TM 55-4920-394-13&P
APPENDIX B
MAINTENANCE ALLOCATION CHART
B-1. Maintenance Allocation Chart.
a. This Maintenance Allocation Chart (MAC) assigns maintenance functions in accordance with the Three
Levels of Maintenance concept for army aircraft. These maintenance levels: Aviation Unit Maintenance
(AVUM), Aviation Intermediate Maintenance (AVIM) and Depot Maintenance are depicted on the MAC as:
AVUM which corresponds to the O code in the Repair Parts and Special Tools List (RPSTL).
AVIM which corresponds to the F code in the Repair Parts and Special Tools List (RPSTL).
DEPOT which corresponds to the D code in the Repair Parts and Special Tools List (RPSTL).
b. The maintenance to be performed below depot and in the field is described as follows:
(1) Aviation Unit Maintenance (AVUM). AVUM activities will be staffed and equipped to perform high
frequency "On Equipment" maintenance tasks required to retain or return equipment to a serviceable condition.
The maintenance capability of the AVUM will be governed by the MAC and limited by the amount and
complexity of support equipment, facilities required, and number of spaces and critical skills available. The
range and quantity of authorized spare modules/components will be consistent with the mobility requirements
dictated by the air mobility concept. (Assignment of maintenance tasks to divisional company size aviation
units will consider the overall maintenance capability of the division, the requirement to conserve personnel and
equipment resources and air mobility requirements).
(a) Company Size Aviation Units. Perform those tasks which consist primarily of preventive
maintenance and maintenance repair and replacement functions associated with sustaining a high level of
equipment operational readiness.
Perform maintenance inspections and servicing to include daily,
intermediate, periodic and special inspections as authorized by the MAC or higher headquarters. Identify the
cause of equipment/system malfunctions using applicable technical manual troubleshooting instructions, Built-
In-Test Equipment (BITE), installed instruments, or easy to use Test Measurement and Diagnostic Equipment
(TMDE). Replace worn or damaged modules/components which do not require complex adjustments or system
alignment and which can be removed/installed with available skills tools and equipment. Perform operational
and continuity checks and make minor repairs. Perform servicing, functional adjustments, and minor
repair/replacement. Evacuate unserviceable modules/components and end items beyond the repair capability
of AVUM to the supporting AVIM.
B-1