APPENDIX B. MAINTENANCE ALLOCATION CHART

TM 55-4920-425-13-13&P

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 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 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 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) 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 the aircraft crew chief or assigned aircraft repairman will normally be limited to preventive maintenance

inspections, servicing, spot painting, spot drilling, 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). AVIM provides mobile, responsive "One Stop" maintenance

support. (Maintenance functions which are not conducive to sustaining air mobility will be assigned to depot

maintenance.) Performs all maintenance functions authorized to be done at AVUM. Repair of equipment for return to

user will emphasize support or operational readiness requirements. Authorized maintenance includes replacement and

repair of modules/components and end items which can be accomplished efficiently with available skills, tools, and

equipment. Establishes the Direct Exchange (DX) program for AVUM units by repairing selected items for return to stock

when such repairs cannot be accomplished at the AVUM level. Inspects, troubleshoots, tests, diagnoses, repairs,

adjusts,

B-1