished through the maintenance technique of

5 in the MAC. In addition, the maintenance category

complete disassembly of the item, inspection of all parts

authorized to use the device is listed along with the item

or components, repair or replacement of worn or

National Stock Number (NSN) and, if applicable, the tool

unserviceable

elements

(items)

using

original

number to aid in identifying the tool/device.

manufacturing tolerances and specifications, and

subsequent reassembly of the item.

B-3