Operating instructions

TM 11-5865-229-12
APPENDIX B
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 the 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)
(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 con-
dition. 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 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 (or phased), 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 test, measurement, and diagnostic equipment (TMDE).
Replace worn or damaged modules/components that do not require complex adjustments or system alignment
and which can be removed/installed with available skills, tools, and ground support equipment. Perform op-
erations 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 fuel systems. Accomplish airframe
repair that 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 ship 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, bat-
talion 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 chief
or inspections, servicing, spot painting, stop drilling application of nonstress patches, minor adjustments, module/
component fault diagnosis, and replacement of selected modules/components. Repair functions will normally
be accomplished by the supporting AVIM unit.
(2) Aviation Intermediate Maintenance (AVIM) provides mobile, responsive “One-Stop” mainte-
nance support. (Maintenance functions which are not conducive to sustaining air mobility will be assigned to
B-1