OPERATING AND SUPPORT

COST-ESTIMATING GUIDE

OFFICE OF THE SECRETARY OF DEFENSE

COST ASSESSMENT AND PROGRAM 

EVALUATION

SEPTEMBER 2020
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Contents

1. INTRODUCTION .................................................................................................................. 1

1.1 Purpose.................................................................................................................................. 1

1.2 Applicability ......................................................................................................................... 1

1.3 Outline................................................................................................................................... 1

2. OVERVIEW OF LIFE-CYCLE COSTS................................................................................ 3

2.1 Life-Cycle Cost Categories................................................................................................... 3

2.2 Cost Categories as a Percentage of Life-Cycle Cost ............................................................ 4

2.3 Overview of O&S Cost Scope and Definitions.................................................................... 6

3. OSD COST ELEMENT STRUCTURE ................................................................................. 7

3.1 Introduction........................................................................................................................... 7

3.2 Definitions............................................................................................................................. 9

4. DIFFERENT METRICS OF O&S COSTS.......................................................................... 19

4.1 Introduction......................................................................................................................... 19

4.2 O&S Cost Categorizations.................................................................................................. 19

4.3 O&S Cost Metrics............................................................................................................... 25

5. ROLE OF O&S COSTS ....................................................................................................... 33

5.1 Acquisition Milestone and Other Reviews......................................................................... 33

5.2 Sustainment Reviews.......................................................................................................... 34

5.3 Other Roles of O&S Cost Estimates and Analyses ............................................................ 34

5.4 Selected Acquisition Report ............................................................................................... 34

6. SOURCES OF O&S COST DATA...................................................................................... 37

6.1 VAMOSC Program........................................................................................................... 37

6.2 Cost Reporting for Sustainment Contracts ......................................................................... 39

7. O&S COST ESTIMATING PROCESS ............................................................................... 47

7.1 Introduction......................................................................................................................... 47

7.2 Program Definition ............................................................................................................. 48

7.3 Cost Estimating Plan........................................................................................................... 50

7.4 Cost Data............................................................................................................................. 56

7.5 Cost Estimate ...................................................................................................................... 58
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Appendices

APPENDIX A Software Maintenance Cost Elements.................................................................. 69

APPENDIX B Indirect Support Cost Elements............................................................................ 73

APPENDIX C Definitions for Acquisition Logistics Support Cost Elements............................. 77

APPENDIX D Mapping from O&S Cost Elements to Budget Appropriations........................... 81

APPENDIX E Analytic Support for Sustainment Reviews.......................................................... 85

APPENDIX F DoD Maintenance and Supply............................................................................ 101

APPENDIX G Product Support Cost Estimate at the Component Level of Detail.................... 109

APPENDIX H Relevant Statutory Requirements....................................................................... 123

APPENDIX I Rates for Military and Civilian Manpower.......................................................... 135

APPENDIX J References ........................................................................................................... 137

Abbreviations.............................................................................................................................. 139

Glossary ...................................................................................................................................... 143

Figures

Figure 2-1. Illustrative System Life Cycle.......................................................................................3

Figure 2-2. Major Cost Categories as % of Total Life-Cycle Cost for Selected System Types......5

Figure 3-1. Second/Third Level of Cost Element Structure ............................................................8

Figure 4-1. O&S Cost Elements ....................................................................................................19

Figure 4-2. O&S Cost Categorizations..........................................................................................24

Figure 4-3. O&S Cost Categorizations (cont.)...............................................................................25

Figure 4-4. Examples of Aircraft O&S Cost Metrics....................................................................26

Figure 4-5. Examples of Aircraft O&S Cost Metrics (cont.).........................................................27

Figure 4-6. Effect of System Usage on O&S Cost Metrics...........................................................28

Figure 4-7. Example of Normalization of $/Flight Hour Metric ...................................................29

Figure 4-8. Example of Various $/Flight Hour Metrics ................................................................30

Figure 6-1. Flexfile Report for Sustainment Data Elements..........................................................41

Figure 6-2. CSDR Sustainment WBS for Maintenance.................................................................42

Figure 6-3. CSDR Standard Functional Categories for Sustainment ............................................43

Figure 6-4. Maintenance and Repair Parts Report Data Elements ................................................44

Figure 6-5. Software Maintenance Report Data Elements ............................................................45

Figure 7-1. Recommended O&S Cost Estimating Process............................................................48

Figure 7-2. Typical System Characteristics and Program Content................................................49

Figure 7-3. Nominal System Life Durations..................................................................................52

Figure 7-4. Nominal System Life Durations (cont.)......................................................................53
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Figure 7-5. Example of O&S Phasing Convention........................................................................54

Figure 7-6. Inflation/Escalation Index Selection Guide ................................................................55

Figure 7-7. Example of Analogy Cost Estimate ............................................................................59

Figure 7-8. Example of Cost Estimate by CER.............................................................................61

Figure 7-9. Example of Sensitivity Analysis.................................................................................63

Figure 7-10. Second Example of Sensitivity Analysis..................................................................64

Tables

Table 4-1. Cost Element Composition of O&S Categorizations...................................................20

Table 4-2. Cost Element Composition of O&S Categorizations (cont.) .......................................21

Table 4-3. Cost Element Composition of O&S Categorizations (cont.) .......................................23

Table 7-1. Comparison of Replacement Systems to Antecedents.................................................60

Table E-1. Track of Aircraft Fuel Efficiency.................................................................................95

Table G-1. Avionics Components Input Data..............................................................................111

Table G-2. Avionics Components Input Data (continued)..........................................................112

Table G-3. Support Equipment Input Data ..................................................................................114

Table G-4. Technical Data Input Data.........................................................................................115

Table G-5. Training and Training Devices Input Data ................................................................116

Table G-6. Total Acquisition Logistics Costs..............................................................................117

Table G-7. Total O&S Costs........................................................................................................117
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1. INTRODUCTION

1.1 Purpose

This guide was prepared by the Office of the Secretary of Defense (OSD) Director of Cost 

Assessment and Program Evaluation (DCAPE) for use by the Department of Defense (DoD) 

military departments and defense agencies in developing estimates of system Operating and 

Support (O&S) costs. 

1.2 Applicability

This guide is focused on analytic methods and data for O&S cost estimates and analyses 

for a wide variety of DoD weapon systems.

1.3 Outline

The remainder of this guide is organized as follows:

• Chapter 2 provides an overview of the concepts of system life-cycle cost and system 

O&S cost.

• Chapter 3 provides the standard OSD O&S cost element structure. The cost element 

structure is an organized and defined taxonomy of O&S cost elements.

• Chapter 4 describes various categorizations of O&S cost elements, and associated O&S 

cost metrics, that are used for a variety of different purposes.

• Chapter 5 discusses the uses of O&S cost estimates and analyses in support of the 

defense acquisition process throughout the program life cycle. 

• Chapter 6 provides a summary of the O&S cost and related data systems that are 

available to the DoD cost community, including contractor cost data reporting for 

major sustainment contracts.

• Chapter 7 provides a tutorial on the best practices for planning, conducting, presenting,

and documenting O&S cost estimates. 

This guide also has several appendices:

• Appendix A provides an optional, more detailed cost element structure for software 

maintenance.

• Appendix B provides terms and definitions for O&S-related indirect costs. 

• Appendix C provides terms and definitions for acquisition cost elements associated 

with system product support.
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• Appendix D provides a mapping from OSD O&S cost elements to budget 

appropriations.

• Appendix E provides a recommended analytic approach that can be used to support 

sustainment reviews of major weapon systems after initial operational capability.

• Appendix F provides background on DoD maintenance and logistics for major weapon 

systems.

• Appendix G provides an example of an O&S cost estimate at the component or black 

box level of detail.

• Appendix H describes the extensive and demanding statutory and regulatory 

requirements associated with O&S cost estimates and analyses, weapon system 

sustainment, and life-cycle product support.

• Appendix I provides information on rates for military and civilian manpower.

• Appendix J provides the references used throughout this guide.

This guide also has a list of abbreviations and a glossary.
3 

2. OVERVIEW OF LIFE-CYCLE COSTS

2.1 Life-Cycle Cost Categories

Life-cycle cost is defined as the sum of four major cost categories: (1) research and 

development costs; (2) investment costs, consisting of procurement and military construction

costs; (3) O&S costs; and (4) disposal costs. 

Figure 2-1 depicts a notional profile of annual program expenditures by major cost 

category throughout the system life cycle for a program acquired using the Major Capability 

Acquisition pathway. The profile for an actual program will vary significantly by system type 

and the program’s Adaptive Acquisition Framework pathway. 

Figure 2-1. Illustrative System Life Cycle
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These costs occur over the phases of an acquisition program as defined in the acquisition 

process. The research and development costs occur during the materiel solution analysis phase, 

the technology maturation and risk reduction phase, and the engineering and manufacturing 

development phase; the investment costs occur during the production and deployment phase; the 

O&S costs occur during the operations and sustainment phase; and the disposal costs occur 

during the disposal phase.

Note that in the standard terminology for life-cycle cost, there are acquisition logistics 

support costs that are part of the program’s procurement cost. These costs are the initial 

investment and a vital enabler for a program’s product support. Definitions for the acquisition 

logistics support cost elements are provided in MIL-STD-881D, Work Breakdown Structures for 

Defense Materiel Items, Appendix K (Common Elements). The acquisition cost elements are part 

of the Work Breakdown Structure (WBS) for each major system type (e.g., aircraft, ground 

vehicle, etc.). The acquisition logistics support cost elements are described in Appendix C of this 

guide.

2.2 Cost Categories as a Percentage of Life-Cycle Cost

For many types of programs, the system O&S costs will be the largest of the four cost 

categories. Figure 2-2 presents the percentage of program life-cycle cost associated with O&S 

costs (for eight system types). 
5 

Figure 2-2. Major Cost Categories as % of Total Life-Cycle Cost for Selected System Types

The percentages are based on data taken from Selected Acquisition Reports (SARs). For 

programs still actively reporting at the time of the publication of this guide, the data were taken 

from the December 2019 SARs. For other programs, the data were taken from the last SAR for 

that program. In all cases, the data were converted to FY 2020 dollars before calculating the 

percentages displayed.

Note that in SARs, the investment cost category is not provided per se. Rather, the SARs 

provide separate costs for procurement and military construction. Military construction costs are 

normally not a significant life-cycle cost element in most programs. 

The actual percentage will vary from program to program, albeit for some system types, 

such as space systems and tactical missiles, the percentages for O&S costs will be much lower. 

Space systems have O&S costs primarily associated with sustainment of the ground stations. 

Tactical missiles have O&S costs primarily associated with stockpile surveillance, storage costs, 

and sustaining engineering and program management. Nevertheless, given the relative 

importance of O&S costs for many DoD major weapon systems, this guide has been issued to 

stress that importance and provide advice on estimating and managing these costs. 
6

2.3 Overview of O&S Cost Scope and Definitions

At the broadest level, O&S costs consist of all sustainment costs incurred from the initial 

system deployment through the end of system operations. This would include all costs of 

operating, maintaining, and supporting a fielded system. Specifically, this consists of the costs 

(organic (government civilian and military) and contractor) of personnel, equipment, supplies, 

software, and services associated with operating, modifying, maintaining, supplying, and 

otherwise supporting a system in the DoD inventory. These costs include those associated with 

the system-specific training of personnel necessary to support the system.

Chapter 3 of this guide provides further structure and definitions for the system O&S cost 

elements.
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3. OSD COST ELEMENT STRUCTURE

3.1 Introduction

This chapter provides the OSD standard O&S cost element structure, with associated 

terms and definitions, which categorizes and defines cost elements that cover the full range of 

O&S costs that could occur in any defense system. This standard is intended to be used by the 

military departments and defense agencies when presenting O&S cost estimates to OSD and the 

Joint Staff. Such presentations include: briefings or documentation reviewed by Cost Assessment 

and Program Evaluation (CAPE), displays of system O&S cost estimates in the program SAR, 

and any other briefings, reports, or displays reviewed by OSD or the Joint staff. However, there 

is flexibility in that some programs may have situations where the cost element structure will 

need to be tailored to the specific circumstances of the program. 

It is also intended that the military department cost data collection systems and activities 

conform to this standard as much as possible. However, in some cases, that may not always be 

possible. For example, the standard OSD cost element structure does not use Interim Contractor 

Support (ICS) or Contractor Logistics Support (CLS) as cost elements. It is intended that in cost 

estimates, the analyst will distribute any contractor sustainment costs to the appropriate 

functional cost element such as depot maintenance or sustaining/systems engineering. However, 

the military department Visibility and Management of Operating and Support Costs (VAMOSC) 

at the present time are not able to make such a distribution, and may have ICS or CLS as cost 

elements. For programs with significant ICS or CLS, it will be necessary for the analyst to 

augment the VAMOSC data with cost data reports from major sustainment contracts and other 

sources in order for the estimate to align with the standard structure. Cost data reporting for 

sustainment contracts is described in Chapter 6 of this guide.

The O&S cost element structure is divided into five major categories: 

1.0 UNIT-LEVEL MANPOWER

Cost of operators, maintainers, and other support manpower assigned to operating units. 

Includes military, government civilian, and/or contractor manpower.

2.0 UNIT OPERATIONS

Cost of unit operating material (e.g., direct fuel and training material) and unit support 

services. Excludes all maintenance and repair material. 

3.0 MAINTENANCE
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Cost of all system maintenance other than maintenance manpower assigned to operating 

units. Consists of organic and contractor maintenance. 

4.0 SUSTAINING SUPPORT

Cost of system support activities other than maintenance that can be attributed to a system 

and are provided by organizations other than the system’s operating units. 

5.0 CONTINUING SYSTEM IMPROVEMENTS

Cost of hardware modifications and software maintenance to keep the system operating and 

operationally current. 

Beneath these five levels, the cost element structure is organized in a hierarchy. Figure 3-1 

presents the next lower level in the hierarchy. Cost estimates, cost reporting, and cost data 

collection may be made at lower levels in the hierarchy, depending on the availability of data. 

Figure 3-1. Second/Third Level of Cost Element Structure

Appendix D provides a mapping from the O&S cost elements to budget appropriations. 
9

The next section explains the types of costs that are included in each major category and 

provides the subcategories at lower levels in the hierarchy. 

3.2 Definitions

The definitions that follow are the ones provided by CAPE for O&S cost estimates and data 

collection. However, this document is a guide, not an instruction; therefore these definitions are 

not mandatory. Compliance is recommended, and deviations from these standard definitions 

should be adequately explained in the cost estimate documentation. 

1.0 UNIT-LEVEL MANPOWER

The Unit-Level Manpower element includes the costs of all operator, maintenance, and 

other support manpower at operating units (or at maintenance and support units that are 

organizationally related and adjacent to the operating units). Unit-Level Manpower includes 

Active, Reserve, and National Guard military, government civilian, and contractor manpower 

costs. 

While the cost elements in this category make the distinction between operators, 

maintainers, and other unit-level manpower, that distinction may not apply to all situations. For 

example, in O&S cost estimates for Navy ships, the ship manpower is typically estimated and 

documented for the entire crew as a whole, and is not broken down into operators, maintainers, 

and other support.

The scope of unit-level manpower consists of the lowest-level operating unit capable of 

independent system operations, and associated augmenting maintenance and support units (if 

any) integral to system operations. For systems owned by deploying units, the scope of unit-level 

manpower includes the operator, maintenance, and other support personnel who are consistently 

deployed with the systems to their deployment locations.1 For example, for an Air Force aircraft, 

the scope of unit-level manpower includes the aircraft operating squadron and associated 

maintenance and support units in the same wing. As another example, for an Army tank, the 

scope of unit-level manpower includes the tank company (resident in an armored brigade combat 

team) and associated maintenance and support companies (resident in a brigade support battalion 

or combat sustainment support battalion supporting the brigade combat team). However, for 

some systems, such as ships, the unit-level concept does not apply, and unit manpower costs are

estimated on an individual system basis.

Costs of military, government civilian, and contractor personnel should be shown 

separately in the estimate of unit-level manpower costs. For contractor manpower, Field Service 

Representatives (FSRs) assigned to support the local unit-level maintenance activities are 

1

 For systems that deploy, the manpower that deploys with the system may be scenario dependent. The scope of 

unit-level manpower in an O&S cost estimate should include only the manpower that routinely deploys with the 

system, regardless of scenario.
10

included in cost element 1.2 (Unit-Level Maintenance), and FSRs assigned to support other local 

unit-level support activities are included in cost element 1.3 (Other Unit-Level). 

The elements of unit-level manpower are defined below.

1.1 Operations

The costs of all military, civilian, and contractor manpower required to operate a system. 

For example:

• Aircraft and Helicopters. Aircrews including pilots, navigators, mission specialists, load 

masters, etc.

• Ships. Ship’s company as specified in the Ship Manning Document (SMD) for each 

class of ship. On ships and submarines, all personnel are considered as both operators 

and maintainers. The costs of all ship personnel are reported under this element (1.1).

• Electronic Systems. Network warfare operator, microwave systems operator, ground 

surveillance radar crewmember.

• Armored Vehicles. Crew chief, commander, gunner, driver, loader.

• Space Systems. Operators at the ground station or similar facility.

For cases in which individuals operate more than one system, or have other duties, 

manpower costs should be allocated on a relative workload (i.e., manhours) basis.

Some types of weapon systems, such as tactical missiles, do not have operations 

manpower.

1.2 Unit-level Maintenance

The costs of all military, civilian, and contractor manpower that performs field-level

maintenance on the system. For the Navy and Air Force, this element consists of the costs of 

organizational maintenance manpower and unit-level intermediate maintenance personnel. The 

costs of intermediate-level maintenance personnel resident in a support organization that is not 

unit-level relative to the operating unit, such as a Navy shore-based Regional Maintenance 

Center, are included in element 3.3 (Intermediate Maintenance (External to Unit-Level)). The 

Army does not conduct intermediate maintenance at the field level, but the field-level manpower 

costs would be captured here. For cases in which individuals maintain more than one system, 

manpower costs should be allocated among the systems on a relative workload (i.e., manhours) 

basis.

1.3 Other Unit-Level

The cost of all military, civilian, and contractor manpower that performs administrative, 

security, logistics, safety, engineering, and other mission support functions at the unit level. 
11

These costs include only the costs of manpower positions that exist to wholly or predominantly 

support the system whose costs are being estimated. For systems that deploy, these costs include 

the costs of manpower positions that routinely deploy to support the system.2

Some examples are:

• Staff. Manpower required for unit command, administration, supervision, operations 

control, planning, scheduling, safety, quality control of crew training, and operational 

proficiency, etc. This may also include staff in a parent organization above the unit 

level where appropriate (i.e., staff is primarily dedicated to the system). 

• Security. Manpower required for system security. Duties may include system-level 

entry control, close and distant boundary support, and security alert operations. (Does 

not include base level access control unless the entire facility exists solely to support 

the weapon system).

• Logistics. Manpower required for logistics support. Functions may include supply, 

transportation, inventory control, fuel handling, etc.

• Ordnance Support. Includes manpower providing munitions handling, weapons 

assembly, etc. Excludes any ordnance support manpower included in element 1.2 (unitlevel maintenance).

• Other Support. Manpower required to provide system-specific fixed and mobile 

communications, information, intelligence, photo interpretation, and other special 

mission support. Note that manpower associated with operations or maintenance of 

simulators or training devices is captured in element 4.7.

For cases in which unit-level individuals support more than one system, manpower costs 

should be allocated among the systems on a relative workload (i.e., manhours) basis.

2.0 UNIT OPERATIONS

Unit Operations consists of the costs of operating material and various support services in 

support of the primary system at the unit level. Unit Operations includes the unit-level 

consumption of operating materials (direct energy, expendable stores, and training munitions),

support services, Temporary Duty travel, and second destination transportation in support of the 

unit. Unit Operations costs provided through a system support contract should be separately 

identified from those provided organically for each cost element.

2

 For example, Air Force aircraft O&S cost estimates for unit-level manpower usually include the costs of security 

police that deploy with the aircraft. In this instance, the security police provide “inside-the-fence” protection 

directly tied to the mission of the aircraft. In contrast, Army tank O&S cost estimates for unit-level manpower 

normally would not include any costs for the sustainment brigade military police. In this instance, the military 

police provide broad “outside-the-fence” support to the theater commander not necessarily tied to the mission of 

the tank.
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2.1 Energy (Fuel, Petroleum, Oil and Electricity)

Costs of fuel, petroleum, oil, and fuel additives used by systems in performing their normal 

missions. For fuel purchased from the Defense Logistics Agency (DLA), these costs include a 

surcharge for DLA overhead and operating expenses (transportation, storage, and inventory 

management). These costs may also include the cost of field-generated electricity and 

commercial electricity necessary to support the operation of a system, when it can be severed 

from the general energy consumption for the location. 

2.2 Training Munitions and Expendable Stores

Costs of the unit-level consumption of training munitions, rockets, missiles, and 

expendable stores in the course of normal peacetime training missions. Includes the cost of live 

and inert ammunition, bombs, rockets, missiles, sonobuoys, and pyrotechnics expended in 

training and non-combat firings such as firepower demonstrations or exercises. This category also 

includes other expendable stores (such as chaff, flares, fuel tanks, and travel pods) that lose their 

identity in use and may be dropped from stock record accounts when issued or used. In some 

cases, may also include the costs of the replacement of war reserve munitions and missiles that 

have reached their shelf life. 

2.3 Support Services

Costs of unit-level support services. These services may vary greatly from one unit to 

another. They may include but are not limited to:

• FSRs who support non-maintenance activities (such as training, data collection, and IT 

support) that are not accounted for in cost element 1.3 (Other Unit-Level Manpower).

• Unreimbursed food services, rations, postal services (postage/box rental), or laundry 

services. 

• Lease or rental of administrative, computational, or support equipment or software.

• Lease costs of special facilities or land (e.g., for the storage of warheads and missiles).

• Unit-funded service contracts for administrative, computational, or support equipment.

• Communications services (e.g., data/voice links, dedicated lines, microwave channels), 

port services, and other unit-funded utilities not part of base operating support costs.

2.4 Temporary Duty (TDY) Travel

Refers to a military service member's or Department of Defense civilian employee's travel 

or other assignment at a location other than the traveler's permanent duty station as authorized by 

the Joint Travel Regulations. This type of assignment is usually of relatively short duration, 
13

typically from two days to 189 days in length. Temporary duty assignments usually come with 

per diem pay, covering lodging, meals, and incidental expenses.

2.5 Second Destination Transportation

Costs of transportation in support of the unit. Typically includes the transportation costs for 

moving equipment, personnel, and supplies to and from training areas, remote operating sites, or 

test ranges. Excludes any transportation costs included in overhead in other cost elements, such 

as the overhead in the depot maintenance cost element for the transportation of systems for depot 

maintenance overhauls.

3.0 MAINTENANCE

Maintenance consists of the costs of labor (outside of the scope of unit-level) and materials 

at all levels of maintenance in support of the primary system. Any maintenance costs provided 

through support contracts should be separately identified from those provided by government

sources for each cost element where applicable.

3.1 Consumables

This element captures the costs for consumables used to operate and maintain the primary 

system at the unit level. Typically, consumables are considered throw-away items (having a 

100% condemnation rate) and are replaced by new items. The term consumables refers to 

materials/parts consumed in the maintenance or support of the primary system; examples include 

temperature sensors, fans, oil filters, valves, switches, probes, coolants, deicing fluids, lubricants, 

gaskets, capacitors, and batteries. Consumables can be system unique or items that are bought in 

bulk for multiple systems. The cost for this element includes the costs of direct material for the 

items, as well as transportation, storage, warehousing, inventory management, and other 

overhead.

Additionally, the costs of all other unit-level consumables are included. Illustrative 

examples include computer supplies, paper, charts, maps, and administrative supplies used for 

housekeeping and health and safety.

3.2 Depot Level Reparables (DLRs)

A DLR is a reparable item/component that is repaired at the depot level of maintenance. 

DLR costs are incurred largely at the unit level. Typically, when a DLR item requires 

maintenance, the item is removed from the system and replaced with another item from 

inventory. This remove and replace action usually takes place at the unit level. When unit 

maintenance turns in a “failed” item/component, that organization is charged with an exchange 

price. This exchange price includes the cost of direct labor and material for item repairs along 

with transportation, storage, inventory management, and other overhead. If unit maintenance 

does not have a “failed” item/component to return to the supply system, that organization is 
14

charged with a standard price. The standard price includes the new item/component purchase 

price along with attrition, transportation, storage, inventory management, and other overhead. 

The DLR element captures the costs of repair of depot level reparable items, as well as the 

replacement of condemned DLR items.

3.3 Intermediate Maintenance (External to Unit-Level)

Consists of the costs of labor, material, and any other costs expended at intermediate 

maintenance locations (such as Navy afloat or ashore Intermediate Maintenance Activities) in 

support of the primary system. This cost element excludes any manpower or material costs for 

intermediate maintenance that is considered unit-level, as described earlier. Includes the costs for 

consumables, government labor, contractor maintenance, and any other intermediate-level 

maintenance costs not otherwise accounted for. 

3.4 Depot Maintenance

Depot maintenance is the cost of labor, material, and overhead incurred in performing 

major overhauls or other similar depot-level maintenance on a system or any of its major end 

items (e.g., aircraft engines) at centralized repair depots, contractor repair facilities, or onsite by 

depot teams.

