TM55-2840-251-23
APPENDIX B
Section I INTRODUCTION
B-1. MAINTENANCE ALLOCATION CHART
a.
This Maintenance Allocation Chart (MAC) (Section II) 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 RPSTL
AVIM which corresponds to the F Code in the RPSTL
DEPOT which corresponds to the D Code in the RPSTL
b.
The maintenance to be performed below depot and in the field is described as follows:
(1)
Aviation Unit Maintenance (AVUM) activities will be staffed and equipped to perform high frequency "On-Aircraft"
maintenance tasks required to retain or return aircraft to a serviceable condition. The maintenance capability of the
AVUM will be governed by the Maintenance Allocation Chart (MAC) and limited by the amount and complexity of ground
support equipment (GSE), facilities required, and number of spares 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. (Assignments 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.
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 aircraft operational readiness.
Perform maintenance inspections and servicing to include preflight, 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 aircraft instruments, or easy to
use/interpret diagnostic/fault isolation devices (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 to the electrical system. Inspect, service
and make operational capacity and pressure checks to hydraulic system. Perform servicing, functional adjustments, and
minor repair/ replacement to the flight control, propulsion, power train and fuel system. Accomplish airframe repair which
does not require extensive disassembly, jigging, or alignment. The manufacture of airframe parts will be limited to those
items which can be fabricated with tools and equipment found in current air mobile tool and shop sets. Evacuate
unserviceable modules/components and end items beyond the repair capability of AVUM to the supporting AVIM.
5-1
B-1
