Maintenance Categories and Work Times - TM-55-4920-425-13-P0047

TM 55-4920-425-13-13&P

accuracy, to detect and adjust any discrepancy in the accuracy of the instrument or test equipment being compared with

the certified standard.

g. Install. To set up for use in an operational environment such as an emplacement, site or vehicle.

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, 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 technique of complete disassembly of

the item, inspection 'of all parts or components, repair or replacement 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 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 perform the

indicated function.

B-6. Tools and Test Equipment (Section III). 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 column 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