Some overhaul activities occur at time intervals ranging from several months to several 

years. For primary systems (e.g., aircraft, tracked vehicles, ships), these costs should be included 

in the estimate for the years in which they are expected to occur, accompanied by documentation 

on the cost per event and the time interval between overhaul events. 

Costs of major end items that have different overhaul cycles (i.e., structural subsystems 

such as hull, frame, or airframe; power subsystems such as engines or drive train; and 

electronic/mechanical subsystems such as fire control system, armaments, guidance, or 

command and control equipment) should be estimated and identified separately within this 

element. In some cases, the interval between end item overhauls may be expressed in terms of 

system operating hours (and not calendar time).

4.0 SUSTAINING SUPPORT

This category includes support activities provided by centrally managed organizations 

external to the units that own the operating systems. Sustaining support costs provided through a 

system support contract should be identified separately from those provided organically for each 

cost element. All efforts should be made to collect and report in accordance with this cost 

element structure for sustaining support. However, sustaining support cost elements may be 

combined as necessary if the costs cannot be made available at the level of detail called for in 

this guide.
15

4.1 System-Specific Training

The costs of system-specific specialty training of individuals in the system operating units 

or individuals who are replacing people in the system operating units due to attrition and normal 

rotation3

. Training costs should include the costs of instructors, training support personnel, per 

diem and travel directly associated with the training, and any costs for trainees not accounted for 

elsewhere. For individuals already assigned to a system operating unit, any expenses for the 

travel of individuals from operational units to training assignment, and return, are included in the 

Temporary Duty Travel (element 2.3). The costs of maintenance or periodic refresh of the 

training equipment or devices is accounted for in element 4.7. The two cost elements below 

capture costs for training individuals prior to their first assignment in a system operating unit.

4.1.1 System-Specific Operator Training

The costs for training conducted in units designated as primary training sites for individuals 

to become proficient in specific system knowledge. This includes units such as Air Force wings 

assigned a primary mission of weapon-specific aircrew training, Navy air readiness training 

units, Navy Afloat Training Groups, and the Army Armor Center. These costs do not include 

skill training not related to a specific system, such as undergraduate aviation training. 

4.1.2 System-Specific Maintenance Training

The costs of advanced system-specific training associated with maintenance functions in 

units designated as primary training facilities.

4.2 Support Equipment Replacement and Repair

The costs incurred to replace or repair unit-level support equipment associated with the 

primary system or its major subsystems4. The support equipment (e.g., tools and test sets) may 

be peculiar to the system or it may be common to a number of systems, in which case the costs 

must be allocated among the respective systems. 

4.3 Sustaining/Systems Engineering

Costs reported in this element capture the government and contractor sustaining 

engineering to ensure the continuing viable operation of the system in the deployed environment. 

Most of the sustaining engineering effort during the sustainment phase will be a continuation of 

the earlier systems engineering effort that took place during the program Engineering and 

Manufacturing Development (EMD) phase and the production and deployment phase. Sustaining 

3 This element includes the costs of recurring training activities that occur during the operations and sustainment 

phase. However, the costs of initial training equipment and training course materials are regarded as investment 

costs, and not as an O&S cost. 4 This includes replacement and repair of support equipment. However, the cost of initial support equipment 

procurement is an investment cost, not as an O&S cost.
16

engineering activities may be resident in the system program office organization, and/or they 

may be resident in external organizations. Examples of sustaining engineering activities include 

aircraft structural integrity monitoring or corrosion monitoring; planning and control of technical 

program efforts; continuing system requirements definition; safety and human systems 

integration engineering; obsolescence engineering; configuration management; and continuing 

specialty engineering, such as Reliability and Maintainability (R&M) Engineering. Specific 

modifications to hardware or software are included in element 5.0 (Continuing System 

Improvements). Sustaining engineering costs provided through a system support contract should 

be identified separately from costs associated with organic sources, if possible.

4.4 Program Management5

This element includes government and contractor costs for management activities 

associated with the administrative, business, and financial management of the program. Program 

management activities performed during the sustainment phase are, in most cases, a continuation 

of those performed during the EMD phase and the production and deployment phase. Program 

management activities may be resident in the system program office organization, and/or they 

may be resident in external organizations. Program management provided through a support 

contract should be identified separately from program management provided by organic sources, 

if possible.

4.5 Data and Technical Publications

The costs associated with maintaining and updating deliverable data and technical 

publications and manuals concerning the operation and support of the system6

. 

4.6 Simulator Operations and Repair

Costs to operate and repair simulators and other training devices for the primary system or 

its major subsystems. This consists of the costs of labor, material, and overhead for simulator 

operations and repair. Also includes the cost of periodic replacement of simulator hardware and 

software.

4.7 Other Sustaining Support 

Costs of any sustaining support not otherwise accounted for. This cost element may be 

used to identify expenses such as those listed below, if they apply to the system for which the 

estimate is being made:

• Test and evaluation7 in support of deployed systems, such as range costs, test support, 

data reduction, and test reporting.

5

 Cost elements 4.3 and 4.4 may be combined if these costs cannot be identified separately. 6

 This element addresses only data and publications maintenance. The cost of developing the data and publications 

is normally regarded as an investment cost, and not as an O&S cost.
17

• Air, sea, and land support not funded by the unit and provided by other activities to 

verify the proper operation of an electronic, communication, sensor, or other similar 

system.

• Communication services (e.g., data/voice links, dedicated lines, microwave channels), 

hardware, and software leases purchased on a DoD-wide or Service-wide basis for 

direct system-specific support of a system. Note that communications services 

purchased at the unit-level are contained in element 2.2 (Support Services). 

• Centrally funded purchases for transportation of system materiel (end items and 

secondary items) not otherwise accounted for in the cost element structure. 

It should be noted that costs for firing ranges or training ranges are not usually regarded as 

system costs and are not included in O&S cost estimates.

5.0 CONTINUING SYSTEM IMPROVEMENTS

This portion of the cost element structure includes the costs of hardware and software 

updates that occur after deployment of a system that improve a system's safety, reliability, or 

maintainability, or otherwise enable the system to meet its basic original operational requirements 

throughout its life.

It is intended that cost estimates for these improvements conform to the definitions 

provided in this guide. However, at the present time, the military department VAMOSC systems 

are not able to separate the costs for system improvements that include new operational 

capabilities from the costs for other system improvements. When using VAMOSC cost data in 

developing cost estimates, analysts must use additional data sources and strategies to remove the 

costs of system improvements that provide new operational capabilities. 

These costs include government and contract labor, materials, and overhead costs. Costs 

should be separated into government and contractor costs within each cost element, if applicable.

5.1 Hardware Modifications 

The cost of procurement, and installation of modification kits. May also include costs 

associated with the modifications for support equipment, training equipment, technical 

publications/data, and initial spares and repair parts (consistent with the approved modification 

content). This cost element only includes those modifications needed to achieve acceptable 

safety levels, overcome mission capability deficiencies, improve reliability, reduce maintenance 

costs, or maintain the system service life. It excludes modifications undertaken to provide 

additional operational capability not called for in the original system design or performance 

7

 This is intended to record periodic testing of operational assets, structured to confirm that the system continues to 

retain its operational capabilities. This would not include testing to support development activities or testing 

integral to system hardware modifications or software maintenance.
18

specifications, or extend the system service life beyond what was originally planned. It also 

excludes retrofit modifications that update earlier fielded systems to the latest production 

configuration.

5.2 Software Maintenance 

All cost and effort incurred to alter, sustain, and support the system software baseline. 

Includes software maintenance that changes the software baseline for adaptive, corrective, 

perfective, additive, and preventive maintenance. Includes efforts related to defect corrections, 

modifications, and patches applied to the software and software-specific support activities. Also 

includes costs for software licenses, hosting, and facilities. Excludes the costs of development of 

new requirements that are major enhancements or significant increases in capability.

Appendix A has an optional, more detailed cost element structure for software 

maintenance. This cost element structure includes correction of deficiencies, cybersecurity, 

independent verification and validation, program management, sustaining engineering, facilities, 

certification and accreditation, help desk support, hosting (in a traditional data center or in the 

cloud), and software licenses.
19 

4. DIFFERENT METRICS OF O&S COSTS

4.1 Introduction

Various analyses, reports, and budget documents associated with system O&S costs use a 

wide variety of categorizations and metrics. A lack of standardization on these categorizations 

and metrics has resulted in confusion in their application. The remainder of this chapter is 

intended to clarify this situation.

4.2 O&S Cost Categorizations

A variety of O&S cost categorizations include or exclude different combinations of the 

O&S cost elements. These O&S cost elements, which are defined in Chapter 3, are shown again 

in Figure 4-1. 

Figure 4-1. O&S Cost Elements
20

The remainder of this section provides standardized definitions for the O&S cost 

categorizations (i.e., groups of cost elements) commonly used. These categorizations have been 

developed for different purposes and provide different perspectives on those O&S costs relevant 

to each purpose. Table 4-1 shows the first three categorizations.

Table 4-1. Cost Element Composition of O&S Categorizations

Operating and Support Parts Cost OPTEMPO Programs

1.0 Unit-Level Manpower 1.0 Unit-Level Manpower 1.0 Unit-Level Manpower

 1.1 Operations Manpower 1.1 Operations Manpower 1.1 Operations Manpower

 1.2 Unit-Level Maint Manpower 1.2 Unit-Level Maint Manpower 1.2 Unit-Level Maint Manpower

 1.3 Other Unit-Level Manpower 1.3 Other Unit-Level Manpower 1.3 Other Unit-Level Manpower

2.0 Unit Operations 2.0 Unit Operations 2.0 Unit Operations

 2.1 Energy 2.1 Energy 2.1 Energy

 2.2 Munitions & Stores 2.2 Munitions & Stores 2.2 Munitions & Stores

 2.3 Support Services 2.3 Support Services 2.3 Support Services

 2.4 Temporary Duty Travel 2.4 Temporary Duty Travel 2.4 Temporary Duty Travel

 2.5 2nd Dest. Transportation 2.5 2nd Dest. Transportation 2.5 2nd Dest. Transportation

3.0 Maintenance 3.0 Maintenance 3.0 Maintenance

 3.1 Consumables 3.1 Consumables 3.1 Consumables

 3.2 Depot Level Reparables 3.2 Depot Level Reparables 3.2 Depot Level Reparables

 3.3 Intermediate Maintenance 3.3 Intermediate Maintenance 3.3 Intermediate Maintenance

 3.4 Depot Maintenance 3.4 Depot Maintenance 3.4 Depot Maintenance

4.0 Sustaining Support 4.0 Sustaining Support 4.0 Sustaining Support

 4.1 System-Specific Training 4.1 System-Specific Training 4.1 System-Specific Training

 4.2 SE Replacement and Repair 4.2 SE Replacement and Repair 4.2 SE Replacement and Repair

 4.3 Sust./Systems Engineering 4.3 Sust./Systems Engineering 4.3 Sust./Systems Engineering

 4.4 Program Management 4.4 Program Management 4.4 Program Management

 4.5 Data and Technical Pubs 4.5 Data and Technical Pubs 4.5 Data and Technical Pubs

 4.6 Simulator Ops and Repair 4.6 Simulator Ops and Repair 4.6 Simulator Ops and Repair

 4.7 Other Sustaining Support 4.7 Other Sustaining Support 4.7 Other Sustaining Support

5.0 Continuing Improvements 5.0 Continuing Improvements 5.0 Continuing Improvements

 5.1 Hardware Modifications 5.1 Hardware Modifications 5.1 Hardware Modifications

 5.2 Software Maintenance 5.2 Software Maintenance 5.2 Software Maintenance

The first three categorizations are described below:

• Operating and Support. This categorization is used for most O&S cost estimates and 

reporting of O&S costs in program SARs.

• Parts Cost. This categorization simply captures the parts costs for consumable and 

reparable items. This is often expressed as a cost per unit of usage, where the unit of 

usage is flying hour, vehicle mile, or something similar.
21

• OPTEMPO Programs. This categorization appears in the budget documents that are 

used to justify the military service operating tempo (OPTEMPO) budgets. For example, 

the OP-20 budget exhibit is used for aircraft flying hours, the OP-25 is used for ground 

vehicle operations, and the OP-41 is used for ship operations. These exhibits are further 

described in Appendix E. 

Table 4-2 shows the next three categorizations.

Table 4-2. Cost Element Composition of O&S Categorizations (cont.)

DoD Reimbursement Rates Total Maintenance Logistics Factors

1.0 Unit-Level Manpower 1.0 Unit-Level Manpower 1.0 Unit-Level Manpower

 1.1 Operations Manpower 1.1 Operations Manpower 1.1 Operations Manpower

 1.2 Unit-Level Maint Manpower 1.2 Unit-Level Maint Manpower 1.2 Unit-Level Maint Manpower

 1.3 Other Unit-Level Manpower 1.3 Other Unit-Level Manpower 1.3 Other Unit-Level Manpower

2.0 Unit Operations 2.0 Unit Operations 2.0 Unit Operations

 2.1 Energy 2.1 Energy 2.1 Energy

 2.2 Munitions & Stores 2.2 Munitions & Stores 2.2 Munitions & Stores

 2.3 Support Services 2.3 Support Services 2.3 Support Services

 2.4 Temporary Duty Travel 2.4 Temporary Duty Travel 2.4 Temporary Duty Travel

 2.5 2nd Dest. Transportation 2.5 2nd Dest. Transportation 2.5 2nd Dest. Transportation

3.0 Maintenance 3.0 Maintenance 3.0 Maintenance

 3.1 Consumables 3.1 Consumables 3.1 Consumables

 3.2 Depot Level Reparables 3.2 Depot Level Reparables 3.2 Depot Level Reparables

 3.3 Intermediate Maintenance 3.3 Intermediate Maintenance 3.3 Intermediate Maintenance

 3.4 Depot Maintenance 3.4 Depot Maintenance 3.4 Depot Maintenance

4.0 Sustaining Support 4.0 Sustaining Support 4.0 Sustaining Support

 4.1 System-Specific Training 4.1 System-Specific Training 4.1 System-Specific Training

 4.2 SE Replacement and Repair 4.2 SE Replacement and Repair 4.2 SE Replacement and Repair

 4.3 Sust./Systems Engineering 4.3 Sust./Systems Engineering 4.3 Sust./Systems Engineering

 4.4 Program Management 4.4 Program Management 4.4 Program Management

 4.5 Data and Technical Pubs 4.5 Data and Technical Pubs 4.5 Data and Technical Pubs

 4.6 Simulator Ops and Repair 4.6 Simulator Ops and Repair 4.6 Simulator Ops and Repair

 4.7 Other Sustaining Support 4.7 Other Sustaining Support 4.7 Other Sustaining Support

5.0 Continuing Improvements 5.0 Continuing Improvements 5.0 Continuing Improvements

 5.1 Hardware Modifications 5.1 Hardware Modifications 5.1 Hardware Modifications

 5.2 Software Maintenance 5.2 Software Maintenance 5.2 Software Maintenance

These three categorizations are described below:

• DoD Reimbursement Rates. These costs are used to calculate reimbursement rates 

that are published each year in the annual DoD Fixed Wing and Helicopter 
22

Reimbursement Rates. These forward-looking rates, expressed in terms of dollars per 

flight hour, are used to charge DoD customers that use the aircraft on a costreimbursable basis. The rates are slightly different for non-DoD customers. These rates 

are updated each year, and are posted on the OSD Comptroller website 

(https://comptroller.defense.gov/Financial-Management/Reports). These rates also 

include a portion of CLS that is regarded as variable with respect to flying hours. CLS 

is not an element in the O&S cost element structure, but is used in O&M 

appropriations. DoD 7000.14-R, Financial Management Regulation, Volume 11A, 

Chapter 6, Appendix E provides guidance on the reimbursement rates.

• Total Maintenance. This categorization is used by some organizations to help assess 

the efficiency of a system’s maintenance activities from a broad perspective beyond 

element 3.0. This is often expressed as a cost per unit of usage.

• Logistics Factors. Some organizations use this particular categorization for analyses of 

resources and cost factors for certain weapon system logistics elements.

Table 4-3 shows the last two categorizations.
23

Table 4-3. Cost Element Composition of O&S Categorizations (cont.)

Direct Operating Operational

1.0 Unit-Level Manpower 1.0 Unit-Level Manpower

 1.1 Operations Manpower 1.1 Operations Manpower

 1.2 Unit-Level Maint Manpower 1.2 Unit-Level Maint Manpower

 1.3 Other Unit-Level Manpower 1.3 Other Unit-Level Manpower

2.0 Unit Operations 2.0 Unit Operations

 2.1 Energy 2.1 Energy

 2.2 Munitions & Stores 2.2 Munitions & Stores

 2.3 Support Services 2.3 Support Services

 2.4 Temporary Duty Travel 2.4 Temporary Duty Travel

 2.5 2nd Dest. Transportation 2.5 2nd Dest. Transportation

3.0 Maintenance 3.0 Maintenance

 3.1 Consumables 3.1 Consumables

 3.2 Depot Level Reparables 3.2 Depot Level Reparables

 3.3 Intermediate Maintenance 3.3 Intermediate Maintenance

 3.4 Depot Maintenance 3.4 Depot Maintenance

4.0 Sustaining Support 4.0 Sustaining Support

 4.1 System-Specific Training 4.1 System-Specific Training

 4.2 SE Replacement and Repair 4.2 SE Replacement and Repair

 4.3 Sust./Systems Engineering 4.3 Sust./Systems Engineering

 4.4 Program Management 4.4 Program Management

 4.5 Data and Technical Pubs 4.5 Data and Technical Pubs

 4.6 Simulator Ops and Repair 4.6 Simulator Ops and Repair

 4.7 Other Sustaining Support 4.7 Other Sustaining Support

5.0 Continuing Improvements 5.0 Continuing Improvements

 5.1 Hardware Modifications 5.1 Hardware Modifications

 5.2 Software Maintenance 5.2 Software Maintenance

These two categorizations are described below:

• Direct Operating. This element consists of all of the O&S cost elements except for 

energy, hardware modifications and software maintenance. Some organizations use this 

categorization to help assess the efficiency of a system’s operations and maintenance 

activities (excluding energy). This is often expressed as a cost per unit of usage. 

• Operational. Some organizations use this particular categorization for analyses of 

resources for weapon system operations.

Figures 4-2 and 4-3 summarize the various O&S cost categorizations.
24 

Figure 4-2. O&S Cost Categorizations
25 

Figure 4-3. O&S Cost Categorizations (cont.)

4.3 O&S Cost Metrics

Measuring the magnitude of a system’s O&S costs uses a wide variety of metrics. The most 

common metrics are usually some form of ratio. The numerator in the metric would be the cost 

categorization used. The denominator in the metric would be the unit of measure. 

There are three types of metrics commonly used. The first type of metric is dollars per 

system per year, where a system is an aircraft, vessel, vehicle, or some other type of system. The 

second type of metric is dollars per unit of usage or OPTEMPO. Ship and submarine costs are 

not normally measured this way since “steaming hours” does not represent a consistent unit of 

measure across ship classes and these platforms have a high fixed cost that is largely insensitive 

to steaming hours. The third type of metric is dollars per typical or notional unit per year, where 

the unit is a squadron, platoon, or something equivalent. 

One common use for these metrics is to compare the costs of a new system to its 

antecedent system or other systems. O&S cost metrics can be useful when comparing different 

systems, but such comparisons have to be made and conveyed carefully. When comparisons are 
26

made without due diligence, confusion occurs and erroneous conclusions can be reached. This 

section provides some examples where such problems have commonly happened.

As one example, senior leaders may ask for data on cost per unit of usage, something like 

cost per flight hour for a group of similar systems. However, the leaders typically do not specify 

the categorization or content that should be used for the cost (numerator) in the metric. A term 

such as cost per flying hour means something different to different people. Some people in one 

part of the leader’s organization might respond with a reimbursement rate, and other people in 

another part of the organization might respond with the complete O&S cost. 

Figures 4-4 and 4-5 show an example of how the use of different categorizations produce 

very different results for cost per system per year, and cost per flying hour, for an aircraft.

Figure 4-4. Examples of Aircraft O&S Cost Metrics
27 

Figure 4-5. Examples of Aircraft O&S Cost Metrics (cont.)

Note that the values for cost per aircraft per year are displayed using the vertical axis on the 

left, and the values for cost per flying hour are displayed using the vertical axis on the right. 

Other issues can arise with O&S cost metrics even when the same categorization is used. 

Even in such cases, the cost per unit of usage for different systems is usually not comparable 

when the systems have different usage or OPTEMPO rates. Not all of the CAPE O&S cost 

elements would vary with changes in usage, and therefore would remain fixed. The cost elements 

in the OPTEMPO Programs categorization (fuel, consumables, and DLRs) and the costs for 

training munitions and expendable stores are those most likely to vary with changes to system 

usage on a total cost basis, but remain constant on a cost per unit of usage basis. Some cost 

elements such as unit-level manpower, depot maintenance, and hardware modifications do not 

vary with usage, but do vary with changes in system quantity. And other costs, much of the 

sustaining support and software maintenance, for the most part do not vary with changes in usage 

or system quantity. 

Figure 4-6 shows the effect of changes to system usage on some O&S cost metrics for an 

aircraft system.
28 

Figure 4-6. Effect of System Usage on O&S Cost Metrics 

In this example, there are two O&S cost metrics. The first is $ million/aircraft/year, and the 

second is $/flight hour. The two metrics are displayed for increasing levels of system usage, 

ranging from 250 to 650 flight hours/aircraft/year. The $ million/aircraft values are displayed 

using the vertical axis on the left, and the $/flight hour values are displayed using the vertical 

axis on the right. The key point here is that the values of the $/flight hour metric decrease with 

increases in flying hours. This is because the fixed O&S cost elements are being divided over a 

larger base. Cost per unit of usage and cost per system per year can be useful, but have 

limitations. It is best to use an array of metrics along with total costs when conveying the 

comparative costs of systems.

The key point is that when making comparisons between systems with different usage 

rates, and comparing those on a cost per unit of usage, normalizing for usage should be 

considered when the systems are similar and have similar missions. Figure 4-7 shows an 

example of a normalization technique. 
29 

Figure 4-7. Example of Normalization of $/Flight Hour Metric

In this example, a comparison of O&S costs is being made between two aircraft with 

different usage (flying hour) rates. As before, $ million/aircraft/year is displayed using the 

vertical axis on the left, and the $/flight hour is displayed using the vertical axis on the right. 

Without normalization, the $/flight hour metric is seriously distorted and misleading. In this 

example, without normalization, the $ million/aircraft for Aircraft 2 is roughly 25 percent less 

than for Aircraft 1, and yet the $/flying hour for Aircraft 2 is only 3 percent less than for 

Aircraft 1. 

With normalization of usage rate, it is possible to make more meaningful comparisons 

between Aircraft 1 and Aircraft 2. In this example, the normalization is made by recalculating 

the $/flight hour for the Aircraft 2 active duty using the same flying hour rate as the Aircraft 1 

active duty aircraft. This was done by assuming that four cost elements (fuel, training munitions, 

consumables, and DLRs) vary with changes in flying hours on a total cost basis, but remain 

constant on a dollar per flight hour basis. It was also assumed that the other cost elements do not 

vary with changes in flying hours. This allows a more accurate comparison of the relative costs 

between Aircraft 1 and Aircraft 2. With normalization, both the $ million/aircraft and the 

$/flying hour for Aircraft 2 are roughly 15 percent less than for Aircraft 1. 
30 

More generally, O&S cost metrics can easily be misapplied and muddled, leading to 

erroneous comparisons and conclusions. There are two reasons for such confusion. First, any 

O&S cost metric is based on a given categorization. Second, it also depends on many different 

ground rules and assumptions. The confusion arises when the categorizations and ground rules 

are not clearly identified. Figure 4-8 provides an example of a $K/flight hour metric for an 

aircraft system.

Figure 4-8. Example of Various $/Flight Hour Metrics

In this example, there are six versions of the $K/flight hour metric, each with a significantly 

different numerical value. The differences arise due to dissimilar data sources, year dollars, 

timeframe of the metric, categorizations, and assumed usage or OPTEMPO. 

The use of consistent, well-defined metrics normalized for major usage differences is 

important in communicating comparisons across weapon systems with senior leaders. It is a best 

practice in presenting these metrics to provide an accompanying description of the metric and 

normalization used to develop the comparison. Analysts should select the appropriate metric and 
31

make normalization when necessary to ensure large usage or quantity differences do not mislead 

the audience.
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33

5. ROLE OF O&S COSTS

5.1 Acquisition Milestone and Other Reviews

For Major Defense Acquisition Programs (MDAPs)—which are one type of Major 

Capability Acquisition programs—life-cycle cost estimates are required to be presented to the 

Milestone Decision Authority (MDA) in advance of milestone reviews, and O&S costs are an 

important element in these estimates. Normally, in fact, there are two estimates that are prepared 

for these reviews. One estimate is the Component Cost Position (CCP), and the other estimate is 

an Independent Cost Estimate (ICE) prepared by either CAPE or the responsible Service cost 

agency or Defense Agency equivalent. When the preparation of the ICE is delegated by CAPE to 

the Component, CAPE reviews and approves the ICE. In cases where the ICE is delegated, the 

ICE may be incorporated into the CCP. For other acquisition programs below MDAP8 dollar 

thresholds, cost estimates are prepared in accordance with guidance issued by each Service cost 

agency or Defense Agency equivalent.

