TM 55-2840-254-23
MAINTENANCE ALLOCATION CHART
Section I. INTRODUCTION
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 aviation. These maintenance levels (categories) - Aviation
Unit Maintenance (AVUM), Aviation Intermediate Maintenance (AVIM), and Depot Maintenance - are
depicted on the MAC as:
AVUM, which corresponds to an O Code in the Repair Parts and Special Tools List ( RPSTL)
AVIM, which corresponds to an F Code in the Repair Parts and Special Tools List (RPSTL)
DEPOT, which corresponds to a 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) activities will be staffed and equipped to perform high
frequency "On-Aircraft" maintenance tasks required to retain or return aircraft systems 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, authorized manning strength, 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 re-
sources, 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
aircraft operational readiness. Perform maintenance inspections and servicing to include preflight, daily,
intermediate, periodic (or phased), and special inspections as authorized by the MAC or high head-
quarters. Identify the cause of equipment/system malfunctions using applicable technical manual trouble-
shooting instructions, built-in test equipment (BITE), installed aircraft instruments, or test, measurement,
and diagnostic equipment (TMDE). Replace worn or damaged modules/components that do not require
complex adjustments or system alinement and which can be removed/installed with available skills, tools,
and ground support 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 sys-
tems. Perform servicing, functional adjustments, and minor repair/replacement to the flight control, pro-
pulsion, power train, and fuel systems. Accomplish airframe repair that does not require extensive disas-
sembly, jigging, or alignment. The manufacture of airframe repair will be limited to those items which can
be fabricated with tools and equipment found in current air mobile tool and shop sets. Evacuate unservice-
able modules/components and end items beyond the repair capability of AVUM to the supporting AVIM.
