TM 55-1680-317-23&P
APPENDIX B
MAINTENANCE ALLOCATION CHART
Section I. INTRODUCTION
B-1. GENERAL
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 con- serve 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