Life-cycle cost estimates are also required for Middle Tier of Acquisition (MTA) 

programs. The MTA process provides two possible acquisition pathways: (1) rapid prototyping 

(prototypes with innovative technologies), and (2) rapid fielding (new or upgraded systems with 

minimal development). For the rapid prototyping programs likely to exceed MDAP dollar 

thresholds, CAPE will prepare an estimate of life-cycle costs for the program, or choose to 

delegate the authority for the conduct of the cost estimate to the Service cost agency or Defense 

Agency equivalent. For the rapid prototyping programs below the MDAP dollar thresholds, cost 

estimates will be prepared in accordance with guidance issued by the responsible Service cost 

agency or Defense Agency equivalent. For the rapid fielding programs likely to exceed MDAP 

or major system9 dollar thresholds, CAPE will prepare an estimate of life-cycle costs for the 

program, or choose to delegate the authority for the conduct of the cost estimate to the Service 

cost agency or Defense Agency equivalent. For the rapid fielding programs below the major 

system dollar thresholds, estimates will be prepared in accordance with guidance issued by the 

responsible Service cost agency or Defense Agency equivalent.

Further details on CAPE policy and guidance for cost estimates for MDAPs and MTA 

programs are provided in DoD Instruction (DoDI) 5000.73, Cost Analysis Guidance and 

Procedures.

8 An MDAP is a program with expenditures expected to exceed $525 million (FY 2020 constant dollars) for 

research, development, test and evaluation, or $3.065 billion (FY 2020 constant dollars) for procurement.

9 A major system is a program with expenditures expected to exceed $200 million (FY 2020 constant dollars) for 

research, development, test and evaluation, or $920 million (FY 2020 constant dollars) for procurement.
34

5.2 Sustainment Reviews

Recent legislation now requires that each military department shall conduct a sustainment 

review of each major weapon system not later than five years after declaration of initial 

operational capability (IOC) and throughout its life cycle. Each sustainment review is required to 

include an ICE for the remainder of the life cycle of the program. Appendix E provides further 

information on sustainment reviews.

5.3 Other Roles of O&S Cost Estimates and Analyses

Over the years, the Congress has established extensive and demanding statutory 

requirements pertaining to O&S cost estimation, as well as sustainment or product support 

management, for major DoD weapon systems. There is also extensive regulatory guidance 

concerning the current DoD implementation of these statutory requirements, as well as other 

O&S and sustainment policy and procedures. The statutory and regulatory guidance associated 

with O&S cost analyses, sustainment considerations in system acquisition, and development of a 

product support strategy for major weapon systems is provided in Appendix H of this guide.

In particular, O&S cost analyses are to be used to influence system design with an 

emphasis on sustainment considerations. For all MDAPs, objectives and thresholds for 

reliability, availability, and maintainability are to be established as requirements to support 

system development. These requirements are to be established by trade studies that balance 

sustainment considerations with acquisition cost and what is achievable based on available 

technologies. O&S cost analyses also are to support design decisions to ensure that sustainment 

factors are fully considered at key life-cycle management decision points and that appropriate 

measures are taken to reduce O&S costs by influencing system design early in development, 

developing sound sustainment strategies, and addressing key drivers of costs.

Appendix H provides additional discussion about the role of O&S costs in the Joint 

Capabilities Integration and Development System (JCIDS).

Distinct from the ICE and CCP, program managers are required to develop a “should cost” 

estimate that is used as a management tool to control and reduce cost. “Should cost” 

management is intended to proactively target cost reduction and drive productivity 

improvements into programs. The “should cost” estimate challenges managers to identify and 

achieve savings below budgeted most-likely costs. For system sustainment, “should cost” targets 

will be established and reviewed annually based on an analysis of acquisition logistics costs and 

O&S cost elements. Guidance on “should cost” management is provided in DoDI 5000.85, 

Major Capability Acquisition. 

5.4 Selected Acquisition Report

Estimates of O&S costs are updated each year for inclusion in the annual program Selected 

Acquisition Report (SAR). The SAR includes a comparison between the program and an 
35

antecedent system (if applicable). This comparison is shown using a unitized cost metric. The 

most common unitized cost metric is $/system/year. Other unitized cost metrics are $/unit of 

usage and $/typical unit/year. In addition, the SAR provides a comparison between the current 

O&S cost estimate and the SAR baseline objective and threshold values for total O&S costs. The 

SAR O&S reporting also includes a cost variance that identifies each change, and the reason for 

it, between the current estimate and the prior estimate. Information on SAR reporting can be 

found in the Annual Selected Acquisition Report Guidance. This guidance states that the O&S 

costs reported in the SAR should conform to the cost element structure provided in this guide.
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37

6. SOURCES OF O&S COST DATA

This chapter describes some sources of O&S cost data that are commonly used in cost 

estimates.

6.1 VAMOSC Program

6.1.1 Background

Each military department has its own unique VAMOSC data system that tracks actual O&S 

costs for major weapon systems. The systems display time-phased data, at various levels of 

detail, by functional cost element (such as depot maintenance, fuel, consumables, and so forth). 

Each VAMOSC system provides not only cost data, but related non-cost data (such as system 

quantities and OPTEMPO) as well. VAMOSC users can analyze trends in O&S costs for each 

major system, and identify and assess major cost drivers. Each military department manages its 

own VAMOSC data system as follows: 

• The Air Force VAMOSC system is known as the Air Force Total Ownership Cost 

(AFTOC) system. AFTOC provides O&S cost data for all manned and unmanned 

aircraft; aircraft engines; missiles; munitions; command, control, and communication 

systems; space systems; and other miscellaneous systems and programs. It also 

provides supplementary data such as aircraft quantities and flying hours, fuel 

consumption, numbers of personnel by skill/function, and other non-cost information. 

AFTOC is managed by the Deputy Assistant Secretary of the Air Force for Cost and 

Economics. See https://aftoc.hill.af.mil for additional information.

• The Army VAMOSC system is known as the Operating and Support Management and 

Information System (OSMIS). OSMIS provides O&S cost data for aviation, tracked 

and wheeled combat vehicles, artillery systems, engineering and construction 

equipment, communication and electronic systems, and other tactical systems and 

equipment. It also provides supplementary data such as system quantities; vehicle 

miles; aircraft flying hours; consumption for repair parts, fuel, and ammunition; and 

man-hours for intermediate and depot maintenance. OSMIS is managed by the Deputy 

Assistant Secretary of the Army for Cost and Economics. See 

https://www.osmisweb.army.mil for additional information. 

• The Department of the Navy system is known as Naval VAMOSC and includes both 

Navy and Marine Corps platforms and systems. Naval VAMOSC provides O&S cost 

data for ships and shipboard systems, Navy and Marine Corps aircraft, weapons 

(missiles and torpedoes), military and civilian personnel, facilities, and Marine Corps 
38

ground systems. Naval VAMOSC also provides key non-cost data such as personnel 

counts for ship crews and aircraft Type Model Series, system quantities, flying 

hours/ship steaming days, fuel consumption, and maintenance hours/days. Naval

VAMOSC is managed by the Naval Center for Cost Analysis. See 

https://www.vamosc.navy.mil for more information. 

The military departments provide training and documentation to their VAMOSC users. The 

training material consists of on-site presentations and online videos. The documentation consists 

of extensive user guides and manuals.

6.1.2 CAPE Policy Guidance

DoDI 5000.73, Cost Analysis Guidance and Procedures, provides the policy guidance for 

the military department VAMOSC systems. This guidance requires each military department to 

collect and manage actual O&S cost data for its fielded major systems. Each military department 

is responsible for the design, maintenance, administration, and quality control of its O&S cost 

data system and will make its VAMOSC data readily available to its registered users—DoD 

government personnel and contractor personnel when endorsed by an appropriate government 

sponsor—through online access. CAPE promotes standardization of O&S cost data collection, 

provides a forum for the exchange of ideas and research, and encourages the effective use of 

VAMOSC data in O&S cost estimates. The Deputy Director for Cost Assessment convenes and 

conducts annual reviews of the military departments’ VAMOSC programs.

The VAMOSC systems should also use a documented and well-defined taxonomy or cost 

element structure. Cost element structures categorize and define specific cost elements that in 

total constitute the full range of potential O&S costs for any defense system. To the greatest 

extent feasible, the VAMOSC systems should support the CAPE cost element structure provided 

in Chapter 3 of this guide. 

6.1.3 EVAMOSC

Recent significant legislation pertaining to weapon system O&S costs and associated O&S 

cost data systems created new VAMOSC requirements. Section 836 (Codification of 

Requirements Pertaining to Assessment, Management, and Control of Operating and Support 

Costs for Major Weapon Systems) of the National Defense Authorization Act (NDAA) for 

FY 2018 established that the DCAPE shall be responsible for developing and maintaining a 

database on (1) operating and support cost estimates, (2) supporting documentation, and (3) 

actual operating and support costs for major weapon systems. In addition, Section 832 

(Implementation of Recommendations of the Independent Study on Consideration of 

Sustainment in Weapon Systems Life Cycle) of the NDAA for FY 2019 requires the Secretary of 

Defense to commence implementation of each recommendation of an independent assessment 

conducted by the MITRE Corporation (of the extent to which sustainment matters are considered 

in decisions related to requirements, acquisition, cost estimating, programming and budgeting, 
39

and research and development for MDAPs). The MITRE recommendations pertaining to O&S 

cost data systems are for DoD to:

• Develop a common data repository for all sustainment-related data.

• Create and implement common data definitions, structure, and business rules for 

sustainment cost data.

• Provide a consistent, predictable funding stream for O&S cost databases, prioritizing 

department-wide accessibility.

• Develop a common data structure, taxonomy, and data dictionary for all three 

VAMOSC systems.

• Establish a common logon procedure for the VAMOSC systems and the Cost 

Assessment Data Enterprise (CADE1

) data system.

As a result, CAPE has a statutory mandate to develop a comprehensive enterprise-wide 

O&S cost data system. The implementing solution is known as the Enterprise VAMOSC 

(EVAMOSC) system. This requirement presents an opportunity to address gaps in coverage 

from the current VAMOSC systems and serve a wider user community. CAPE formed a 

VAMOSC Data Working Group with the military departments. The vision is to collaboratively 

develop and implement a common taxonomy, data definitions, and business rules as 

collaboratively defined by the DoD cost community and codified in policy. To date, pilot 

programs have been used to establish and demonstrate preliminary concepts for the data 

structures and definitions that will establish data standardization across DoD. In the future,

CAPE will award a contract for database design, implementation, and data platform services. 

This platform will incorporate modern data fusion and analytics technologies for ingesting, 

aggregating, standardizing, visualizing, reporting, and securing a large amount of data from an 

array of systems, including the current military department VAMOSC systems. Development of 

the EVAMOSC platform will occur incrementally between 2020 and 2025.

As an interim measure, CAPE is developing a Consolidated VAMOSC Tool (CVT) that 

allows each military department’s VAMOSC data to be retrieved and analyzed in a common 

framework using a common tool. The first version of this tool was made available in August 

2019, and is applicable to Navy ships and aircraft, Air Force aircraft, and all Army weapon 

systems. The tool can convert military department VAMOSC cost and programmatic data into 

the standard OSD CAPE structure. It can also calculate commonly used cost metrics and display 

the data graphically.

6.2 Cost Reporting for Sustainment Contracts

6.2.1 Background

1 Information on CADE can be found at the CADE public website at https://cade.osd.mil.
40

Section 832 (Assessment, Management and Control of Operating and Support Costs for 

Major Weapon Systems) of the NDAA for FY 2012 directed that DoD will establish standard 

requirements for the collection and reporting of data on O&S costs in an appropriate format for 

major weapon systems by contractors performing weapon system sustainment functions, and 

develop contract clauses to ensure that contractors comply with such requirements. In response, 

CAPE has implemented the initiatives described in the remainder of this chapter. The details of 

the CAPE implementation guidance are provided in DoDI 5000.73.

6.2.2 CSDR for Sustainment

In 2012, CAPE extended Cost and Software Data Reporting (CSDR) data collection to 

apply to most major weapon system sustainment contracts and subcontracts above specified 

dollar thresholds. This reporting is important because the military department VAMOSC systems 

provide limited visibility into actual costs when a weapon system is sustained through a CLS 

contract or a similar arrangement. The VAMOSC systems may in some cases collect and display 

CLS costs in aggregate, but without providing any details by cost element, such as depot 

maintenance or sustaining engineering. Since then, CAPE has continued to improve the 

collection and reporting of contractor actual costs for major sustainment, logistics, and 

maintenance contracts.

Most recently, cost data reporting for sustainment contracts has been modernized by an 

initiative known as FlexFiles. In Flexfile reporting, monthly time-phased data (dollars and hours) 

are submitted directly from contractor’s accounting systems at a low-level of detail (i.e., account, 

work package, or charge code) that is below the WBS level of detail. The data are submitted 

using the contractor native functional categories for direct costs and overhead. Flexfile reporting 

provides continuity with the prior reporting by requiring tags (based on a contractor allocation) 

to the standard government WBS and functional categories. Additional information on the 

FlexFiles initiative is available on the CADE public website at 

https://cade.osd.mil/policy/flexfile.

Figure 6-1 shows the structure of the Flexfile report for sustainment.
41 

Figure 6-1. Flexfile Report for Sustainment Data Elements

CAPE and the Service cost agencies have developed templates for CSDR plans for each 

weapon system commodity type (such as aircraft, electronic system, or missile). These templates 

are known as standard plans. There is also a standard plan for the Cost Data Summary Report for 

sustainment. The standard plans are available on the CADE public website at 

https://cade.osd.mil/policy/csdr-plan. The sustainment standard plan provides the WBS that is 

used in sustainment cost reporting. Figure 6-2 provides an extract of the standard plan WBS for 

maintenance (O&S cost element 3.0). 
42 

Figure 6-2. CSDR Sustainment WBS for Maintenance

The entire CSDR contractor WBS for sustainment for all of the O&S cost elements is 

provided in the standard plan for sustainment. This WBS is consistent with the O&S cost 

element structure provided in Chapter 3 of this guide, but provides considerably more detail.

The Flexfile report also stratifies the data by standard functional categories for direct labor, 

material, and overhead. Using pivot tables, the analyst can structure the data where the WBS 

elements can be displayed as rows in a matrix, and the functional categories can be displayed as 

columns. Figure 6-3 provides the standard functional categories for sustainment. 
43 

Figure 6-3. CSDR Standard Functional Categories for Sustainment

CSDR reporting for sustainment is required on major contracts, subcontracts, and 

government-performed efforts worth more than $50 million (then-year dollars) for current and 

former MDAPs and major systems. Commercial items are exempt if the program manager

requests and obtains approval from CAPE for a reporting waiver. Additional information on 

CSDR sustainment data can be found on the CADE public website at 

https://cade.osd.mil/policy/sustainment. 

6.2.3 Maintenance and Repair Parts Data Report

An additional data report known as the Maintenance and Repair Parts Data Report has been 

developed to collect detailed cost and technical data for maintenance events and repair parts, 

similar to the data already collected by maintenance data collection systems for major weapon 

systems supported under organic maintenance. This report will collect for each maintenance 

event (1) maintenance data such as reason for failure, maintenance type, and labor hours; and (2) 

repair data such as the name and repair or replacement cost of the repair part. 

Figure 6-4 provides the structure for this report.
44 

Figure 6-4. Maintenance and Repair Parts Report Data Elements

The latest version was completed in November 2017. A Maintenance and Repair Parts Data 

Report is required on all sustainment contracts and government-performed efforts worth more 

than $50 million (then-year dollars) for programs that exceed MDAP and major system level 

thresholds when equivalent information cannot be provided by the program manager. The 

various acronyms shown in Figure 6-4 are spelled out in the Abbreviations section of this guide. 

Additional information on the Maintenance and Repair Parts Data Report can be found on the 

CADE public website at https://cade.osd.mil/policy/maintandrepair. 

6.2.4 Contractor Reporting for Software Maintenance

The Software Resources Data Reporting (SRDR) system collects software cost metrics data 

(such as software size, schedule, and labor hours) for software development efforts (contracts, 

subcontracts, and government-performed efforts) valued at more than $20 million (then-year 

dollars), for programs that exceed MDAP and major system dollar thresholds, and MTA 

programs anticipated to exceed $100 million (then-year dollars) in acquisition expenditures. 

SRDR reporting has been expanded to include major software maintenance activity. SRDR 
45 

reporting for maintenance is required for contracts, subcontracts, and government-performed 

efforts for programs with previous SRDR development reporting, software maintenance efforts 

of more than $20 million, and programs that exceed MDAP and major system level thresholds. 

Figure 6-5 provides the structure for this report.

Figure 6-5. Software Maintenance Report Data Elements

Additional information about the software maintenance report can be found on the CADE 

public website at https://cade.osd.mil/policy/srdr.
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47

7. O&S COST ESTIMATING PROCESS

7.1 Introduction

This chapter describes a recommended analytic approach for planning, conducting, 

documenting, and presenting an O&S cost estimate. 

A more comprehensive discussion on the cost estimating process in general is provided in 

the DoD Cost Estimating Guide. The guide provides important background, including a review 

of relevant policy established in statutes and instructions, and an explanation of standard cost 

terms and definitions. The Guide takes the reader through each critical step in the cost estimating 

process: (1) program definition, (2) cost estimate planning, and the establishment of the basis for 

the cost estimate (3) identification, collection, and validation of data, (4) selection of estimating 

methods and models, (5) model validation and sensitivity analysis, (6) risk and uncertainty, and 

(7) documentation and presentation of results. The Guide also provides an extensive list of 

references, including various best practices checklists, and relevant training and education 

opportunities at Defense Acquisition University and other institutions. The intent of this chapter 

is to augment (not replace) the guide with additional discussion focused on O&S cost estimation.

Figure 7-1 shows the recommended analytic approach for the O&S cost estimating process. 
48 

Figure 7-1. Recommended O&S Cost Estimating Process

The remainder of this chapter describes this process further. 

7.2 Program Definition

7.2.1 System and Support Descriptions

One of the early steps in a cost estimate is to define the system characteristics and program 

content (i.e., describe what it is that will be costed). Figure 7-2 provides a list of the topics that 

are commonly addressed prior to the initiation of an O&S cost estimate. 
49 

Figure 7-2. Typical System Characteristics and Program Content

For MDAPs approaching an acquisition milestone review, the program office is required to 

define its program in a comprehensive formal written document known as a Cost Analysis 

Requirements Description (CARD). The CARD narrative document is augmented by a CARD 

table that provides the key technical, programmatic, and operational characteristics of an 

acquisition program using concise tabular entries for the data. CAPE has developed CARD table 

templates for each commodity type (aircraft, ground vehicle, etc.). Guidance for the CARD 

document and CARD table templates is available on the CAPE public website at 

https://cade.osd.mil/policy/card. The CARD is also required for sustainment reviews. For MTA 

programs, the CARD is not required; however, the program management office is required to 

submit a program description with sufficient level of detail upon which to base a cost estimate. 

For other programs preparing an O&S cost estimate, an abbreviated version of the CARD 

format, with appropriate tailoring, provides a useful and flexible framework for developing a 

written program description suitable to support an O&S cost estimate.

There may be other program documents besides the CARD that can be referenced for 

program definition. Examples include the Product Support Strategy, Acquisition Strategy, or 
50

Independent Logistics Assessment. However, it is important to verify that any other source 

documents are current and not in conflict with the CARD.

In cases where there are gaps or uncertainties in the various program descriptions, this 

should be acknowledged in the written document. This applies to uncertainties in either general 

program concepts or specific program data. For uncertainties in program concepts, one or more 

specific candidate concepts (such as organic versus contractor depot maintenance concepts) 

should be assumed for cost estimation purposes. For uncertainties in numerical data, ranges that 

bound the likely values (such as low, most likely, and high estimates of system reliability) should 

be included. Any assumptions made should be coordinated with the program subject-matter 

experts and other stakeholders. Dealing with program uncertainty will facilitate future sensitivity 

analyses in the O&S cost estimate. 

7.2.2 Cost Element Structure

Another early step in the O&S cost estimating process is the establishment of the cost 

element structure that will be used as the format for the estimate. The cost element structure 

describes and defines the specific elements to be included in the O&S cost estimate in a 

disciplined hierarchy. Using a formal cost element structure (prepared and coordinated in 

advance of the actual estimating) identifies all of the costs to be considered, and organizes the 

estimate results. In instances with both program office and independent cost estimates, a 

common cost element structure facilitates meaningful comparisons. 

One of the decisions in the choice of the cost element structure is the level of detail for the 

estimate. For programs early in the acquisition process, the cost element structure will typically 

be less detailed. For more mature programs, the cost element structure will typically be more 

detailed.

Chapter 3 of this guide describes the standard CAPE cost element structure, with associated 

terms and definitions, which the components should use when presenting O&S cost estimates to 

OSD, including the display of system O&S cost estimates in the program SAR.

Appendix C describes the WBS taxonomy that is used for acquisition logistics costs.

7.3 Cost Estimating Plan

7.3.1 Purpose and Scope

The plan for the estimate should describe the intended use of, and the target audience for, 

the cost estimate. Some of the possible purposes for an O&S cost estimate include the following: 

a milestone or other review in the acquisition process, a sustainment review, support to cost 

versus capability trades or Analyses of Alternatives (AoAs), support to the product support 

strategy business case analysis, and the development of a program or budget estimate for 

sustainment resources. The scope of the estimate identifies the level of detail and fidelity that are 
51

required to achieve the purpose of the estimate. The purpose and scope determine the resources 

required to complete the remaining steps of the cost estimating process. 

The plan will also include a preliminary assessment of required data necessary to support 

the cost estimate. However, data needs and availability are not always clear at the beginning, and 

data requirements and sources often evolve during the development of the estimate. Issues 

pertaining to O&S cost data are discussed later in this chapter.

7.3.2 Ground Rules and Assumptions

There are usually several ground rules that must be established and assumptions that must 

be made before the actual O&S cost estimating can begin. Ground rules are guidance from 

program management or understandings from program subject matter experts that characterize 

the program. Assumptions are additional presumptions made by the cost analyst as necessary.

The analyst should coordinate the assumptions with all stakeholders. Additional discussion about 

ground rules and assumptions, including examples, is provided in the DoD Cost Estimating 

Guide. Some of the common ground rules and assumptions that need to be documented are:

System Life. The term system life, sometimes called expected service life, refers to the 

duration of the system sustainment phase. For most O&S cost estimates, the estimate should extend 

over the full life expectancy of the system. Figure 7-3 and Figure 7-4 display representative life 

expectancies for some of the common classes of major weapon systems. These numbers are taken

from actual current programs as documented in their December 2019 SARs and from historical 

programs as documented in the last SAR for that program. These numbers are illustrative and are 

not necessarily intended to be prescriptive for future programs. Actual life expectancies will vary, 

and will depend on the system’s fatigue/durability requirements or specifications. For many 

programs, the planned service life can be found in the CARD. Any assumptions about mid-life 

upgrades or service life extension programs that are associated with the current planned system life 

also should be noted. 
52 

Figure 7-3. Nominal System Life Durations
53 

Figure 7-4. Nominal System Life Durations (cont.)

O&S Phasing. The O&S phasing will include a phase-in period, the period during which 

the system is in steady-state operations, and a phase-out period. The timing of these three periods 

should be consistent with the planned deployment and retirement schedule. Figure 7-5 provides an 

example of this phasing for a system with a 20-year life expectancy. In this example, the program 

has a 4-year phase-in period, 16 years of steady-state operations with an inventory of 50 systems, 

and a 4-year phase-out period. 
54

Figure 7-5. Example of O&S Phasing Convention

Year Dollars/Inflation/Price Escalation. Inflation refers to an increase in the general 

price level across the economy as a whole. To account for inflation in budgeting and cost 

estimates, each year the Under Secretary of Defense (Comptroller) issues inflation guidance 

derived from forecasts made by the administration and issued by the Office of Management and 

Budget (OMB).

Price escalation refers to changes in prices of a specific good or service—in other words,

any economic activity smaller in scope than the economy as a whole. Escalation accounts for not

only inflation, but also any real price change experienced in such an economic activity. 

The cost community now considers the use of both inflation and appropriate escalation 

indices in cost estimates to be a best practice. This approach is intended to provide the most 

realistic forecast of future prices, taking specific markets, products, and contractors into 

consideration. To institutionalize this practice throughout the Department, CAPE published 

Inflation and Escalation Best Practices for Cost Analysts in April 2016. CAPE then continued to 

work with the military department cost organizations to implement these best practices. A second 

publication, Inflation and Escalation Best Practices for Cost Analysis: Analyst Handbook, was 

published in January 2017. This document is a more in-depth handbook explaining specific 

processes, computations, and data sources that analysts can use in the preparation and 

documentation of inflation and price escalation in cost estimates. This information is important 

for weapon system cost estimates, program cost reporting thresholds, and general programming 

and budgeting. At the time of the publication of this guide, the two inflation and escalation 

publications are being updated to clarify terminology and include more step-by-step instructions. 
55

The handbook also provides links to the latest inflation calculators. These current publications 

are available on the CAPE website (https://www.cape.osd.mil) at “Public Reports.” 

