TM 55-2840-231-23
APPENDIX B
MAINTENANCE ALLOCATION CHART
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 an F Code in the RPSTL
DEPOT which corresponds to a 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 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. (Assignments of main-
tenance 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
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 isola-
tion devices (TMDE). Replace worn or damaged modules/components which do not require complex adjust-
ments or system alinement 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 systems. Perform servicing, functional
adjustments, and minor repair/replacement to the flight control, propulsion, power train and fuelsystems.
Accomplish air frame repair which does not require extensive disassembly, jigging, or alinement. The manu-
facture of air frame 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.
(b) Less than Company Size Aviation Units: Aviation elements organic to brigade, group,
battalion headquarters and detachment size units are normally small and have less than ten aircraft assigned.
Maintenance tasks performed by these units will be those which can be accomplished by the aircraft crew
B-1