Inflation and price escalation are especially important in O&S cost estimating due to the 

long time periods over which costs can grow. Analysts should assess the sensitivity of their 

estimates to their long-term inflation and escalation assumptions, and adhere to established best 

practices to ensure all inputs are normalized properly. Although all costs to be used for budgeting 

must be reported in then-year dollars, analysts may also wish to present some information in 

constant-year dollars or constant prices to remove the effects of inflation and price escalation

(the combined effects of inflation and real price change), respectively; in some cases,

normalizing for these forces helps visualize trends and cost drivers. Constant-year dollars should 

also be used to set program baseline values. 

The indices used to adjust for inflation or price escalation should be specified and 

documented. See Figure 7-6 below for a general guide on the indices to use for reporting O&S 

costs, and refer to the Inflation and Escalation Best Practices for Cost Analysis: Analyst 

Handbook for more detailed guidance on how to apply inflation and price escalation in cost 

estimates. 

Figure 7-6. Inflation/Escalation Index Selection Guide

For example, an estimate of military pay costs would require both a military pay index 

(escalation) and the GDP deflator. Given a salary of $100,000 in FY 2021 (Constant Price, or 

CP21$), an analyst must provide then-year (TY$) and constant-year 2021 (CY21$) estimates of 

the same person’s salary in FY 2022-2025. Indices from the FY 2021 President’s Budget Green 

Book are provided below, along with the annual estimate results; the CY21$ estimate preserves 

the forecasted real price change, or the portion of military pay escalation that is not explained by 

TY$→TY$ TY$→CY$

Appropriation / Cost Category (Forecasting Escalation) (Removing Inflation)

RDT&E RDT&E Escalation 

(Weighted by RDT&E Outlays)

GDP Deflator 

(Weighted by RDT&E Outlays)

Procurement Procurement Escalation 

(Weighted by Procurement Outlays)

GDP Deflator 

(Weighted by Procurement Outlays)

Military Personnel Military Personnel Escalation 

(Raw)

GDP Deflator 

(Raw)

Civilian Personnel Civilian Personnel Escalation 

(Raw)

GDP Deflator 

(Raw)

Fuel Fuel Escalation 

(Raw)

GDP Deflator 

(Raw)

Operations & Maintenance 

(excluding personnel & fuel)

O&M Escalation 

(Weighted by O&M Outlays)

GDP Deflator 

(Weighted by O&M Outlays)

INDEX SELECTION GUIDE
56

inflation. Note that the selection of an index with a base year matching that of the CY$ estimate 

simplifies the calculations, and the use of an index with a different base year would require 

additional calculations (see the Inflation and Escalation Best Practices for Cost Analysis: 

Analyst Handbook for further guidance).

Fiscal 

Year

Salary Input

(CP21$)

2021 Military 

Pay Index 

(Escalation)

2021 GDP 

Deflator 

(Inflation)

TY$ Estimate

(multiply CP$ by 

escalation index)

CY21$ Estimate

(divide TY$ by 

inflation index)

2021 100,000 1.0000 1.0000 = 100,000 * 1.0000

= 100,000

= 100,000 / 1.0000

= 100,000

2022 100,000 1.0270 1.0200 = 100,000 * 1.0270

= 102,700

= 102,700 / 1.0200

= 100,686

2023 100,000 1.0537 1.0404 = 100,000 * 1.0537

= 105,370

= 105,370 / 1.0404

= 101,278

2024 100,000 1.0811 1.0612 = 100,000 * 1.0811

= 108,110

= 108,110 / 1.0612

= 101,875

2025 100,000 1.1092 1.0824 = 100,000 * 1.1092

= 110,920

= 110,920 / 1.0824

= 102, 476

7..3.3 Team Members and Assignments

Ideally, O&S cost estimates are prepared by a multi-disciplinary team with functional skills 

in cost analysis, financial management, logistics, engineering (including reliability and 

maintainability), and other talents. The team also should include participants providing 

stakeholder input from major affected organizations, such as the system’s operating command or 

other user organization, product support center, maintenance depot, training center or command, 

and so forth. Each team member should have well-defined roles and responsibilities. 

7.3.4 Documentation of the Cost Estimate Plan

Ideally, the plan for the cost estimate will be prepared in a written document. This will be 

an important element of the documentation of the cost estimate that will be required later, since 

the written plan describes the process followed to achieve the estimate results. In addition, a 

presentation of the plan is typically presented at some kind of kick-off meeting for the estimate. 

It is important that the plan for the O&S cost estimate be reviewed by all appropriate 

stakeholders before the actual work on preparing the cost estimate begins. This helps ensure that 

there are no false starts or misunderstandings later in the process. However, in real life, it is most 

likely that the original plan is going to change over the course of the estimate. Any changes from 

the original plan should be noted in the final documentation of the cost estimate.

7.4 Cost Data

7.4.1 Data Identification and Collection 
57

The cost estimating process includes the identification of the best data available that is 

appropriate for the purpose and scope of the estimate. For programs that are early in the 

acquisition process, the planning for the O&S cost estimate should identify and document the 

needed cost, performance, and technical data for appropriate legacy systems in order to support 

estimates using analogies or cost estimating relationships (CERs) described later in this chapter. 

For programs that are later in the acquisition process, plans for O&S cost estimates should 

establish requirements for predictions by contractor, program office, or other external support 

organizations for O&S cost factors, reliability and maintainability parameters, and other 

suitability and logistics support factors. Plans should also address associated test and evaluation 

requirements and experience to date for the same factors and parameters. For mature programs, 

the best sources of available data that reflect actual cost experience for the program should be 

identified.

There are many possible sources of data that can be used in O&S cost estimates. For 

currently fielded major systems, historical cost data for the most part is available from the 

VAMOSC data system managed by each military department as discussed in Chapter 6. 

However, the VAMOSC systems provide limited visibility into CLS costs. In many cases, it may 

be necessary to augment VAMOSC data with CSDR data for costs of major sustainment, 

logistics, and maintenance contracts. Additionally, in many cases, for weapon systems supported 

by a mix of organic maintenance and CLS, it is necessary for the analyst to fuse the two data 

sources into a consistent understanding of the total costs for each major cost element.

The cost estimate often will require reliability and maintainability data, which can be 

obtained from the military department maintenance data collection systems or from test results. 

In addition, VAMOSC data for unit-level manpower is often supplemented with information 

from unit manning documents or tables of organization and equipment. In such cases, it is 

necessary to apply manpower rates to the unit manning documents. Manpower rates are

discussed in Appendix I of this guide.

7.4.2 Data Validation and Normalization

O&S cost data, such as VAMOSC and CSDR data, should be carefully examined before 

use in a cost estimate. The data should be displayed over a period of a few years (not just a single 

year), and stratified by organization or location (such as major command or base) so that

abnormal outliers in the data can be identified, investigated, and considered as appropriate. 

Data that can be used for detailed bottom-up engineering estimates often come from 

contractor databases (such as logistics management data systems). It is important for analysts to 

understand the sources and business rules used in the generation of the data. Appropriate 

government personnel should validate this type of data before use, at least for the high-cost 

items. This is especially important in cases when the hardware being costed is not mature (e.g., 

not yet tested or deployed). The validation should address the completeness of the component 
58

population, the realism of component reliability and maintainability estimates, the validity of the 

component unit prices, and so forth. 

It may also be necessary to normalize historical data to adjust for accounting or definitional 

changes that have occurred over time. In such cases, the earlier data may need to be adjusted in 

order to be comparable to the current data. For example, a system may have a change in its 

support concept where the mix of organic and CLS sustainment has changed, or where the source 

of CLS is changed from the prime contractor to a major subcontractor. As another example, there 

could be force structure changes such as a change in active-reserve mix.

In addition, system O&S cost estimates generally reflect peacetime conditions. DoD 

considers the incremental costs due to a contingency to be part of the cost of the contingency, not 

part of the operating cost of the system. However, for some systems in recent years, the usage or 

OPTEMPO reported in the VAMOSC data systems or other data sources may capture a 

combination of peacetime and contingency operations. In such cases, the actual usage and 

associated costs may need to be adjusted to the peacetime level. On the other hand, the actual 

usage and associated costs may represent a new more or less permanent reality, and should be 

considered the new norm for the program or its replacement. The cost validation process should 

establish the appropriate assumption, most likely with the help of subject matter experts. The 

different levels of usage should also be considered in the sensitivity analysis and risk/uncertainty 

discussed later in this chapter.

7.5 Cost Estimate

7.5.1 Methods or Models 

Several techniques may be employed to estimate the O&S costs of a weapon system. The 

cost estimation techniques selected typically depend on the acquisition phase and maturity of the 

program. In the earlier acquisition phases, cost estimates are commonly based on analogies and 

parametric CERs. In some cases, as the program definition is refined, the use of analogies and 

parametric estimates may be improved by increasing the level of detail of the cost estimate, 

where, for some cost elements, distinct estimates are made for major subsystems and 

components. As the program enters subsequent acquisition phases, it is desirable to incorporate 

any actual cost experience available from early fielded systems. Emerging test and evaluation 

results, including projections of reliability and maintainability performance, also can be used to 

refine O&S cost estimates. 

In many instances, it is a common practice to employ more than one cost estimating method, 

so that a second method can serve as a cross-check to the primary method. For mature systems, 

using a build-up method or extrapolation from actuals method described later, analogy and 

parametric estimates are often used as cross-checks.
59 

Each of the four most common estimating techniques is described in the remainder of this 

section. 

Analogy. An analogy is a technique used to estimate a cost based on historical data for one 

analogous system. An analogy may also be used to estimate the cost of a subsystem such as a 

propulsion or electronic warfare subsystem. In this technique, a currently fielded system, similar 

in design and operation to the proposed system, is used as a basis for the analogy. The cost of the 

proposed system is then estimated by adjusting the historical cost of the current system to 

account for differences between the proposed and current systems. Such adjustments can be 

made by using factors (sometimes called scaling parameters) that represent differences in size, 

performance, technology, reliability and maintainability, complexity, or other attributes. 

Adjustment factors based on quantitative data are usually preferable to adjustment factors based 

on judgments from subject-matter experts.

Figure 7-7 provides an example of an analogy for an estimate of DLR cost.

Figure 7-7. Example of Analogy Cost Estimate

In this example, the cost is estimated on a dollar per unit of usage basis. The cost for the old 

system is used to estimate the cost for the new system. There are two scaling parameters. The first is 
60

reliability. Common reliability parameters include Mean Time Between Failure, Mean Time 

Between Removal, and Mean Time Between Maintenance. However, the actual effect on cost 

would be a failure rate, removal rate, or maintenance rate. Since reliability parameters are usually 

expressed as a reciprocal, this leads to the reversal in the reliability ratio, where the value for the old 

system is in the numerator and the value for the new system is in the denominator. The second 

scaling parameter is unit hardware cost. Unit hardware cost is typically expressed as prime mission 

product, recurring flyaway, or simply flyaway. The exponents b1 and b2 may optionally be used to 

account for diminishing returns on the effects of the scaling parameters. Typically, the values of 

these exponents would come from relevant studies or analyses such as the regression analysis 

discussed in the next section. The analogy approach could be used for the entire weapon system, or 

could be used for a subsystem or component.

Unit hardware cost, along with system reliability, is commonly used in analogies and 

parametric estimates that are discussed later in this chapter. The unit hardware cost is used to 

represent a proxy for system size and complexity. Historically, many new systems have had 

superior reliability relative to the antecedent systems being replaced, due to advancements in new 

technologies. However, improvements in reliability are typically more than offset by increases in 

unit hardware cost. The increases in unit hardware cost indicate an increase in complexity, which 

results in an increase in maintenance and other O&S costs. Table 7-1 shows an example of this 

pattern for two replacement systems.

Table 7-1. Comparison of Replacement Systems to Antecedents

Parametric. The parametric technique uses regression to develop CERs. A CER is an 

equation used to estimate a given cost element using an established relationship with one or more 

independent variables. The relationship is often derived from regression analysis of historical 

systems or subsystems. CERs should be current, applicable to the system or subsystem in question, 

and appropriate for the range of data being considered. The strength of a parametric estimate lies in 

the relevance and quality of the data and in the validity of the assumed behavior between the 
61 

independent variables and the dependent variable. The analyst should also consider the number of 

data observations sufficient to form a statistically meaningful data set. 

Figure 7-8 provides an example of a CER for an estimate of DLR cost.

Figure 7-8. Example of Cost Estimate by CER

In this example, the DLR cost, which is the dependent variable in the regression, is 

estimated on a dollar per unit of usage basis. The independent variables are reliability and unit 

hardware cost. To perform the regression, it is necessary to assemble the data (both the 

dependent variable and the independent variables) for a group of historical systems relevant to 

the system being estimated. The functional form of the equation is nonlinear, but can be 

converted to a linear form by taking logarithms of both sides of the equation. The regression 

using the data for the historical systems then provides the three coefficients (b0, b1, and b2). The 

equation for the CER can then be used to estimate the DLR cost for a new system.

A more complete and advanced discussion about the development and application of CERs 

can be found in the Joint Agency Cost Estimating Relationship Development Handbook. 

Build-up Estimate. This technique uses discrete estimates of labor and material costs for 
62

maintenance and other support functions. The system being costed normally is broken down into 

lower-level components (such as parts or assemblies), each of which is costed separately. The 

component costs are then aggregated using simple accounting equations to estimate the total system 

cost (hence the common name “bottom-up” estimate). For example, system maintenance costs 

could be calculated for each system component using data inputs such as system OPTEMPO, 

component mean time between failure or maintenance, component mean labor hours to repair, and 

component mean material cost per repair. Engineering estimates require extensive knowledge of a 

system’s components characteristics, and a sizeable amount of detailed data. An example of a buildup estimate is provided in Appendix G of this guide.

Extrapolation from Actuals. With this technique, actual cost experience or trends (from 

prototypes, engineering development models, and/or early production items) are used to project 

future costs for the same system. Such projections may be made at various levels of detail, 

depending on the availability of data. In some cases, it may be necessary to account for growth in 

reliability and maintainability. 

There are other methods in addition to the four discussed in this section, including expert 

opinion, head-count (level of effort), and industrial engineering standards. These other methods are 

described in the DoD Cost Estimating Guide.

7.5.2 Baseline Cost Estimate 

The complete O&S cost estimate is composed of the individual estimates for each cost 

element. The framework holding the estimate together is the cost element structure. The analyst 

populates the cost element structure with the selected estimating methods supported by inputs 

from the data collection process. The analyst then applies inflation, price escalation, and phasing 

methods as needed. Often, an estimate may use a comprehensive cost model built in Excel or a 

cost estimating software application such as Automated Cost Estimating Integrated Tools 

(ACEIT). 

Usually the development of the baseline cost estimate is an iterative process. Starting the 

baseline cost estimate as early as possible helps focus discussion among the team members, 

inspires timely questions, and uncovers weaknesses in the estimating methods or gaps in the data 

collection process.

The term baseline cost estimate is used because this estimate serves as the point of 

departure for the sensitivity analysis and risk/uncertainty assessment discussed in the next two 

sections. 

7.5.3 Sensitivity Analysis

Sensitivity analysis attempts to demonstrate how the cost estimate would react to changes

in cost drivers. Typically, for the high-cost elements, the analyst identifies the relevant costdrivers and then examines how costs vary with changes in the cost-driver values. For example, a 
63 

sensitivity analysis might examine how maintenance manning varies with different assumptions 

about system reliability and maintainability values, or how system fuel consumption increases 

with system weight growth. In good sensitivity analyses, the cost-driver values are not changed 

by arbitrary plus/minus percentages, but rather by a careful assessment of the plausible ranges of 

values. 

Figure 7-9 shows an example of a sensitivity analysis for an aircraft system.

Figure 7-9. Example of Sensitivity Analysis

In this example, the costs being considered are costs for DLRs plus costs for consumables. 

These costs are expressed on a dollars-per-flight hour basis. The sensitivity analysis is focused 

on aircraft reliability, which has been identified as a concern. In this example, the aircraft is 

undergoing test and evaluation. For this aircraft, the Director of Operational Test and Evaluation 

(DOT&E) projection for reliability at maturity, based on test experience to date, is provided as a 

range of values. The entire range of the projection is significantly deficient relative to the 

threshold and objective reliability requirements established in the Capability Development 

Document (CDD). 
64 

In most cases, maintenance costs do not vary linearly with reliability. In this example, 

achieving the CDD threshold represents a 22 percent improvement in reliability compared to the 

DOT&E projection. Such an achievement is estimated to reduce the costs for DLRs plus 

consumables by 13 percent. 

Figure 7-10 shows a second example of sensitivity analysis that considers both reliability 

and maintainability for the same aircraft system.

Figure 7-10. Second Example of Sensitivity Analysis

In this example, the output measure being considered is maintenance manpower per 

squadron. Here, both reliability (measured as Mean Time Between Maintenance (MTBM)) and 

maintainability (measured as Mean Time to Repair (MTTR)) are varied. These results were 

derived from a simulation model of aircraft squadron operations and maintenance. The level of 

maintenance manpower is a decision variable in the simulation. For given reliability and 

maintainability, the model is used to establish the minimum level of manning necessary to 

achieve targets for sortie generation rates.
65

In most cases, maintenance manpower does not vary linearly with improvements in 

reliability or maintainability. Typically, a given percentage of a reliability or maintainability 

improvement would result in a lower percentage manpower reduction. This is because the 

workload for maintenance manpower is not limited to touch labor for replacements and repairs, 

but also includes other activities such as weapons loading, inspections, and overhead such as 

quality control and supervision. In this example, the increase in reliability between medium and 

high represents a 50 percent improvement. This reliability improvement at the medium level of 

maintainability results in only a 7 percent reduction in maintenance manpower.

In addition, for many systems, the maintenance manpower system can also vary with the 

number of systems in the operating unit. Typically, there can be an economies of scale effect as 

the unit size is increased. However, this is not true for all system types. 

More generally, sensitivity analysis helps identify where the analyst should focus risk and 

uncertainty analysis. That topic is briefly introduced in the next section.

7.5.4 Risk and Uncertainty

A program risk is a potential event or condition that may have an effect on cost, schedule, 

and/or performance. A risk has three characteristics: a triggering event or condition, the 

probability that event or condition will occur, and the consequence of the event or condition 

should it occur. Uncertainty is the indefiniteness of the outcome of a situation. In the context of 

cost estimating, uncertainty refers to the range of possible values for the eventual cost outcome.

Cost analysts address risk and uncertainty in different ways. The DoD Cost Estimating 

Guide provides a summary of the most common methods used to address them. One of the 

methods described is simulation. A simulation model is used to capture the uncertainty in 

parametric CERs, CER inputs, any other cost drivers, program schedule, and other identified risk 

events (and the probability of occurrence and the consequence of it for each event) that impact 

the cost model. A simulation model can be used to develop a so-called S-curve, which is the 

cumulative distribution function of the system cost. A complete description of this approach is 

provided in the Joint Agency Cost Schedule Risk and Uncertainty Handbook. The handbook 

provides several examples of this approach.

7.5.5 Documentation and Presentation

A complete cost estimate should be formally documented. The documentation serves as an 

audit trail of source data, methods and results. The documentation should be easy to read, 

complete and well organized—to allow any reviewer to understand the estimate fully. The 

documentation also serves as a valuable reference for future cost analysis, as the program moves 

from one acquisition milestone to the next. The key standard is that an outside professional cost 

analyst should be able to replicate the estimate, given the documentation. 
66

The documentation should address all aspects of the cost estimate: a brief summary of the 

program definition and a reference to the CARD; the background described in the cost estimating 

plan, including all ground rules and assumptions; the selection of cost data sources and cost 

estimating methods; the actual estimate computations; and the results of the sensitivity and 

risk/uncertainty analyses. 

Typically, a presentation concerning an O&S cost estimate would include the following:

• O&S Cost Summary. The presentation will begin with a brief summary of 

ground rules and assumptions (such as O&S period, number of deployed systems, 

operations and support concepts, etc.), and follow with a brief table-format 

summary of total O&S costs in constant dollars by cost element and sub-elements.

• Estimating Methods for Major Cost Elements. The presentation will include a 

discussion of estimating methods (and source data) for the high-cost cost elements 

and sub-elements.

• Sensitivity Analysis. This section of the presentation would include an 

identification of the major cost-drivers (such as system reliability and 

maintainability) associated with the high-cost cost elements and sub-elements, and 

show the sensitivity of the costs to changes in cost-drivers. 

• Risk/Uncertainty Analysis. If conducted, a formal quantitative assessment of risk 

and uncertainty such as an S-curve display would be provided here in the 

presentation.

• Time-Phased O&S Display. The presentation will include a display of timephased O&S costs by major time periods (such as phase-in, steady-state, and 

phase-out periods), as well as a display of annual steady-state recurring O&S 

costs1

. These costs are displayed in then-year dollars when used to support a 

comparison to program funding in the budget.

• Annualized Steady-State Costs for Typical Unit. The presentation should 

include a display of the annual system O&S costs for a typical deployable or 

operating unit (such as squadron or battalion) or single system (such as ship or 

missile), compared to similar costs for the predecessor and/or reference system. 

This is one of the presentation formats often used in the program SAR. 

1 In the steady-state period, annual O&S costs may or may not be constant. In some cases, variations may occur due 

to long overhaul cycles or other reasons. In these cases, annual-steady state O&S costs would be calculated as the 

average annual O&S cost over the steady-state period.
67

• Cost Track to Prior Estimate. If applicable, the presentation should also 

include a comparison between the current O&S cost estimate, and the most recent 

previous estimate. Major differences should be explained.

• Comparison to Program Baseline. Where applicable, the presentation should 

include comparisons between the current estimate and any ADM metrics, SAR 

baselines, cost Key System Attributes (KSAs), etc.
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APPENDIX A

Software Maintenance Cost Elements

Introduction

This appendix provides an optional, more detailed cost element structure for software 

maintenance.

Definitions

5.2 Software Maintenance

The rollup of the costs of the lower level elements.

5.2.1 Software Changes 

The rollup of the costs of the lower level elements.

5.2.1.1 Release 1...n (Specify) 

The rollup of the costs of the lower level elements.

5.2.1.1.1 Correction of Deficiencies 

This element captures software change costs associated with the correction of deficiencies, 

defects, and cybersecurity. It can also capture the cost of any refactoring (restructuring the 

existing body of code without altering behavior).

5.2.1.1.2 Enhancements 

This element captures software change costs associated with minor enhancements.

5.2.1.1.3 Independent Verification and Validation (IV&V) 

This element captures all costs associated with software release IV&V. IV&V is a review 

secured through a separate contract with a third party that ensures that the system is wellengineered and meets agreed upon requirements (verification) and that the system meets the 

users’ needs (validation). 

5.2.2 Software Program Management 

Includes all costs associated with the management of software, including the 

implementation, delivery, and sustainment of software.

5.2.3 Software Sustaining Engineering 
70

Includes all costs associated with software-specific sustaining engineering. Costs reported 

in this element may include, but are not limited to, contract engineering services, studies, and 

technical advice. This element does not include effort associated with directly changing the 

software baseline but may support the activities associated with those changes.

5.2.4 System Facilities 

This element includes the system-specific cost associated with establishing and operating 

an environment such as a Software Integration Laboratory (SIL) for software 

maintenance-related development and testing.

5.2.5 Field Service Engineers

This element includes the cost associated with on-site support of a deployed software 

product or system in its operational environment. 

5.2.6 Certification and Accreditation

This element includes activities such as Cybersecurity, Information Assurance 

Vulnerability Management (IAVM), Airworthiness, Safety, and Networthiness. Cybersecurity, 

formerly Information Assurance (IA), and the Risk Management Framework (RMF) for DoD 

Information Technology, formerly DoD Information Assurance Certification and Accreditation 

Process (DIACAP), are processes that verify the software system against externally defined 

domain performance criteria.

5.2.7 Help Desk

This element captures the costs of providing help desk support for end users. Cost may 

include effort associated with answering and filtering help desk calls, troubleshooting, account 

management, system administration, software upgrades, and break/fix.

5.2.7.1 Tier 1 

This element captures the costs of providing Tier 1 help desk support to end users. This 

element includes the cost of support provided by a central call center for basic customer issues 

such as solving usage problems and fulfilling service desk requests that need IT involvement. If 

no solution is available, Tier 1 personnel escalate incidents to a higher tier.

5.2.7.2 Tier 2 

This element captures the costs of providing Tier 2 help desk support to end users. This 

element includes the cost of support provided by experienced and knowledgeable support 

personnel who assess issues and provide solutions for problems that cannot be handled by Tier 1. 

Typically, Tier 2 personnel have an in-depth functional knowledge of the product or service. If 

no solution is available, Tier 2 support escalates the incident to Tier 3.
71

5.2.7.3 Tier 3 

This element captures the costs of providing Tier 3 help desk support to end users. This 

element includes the cost of support provided by highly skilled product specialists who have an 

expert knowledge of the application and can resolve issues or problems and fix defects in the 

production baseline by changing the system software.

5.2.8 Hosting

This element includes all costs associated with hosting, either in a traditional data center or 

in the cloud. Includes activities associated with computing resources and servers that execute all 

or some portion of an application from a central location across a network. Also includes storage 

and services necessary to maintain and manage server hardware and operations. If system is 

cloud hosting, specify if costs represent infrastructure as a service, platform as a service, or 

software as a service. 

5.2.9 Software Licenses

This element includes the cost associated with license procurement and license maintenance 

fees for all licenses necessary to operate and maintain the system. This includes licenses in the 

development environment as well as the deployed software system.
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APPENDIX B

Indirect Support Cost Elements

Introduction

Indirect support costs are those installation and personnel support costs that cannot be 

identified directly (in the budget or Future Years Defense Program) to the units and personnel 

that operate and support the system being analyzed, but nevertheless can be logically attributed 

to the system and its associated manpower.

Such indirect costs are not included in operating and support (O&S) cost estimates made 

in support of the defense acquisition process. However, indirect support costs are often 

considered in workforce mix cost comparisons, product support business case analyses, and

broad force structure studies such as those focused on active-reserve mix. These costs also may 

be considered and addressed separately in programming and budgeting. These indirect costs 

may optionally be collected in the VAMOSC systems, at the discretion of each military 

department.

Since indirect support costs lack direct visibility with the system under consideration, they 

are often allocated, either on a per-capita or some other basis. Some O&S cost estimates attempt 

to partition the indirect support costs into fixed and variable elements, and use only the variable 

costs in the estimate. The intention is to include only the costs that would likely change for the 

action being analyzed (e.g., new system development is initiated).

The remainder of this appendix provides terms and definitions for indirect support cost 

elements.

Definitions

6.0 INDIRECT SUPPORT

6.1 Installation Support

The costs of services funded and provided by the host installation that support the day-today operations of the system’s force unit. Excludes the costs of personnel support services 

purchased by the unit that are reflected in element 2.2 (Support Services). Consists of:

6.1.1 Base Operations Support

The costs of services for functions such as base physical security, base administration, 

maintenance of installation equipment, base transportation, and other base and personnel support 

services.
74

6.1.2 Base Communications

The costs of local communication services provided by the host installation. May be 

combined with 6.1.1 (Base Operations Support) if it cannot be identified separately.

6.1.3 Facilities Support

The costs of facilities sustainment, restoration and modernization (formerly known as real 

property maintenance).

6.2 Personnel Support

The costs for the management, acquisition, initial training, and quality of life programs 

necessary to maintain a quality force. 

6.2.1 Personnel Administration

The costs of programs that acquire and administer the DoD workforce.

6.2.1.1 Personnel Management

The costs of programs to administer the DoD military and civilian workforce. Major 

activities include reassigning on-board personnel, and managing end strength and occupational 

skills to the levels needed.

6.2.1.2 Acquisition of New Personnel

The costs for recruiting, examining, and processing individuals into the military service and 

for advertising in support of recruiting activities.

6.2.1.3 Personnel Not Available For Duty (Transients, Prisoners, Patients, Students)

The costs for military personnel placed in the personnel holding account because they are 

not available for assignment to a unit for medical or disciplinary reasons, or are about to be 

discharged. Includes military personnel not assigned to a unit because they are in transit to the 

next permanent duty station, to schooling, or other training. 

6.2.2 Personnel Benefits

Consists of the costs for operations and maintenance of family housing, dependent and 

family support programs, and DoD commissaries and exchanges.

6.2.2.1 Family Housing

The costs for operations and maintenance of dwelling units, community facilities, roads, 

driveways, walkways, and utilities for use by family housing occupants.

6.2.2.2 Dependent Support Programs

The costs of child development centers, youth development programs, family centers, 

family advocacy programs, counter-drug demand reduction programs, and other similar 
75

programs necessary to support the families of military service members. Includes the education 

of dependents of federal employees in overseas assignments and for eligible dependents of 

federal employees residing on federal property where an appropriate public education is 

unavailable in the nearby community. These education costs are primarily funded by the DoD 

Education Activity (DoDEA). 

6.2.2.3 Commissaries and Exchanges 

The appropriated costs of employee salaries and other expenses at defense commissaries. 

These costs are primarily funded by the Defense Commissary Agency (DeCA). 

6.2.3 Medical Support

The costs for medical care for active duty personnel and their dependents. Includes 

provisions for in-house patient care in regional defense facilities, station hospitals, and medical 

clinics; and dental facilities; as well as care in non-defense facilities. Also includes costs for 

private-sector care such as TRICARE or other similar activities. Medical care is funded by a 

combination of the military departments and the Defense Health Program. The active-duty 

composite rates described in Appendix I also provide an acceleration factor to account for the 

costs of medical support.

6.3 General Training and Education

The costs for institutional or schoolhouse training and education not associated with a 

specific weapon or other system. Consists of the costs of:

6.3.1 Recruit and Initial Officer Training

The costs of programs that provide basic military training and indoctrination to enlisted 

recruits, and of programs that provide basic military training and indoctrination to officer 

candidates (through college commissioning programs, officer candidate/training schools, and the 

three military service academies).

6.3.2 General Skill Training

The costs of programs that teach (1) entry-level job skills after completion of initial 

military training, and (2) intermediate and advanced job skills later in the career. 

6.3.3 Professional Military Education

The costs of programs that provide (1) professional military education at each level of 

career progression, and (2) advanced academic degrees needed for work in specific organizations 

and tasks.
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APPENDIX C 

Definitions for Acquisition Logistics Support Cost Elements

This appendix provides cost terms and definitions for acquisition logistics support cost 

elements procured during the system production and deployment phase. In the standard 

terminology for life-cycle cost, acquisition logistics support costs are procurement costs that are 

the initial investment for a program’s product support that will support the sustainment that takes 

place during the system operations and sustainment phase. 

Figure C-1 shows the placement of a program’s acquisition logistics support costs as part 

of its procurement cost. 

Figure C-1. Acquisition Logistics in a Procurement Cost Estimate 

Basic terms and definitions for the acquisition logistics support cost elements are provided 

in MIL-STD-881D, Work Breakdown Structures for Defense Materiel Items, Appendix K 

(Common Elements). These cost elements are defined as follows:

• Training. Consists of operational and maintenance training equipment, training courses 

and course materials, and other training services. 
78

• Data. The deliverable data procured by the Government as required on a contract data 

requirements list. This typically includes technical publications, engineering data, 

management data, and other support data. This may also include the Government’s 

license rights to contractor intellectual property. 

• Peculiar Support Equipment. Items and associated software required to support and 

maintain the weapon system or portions of the system, and which are not common 

support equipment.

• Common Support Equipment. Items and associated software required to support and 

maintain the weapon systems or portions of the system, and which are presently in the 

DoD inventory for support of other systems. 

• Operational/Site Activation. Facilities, materials, and services required to house, 

service, and launch prime mission equipment at the initial system sites or bases. 

• Industrial Facilities. The construction, conversion, or expansion of industrial facilities 

for production, inventory, and contractor depot maintenance when that service is for the 

specific system.

• Initial Spares and Repair Parts. Repairable spares and repair parts required as initial 

stockage to support and maintain newly fielded systems during the initial phase of 

service. This includes pipeline and war reserve quantities, at all levels of maintenance 

and support. 

Although these acquisition logistics support costs are for the most part procurement funded, 

they nevertheless are a critical investment necessary for a program’s overall sustainment and 

product support package. Figure C-2 shows a graphical depiction of this concept.
79 

Figure C-2. Acquisition Logistics Costs in a Life-Cycle Cost Estimate

There is a transition between the investments in the acquisition logistics support cost 

elements and the support in the O&S cost elements. Often, much of this transition is provided by 

Interim Contractor Support (ICS). ICS is temporary contractor support provided before a 

permanent support solution (organic or contractor) is established. This support consists of labor, 

material and overhead for maintenance, supply management, and other support functions during 

the early fielding of the system. 

Additional background about ICS, Contractor Logistics Support (CLS), and PerformanceBased Logistics (PBL) is provided in Appendix F. 

Table C-1 illustrates the transition from the acquisition logistics cost elements through 

various functions to the O&S cost elements. 
80

Table C-1. Transition from Acquisition Logistics to O&S

Acquisition Logistics Cost 

Elements Transition Function O&S Cost Element

Training (Equipment) Repair of Training Equipment Simulator Operations and Repair

Training (Services) Interim Training (Training the 

Trainers)

System-Specific Training

Data Interim Updates to Data and 

Technical Publications

Data and Technical Publications

Support Equipment Repair of Support Equipment Support Equipment Replacement 

and Repair

Operational Site Activation (Local 

Manpower)

Field Service Representatives Unit-Level Manpower

Operation Site Activation (Other 

Support)

Site Activation Support Support Services

Industrial Facilities Conversion or Expansion of 

Industrial Facilities

Maintenance (overhead for 

depreciation)

Initial Spares and Repair Parts 

(Reparables)

Repair of Reparable Items Depot Level Reparables

Initial Spares and Repair Parts 

(Reparables)

Depot Activation Depot Level Reparables

Initial Spares and Repair Parts 

(Consumables)

Replacement of Consumable 

Items

Consumables

Note that the costs for the sustainment of the industrial facilities for the inventory control 

points and maintenance depots are captured in the overhead for facilities depreciation in the 

maintenance cost elements (consumables, depot level reparables, and depot maintenance).
81

APPENDIX D

Mapping from O&S Cost Elements to Budget Appropriations

Introduction

This appendix provides a mapping from individual O&S cost elements to the major 

appropriation categories: Research, Development, Test, and Evaluation (RDT&E); Procurement; 

Military Personnel; and Operations and Maintenance (O&M). This mapping is important because 

it permits an O&S cost estimate to project required funding resources by fiscal year by 

appropriation for the weapon system. In particular, one specific chart, known as the Program 

Funding and Quantities chart, displays for a program cost estimate a comparison between 

required versus programmed funding by fiscal year for each appropriation. This chart is updated 

at each milestone review throughout the acquisition process. The Program Funding and 

Quantities chart1 is described in the DoD Cost Estimating Guide.

O&S Cost Element Structure Mapping

Figure D-1 provides a notional mapping from cost element to appropriation category, 

although the specific mapping for each program might vary.

1

 The Program Funding and Quantities chart is known colloquially as the Spruill chart, named after Dr. Nancy 

Spruill, a prominent senior acquisition official for many years and originator of the chart format.
82

Figure D-1. Mapping of O&S Cost Elements to Appropriation Categories

Notes:

1. For manpower costs, military personnel appropriations are used for military personnel, 

and O&M funds are used for contractor and government civilian personnel.

2. Some cost estimates or cost data reports might have Interim Contractor Support (ICS) 

or Contractor Logistics Support (CLS) as cost elements. Normally, ICS costs are funded 

with procurement appropriations, and CLS costs are funded with O&M appropriations.

3. Training munitions may be funded with Ammunition Procurement, Weapons 

Procurement, or O&M appropriations.

Military Operations &

RDT&E Procurement Personnel Maintenance

CAPE O&S Cost Element

1.0 Unit-Level Manpower

 1.1 Operations Manpower X

 1.2 Unit-Level Maintenance Manpower X X

 1.3 Other Unit-Level Manpower X X

2.0 Unit Operations

 2.1 Energy (Direct Fuel, Electricity, etc.) X

 2.2 Training Munitions and Expendable Stores X X

 2.3 Support Services X

 2.4 Temporary Duty (TDY) Travel X

 2.5 Second Destination Transportation X

3.0 Maintenance

 3.1 Consumables X

 3.2 Depot Level Reparables X

 3.3 Intermediate Maintenance (External to Unit-Level) X X

 3.4 Depot Maintenance X

4.0 Sustaining Support

 4.1 System-Specific Training X X X

 4.2 Support Equipment Replacement and Repair X X

 4.3 Sustaining/Systems Engineering X X

 4.4 Program Management X X

 4.5 Data and Technical Publications X X

 4.6 Simulator Operations and Repair X X

 4.7 Other Sustaining Support X

5.0 Continuing System Improvements

 5.1 Hardware Modifications X X

 5.2 Software Maintenance X X
83

4. For Navy ships and submarines, most overhauls and availabilities are treated as depot 

maintenance in the cost element structure, and are funded with O&M appropriations. 

Fleet modernization costs are treated as hardware modifications, and are funded with 

procurement (“Other Procurement”) funds. However, for a Navy procurement 

appropriation known as Shipbuilding and Conversion, Navy (SCN) may be used for 

major ship service-life extension programs. SCN funding is also used for the Refueling 

and Complex Overhaul (RCOH) of nuclear-powered carriers. In addition, the cost 

estimates for ships with nuclear reactors normally do not include the costs associated 

with the Department of Energy/National Nuclear Security Administration.

5. Civilian and contractor support, which is O&M funded, can be used for operations 

manpower for a few system types such as space systems and some unmanned aerial 

vehicles.
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APPENDIX E

Analytic Support for Sustainment Reviews

Introduction

10 U.S.C. 2441 (Sustainment Reviews), added by the National Defense Authorization Act 

(NDAA) for FY 2017, requires the military departments to conduct a sustainment review of each 

major weapon system not later than five years after declaration of initial operational capability 

(IOC) of a Major Defense Acquisition Program (MDAP) and throughout the life cycle of the 

weapon system to assess the product support strategy, performance, and operating and support

(O&S) costs of the weapon system. For any review after the first one, the Secretary concerned 

shall use availability and reliability thresholds and cost estimates as the basis for the 

circumstances that prompt such a review. In 10 U.S.C. 2379f (Major Weapon System Defined), 

the term major weapon system means a weapon system acquired pursuant to an MDAP. 

Each sustainment review is required to include the following elements:

• An independent cost estimate for the remainder of the life cycle of the program.

• A comparison of actual costs to the amount of funds budgeted and appropriated in the 

previous five years, and if funding shortfalls exist, an explanation of the implications on 

equipment availability.

• A comparison between the assumed and achieved system reliabilities.

• An analysis of the most cost-effective source of repairs and maintenance.

• An evaluation of the cost of consumables and depot level reparables (DLRs).

• An evaluation of the costs of information technology, networks, computer hardware, 

and software maintenance and upgrades.

• As applicable, an assessment of the actual fuel efficiencies compared to the projected 

fuel efficiencies as demonstrated in tests and operations.

• As applicable, a comparison of actual manpower requirements to previous estimates.

• An analysis of whether accurate and complete data are being reported in the cost 

systems of the military department concerned, and if deficiencies exist, a plan to update 

the data and ensure accurate and complete data are submitted in the future.

Current DoD guidance concerning sustainment reviews is provided in DoD Instruction 

(DoDI) 5000.85, Appendix 3D (“Product Support”).
86

There is also an additional statutory provision that establishes a requirement to update 

estimates of O&S costs periodically throughout the life cycle of a major weapon system. This 

provision is described at the end of this appendix.

Analytic Methods for Sustainment Reviews

The purpose of this appendix is to describe suggested analytic methods that could be used 

in support of such reviews. Specific remarks and examples are provided for each element 

required to be addressed in the review. The examples provided in this appendix concern major 

weapon systems. However, in some cases, the sustainment review could address a system 

upgrade. The analytic approach and examples would need to be tailored for that situation. The 

cost analyst would need to work with the sponsor of the sustainment review to establish the 

expectations and approach for a sustainment review of a system upgrade.

Independent Cost Estimate

The Office of Cost Assessment and Program Evaluation (CAPE) has established 

procedures for independent cost estimates (ICEs) for sustainment reviews in the most recent 

revision to DoDI 5000.73, Cost Analysis Guidance and Procedures. In this guidance, a 

sustainment review is supported by an ICE. There are three possibilities for the responsibility for 

the ICE. CAPE may choose to either prepare the ICE, review and approve a Service cost agency 

or Defense Agency equivalent ICE, or delegate the responsibility for the ICE to the DoD 

Component. If CAPE does not choose to conduct or approve the ICE, the ICE is prepared in 

accordance with the policies and procedures of the Service cost agency or Defense Agency 

equivalent. In any case, the ICE should be briefed at the sustainment review, and a copy of the 

ICE report should be provided to CAPE within seven days of the sustainment review. Additional 

guidance and timelines are provided in DoDI 5000.73. General discussion about the planning, 

conducting, documenting, and presenting an O&S cost estimate is provided in Chapter 7 of this 

guide.

Comparison of Actual Costs and Funds Budgeted

After the program enters Engineering and Manufacturing Development (EMD) and is 

approaching Low-Rate Initial Production (LRIP), preliminary information and projections about 

the system support can be used to establish an initial baseline for sustainment resource 

requirements. This information may initially be based on engineering estimates, but can be 

updated after IOC and beyond with test results and actual cost experience to ensure realistic

funding of sustainment resource requirements. 

For the programming process, in the Future Years Defense Program (FYDP), most of a

system or unit O&S cost (such as unit manpower and unit operations) is typically programmed in 

a primary program element associated with the system or unit. Examples of primary program 

elements are F-16 squadrons, guided missile destroyers, and heavy armored brigade combat 
87 

teams. Comparisons between most likely cost and programmed funding can be made and 

presented for these direct costs. Other O&S costs (e.g., some depot maintenance and some 

training units) are centrally programmed (i.e., not programmed by the individual weapon system 

or unit accounts). It is more difficult, if not impossible, to compare these system or unit costs to 

programmed funding. Care must be taken to fully understand the scope and content of the 

programmed funding in the primary program element. 

Figure E-1 shows an example of such a comparison for a Navy ship. 

Figure E-1. Sample System O&S Comparison of Funding to Actual Cost

This figure provides a comparison of the programmed funding reflected in the most recent 

FYDP, the actual costs obtained from the Naval Visibility and Management of Operating and 

Support Costs (VAMOSC) data system, and the most recent program Selected Acquisition 

Report (SAR) estimate. These costs are based on the O&S categorization described in Chapter 4 

of this guide. For many mature programs that have completed their procurement, SAR reporting 

will have ceased and a current SAR estimate will not be available. The figure displays the trends 

associated with the annual costs and programmed funding, as well as a comparison of the 
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averages between the two over the last five years. This example is shown for the ship class 

average. In some cases, it would be necessary to stratify the data by flight or block.

The comparison of programmed funding to actual cost experience for individual weapon 

systems is not always possible. For most Army and US Marine Corps (USMC) ground systems, 

the unit structure (and associated program element) is not oriented toward individual weapon 

systems, but rather is associated with a more aggregate unit (e.g., heavy brigade combat team) 

that is equipped with multiple weapon systems. For these types of weapon systems, an 

alternative approach would be to address funding for selected individual cost elements for that 

system from budget data.

For the budget process, analytic support to the budget process is not usually conducted in 

terms of the aggregate total system O&S cost, but rather at lower levels of detail—normally, 

individual high-cost Operations and Maintenance (O&M) elements, and system or unit 

manpower. These two areas are discussed further later in this appendix. The analyses presented 

later in this appendix are illustrative examples of the kinds of analyses that could also be used to 

support a sustainment review. Additional remarks about methods for addressing how any 

funding shortfalls affect equipment availability are provided later in this appendix. 

Comparison of Assumed and Achieved Reliabilities

In tracking system reliability, normally each program may select the reliability metric or 

metrics to be used. It is important for analysts to understand the definition and ground rules for 

each reliability metric.

Figure E-2 provides an illustrative example of a track of the reliability for an aircraft. 
89 

Figure E-2. Track of Aircraft Reliability Metric

In this example, reliability is measured as Mean Time Between Maintenance (MTBM) 

events, where the events are corrective maintenance actions. The program has two baseline 

values for reliability that are part of the contract specification. The first reliability value is the 

minimum requirement or threshold (which must be met), and the second is the desired goal or 

objective that is slightly better than the requirement. Typically, there would be appropriate 

incentives (such as award fees associated with performance demonstrated in a Reliability, 

Availability, and Maintainability (RAM) Evaluation) for the contractor to surpass the minimum 

requirement. The reliability growth curves associated with the specification values assume that 

the reliability is improved over time due to design changes to correct deficiencies discovered in 

test and evaluation, or due to improvements in parts quality as the production process matures, 

up to the point of reliability maturity (which is assumed to occur at 100,000 cumulative flying 

hours in this example). The track also shows the actual test data for the same points in time as the 

program baseline (requirement and goal). In this example, the early reliability was deficient 

relative to the baseline, but over time the contractor was able to address the problem and reach a 

reliability value at maturity that significantly surpassed the specification values.
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As part of the Defense Acquisition Executive Summary (DAES) reporting system, 

programs undergoing test and evaluation are required to provide quarterly reports on their status 

in achieving program requirements (goals and thresholds) for reliability. Each program may 

select its own reliability metric and associated definition. These reports provide the results from 

test data relative to reliability growth curves consistent with program requirements. These reports 

are available to analysts with access to the DAES system. More importantly, cost analysts can 

obtain assessments concerning test results for reliability and maintainability from the Director of 

Operational Test and Evaluation (DOT&E) annual report and from reports from other military 

department test organizations. For mature programs, reliability data may be obtained from a 

maintenance data collection system such as the Air Force Reliability and Maintainability 

Information System (REMIS) or the Navy DECision Knowledge Programming for Logistics 

Analysis and Technical Evaluation (DECKPLATE) maintenance data management and 

warehousing system.

Analysis of Cost-Effective Source of Repairs and Maintenance

Every MDAP program manager or product support manager is required to develop and 

implement an affordable and effective performance-based product support package. This 

package is described in the product support strategy, the primary document used to describe the 

program plans for sustainment across the life cycle. Guidance on the product support strategy is 

provided in DoDI 5000.85, Appendix 3D (“Product Support). 

The product support strategy is supported by a business case analysis, which is an annex to 

the strategy. A business case analysis is a type of economic analysis that a program manager may 

use when deciding among any number of product support alternatives. It is a structured approach 

to identify the cost, benefits, and risks of the alternatives. To ensure accurate results, the business 

case analysis depends on valid O&S cost data and estimates as well as user requirements and 

related supportability analysis results.

The business case analysis may consider alternatives of organic, contractor, or some 

combination for sources of sustainment support. In addition, the business case analysis may 

evaluate other sustainment alternatives, such as choice of contract type, various technical data 

rights strategies, and whether or not to establish competition—or the option of competition—for 

the supported system or major subsystems. 

Further information may be found in the DoD Product Support Business Case Analysis 

Guidebook.

Evaluation of Costs of Consumables and DLRs

Each military department provides an annual budget submission for its O&M 

appropriations. Much of the submission consists of numerous detailed budget justifications. 

These justifications provide visibility into various O&M activities, and can be used in analyses to 
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help ensure that the O&M accounts are executable, properly priced, and adequately funded for 

proper readiness. 

For the major weapon systems, several specific budget reports provide visibility into 

system inventories; usage or operating tempos (OPTEMPOs); and funding for DLRs, 

consumables, fuel, and depot maintenance. The specific report format is tailored to the type of 

weapon system involved. The instructions, terms, and definitions for these reports are provided 

in the DoD Financial Management Regulation, Volume 2A, Chapter 3. Figure E-3 provides a 

summary of the key O&M budget justification documents. 

Figure E-3. Key O&M Budget Justification Reports

• The OP-20 report is used for aviation assets by all of the military departments. The

OP-20 combines information on aircraft inventories and flying hours with funding for

consumables, DLRs, and fuel.

• Similarly, the OP-25 presents data for ground vehicles. These include information on

vehicle quantities and miles driven, with funding for consumables, DLRs, and fuel.
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• The PB-61 report provides information on the depot maintenance accounts, including

planned or completed overhauls and the funding associated with depot maintenance.

The report for Navy ships provides information on overhauls, restricted availabilities,

and phased maintenance availabilities.

• Specific to ships, the OP-41 report provides operating information about ship quantities

and steaming days, with funding for DLRs, fuel, and consumables.

Information extracted from the various O&M budget reports can be compared to actual 

cost experience to assess the funding adequacy for the major O&M cost elements. Figure E-4 

shows an example of such an assessment for the funding for DLRs for an aircraft system. 

Figure E-4. Sample Budget Assessment for an O&M Cost Element

The actual cost data could be taken from a VAMOSC system. The figure displays the 

trends associated with the annual costs and the budgeted funding. In addition, the averages for 

costs and funding over the last five years are shown in the box on the right. Similar charts could 

be prepared for depot maintenance, fuel, consumables, and other cost elements. 
93 

The O&M budget reports and the VAMOSC data address funding and costs for organic 

maintenance, but do not address Contractor Logistics Support (CLS). For systems with 

significant CLS, it would also be necessary to obtain system CLS funding from the O&M budget 

and CLS costs from the Cost and Software Data Reporting (CSDR) reports for sustainment and 

the Maintenance and Repair Parts Data Report discussed in Chapter 6 of this guide. 

Figure E-5 shows an alternative approach for addressing the costs of consumables and 

DLRs.

Figure E-5. Alternative Approach for Consumables and DLRs

The pie chart on the right shows the percentage breakdown of the major O&C cost 

elements. The bar chart on the left shows the top DLR cost drivers. 

In making such assessments, it is important to determine that the funding supports a proper 

level of readiness. The various budget reports summarized in Figure E-3 only provide some of 

the information to help make such a determination. For example, in assessing the adequacy of 

funding for depot maintenance, it would be important to ensure that the funding was not resulting 

in growth of maintenance backlogs. Similarly, for O&M cost elements such as fuel, DLRs, and 
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consumables, it would be important to ensure that the funding supported the required OPTEMPO 

and availability for the system. 

Evaluation of Costs of Information Technology, Networks, Computer Hardware, and 

Software Maintenance and Upgrades

For this assessment, it is likely that it will be necessary to identify the applicable 

components in the weapon system relevant to this particular element of the sustainment review. 

This could include embedded prime mission product components such as sensors, data links and 

communication relays, SATCOM antennas, and processors and memory devices; ancillary 

equipment such as servers, workstations, and laptops; and hardware/software used for 

malfunction detection and isolation. These items would not only be identified for a baseline 

configuration, but also for any planned upgrades and technology insertion. For the individual 

components, it would then be necessary to obtain relevant data pertaining to sustainment such as 

reliability and supply support, item cost to repair and cost to replace, training workload and 

frequency, technical data and support equipment, software maintenance, and any contractor 

logistics data. In some cases, the sustainment review ICE could also be a source of data. These

data could then be used to construct a cost estimate by using an accounting model at the 

component level of detail such as the model described in Appendix G of this guide. 

Assessment of Fuel Efficiency

It was previously noted that fuel consumption can often be a major high-cost O&M 

element for many systems, and the earlier section of this appendix already discussed an approach 

for the assessment of the costs of such elements. What is unique to fuel is that metrics for fuel 

efficiency are normally associated with fuel consumption, and not in dollars. This is because the 

price of fuel can vary quite a bit from one year to the next.

For example, for an aircraft system, fuel consumption would normally be assessed in terms 

of gallons per flight hour. The track of actual fuel efficiencies compared to previous projections 

could be displayed in a format similar to the format shown in Table E-1.
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Table E-1. Track of Aircraft Fuel Efficiency

Year Event Fuel Gallons per Flight Hour

2003 Milestone B Estimate 2,290

2007 Milestone C Estimate 2,370

2014 Full-Rate Production Decision Estimate 2,450

2019 Current Operations (FY 2015–2019) 2,740

The various VAMOSC systems provide data on fuel consumption for most weapon 

systems.

Comparison of Actual Manpower to Previous Estimates

Manpower is an important element in system O&S costs, since manpower often accounts 

for a large fraction of the total program O&S cost. For example, for Navy surface ships, ship 

manpower accounts for, on average, roughly 40 percent of the ship’s total O&S cost.

Manpower estimates serve as the authoritative source for a program’s projected manpower 

requirements. The manpower estimate (formerly known as the Manpower Estimate Report) is 

approved by the cognizant military department manpower authority (normally the Assistant 

Secretary for Manpower and Reserve Affairs).

The manpower estimate provides the program manpower needed for system operations, 

maintenance, support, and system-related training. The manpower is provided separately for 

active-duty officer and enlisted end-strength, reserve officer and enlisted drill and full-time endstrength, civilian full-time equivalents, and contractor support work-years. If applicable, it is also 

necessary to display the manpower requirements by Component (Active, Guard, or Reserve). 

Each military department has its own process to continually review and update program 

manpower requirements as the program matures and begins operations. These requirements are 

typically documented in some form of unit manning document or table of organization and 

equipment, although the specific format will vary among the military departments. Although the 

manpower estimate described earlier does not include grade structure or skill level, the unit 

manning document typically does. For example, in the case of surface ships, the Navy publishes 

a Ship Manning Document for each class (and configuration) of ship. The Ship Manning 

Document provides manpower requirements in terms of grade, occupation, and skill level, 

predicated on the program’s required capabilities and operational environment, computed 

workload, and productivity assumptions (such as standard workweeks, leave policy, etc.). The 

Navy reviews its Ship Manning Documents each year, and updates them when there are 

significant changes to the mission, operational concept, or ship configuration. 

It is important to verify that the approved manning levels are programmed and funded as 

the program nears system operations and beyond. One way to accomplish this would be to 
96 

compare the approved manning levels, the programmed manpower authorizations as reflected in 

the FYDP, and (when available) the actual manning. Figure E-6 shows such a comparison for a 

Navy surface ship. 

Figure E-6. Assessment of Ship Manning

In this example, the data are provided for the ship class average. Again, in some cases, the 

data would need to be stratified by flight or block. 

The actual manning can be provided by the Naval VAMOSC data system. In general, the 

approved manning, programmed manning, and actual manning should be reasonably consistent 

on average over a multiple-year period, although there may be variations among the three in any 

one year due to lags in programming, budgeting, and execution. In this example, the approved 

manning, programmed manning, and actual manning align quite closely. If that were not the 

case, it would be appropriate to investigate the reasons for and implications of any significant 

discrepancies.

Analysis of Data Accuracy and Completeness 
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For currently fielded major systems, historical O&S cost data for the most part are 

available from the VAMOSC data system managed by each military department. VAMOSC data 

should always be carefully examined before use in a cost estimate. The data should be displayed 

over a period of a few years (not just a single year), and stratified by organization or location 

(such as major command or base). This should be done so that abnormal outliers in the data can 

be identified and documented, investigated, and resolved as necessary. 

VAMOSC data are sometimes supplemented with other data. As noted in Chapter 6 of this 

guide, CSDR data collection and reporting now applies to major weapon system sustainment 

contracts and subcontracts above specified dollar thresholds. There are also more specialized 

reliability and maintainability data, which can be obtained from military department maintenance 

data collection systems. In addition, VAMOSC data for unit-level manpower are often 

supplemented with information from more detailed unit manning documents or tables of 

organization and equipment.

Post-IOC O&S Cost Estimates

10 U.S.C. 2337a (Assessment, Management, and Control of Operating and Support Costs 

for Major Weapon Systems) requires the military departments to update estimates of O&S costs 

periodically throughout the life cycle of a major weapon system, to determine whether 

preliminary information and assumptions remain relevant and accurate, and identify and record 

reasons for variances. This provision also requires the military departments to conduct periodic 

reviews of O&S costs of major weapon systems after such systems achieve IOC to identify and 

address factors resulting in growth in O&S costs and adapt strategies to reduce such costs. 

CAPE guidance concerning this provision is provided in DoDI 5000.73. This guidance 

states that:

• After IOC, DoD Components must continue to track O&S costs and update O&S cost 

estimates yearly throughout an MDAP’s or major system’s life cycle to determine 

whether preliminary information and assumptions remain relevant and accurate and to 

identify and record reasons for variances.

• O&S cost estimates are independently reviewed at post-IOC reviews.

• Each O&S cost estimate must be compared to earlier estimates and the program’s 

sustainment goals. This comparison must identify the reasons for significant changes.

A notional example of such a comparison (based on an actual case study) follows. Figure E-7

shows an example of a track of various O&S cost estimates that were made for an aircraft 

program. 
98 

Figure E-7. Track of O&S Cost Estimates

The chart shows the annual steady-state O&S costs for a typical aircraft squadron, where 

the costs are broken down and displayed using the standard direct cost elements described in 

Chapter 3 of this guide. The chart shows a comparison of four cost estimates made at different 

points in time. The first estimate supported a Milestone B decision in 1996, the second estimate 

supported a Milestone C decision in 2002, the third estimate supported a Full-Rate Production 

decision in 2008, and the fourth estimate supported a sustainment review in 2020. Alternatively, 

the track of O&S costs could be displayed as cost per system per year, or cost per unit of usage 

or OPTEMPO (in this case, flight hour). The earlier cost estimates included indirect costs; these 

indirect costs have been removed for this comparison. 

In this example, the fourth (current O&S) cost estimate is significantly higher than the earlier 

estimates. The various reasons for the cost growth between the current estimate (2020) and the 

Milestone B estimate (1996) were identified. Figure E-8 displays the results of this assessment. 
99 

Figure E-8. Assessment of O&S Cost Growth

The Milestone B estimate is shown at the bottom of the stacked bar chart. The variances 

that result in the cost growth reflected in the current estimate are displayed individually. In this 

example, a key difference between the two estimates is that the Milestone B estimate had 

assumed an organic maintenance strategy, whereas the current estimate is based on a Contractor 

Logistics (CLS) strategy. These variances between the two estimates are as follows: 

• Change in active-reserve mix.

• Unanticipated real growth (or price escalation) in manpower costs per military member

for incentive and special pays, housing, and Permanent Change of Station (PCS)

moves.

• Unanticipated modification costs associated with safety upgrades necessary to meet

evolving flight-worthiness standards mandated by the Federal Aviation Administration.

• Higher fuel consumption, due to airframe weight growth during development.

• Higher dollars per flight hour for DLRs and consumables due to cost growth from

major suppliers.
100

• Higher costs for engine depot maintenance associated with the CLS strategy (relative to 

comparable organic support).

• Addition of significant resources for contractor field service representatives, with no 

offset in organic maintenance manpower.

• Higher costs for training support associated with the CLS strategy.

• Significant increase in the level of effort for sustaining engineering and program 

management associated with the CLS strategy.

For programs that have submitted recent SARs, the SARs can be a useful source of the 

reasons for cost variances in the program O&S cost estimates over time. The SAR O&S 

reporting includes a cost variance analysis that identifies each change, and the reason for it, 

between each estimate and the prior year’s estimate. In the Annual Selected Acquisition Report 

Guidance, the reasons for the variances are classified into the following categories:

• Programmatic/planning factors,

• Cost estimating methodology,

• Cost data update,

• Labor rates,

• Energy rates,

• Technical inputs, and

• Other.

The SAR annual guidance provides further discussion about these categories.

In this example, the change in active-reserve mix would be matched with the 

programmatic/planning factors category. The growth in military manpower costs would be 

matched with the labor rate category. Modifications due to new requirements, and the increase in 

fuel consumption, would be matched with the technical inputs category. The growth in costs for 

DLRs and consumables would be matched with the cost data update category. The other 

variances are due to an increase in level-of-effort due to the CLS strategy, and would be matched 

with the cost data update category.
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APPENDIX F

DoD Maintenance and Supply

Background

Introduction

This appendix is intended to provide a brief introduction to the concepts, terminology, and 

processes for DoD maintenance and supply chain management for major weapon systems. 

Effective maintenance and supply chain management are critical in ensuring weapon system 

readiness. Figure F-1 portrays an overview of this idea. 

Figure F-1. Overview of DoD Maintenance and Supply

Achieving system availability goals requires responsive maintenance that is adequately 

resourced in terms of maintenance manpower and is supported by an effective supply chain that 

provides timely delivery of reparable and consumable items. 
102

DoD maintenance is conducted at different levels. The next three sections introduce the 

different levels of maintenance. Note that the organizational concepts and terminology vary 

somewhat by military service. 

Unit-Level Maintenance

Unit-level maintenance is field-level maintenance conducted by personnel in the system 

operating unit (e.g., squadron, ship, or company) or a nearby support unit. Unit-level 

maintenance consists of organizational maintenance and sometimes unit-level intermediate 

maintenance. Organizational maintenance or on-equipment maintenance includes the removal 

and replacement of system reparable or consumable components, and also includes minor 

adjustments or fault/failure diagnoses that are performed in-place on the system. Organizational 

maintenance also includes other support activities such as inspections, servicing, handling, and 

preventative maintenance. Intermediate maintenance or off-equipment shop-type work consists 

of limited repair of components that have been removed from the system by organizational 

maintenance personnel. The Army employs a two-level maintenance concept (field and 

sustainment) and does not use the terms “organizational maintenance” and “intermediate 

maintenance” in doctrine or practice. For Navy ships, intermediate maintenance is not conducted 

by ship (unit) personnel and hence is not considered unit-level.

Intermediate Maintenance (External to Unit-Level)

In some cases, intermediate maintenance is performed by organizations that are not 

considered unit- or field-level. The term intermediate is used to refer to a maintenance capability 

that falls between the capabilities of organizational maintenance and depot maintenance. Navy 

Regional Maintenance Centers, Aviation Intermediate Maintenance Departments, and the 

Trident Refit Facility are examples of Navy intermediate maintenance organizations. Note that 

such organizations not only provide off-equipment component repair, but also can provide 

limited on-equipment overhauls and repairs for the system as a whole. In addition, there are two 

public shipyards, Pearl Harbor and Puget Sound, that are hybrid in character and provide both 

intermediate and depot maintenance.

The Air Force has only a few organizations, known as Centralized Intermediate Repair 

Facilities, which provide shop-type work, that are not considered unit-level. 

As noted above, the Army employs a two-level maintenance concept, consisting of fieldlevel maintenance and sustainment maintenance. Within the sustainment level, the Army 

conducts what is called “below depot sustainment maintenance.” This type of maintenance 

involves component repair and is roughly equivalent to intermediate maintenance performed 

external to the unit level. In particular, the Army now has component repair companies that 

provide repairs of components for electronic systems, armament and artillery systems, 

automotive equipment, and other types of equipment.
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Depot Maintenance

Depot maintenance is the major on-equipment repair and overhaul of weapon systems and 

other end items such as aircraft engines, and the off-equipment repair of system components at a 

maintenance depot. This requires a more industrial-type facility and a higher skill level of 

maintenance personnel than available at organizational and intermediate maintenance activities. 

Depots normally have high-cost tooling and facilities that are not found at unit- or intermediatelevel maintenance facilities. 

Depot maintenance is provided by a mix of government and contractor sources. These 

contractor sources include the weapon system original equipment manufacturer (OEM) and other 

contractor facilities including private shipyards. There are also some arrangements for depot 

maintenance known as public-private partnerships, or “P3s,” where the work is shared or 

subcontracted between the contractor and a government entity.

Note that as described in this appendix, the term depot maintenance is associated with two 

distinct elements of the cost element structure presented in Chapter 3 of this guide: depot level 

reparables (DLRs) (element 3.2) and depot maintenance (element 3.4). 

A DLR is a reparable item/component that is repaired at least in part at the depot level of 

maintenance. DLR costs are incurred largely at the unit level. Typically, when a DLR item 

requires maintenance, the item is removed from the system and replaced with another item from 

local inventory. This remove and replace action usually takes place at the unit level. When unit 

maintenance turns in a “failed” item/component (sometimes referred to as a “carcass”), that 

organization (“customer”) is charged with an exchange price (sometimes called the net price). 

This exchange price includes the cost of direct labor and material for item repairs along with a 

surcharge for transportation, storage, inventory management, and other overhead. The direct 

material costs consist of consumables and sometimes nested reparable items. If unit maintenance 

does not have a “failed” item/component to return to the supply system, that organization is 

charged with a standard price. The standard price includes the new item/component purchase 

price along with a surcharge for attrition, transportation, storage, inventory management, and 

other overhead. Also, in cases where a failed item is turned in but the item is determined to be 

irreparable due to customer negligence or maliciousness, the customer is charged the difference 

between the exchange price and the standard price.

Also, much work associated with system hardware modifications and other modernization 

upgrades takes place at a maintenance depot. Although the hardware upgrades are regarded as 

distinct from the system depot maintenance, and are funded separately, in practice the two 

activities are often synchronized in planning and execution.

Extensive statutory requirements associated with depot maintenance are described in 

Appendix H of this guide.
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Supply Chain or Materiel Management

The supply chain management function is critical to ensuring the timely delivery of 

reparable and consumable items. The key elements to supply chain management are:

• Cataloging and configuration management,

• Demand forecasting,

• Setting of inventory levels,

• Procurement of consumable items and materials,

• Storage,

• Processing customer requisitions,

• Sourcing of repairs, and 

• Distribution.

For the Air Force and Navy, this function is conducted at the enterprise level by the Air 

Force Sustainment Center and the Navy Supply Systems Command, respectively. The Army has 

a more decentralized approach, and the supply chain management function resides at each of the 

commodity Life Cycle Management Commands. In addition, as explained later in this appendix, 

the supply chain management function for most consumable items resides at the Defense 

Logistics Agency (DLA).

Additional Topics

Role of the Defense Logistics Agency

For cost analysts, it is important to not only understand the basic concepts and terminology 

for maintenance conducted within each military department, but also to understand the role of 

DLA in providing essential logistics support for the armed forces. This support includes two 

important aspects. First, DLA is responsible for contracting, purchasing, and—where needed—

storing and distributing most of the consumable items for DoD. In other cases, DLA is 

responsible for managing the delivery of these items from the vendors directly to the military 

units. DLA manages several supply centers (inventory control points) and a global network of 

distribution centers (warehouses). Second, DLA is responsible for the petroleum supply chain 

and associated transportation services and infrastructure. DLA manages the transportation and 

contractor support required for distribution of petroleum to military units and other customers 

throughout the United States, Europe, the Western Pacific, and the Middle East. In addition, 

DLA manages the worldwide acquisition of other fuels and propellants such as missile and 

rocket fuels, and satellite propellants. 
105

Background on the Defense Working Capital Fund

Many of the military department and DLA activities for the maintenance and logistics of 

major weapon systems are financed through an arrangement known as the Defense Working 

Capital Fund (DWCF). For the most part, the DWCF is used to finance consumables, DLRs, 

depot maintenance, and fuel. The basic tenet of the DWCF is to create a business-like, customerprovider relationship between the military operating units and the support organizations. This 

arrangement is designed to establish incentives for efficiency. 

For example, if depot maintenance were centrally funded by the military department 

headquarters, the operating units would regard such depot maintenance as a free good or service. 

Requiring the operating forces to pay for the support that they receive as customers provides 

increased assurance that the services obtained and provided are scrutinized and actually needed. 

In addition, the DWCF providers are expected to operate under business financial management 

principles. For support organizations within the fund, they are required to establish a cost 

accounting system that identifies costs (direct labor, material, and overhead) with the outputs of 

the business. This provides visibility into the cost drivers and encourages management to 

scrutinize costs based on financial operating results. 

For cost analysts, there are two perspectives on cost data for DWCF maintenance and 

logistics activities. One perspective is the prices that users pay for goods and services, which 

normally is what is captured by the military department VAMOSC systems. A second 

perspective is the actual costs—for direct labor and material, as well as a surcharge for 

overhead—experienced by the support organizations. Data on these costs from this perspective 

can often be obtained from military department Enterprise Resource Planning systems and the 

operating budgets of the military department and DLA working capital funds. 

Product Support Management and Integrated Product Support

Each major weapon system is required to have a product support strategy document that 

addresses all aspects of system sustainment throughout the life cycle. Each system has a product 

support manager (PSM) responsible for the development and implementation of this strategy. 

The PSM reports to the Program Manager and the two together are responsible for the execution 

of the product support strategy within specified budgets.

The Integrated Product Support (IPS) elements are used as a guide for the development and 

implementation of the product support strategy. However, the IPS elements are a management 

framework, and do not map directly to the CAPE O&S cost element structure. O&S cost data 

collection and estimation should maintain the discipline of the standard structure in order to have 

standardized cost estimates and analyses and consistent reporting to higher authorities and 

Congress. Further information on the IPS elements can be found in the Integrated Product 

Support (IPS) Elements Guidebook.
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Terminology About Contractor Support

The remainder of this appendix provides additional remarks about contractor support, 

initially during the production and deployment phase, which later transitions into support during 

the operations and sustainment phase. 

Interim Contractor Support (ICS) is temporary contractor support provided before a 

permanent support solution (organic or contractor) is established. This support consists of labor, 

material, and overhead for maintenance, supply management, and other support functions 

required to sustain the system during the early fielding of the system. The actual scope of an ICS 

effort varies among programs and contracts.

If the permanent support solution is provided by a contractor, it is known as Contractor 

Logistics Support (CLS). Like ICS, CLS consists of labor, material, and overhead for 

maintenance, supply management, and other support functions required to sustain the system. 

The only difference between ICS and CLS is the period of performance. If CLS is used, it begins

when the ICS period has ended. DoD 7000.14-R, Financial Management Regulation, Volume 

2A, Chapter 1, section 010208, provides guidance for funding policies for ICS and CLS. ICS is 

funded with procurement appropriations for the period established in the program baseline before 

the establishment of a permanent support solution. After that period, contractor support is 

regarded as CLS, and is funded with O&M appropriations. However, for some programs, the ICS 

and CLS may in practice overlap.

For many years, DoD policy has favored a product support strategy known as PerformanceBased Logistics (PBL). PBL is synonymous with performance-based support. Current DoD 

policy states that program managers and product support managers will develop and implement 

an affordable and effective performance-based support, or PBL, package that utilizes 

performance metrics. PBL integrates the various product support activities with appropriate 

metrics and incentives, and product support requirements are described in terms of the desired 

results rather than in terms of how work is to be performed. The PBL strategy can apply to both 

CLS and organic maintenance. The PBL strategy is implemented through a formal arrangement 

known as a Performance-Based Arrangement (PBA). The PBA establishes a system or 

subsystem/component measurable level of performance in a contract, Memorandum of 

Agreement, Service Level Agreement, or other formal arrangement.

For programs employing CLS, DoD policy states that a performance-based contract is to be 

used wherever possible.

For CLS using the traditional transactional product support model, the Government 

purchases parts or maintenance services from the contractor. When equipment fails or is 

overhauled, the contractor charges the Government for repair, replacement, or overhaul on a 

transaction-by-transaction basis. The contractor often is not incentivized to reduce sustainment 

costs or improve materiel availability.
107

Under a PBL contracting strategy, the contractor is responsible for providing a specified 

level of performance, usually material availability, and is paid based on system usage or activity 

(operating tempo or OPTEMPO). The contract is structured to provide positive incentives for 

achieving improved performance fostering innovations and efficiencies, and negative incentives 

for achieving inferior performance. In some cases, the contractor can also be allowed to reduce 

sustainment costs by improving system or component reliability, and can then financially receive 

a fraction of the savings.

Further guidance on PBL can be found in the Performance Based Logistics (PBL) 

Guidebook.
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109

APPENDIX G

Product Support Cost Estimate at the Component Level of Detail

Introduction

Much of the discussion in this guide is focused on O&S cost estimates for major weapon 

systems. In contrast, this appendix provides an illustrative example of how to prepare an O&S 

cost estimate at the component or black box level of detail. In addition, cost estimates are also 

provided for acquisition logistics cost elements such as the procurement of initial spares, support 

equipment, and initial training. The acquisition logistics support cost elements are described in 

Appendix C of this guide.

Specifically, the estimate in this example concerns costs for an avionics or electronic 

subsystem that is to be installed on a host platform or vehicle. The approach is to obtain detailed 

data concerning component unit cost, reliability, maintainability, and other characteristics. There 

are also other general data such as subsystem service life, platform system quantities and 

operating hours, and maintenance level information. The data can then be used in various 

accounting equations to estimate the yearly and total costs.

This example uses the Cost Analysis Strategy Assessment (CASA) model managed by the 

Army Logistics and Engineering Center (LEC) in the Army Logistics Data Analysis Center of 

the U.S. Army Materiel Command. The CASA model is a bottom-up, accounting type tool that 

can be used for estimating system life-cycle costs. The model software provides extensive online help to the analyst, including complete descriptions of the accounting equations that are used 

in the model. The model also provides several features such as automated tools for sensitivity 

analysis or risk and uncertainty analysis. This model is available free of charge to US personnel 

within the public and private sectors. Further information is available at the CASA home page at 

www.logsa.army.mil/#/lec/casa. 

Ground Rules and Assumptions 

The major ground rules and assumptions for the cost analysis are shown below:

• 120 avionics subsystems are to be installed and operated on the host platforms. 

• Each subsystem has a service life of 20 years.

• The host platforms are operated in 10 units, with 12 platforms in each unit. Each platform 

is operated at 20 hours per month. 

• There are two levels of maintenance for the subsystem: (1) unit (or field) level 

maintenance, where each unit conducts maintenance, consisting of both organizational 
110

maintenance and intermediate maintenance resident in the unit, and (2) depot 

maintenance, which supports the entire fleet with a more extensive repair capability.

• The avionics subsystem consists of three black boxes or Line Replaceable Units (LRUs). 

Each LRU consists of various Shop Replaceable Units (SRUs) such as electronic circuit 

boards. 

• There will be an inventory of initial spares (LRUs and SRUs) for each platform unit, and 

at depot-level.

• The avionics subsystem will require new support equipment for both unit-level and 

depot-level maintenance. 

• The avionics subsystem will require a new training course to support training for system 

maintenance. This training course will require a new type of training device. 

• The avionics subsystem will require a new unit-level maintenance manual, and a new 

depot-level maintenance manual. 

• The costs for maintenance man-hours for both unit-level and depot-level maintenance are

based on an hourly labor rate for each level.

Detailed Component Data

Tables G-1 and G-2 show the major reliability, maintainability, and other data assumed 

for the subsystem components.
111

Table G-1. Avionics Components Input Data

WBS 

Level

Unit cost 

of a 

spare in 

$

Quantity 

per next 

higher 

assembly

Mean 

time 

between 

failures 

in hours

Mean 

time 

to 

repair 

(Manhours)

Shipping 

weight

Item ITYPE COST QPNHA MTBF MTTR WT

Avionics Subsystem 1 0 1 135 0 0

Black Box Type 1 2 750,000 1 385 16 160

Circuit Board Type 

1A

3 100,000 3 3,000 24 10

Circuit Board Type 

1B

3 150,000 3 2,000 24 10

Board Rack Type 1 3 50,000 1 10,000 32 100

Black Box Type 2 2 1,200,000 1 435 16 160

Circuit Board Type 

2A

3 200,000 3 1,500 24 10

Circuit Board Type 

2B

3 200,000 3 15,000 24 10

Board Rack Type 2 3 50,000 1 10,000 32 100

Black Box Type 3 2 1,000,000 1 400 16 80
112

Table G-2. Avionics Components Input Data (continued)

Level 

Repair

Level 

Remove

Portion of 

failures 

expected 

to retest 

okay, 

expressed 

as a 

decimal 

fraction of 

real 

failures

Matl 

Cost 

Per 

Repair 

$

Portion of 

failures not 

repairable at 

the 

designated 

primary 

maintenance 

level, 

expressed 

as decimal

Portion of 

failures 

expected to 

be 

condemned 

expressed 

as a 

decimal 

fraction

ITEM LRPR LREM RTOK MCPR NRTS COND

Avionics Subsystem 0 0 0.0 0 0.0 0.000

Black Box Type 1 1 1 0.1 0 0.1 0.001

Circuit Board Type 

1A

2 1 0.0 1,000 0.0 0.025

Circuit Board Type 

1B

2 1 0.0 1,500 0.0 0.025

Board Rack Type 1 2 2 0.0 500 0.0 0.001

Black Box Type 2 1 1 0.1 0 0.1 0.001

Circuit Board Type 

2A

2 1 0.0 2,000 0.0 0.025

Circuit Board Type 

2B

2 1 0.0 2,000 0.0 0.025

Board Rack Type 2 2 2 0.0 500 0.0 0.001

Black Box Type 3 2 1 0.1 10,000 0.0 0.001

Some explanatory remarks for these data are shown below:

• The components are displayed in a work breakdown structure (WBS) hierarchy 

associated with levels of assembly. In this example, the avionics subsystem consists of 

three types of black boxes, where there is one of each black box type per subsystem. The 

first two types of black boxes consist of various circuit boards and a board rack.

• Each component has a unit cost that is used in the calculations of initial spares and 

replenishment spares.

• Each component has a specified reliability that is expressed as Mean Time Between 

Failures in hours. In this example, the subsystem operating hours are assumed to be the 

same as the operating hours of the host platform.

• A specified portion of the component failures Retest Okay, and do not result in repairs.

• Each component repair has an associated Mean Time to Repair (in manhours) and an 

associated Material Cost per Repair (in dollars).
113

• Each component has a specified maintenance concept, which consists of the level of 

removal and the level of repair for each component. In this example, Black Box Types 1 

and 2 are primarily repaired at the unit level. However, they may require repair at the 

depot level a fraction of the time. 

• Each component has a shipping weight that can be used in the calculations of 

transportation costs associated with the various maintenance activities.

• A specified portion of the failures result in component condemnations, which in turn 

result in the purchase of replenishment spares.

Other Input Data

There is also additional input data associated with the estimates for acquisition logistics and 

O&S costs. Examples are shown for support equipment, initial spares, technical data, and 

training.

Support Equipment

In this example, the avionics subsystem requires two items of support equipment: UnitLevel Test Equipment, and Depot-Level Test Equipment. Table G-3 provides the input data 

associated with support equipment procurement and maintenance.
114

Table G-3. Support Equipment Input Data

Unit-Level Test Equipment Data

Unit Cost for Support Equipment ($) 500,000

Annual Maintenance Factor (%) 0.025

Hours Required for SE

Black Box Type 1 8

Black Box Type 2 8

Depot-Level Test Equipment Data

Unit Cost for Support Equipment ($) 3,000,000 

Annual Maintenance Factor (%) 0.025

Hours Required for SE

Black Box Type 1 8

Circuit Board Type 1A 12

Circuit Board Type 1B 12

Board Rack Type 1 16

Black Box Type 2 8

Circuit Board Type 2A 12

Circuit Board Type 2B 12

Board Rack Type 2 16

Black Box Type 3 8

The model calculates the required quantities of the support equipment to be procured based 

on the anticipated maintenance workload. There is also consideration of the availability of the 

support equipment. In this example, it is assumed that the unit-level maintenance has two shifts 

per day, and that the unit-level test equipment is available 343 hours per month. The depot-level 

maintenance is assumed to have one shift per day, and that the depot-level test equipment is 

available 171 hours per month. It is also assumed that the maximum utilization of the support 

equipment is a utilization rate of 90%. For support equipment maintenance costs, the model uses 

an “Annual Maintenance Factor.” This factor represents the annual maintenance cost of each 

support equipment item expressed as a fraction of the support equipment item unit cost.

Initial Spares 

In this example, the avionics subsystem requires procurement of initial spares for both 

unit-level and depot-level maintenance. For unit level, it is assumed that initial spares are 

procured for the three black box types and the various circuit boards. For depot level, it is 

assumed that initial spares are procured for the three black box types, the circuit boards, and the 

board racks. Note that the model calculates the required quantities of initial spares to be procured 

based on the anticipated maintenance workload and a required confidence level for spares 

availability. The calculations also consider the average turnaround time for spares for both 

unit-level and depot-level maintenance. The turnaround time is the amount of time from when a 
115

spare is taken out of the inventory until it is replaced by another (either by repair of the failed 

item or the shipping of a replacement item from another maintenance level). In this example, the 

average unit-level turnaround time was assumed to be 0.25 months for the three black box types 

and the circuit boards. The average depot-level turnaround time was assumed to be 0.50 months 

for the circuit boards, and 1.00 months for the other hardware items.

Technical Data 

In this example, the avionics subsystem requires two items of technical data: a Unit-Level 

Maintenance Manual, and a Depot-Level Maintenance Manual. Table G-4 displays the input data 

associated with the procurement and maintenance of technical data.

Table G-4. Technical Data Input Data

Unit-Level Maintenance Manual Data

Year Cost Incurred 2020

Total Number of Pages 100

Cost per Page to Develop ($) 5,000

Cost per Page to Publish ($) 0.6

Total Number of Copies 20

Annual Number of Revised Pages 5

Revision Cost per Page ($) 5,000

Depot-Level Maintenance Manual Data

Year Cost Incurred 2020

Total Number of Pages 300

Cost per Page to Develop ($) 7,500

Cost per Page to Publish ($) 0.6

Total Number of Copies 5

Annual Number of Revised Pages 15

Revision Cost per Page 7,500

Training and Training Devices 

In this example, the avionics subsystem will require a new training course to support 

training for system maintenance. This training course will require a new type of training device. 

Table G-5 provides the input data associated with initial training, recurring training and the 

training devices.
116

Table G-5. Training and Training Devices Input Data

Initial Training Data

Per Diem ($/day) 150

Round Trip Cost ($) 1,500

System Maintainer Course

Year 2020

Class Hours 24

Development Cost per Class Hour 50,000

Trainee Labor Rate ($/hour) 45

Number of Trainees 30

Number of Days 3

Number of Instructors 3

Instructor Labor Rate ($/hour) 75

Recurring Training Data

Unit-Level

Recurring Training Hours 24

Development Cost per Class Hour 50,000

Annual Turnover Rate 0.33

Training Devices Data

Repair Trainer Unit

Year Cost Incurred 2020

Quantity of Devices 15

Init Cost for Device ($) 200,000

Model Output

Acquisition Logistics Costs

Table G-6 shows the estimated acquisition logistics costs for the avionics subsystem.
117

Table G-6. Total Acquisition Logistics Costs

FY 2020 Dollars in Thousands Total

Initial Support Equipment 12,100 

Initial Spares 51,150 

Initial Tech Data 2,754 

Initial Training 1,307 

Training Devices 3,000 

Total 70,311 

O&S Costs

Table G-7 shows the estimated O&S costs for the avionics subsystem.

Table G-7. Total O&S Costs

FY 2020 Dollars in Thousands Unit Level

Depot 

Level Total

Repair Labor 1,536,622 4,621,407 6,158,029 

Support Equipment Maintenance 2,032,292 2,531,250 4,563,542 

Recurring Training 1,257,945 - 1,257,945 

Repair Parts and Material - 14,054,148 14,054,148 

Consumables - 1,405,415 1,405,415 

Condemnation Spares 2,236,611 9,716,861 11,953,472 

Technical Data Revisions 493,750 2,221,875 2,715,625 

Total 7,792,217 35,403,940 43,196,157 

Other Considerations

This example was limited in scope for demonstration purposes, and did not address other 

costs that might be appropriate for a specific application. The CASA model has equations that 

could be used for other costs not illustrated in this example. Examples that could be added 

include costs for facilities modifications and maintenance, item management, contractor services, 

engineering changes, software maintenance, transportation, and warranties. The model also 

permits a more sophisticated approach for hardware reliability that allows the use of reliability 

growth models.

The model also provides an extensive menu of a wide range of output reports not shown in 

this appendix. There are options for reports on annual costs in constant, then-year, and 

discounted dollars. In addition, more detailed reports provide visibility into the costs of the 

distinct LRUs and SRUs, support equipment utilization, and maintenance workload at each 

location. There are also input data reports that the analyst can use for study data verification. The 

model also provides the analyst with a wide variety of sensitivity analysis reports concerning the 
118

major input data. The model also provides features that enable the development of an S-curve 

risk model for the cost estimate. 

Equations

The remainder of this appendix provides a simplified review of the accounting equations 

used for the elements of annual O&S cost for this example. Equations are provided for repair 

labor, support equipment maintenance, recurring training, repair parts and material, 

condemnation spares, and technical data revisions. Note that the equations are different for each 

level of maintenance.

 Repair Labor

Unit Level

�(NNNN)(OOOO)(QQQQ QQii)((1 − CC CCii)(MMMMMMMMii)(UU UU )

MMMMMMMMii

ii

Depot Level

�(NNNN)(OOOO)(QQQQ QQii)((1 − CC CCii)(NN NNii)(MMMMMMMMii)( )

MMMMMMMMii

+

ii

�(NNNN)(OOOO)(QQQQ QQii)(QQQQ QQiiii)((1 − CC CCiiii)(MMMMMMMMiiii)( )

MMMMMMMMiiii

ii,

Support Equipment Maintenance

Unit Level

�(QQ QQ kk)(NN )(UU UUkk)( kk)

kk

Depot Level

�(QQ QQ ll)(UU ll)( ll)

ll
119

Recurring Training

Unit Level

(NN )(UU UU )(UU )(UU )(UU UU )

160

Depot Level

( )( )( )( )

160

Repair Parts and Material

Unit Level

�(NNNN)(OOOO)(QQQQ QQii)((1 − CC CCii)(1 − NN NNii)(MM MMii))

MMMMMMMMii

ii

Depot Level

�(NNNN)(OOOO)(QQQQ QQii)((1 − CC CCii)(NN NNii)(MM MMii)

MMMMMMMMii

+

ii

�(NNNN)(OOOO)(QQQQ QQii)(QQQQ QQiiii)((1 − CC CCiiii)(MM MMiiii)

MMMMMMMMiiii

ii,

Condemnation Spares

Unit Level

�(NNNN)(OOOO)(QQQQ QQii)((CC CCii)(UU ii)

MMMMMMMMii

ii

Depot Level

�(NNNN)(OOOO)(QQQQ QQii)(QQQQ QQiiii)((CC CCiiii)(UU iiii)

MMMMMMMMiiii

ii,
120

Technical Data Revisions

Unit Level

(UU UU UU)(UU UU)

Depot Level

( )( )

Model Inputs

NS = Number of systems

OH = Operating hours per system

NU = Number of units

UMLR = Unit-level maintenance labor rate (dollars per hour)

DMLR = Depot-level maintenance labor rate (dollars per hour)

For LRUs:

QPNHAi = Quantity per next higher assembly for the ith item

CONDi = Decimal fraction of failures that result in condemnation for the ith item

MTTRi = Mean time to repair for the ith item

MTBFi = Mean time between failure for the ith item

NRTSi = Decimal fraction of failures that are Not Repairable This Station for the ith item

MCPRi = Material cost per repair for the ith item

UCi = Unit cost (for spares) for the ith item

For SRUs:

QPNHAij = Quantity per next higher assembly for the jth item of the ith LRU

CONDij = Decimal fraction of failures that result in condemnation for the jth item of the ith 

LRU

MTTRij = Mean time to repair for the jth item of the ith LRU

MTBFij = Mean time between failure for the jth item of the ith LRU

NRTSij = Decimal fraction of failures that are Not Repairable This Station for the jth item of 

the ith LRU
121

MCPRij = Material cost per repair for the jth item of the ith LRU

UCi j = Unit cost (for spares) for the jth item of the ith LRU

For support equipment:

QSEUk = Quantity per unit of the kth item of unit-level support equipment

UCSEUk = Unit cost of the kth item of unit-level support equipment

AMFUk = Annual maintenance cost (as a decimal fraction of unit cost) of the kth item of 

unit-level support equipment

QSEDl = Quantity of the lth item of depot-level support equipment

UCSEDUl = Unit cost of the lth item of depot-level support equipment

AMFDl = Annual maintenance cost (as a decimal fraction of unit cost) of the lth item of 

depot-level support equipment

For recurring training:

UTOR = Annual turnover rate of unit-level maintenance personnel

UTRHRS = Number of hours required to train new unit-level maintenance personnel

DTOR = Annual turnover rate of depot-level maintenance personnel

DTRHRS = Number of hours required to train new depot-level maintenance personnel

For technical data revisions:

UQTYRPG = Number of pages of technical documentation that will be revised each year at 

the unit level 

UCSTRPG= Average cost per page to develop technical document revisions at the unit level

DQTYRPG = Number of pages of technical documentation that will be revised each year at 

the depot level 

DCSTRPG= Average cost per page to develop technical document revisions at the depot 

level

Model Intermediate Calculations

UMAXMMH = Unit-level maintenance man-hours per month per location

DMAXMMH = Depot-level maintenance man-hours per month
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123

APPENDIX H

Relevant Statutory Requirements

Introduction

Over the last decade, the Congress has established extensive and demanding statutory 

requirements pertaining to operating and support (O&S) cost estimation, as well as 

sustainment or product support management, for major Department of Defense (DoD)

weapon systems. This appendix is intended to summarize these requirements. This appendix 

also provides discussion and references relevant to the current DoD implementation of these 

statutory requirements.

Relevant Statutory Requirements in Title 10, United States Code

Section 2334, Independent Cost Estimation and Analysis

Section 2334 establishes numerous responsibilities and authorities for the Director of 

Cost Assessment and Program Evaluation (DCAPE) pertaining to cost estimation and cost 

analysis for the acquisition programs of DoD. In particular, this section requires the 

Director to issue guidance relating to full consideration of life-cycle management and 

sustainability costs in Major Defense Acquisition Programs (MDAPs) and major 

subprograms. In addition, this section also provides responsibilities and authorities 

concerning cost data collection. This section was most recently revised in the National 

Defense Authorization Act (NDAA) for FY 2018.

Further explanation of the policies and procedures that address the DoD 

implementation of this section are provided in DoD Instruction (DoDI) 5000.73, Cost 

Analysis Guidance and Procedures. Some of the topics addressed in this instruction include 

Independent Cost Estimates (ICEs) and other cost analyses, Component Cost Positions 

(CCPs), Full Funding Certification Memoranda, and requirements for cost data collection 

and reporting. Cost Assessment and Program Evaluation (CAPE)’s perspective on the best 

practices for cost estimation in general is provided in the DoD Cost Estimating Guide. 

Additional discussion specific to O&S cost estimation and weapon system sustainment are 

provided in this guide. 

Section 2366a, Major Defense Acquisition Programs: Determination Required Before 

Milestone A Approval

Section 2366a states that an MDAP may not receive Milestone A approval until the 

Milestone Decision Authority (MDA) determines in writing that the program meets several 
124

specific criteria. One of the criteria that must be met is that planning for sustainment has 

been addressed and that a determination of applicability of core logistics (i.e., depot-level 

maintenance and repair) capabilities requirements has been made. Another one of the 

criteria that must be met is that a cost estimate for the program has been submitted, with the 

concurrence of DCAPE, and that the level of resources required to develop, procure, and 

sustain the program is sufficient for successful program execution. 

Additionally, within 15 days of granting Milestone A approval, the MDA is required 

to submit the program cost and schedule estimates, as well as the ICE, to the congressional 

defense committees. This section was most recently revised in the NDAA for FY 2019.

Section 2366b, Major Defense Acquisition Programs: Determination Required Before 

Milestone B Approval

Section 2366b states that an MDAP may not receive Milestone B approval until the 

MDA determines in writing that the program meets several specific criteria. One of the 

criteria that must be met is that life-cycle sustainment planning, including corrosion 

prevention and mitigation planning, has identified and evaluated relevant sustainment costs 

throughout development, production, operation, sustainment, and disposal of the program, 

and any alternatives, and that such costs are reasonable and have been accurately estimated. 

Another one of the criteria that must be met is that reasonable cost and schedule estimates 

have been developed to execute—with the concurrence of the Director, CAPE (DCAPE)—

the product development and production plan under the program. 

Additionally, within 15 days of granting Milestone B approval, the MDA is required 

to submit the program cost and schedule estimates, as well as the ICE, to the congressional 

defense committees. This section was most recently revised in the NDAA for FY 2019.

Section 2366c, Major Defense Acquisition Programs: Submissions to Congress on 

Milestone C

Section 2366c requires that the MDA provide the congressional defense committees a 

brief summary report not later than 15 days after granting Milestone C approval for an

MDAP. This report includes the estimated cost and schedule for the program established by 

the military department concerned, including (1) the dollar values estimated for the program 

acquisition unit cost, average procurement unit cost, and total life-cycle cost, and (2) the 

planned dates for initial operational test and evaluation (IOT&E) and initial operational 

capability (IOC). This report also includes the ICE for the program and any independent 

estimated schedule for the program, including (1) the dollar values estimated for the 

program acquisition unit cost, average procurement unit cost, and total life-cycle cost, and 

(2) the planned dates for IOT&E and IOC. This section was most recently revised in the 

NDAA for FY 2018.
125

Section 2337, Life-Cycle Management and Product Support

Section 2337 requires DoD to issue and maintain comprehensive guidance on lifecycle management and the development and implementation of product support strategies 

for major weapon systems. Specifically, each major weapon system shall have a product 

support manager responsible for the development and implementation of the weapon system 

product support strategy. This section was most recently revised in the NDAA for FY 2014.

Further explanation of the policies and procedures that address the DoD 

implementation of this section are provided in DoDI 5000.85, Appendix 3D (“Product 

Support”). Additional discussion specific to weapon system sustainment and O&S cost 

management are provided in the following:

• Chapter 4 (“Life Cycle Sustainment”) of the Defense Acquisition Guidebook,

• Performance Based Logistics Guidebook,

• Product Support Manager Guidebook, and

• Operating and Support Cost Management Guidebook.

Section 2337a, Assessment, Management, and Control of Operating and Support Costs 

Section 2337a requires DoD to issue and maintain guidance on a wide range of actions 

to be taken to assess, manage and control DoD costs for the operation and support of major 

weapon systems. This section was added by the NDAA for FY 2012, and codified into 

statute by the NDAA for FY 2018. Note that this section requires that the guidance for this 

section be issued in conjunction with the guidance for the requirements of Section 2337, 

Life-Cycle Management, described earlier. 

Specifically, Section 2337a requires DoD guidance to address the following elements:

• Establish policies and procedures for the collection, organization, maintenance, 

and availability of standardized data on O&S costs for major weapon systems.

• Establish standard requirements for the collection and reporting of O&S costs for 

major weapon systems by contractors performing weapon system sustainment 

functions in an appropriate format, and develop contract clauses to ensure that 

contractors comply with such requirements.

• Include reliability metrics for major weapon systems and requirements on the use 

of metrics as triggers—

– to conduct further investigation and analysis into drivers of the metrics, and

– to develop strategies for improving reliability, availability, and maintainability 

of such systems at an affordable cost.
126

Further explanation of the policies and procedures that address the DoD 

implementation of the first two elements is provided in Chapter 6 of this guide. Further 

explanation of the policies and procedures that address the DoD implementation of the third 

element are provided in DoDI 5000.85, Appendix 3D (“Product Support”). Additional 

discussion is provided in Chapter 4 (“Life Cycle Sustainment”) of the Defense Acquisition 

Guidebook. Note that this particular element (reliability metrics) has been expanded by 

more recent legislation (Section 2443, Sustainment Factors in Weapon System Design) 

described later in this appendix.

In addition, the DCAPE is responsible for developing and maintaining a database on 

O&S cost estimates, supporting documentation, and actual O&S costs for major weapon 

systems. The implementation of this element is described in Chapter 6 of this guide, which 

described the military department Visibility and Management of Operating and Support 

Costs (VAMOSC) systems, and the EVAMOSC initiative. In addition, CAPE now collects 

independent cost estimates, CCPs, and various related cost estimation and acquisition 

documents and briefings and stores them in the Cost Assessment Data Enterprise (CADE) 

library.

Each military department is responsible for the following elements:

• Retain each estimate of O&S costs that is developed at any time during the life 

cycle of a major weapon system, together with the supporting documentation used 

to develop the estimate.

• Update estimates of O&S costs periodically throughout the life cycle of a major 

weapon system, to determine whether preliminary information and assumptions 

remain relevant and accurate, and identify and record reasons for variances.

• Collect and retain data from operational and developmental testing and evaluation 

on the reliability and maintainability of major weapon systems, and use such data to 

inform system design decisions, provide insight into sustainment costs, and inform 

estimates of O&S costs for such systems.

• Ensure that sustainment factors are fully considered at key life-cycle management 

decision points and that appropriate measures are taken to reduce O&S costs by 

influencing system design early in development, developing sound sustainment 

strategies, and addressing key drivers of costs.

• Conduct an Independent Logistics Assessment (ILA)13 of each major weapon 

system prior to key acquisition decision points (including milestone decisions) to 

13 An ILA is an analysis of a program’s supportability planning and execution conducted by a team of 

impartial subject matter experts. An ILA assesses the program’s product support strategy, as well as how 

this strategy is resulting in the effective operation of the system at an affordable cost. ILAs are described in 

the Logistics Assessment Guidebook.
127

identify features that are likely to drive future O&S costs, and effective strategies 

for managing such costs.

• Conduct periodic reviews of O&S costs of major weapon systems after such 

systems achieve IOC to identify and address factors resulting in growth in O&S 

costs and adapt support strategies to reduce such costs.

Estimates of O&S costs are updated at each program milestone review, and also may

be updated each year for inclusion in the annual program Selected Acquisition Report 

(SAR). The format for SAR reporting is described in Chapter 5 of this guide.

The tracking of reliability and maintainability data from test and evaluation is

described in Appendix E of this guide. These data can be used to inform design trades and 

cost estimates in one of two ways, depending on the maturity of the program. One way 

would be to use parametric cost estimating relationships that estimate maintenance costs as 

a function of reliability and other independent variables, as discussed in Chapter 7 of this 

guide. Another way would be to use a bottom-up accounting model for O&S costs that 

considers reliability and maintainability factors as model inputs, as discussed in 

Appendix G of this guide.

Discussion about the consideration of sustainment factors in the influence of system 

design at all key management decision points is provided in DoDI 5000.85, Appendix 3D 

(“Product Support”). Additional discussion is provided in Chapter 4 (“Life Cycle 

Sustainment”) of the Defense Acquisition Guidebook.

Section 2379f, Major Weapon System Defined 

In Section 2379f, the term major weapon system means a weapon system acquired 

pursuant to an MDAP. The term major weapon system is used throughout this guide.

Section 2437, Development of Major Defense Acquisition Programs: Sustainment of 

System to be Replaced 

Section 2437 states that whenever a new MDAP begins development, the defense 

acquisition authority responsible for that program shall develop a plan (to be known as a 

“sustainment plan”) for the existing system that the system under development is intended 

to replace. This section was added by the NDAA for FY 2005.

Guidance on the replaced system sustainment plan is provided in DoDI 5000.85, 

Appendix 3D (“Product Support”).

Section 2441, Sustainment Reviews 

Section 2441 requires that the Secretary of each military department shall conduct a 

sustainment review of each major weapon system not later than five years after declaration 
128

of IOC of an MDAP and throughout the life cycle of the weapon system to assess the 

product support strategy, performance, and O&S costs of the weapon system. For any 

review after the first one, the Secretary concerned shall use availability and reliability 

thresholds and cost estimates as the basis for the circumstances that prompt such a review.

This section was added by the NDAA for FY 2017. 

Each sustainment review is required to include the following elements:

• An independent cost estimate for the remainder of the life cycle of the program.

• A comparison of actual costs to the amount of funds budgeted and appropriated in 

the previous five years, and if funding shortfalls exist, an explanation of the 

implications on equipment availability.

• A comparison between the assumed and achieved system reliabilities.

• An analysis of the most cost-effective source of repairs and maintenance.

• An evaluation of the cost of consumables and depot level reparables.

• An evaluation of the costs of information technology, networks, computer 

hardware, and software maintenance and upgrades.

• As applicable, an assessment of the actual fuel efficiencies compared to the 

projected fuel efficiencies as demonstrated in tests and operations.

• As applicable, a comparison of actual manpower requirements to previous 

estimates.

• An analysis of whether accurate and complete data are being reported in the cost 

systems of the military department concerned, and if deficiencies exist, a plan to 

update the data and ensure accurate and complete data are submitted in the future.

Guidance on sustainment reviews is provided in DoDI 5000.85, Appendix 3D 

(“Product Support”). Suggested analytic methods that can support sustainment reviews are 

provided in Appendix E of this guide.

Section 2443, Sustainment Factors in Weapon System Design 

Section 2443 states that DoD shall ensure that the defense acquisition system gives 

ample emphasis to sustainment factors, particularly those factors that are affected 

principally by the design of a weapon system, in the development of a weapon system. DoD 

also shall ensure that reliability and maintainability are included in the performance 

attributes of the key performance parameter on sustainment during the development of 

capabilities requirements. In addition, DoD shall ensure that sustainment factors, including 

reliability and maintainability, are given ample emphasis in the process for source selection 
129

of a contract for engineering and manufacturing development of a weapon system. This 

section was added by the NDAA for FY 2018.

Guidance on this requirement is provided in Annex D (“Sustainment KPP Guide”) to 

Appendix G (“Development of Performance Attributes”) of the Joint Capabilities 

Integration and Development System (JCIDS) Manual, and in DoDI 5000.85, Appendix 3D 

(“Product Support”). The JCIDS Manual establishes that the capabilities needs documents 

for all MDAPs will include a Sustainment Key Performance Parameter (KPP). This is 

intended to ensure that the requirements and acquisition communities consider sustainment, 

including reliability and maintainability, as a requirement in the development of the 

program design. The Sustainment KPP is supported by several elements:

• Requirements for Materiel Availability and Operational Availability.

• A supporting Key System Attribute (KSA) or Additional Performance Attribute 

(APA) for Reliability.

• A supporting KSA or APA for Maintainability.

• A supporting KSA or APA for O&S costs.

This KPP is mandatory for a program’s Capability Development Document and is 

included in the Acquisition Program Baseline. Beginning at Milestone B, the parameters of 

the KPP are subject to reporting and tracking as the program proceeds through the 

acquisition phases.

The JCIDS Manual states that the O&S costs included with the Sustainment KPP 

should conform to the cost element structure provided in this guide.

The developers of the sustainment KPP requirements are expected to conduct up-front 

trade studies and other analyses to determine sustainment requirements that are balanced 

with program acquisition cost and what is achievable based on technology maturity. The 

process for conducting these trade studies is described in the Reliability, Availability, 

Maintainability, and Cost (RAM-C) Manual. A RAM-C Report documents the rationale 

behind the development of the sustainment metric requirements, including reliability 

metrics, along with underlying assumptions and supporting analyses. The RAM-C Manual

also provides guidance to the acquisition community to ensure that the sustainment 

requirements can be measured and tested throughout the program life cycle.

Regarding the requirement concerning the source selection process, DoDI 5000.85, 

Appendix 3D “(Product Support”) requires that solicitations to be used in weapon system 

procurements include criteria for sustainment factors principally affected by design and 

development, and that those criteria receive ample emphasis in source selection.
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Section 2448a, Program Cost, Fielding, and Performance Goals in Planning for Major 

Defense Acquisition Programs 

Section 2448a requires the MDA to establish program cost and fielding targets for an

MDAP before Milestone A, B, or C approval. The program cost targets are the procurement 

unit cost and sustainment cost. The program fielding target is the date for IOC. This section 

was added by the NDAA for FY 2017.

Guidance on this requirement is provided in DoDI 5000.85, Appendix 3C 

(“Additional Program Management Considerations”). In this guidance, the term sustainment 

cost is treated as synonymous with operating and support cost.

Section 2460, Definition of Depot-Level Maintenance and Repair

Section 2460 defines the term depot-level maintenance and repair as material 

maintenance or repair requiring the overhaul, upgrading, or rebuilding of parts, assemblies, 

or subassemblies, and the testing and reclamation of equipment as necessary, regardless of 

the source of funds for the maintenance or the location at which the maintenance or repair is 

performed. The term includes (1) all aspects of software maintenance classified by DoD as 

depot-level maintenance and repair, and (2) interim contractor support or contractor 

logistics support, to the extent that such support is for the performance of services described 

in the preceding sentence. This section was last modified by the NDAA for FY 2013.

Section 2464, Core Logistics Capabilities 

Section 2464 establishes the policy that it is essential for DoD to maintain a core 

logistics capability that is Government-owned and Government-operated to ensure a ready 

source of technical competence and resources necessary to ensure effective and timely 

response to a mobilization, national defense contingency situations, and other emergency 

requirements. DoD is required to identify this core logistics capability, and the peacetime 

workload required to maintain this capability, that is necessary to maintain and repair the 

weapon systems and other military equipment (including mission-essential weapon systems 

or materiel not later than four years after achieving IOC) necessary to support the 

Department’s strategic and contingency plans. DoD is required to submit a biennial report 

on whether or not it has the required core capability in military depots to support fielded 

systems. This section was last modified by the NDAA for FY 2019.

The process to define the numerical magnitude of the workload to maintain core 

logistics capabilities is documented in DoDI 4151.20, Depot Maintenance Core 

Capabilities Determination Process. 
131

Section 2466, Limitations on the Performance of Depot-Level Maintenance of Materiel 

Section 2466 states that not more than 50 percent of the funds made available in a 

fiscal year to a military department or defense agency for depot-level maintenance and 

repair workload may be used to contract for the performance by non-Federal Government 

personnel of such workload for the military department or the defense agency. This 

restriction is applied to each military department or defense agency as a whole, and is not 

applied to individual systems or commodity types. Any such funds that are not used for 

such a contract shall be used for the performance of depot-level maintenance and repair 

workload by employees of DoD. DoD is required to submit an annual report identifying, for 

each of the armed forces and each defense agency, the percentage of the funds that was 

expended during the preceding fiscal year, and are projected to be expended during the 

current fiscal year and the ensuing fiscal year, for performance of depot-level maintenance 

and repair workloads by the public and private sectors. This section was last modified by 

the NDAA for FY 2010.

Section 2474, Centers of Industrial and Technical Excellence: Designation, PublicPrivate Partnerships

Section 2474 states that the Secretary of each military department shall designate each 

depot-level activity in that department as a Center of Industrial and Technical Excellence 

(CITE) in one or more specific technical competencies required for the core capability

required to be identified by Section 2464 described earlier. Work for depot maintenance 

performed at an organic depot designated as a CITE, related to the technical competencies 

of the CITE, by a contractor pursuant to a public-private partnership is not counted for 

purposes of applying the 50/50 percentage limitation on contractor workload established by 

Section 2466 described earlier. The three basic types of public-private partnerships are:

• Workshare: An arrangement where workload at the CITE is shared between the 

contractor and the organic activity.

• Direct Sale: An arrangement where workload at the CITE is handled through a 

contractual relationship between the contractor and organic activity for the 

purchase of depot maintenance services.

• Lease: An arrangement where a contractor may have access to facilities and 

equipment located at an organic depot designated as a CITE through a lease.

This section was last modified by the NDAA for FY 2019.
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Other Relevant Statutory Requirements

Section 804, Middle Tier of Acquisition for Rapid Prototyping and Rapid Fielding

Section 804 of the NDAA for FY 2016 establishes a “middle tier” of acquisition 

programs that are intended to be completed within five years. These programs would fall 

between “rapid acquisitions” that are generally completed within six months to two years, 

and “traditional” acquisition programs that last much longer than five years. Middle tier 

acquisition provides for two acquisition pathways: (1) rapid prototyping (prototypes with 

innovative technologies), and (2) rapid fielding (new or upgraded systems with minimal 

development). Programs in this middle tier are to follow streamlined procedures, and are to 

be exempt from the traditional requirements and acquisition processes. DoD guidance for 

middle tier acquisition must establish a process for transitioning successful prototypes to 

new or existing programs for production and fielding under the rapid fielding pathway or 

the traditional acquisition process. 

This guidance was provided in DoDI 5000.80, Operation of the Middle Tier of 

Acquisition (MTA). As stated in this instruction, program managers and product support 

managers are to develop and implement sustainment programs addressing product support

elements to deliver affordable readiness. For the rapid fielding programs, the DoD 

Components are to develop a process for considering life-cycle costs, address issues of 

logistics support and training, and identify and exploit opportunities to reduce total 

ownership costs. This process will result in a tailored life-cycle sustainment plan. DoDI 

5000.80 also states that the DCAPE establishes policies and prescribes procedures for the 

collection of cost data and cost estimates for MTA programs, as appropriate.

CAPE has established new procedures for cost estimates for MTA programs in the 

most recent revision to DoDI 5000.73, Cost Analysis Guidance and Procedures. Procedures 

for MTA cost estimates were briefly mentioned in Chapter 5 of this guide and additional 

details including timelines are provided in DoDI 5000.73.

Section 809, Advisory Panel on Streamlining and Codifying Acquisition Regulations

Section 809 of the NDAA for FY 2016 called for the Secretary of Defense to establish 

an independent advisory panel on streamlining acquisition regulations. A Defense Technical 

Information Center website (discover.dtic.mil/section-809-panel/) provides the various 

reports and recommendations made by the panel from August 2016 to its conclusion in July 

2019. Recommendation 41 of the panel calls for DoD to establish a sustainment program 

baseline, implement key enablers of sustainment, elevate sustainment to equal standing with 

development and procurement, and improve the defense materiel enterprise focus on 

weapon system readiness.
133

The Department has not implemented this recommendation at the time of the 

publication of this guide. However, as noted earlier in this appendix, Section 2337a already 

requires the military departments to update estimates of O&S costs periodically throughout 

the life cycle of a major weapon system. In addition, the program SAR reporting provides a 

comparison between the current O&S cost estimate and the SAR baseline objective and 

threshold values for total O&S costs.

Section 832, Implementation of Recommendations of the Independent Study on 

Consideration of Sustainment in Weapon Systems Life Cycle

Section 832 of the NDAA for FY 2019 requires the Secretary of Defense to 

commence implementation of each recommendation of an independent assessment 

conducted by the MITRE Corporation (of the extent to which sustainment matters are 

considered in decisions related to requirements, acquisition, cost estimating, programming 

and budgeting, and research and development for MDAPs). The specific MITRE 

recommendations pertaining to O&S cost data systems for the Department, which are now 

being addressed by the EVAMOSC initiative, are described in Chapter 6 of this guide.

Section 879, Briefing on Funding of Product Support Strategies

Section 879 of the National Defense Authorization Act for FY 2019 requires the 

Secretary of Defense to provide an annotated briefing to the congressional defense 

committees regarding the funding for product support strategies for major weapon systems 

for each of the fiscal years 2020, 2021, and 2022. The briefing shall include for each major 

weapon system:

• A current estimate of the total funding required for the product support strategy for 

specific costs of the weapon system over its expected life cycle.

• A current estimate of the funding required for the product support strategy per 

year over the Future Years Defense Program (FYDP) for the specific product 

support costs of the weapon system.

• A summary of the funding requested for the product support strategy in the FYDP 

per year specifically for the weapon system.

• A summary of the amounts expended to support costs specific to the weapon 

system as described in the product support strategy of the weapon system during 

the prior fiscal year.

• A summary of the improvements made to data collection and analysis capabilities 

of DoD, including in the military services, to improve the analysis and cost 

estimation of life-cycle costs, improve the analysis and identification of cost 

drivers, reduce life-cycle cost variance, identify common and shared costs for 
134

multiple weapon systems, and isolate the life-cycle costs attributable to specific 

individual weapon systems.
135

APPENDIX I

Rates for Military and Civilian Manpower

Some cost estimates use manpower estimates obtained from unit manning documents 

or tables of organization and equipment. In such cases, it is necessary to apply manpower 

rates to the unit manning documents.

Manpower costs for active officers and enlisted personnel include the elements of the 

DoD Standard Composite Rates for military personnel, which include the following items: 

basic pay, retired pay accrual, Medicare-Eligible Retiree Health Care (MERHC) accrual, 

basic allowance for housing, basic allowance for subsistence/subsistence-in-kind, incentive 

and special pays, Permanent Change of Station (PCS) expense, and miscellaneous expenses 

such as the employer’s contribution to social security (FICA) and uniform/clothing 

allowances. Each year, the OSD Comptroller issues the military personnel composite 

standard pay rates for each military service to be used in cost estimates. These rates can be 

found at the OSD Comptroller public website http://comptroller.defense.gov/FinancialManagement/Reports (Tab K). 

Manpower costs for officers and enlisted personnel in the reserve components 

(National Guard and Reserve) include basic pay, retired pay accrual, MERHC accrual, basic 

allowance for housing, subsistence, and miscellaneous expenses. PCS costs are included for 

full-time members. Reserve manpower costs vary among different pay categories of reserve 

personnel. Cost estimates of reserve personnel should separately identify the number of 

personnel using the following categories:

• Full-time – Active/Guard/Reserve (AGR) members

• Drill Personnel (Pay Group A) – drilling members of a Selected Reserve Unit 

The cost of drill personnel depends on the extent of their annual drill time. The 

average annual drill time should be used and documented in developing a cost estimate. 

Some military departments also have reserve military technicians, federal civilian 

employees who also serve in a dual status as military reservists, who receive both civilian 

and drill pay.

Rates for reserve personnel for each pay category can be derived from the military 

personnel budget justification material submitted by the National Guard and Reserve of 

each military service. In these budget justification materials, the funding for reserve 

personnel can be found in a table known as the Summary of Entitlements by Subactivity, 

and the end-strength can be found in a table known as the Summary of Personnel. 
136

The Naval VAMOSC system obtains actual Active and Reserve military manpower 

costs for pay and allowances from Defense Finance and Accounting Service pay files that 

are provided by the Defense Manpower Data Center. Additionally, PCS costs are obtained 

from the Bureau of Navy Personnel, FICA and retired pay accrual are calculated as 

percentages of basic pay, and MERHC accrual is the annual published per capita actuarial 

allocation amount. 

The costs of government civilian manpower consist of the elements of the DoD 

Composite Standard Rates for civilian employees, which are the following: regular salaries 

and wages, additional variable payments (for overtime, holiday pay, night differentials, and 

awards), cost-of-living allowances, and the government contribution to employee benefits: 

insurance, retirement, Social Security contributions, and certain relocation expenses that are 

regarded as benefits.

A version of the OP-8 budget exhibit (“Total Civilian Personnel Costs”) for DoD as a 

whole can be found in the DoD Operations and Maintenance (O&M) budget overview. 

Rates are provided for the Senior Executive Schedule, General Schedule, Wage System, and 

other categories of US DoD employees. The exhibit also provides rates for foreign national 

direct and indirect hires. Additionally, each military department prepares its own version of 

an OP-8 display for each appropriation with civilian personnel costs. 
137

 APPENDIX J

References

Directives, Instructions, Manuals and Regulations

(a) DoD Directive 5105.84, Director of Cost Assessment and Program Evaluation 

(DCAPE), May 11, 2012

(b) DoD Instruction 5000.73, Cost Analysis Guidance and Procedures, March 13, 

2020

(c) DoD 5000.04-M-1, Cost and Software Data Reporting (CSDR) Manual, 

November 4, 2011

(d) DoD Directive 5000.01, The Defense Acquisition System, May 12, 2003, as 

amended

(e) DoD Instruction 5000.02, Operation of the Adaptive Acquisition Framework, 

January 23, 2020

(f) DoD Instruction 5000.85, Major Capability Acquisition, August 6, 2020

(g) DoD Instruction 5000.80, Operation of the Middle Tier of Acquisition (MTA), 

December 30, 2019

(h) MIL-STD-881D, Work Breakdown Structures for Defense Materiel Items, April 9, 

2018

(i) CJCS Manual, Joint Capabilities Integration and Development System (JCIDS) 

Manual, August 31, 2018

(j) Department of Defense Reliability, Availability, Maintainability, and Cost 

Rationale Report Manual, June 1, 2009

(k) DoD 7000.14-R, DoD Financial Management Regulation, May 2019

(l) DoD Instruction 4151.20, DoD Maintenance Core Capabilities Determination 

Process, May 4, 2018, as amended

Guides and Other Publications

(m) DoD Cost Estimating Guide, publication pending

(n) Inflation and Escalation Best Practices for Cost Analysis, April 2016

(o) Inflation and Escalation Best Practices for Cost Analysis: Analyst Handbook, 

January 2017
138

(p) Joint Agency Cost Estimating Relationship (CER) Development Handbook, 

February 9, 2018

(q) Joint Agency Cost Schedule Risk and Uncertainty Handbook, March 12, 2014

(r) Defense Acquisition Guidebook

(s) Operating and Support Cost Management Guidebook, February 2016

(t) Product Support Manager Guidebook, December 2019

(u) Integrated Product Support (IPS) Elements Guidebook, July 31, 2019

(v) Performance Based Logistics Guidebook, April 2016

(w)DoD Product Support Business Case Analysis Guidebook, March 2014

(x) Logistics Assessment Guidebook, July 2011

(y) Reliability, Availability, Maintainability, and Cost (RAM-C) Rationale Report 

Outline Guidance, February 28, 2017
139

Abbreviations

AC Aircraft

ACEIT Automated Cost Estimating Integrated Tools

ADM Acquisition Decision Memorandum

AFTOC Air Force Total Ownership Cost

AGR Active/Guard/Reserve

AoA Analysis of Alternatives

APB Acquisition Program Baseline

APA Additional Performance Attribute

CADE Cost Assessment Data Enterprise

CAPE Cost Assessment and Program Evaluation

CARD Cost Analysis Requirements Description

CASA Cost Analysis Strategy Assessment

CCP Component Cost Position

CDD Capability Development Document

CER Cost Estimating Relationship

CITE Center of Industrial and Technical Excellence

CLS Contractor Logistics Support

CSDR Cost and Software Data Reporting

CVT Consolidated VAMOSC Tool

CY Constant-Year

DAES Defense Acquisition Executive Summary

DCAPE Director of Cost Assessment and Program Evaluation

DeCA Defense Commissary Agency

DLA Defense Logistics Agency
140

DLR Depot Level Reparable

DoD Department of Defense

DoDEA DoD Education Activity

DoDI DoD Instruction

DOT&E Director of Operational Test and Evaluation

DWCF Defense Working Capital Fund

EMD Engineering and Manufacturing Development

EVAMOSC Enterprise VAMOSC

FH Flying Hour

FICA Social Security (Federal Insurance Contributions Act)

FSR Field Service Representative

FWG Functional Working Group

FY Fiscal Year

FYDP Future Years Defense Program

GDP Gross Domestic Product

IAVM Information Assurance Vulnerability Management

ICE Independent Cost Estimate

ICS Interim Contractor Support

ILA Independent Logistics Assessment

IOC Initial Operational Capability

IOT&E Initial Operational Test and Evaluation

IPS Integrated Product Support

IT Information Technology

JCIDS Joint Capabilities Integration and Development System

KPP Key Performance Parameter

KSA Key System Attribute

LCN Logistics Control Number
141

LEC Logistics and Engineering Center

LRIP Low-Rate Initial Production

LRU Line Replaceable Unit

MDA Milestone Decision Authority

MDAP Major Defense Acquisition Program

MERHC Medicare-Eligible Retiree Health Care

MTA Middle Tier of Acquisition

MTBF Mean Time Between Failures

MTBM Mean Time Between Maintenance

MTBR Mean Time Between Removals

MTTR Mean Time to Repair

NDAA National Defense Authorization Act

NIIN National Item Identification Number

NSN National Stock Number

O&M Operations and Maintenance

O&S Operating and Support

OEM Original Equipment Manufacturer

OMB Office of Management and Budget

OPTEMPO Operating Tempo

OSD Office of the Secretary of Defense

OSMIS Operating and Support Management Information System

P3 Public-Private Partnership

PBA Performance-Based Arrangement

PBL Performance-Based Logistics

PCS Permanent Change of Station

PE Program Element

R&M Reliability and Maintainability
142

RAM Reliability, Availability, and Maintainability

RAM-C Reliability, Availability, Maintainability and Cost

RCOH Refueling and Complex Overhaul

RDT&E Research, Development, Test and Evaluation

REMIS Reliability and Maintainability Information System

RMF Risk Management Framework

SAG Sub-Activity Group

SAR Selected Acquisition Report

SCN Shipbuilding and Conversion

SIL Software Integration Laboratory

SLOC Source Lines of Code

SMD Ship Manning Document

SRDR Software Resources Data Reporting

SRU Shop Replaceable Unit

TDY Temporary Duty

TY Then-Year

US United States

U.S.C. United States Code

USMC US Marine Corps

VAMOSC Visibility and Management of Operating and Support Costs

WBS Work Breakdown Structure

WUC Work Unit Code
143

Glossary 

Availability. A measure of the degree to which a system is in an operable state and can be 

committed at the start of a mission when the mission is called for at an unknown (random) point 

in time.

Contractor logistics support. Contracted weapon system sustainment consisting of multiple 

maintenance and support functions that occurs over the life of a weapon system.

Depot maintenance. Action performed for the major overhaul or complete rebuild of end items, 

and the repair of secondary items. Depot maintenance requires extensive industrial facilities, 

specialized tools and equipment, and uniquely experienced and trained personnel that are not 

available at other levels of maintenance.

End item. The final production product when assembled or completed, and ready for issue or 

deployment.

Independent logistics assessment. A comprehensive review of a program’s supportability 

conducted by a team of impartial subject matter experts.

Interim contractor support. Temporary contractor support required to sustain a system during 

its initial fielding before the period where a permanent support solution (organic, contractor, and 

hybrid) is established.

Integrated product support. A management framework consisting of twelve elements (e.g., 

sustaining engineering, supply support, etc.) that guides the develop and implementation of a 

program product support strategy.

Intermediate maintenance. The maintenance and repair of items that cannot be provided by the 

organizational level of maintenance and that does not need to go to the depot level of 

maintenance for major work.

Logistics reliability. The measure of the ability of an item to operate without placing a demand 

on the logistics support structure for repair or adjustment.

Line replaceable unit. An item removed and replaced at the organizational level of maintenance 

to restore an end item to an operationally ready condition. Also called weapon replacement 

assembly.

Maintainability. The ability of an item to be retained in, or restored to, a specified condition 

when maintenance is performed by personnel having specified skill levels, using prescribed 

procedures and resources, at each prescribed level of maintenance and repair.

Maintenance. An action necessary to retain or restore an item to a specified condition.
144

Manpower estimate. An estimate of the most effective mix of DoD manpower and contract 

support for an acquisition program. Includes the number of personnel required to operate, 

maintain, support, and train for the system fielded by an acquisition program upon full 

operational deployment.

Materiel availability. The measure of the percentage of the total inventory of a system 

operationally capable, based on materiel condition, of performing an assigned mission. This can 

be expressed mathematically as the number of operationally available end items/total population.

The total system population includes all operational systems necessary to support the operational 

context of the Capability Development Document including operational systems for training, 

systems for attrition reserve and prepositioning, and systems temporarily in a non-operational 

materiel condition, such as planned depot maintenance.

Mean time between failure. A measure of reliability for an item that represents the average time 

between inherent failures during normal operation.

Mean time between maintenance. A measure of reliability for an item that represents the 

average time between all maintenance actions, both corrective and preventative.

Mean time to repair. The total elapsed time (clock hours) for corrective maintenance for an 

item divided by the total number of corrective maintenance actions during a given period.

Mission reliability. A measure of the ability of a system or item to perform its required function 

for the duration of a specified mission profile, defined as the probability that the system or item 

will not fail to complete the mission (without reference to battle damage).

Operating metric. A measure of system usage. Common operating metrics are flying hours 

(aircraft), steaming hours (ships and submarines), and driving miles (vehicles).

Operational availability. A measure of the percentage of time that a system is operationally 

capable of performing an assigned mission and can be expressed as (uptime/(uptime + 

downtime)).

Organizational maintenance. The maintenance and repair of a system performed by the unit or 

activity that employs the system. This maintenance includes inspections, servicing, handling, and 

removal and replacement of parts. 

Performance-based arrangement. A formal arrangement such as a contract or Memorandum of 

Agreement for implementing a performance-based logistics strategy.

Performance-based logistics. A strategy for weapon system sustainment that is based on 

specified performance outcomes as defined by performance metric(s) for a system. Applicable to 

contracts with industry and inter-governmental agreements. 

Product support. The package of support functions required to field and maintain the readiness 

and operational capability of a major weapon system, subsystems, and components.

Product support business case analysis. An economic analysis that the program manager or 

product support manager uses to decide among alternative product support strategies.
145

Product support manager. The individual responsible for managing the package of product 

support functions.

Product support strategy. The primary document that describes the business and technical 

approach to plan, acquire, and implement the product support package.

Reliability. A measure of the probability that a system or item will perform without failure over 

a specific interval, under specified conditions, without reference to battle damage. Measures 

include mission reliability and logistics reliability.

Secondary item. Any item, including assemblies, subassemblies, and parts, that is not classified 

as an end item.

Shop replaceable unit. An item removed and replaced at the intermediate level of maintenance. 

Also called shop replaceable assembly. 

Supply chain management. The integration of procurement, supply, maintenance, and 

transportation functions with the physical, financial, information, and communications networks 

to satisfy force materiel requirements.

Unit of usage. A measure of system usage or operating tempo (OPTEMPO). Common units of 

usage are flying hours (aircraft), steaming hours (ships and submarines), and driving miles 

(vehicles). Synonymous with usage metric.
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