FMS2010 IMP Paper - ASNE

Capt. Talbot Manvel, USN (Ret), Brad Toncray, Randy Harrington, 

Nick D’Amato and Jeff Newton 

The Incremental Maintenance Plan for NIMITZ Class 

Carriers: Origins, History and Future 

ABSTRACT 

Toward the end of the 1980s the Navy realized 

that unless it changed the maintenance strategy 

for its’ Nimitz Class, four of nine carriers would 

be in overlapping extended complex overhauls 

and that such a pile-up would occur again in the 

future. This realization lead to the development 

of a new maintenance strategy, the Incremental 

Maintenance Plan (IMP), developed jointly by 

Naval Sea Systems Command (NAVSEA), 

Program Executive Office (PEO) Carriers, 

Planning and Engineering for Repairs and 

Alterations Activity for Carriers (PERA CV), 

the Type Commanders (TYCOM), and both the 

Hull and Reactor Plant Planning Yards. 

This paper will discuss the origins of the IMP, 

the effectiveness of the plan to date, how new 

strategies are continually being added to the 

plan, and how maintenance problem areas and 

requirements are continuously being challenged. 

These elements are properly aligned, providing 

an agile and flexible approach to an engineered 

strategy designed to optimize assets available to 

the Fleet for tasking with an optimum Total 

Ownership Cost (TOC). 

plan. The EOC was the existing legacy 

maintenance plan used for conventional carriers 

and USS Enterprise (CVN 65). Once the high 

investment cost was realized, the ship’s service 

life was extended to 50 years. The ship had only 

been designed for a 30 year in-service life, so 

there was a need for a large Service Life 

Extension Program (SLEP) and a Refueling 

Complex Overhaul (RCOH) availability to be 

added to the EOC. The EOC was changed to 

support the 24-month Fleet Operational Cycle as 

well. USS Nimitz and her follow-on carriers USS 

Dwight D. Eisenhower (CVN 69), USS Carl 

Vinson (CVN 70) and USS Theodore Roosevelt 

(CVN 71) underwent routine scheduled EOC 

availabilities consisting of (Selected Restricted 

Availability (SRAs), Extended Docking Selected 

Restricted Availability (EDSRAs), and Complex 

Overhaul (COHs) when the Navy realized, in the 

late 1980s, there would be a pending stack-up of 

extended COHs and RCOHs (Figure 1 depicts 

the EOC schedule in 1992 extrapolated to reflect 

the second half of the first decade of the 21 st 

century (Manvel et al. (1993)) showing the 

overlapping availabilities). 

HISTORY 

Nimitz Class aircraft carriers were designed by 

the Bureau of Ships (BuShips) during the early 

1960s under guidance provided by Office of the 

Chief of Naval Operations (OPNAV) Ship 

Characteristics Board 250. This board called for 

a nuclear aircraft carrier with two long stroke 

and two short stroke catapults, four reactors and 

a full load displacement of 90,000 long tons. By 

1964, BuShips had produced the preliminary 

design of a two-reactor aircraft carrier with a full 

load displacement of 93,000 tons and a designed 

in-service life of 30 years. The USS Nimitz (CVN 

68) entered service in 1974 under the 

Engineered Operating Cycle (EOC) maintenance 

FIGURE 1. EOC COH/RCOH Overlaps 

This realization of overlaps led to the 

development of a new maintenance strategy, the 

IMP. The new plan had some tangible benefits, 

including strategies to eliminate the need for the 

SLEP availability at the 30 to 35 year point in 

the carrier service life. SLEP availabilities, even 

more so than COHs, proved to be costly budget 

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DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.

targets and reduced carrier operational 

availability and were found to miss the mark on 

completely re-baselining material readiness due 

to underfunding maintenance requirements. 

COHs themselves were also problematic in that 

availability durations routinely extended far 

beyond proscribed Chief of Naval Operations 

(CNO) completion dates, with delays averaging 

101 days between 1983 and 1995. Figure 2 

shows the improved IMP FY05 to FY10 

maintenance schedule. 

 

 

 

 

 

Focus on published technical requirements 

Learn from depot level repair experiences 

Incorporate data from similar equipment and 

maintenance strategies used elsewhere in the 

fleet 

Enact best practices and LEAN initiatives 

where appropriate and, 

Create ship alterations to address barriers 

when required. 

Under the EOC plan the strategy was to allow 

the ships material condition to gradually 

degrade, then return the material condition to a 

higher state of readiness during COHs. In 

practice, the resulting readiness state never 

reached the previous benchmark (Figure 3). 

FIGURE 2. IMP Actual PIA/DPIA/RCOH 

Overlaps 

PHILOSOPHY, STRATEGY, 

PLAN DEVELOPMENT AND 

RESULTS 

The philosophy of the IMP is simple: 

Create a plan that maintains carriers in a 

more consistent state of material readiness 

throughout its service life by executing a 

series of more consistently sized 

availabilities. This reduces the budget and 

shipyard workload spikes and mitigates the 

loss of sailor readiness suffered under the 

EOC’s long duration (12 to over 18 month) 

COHs. 

Do away with the need for historically time 

consuming and unsuccessful SLEP 

availabilities at the 30 to 35 year service life 

point by better managing carrier 

infrastructure and distributive system 

deterioration. 

FIGURE 3. EOC Strategy 

One of the strategies transitioning from EOC to 

IMP was to reduce or eliminate the ―gap‖ 

created from the COH inefficiencies. The plan 

took mandatory and condition based 

maintenance man days and applied them 

throughout the ship’s life in a robust continuous 

maintenance process rather than allowing a build 

up to be addressed during COHs (Figure 4). In 

Figure 4, the EOC strategy of allowing the 

ship’s material condition to gradually degrade is 

shown as the bottom saw tooth curve, while the 

IMP strategy for 24-month and 32-month, with 

reduced long term readiness ―gap‖, are depicted 

as the red and blue lines, respectively. 

Following the IMP philosophy, the strategy is 

also simple: 

Build on historical knowledge 

Utilize maintenance history successes and 

failures 

2 


Level of Maintenance Condition 

SRA 

PIA 

PIA 

DSRA 

PIA 

PIA 

DPIA 

SRA 

DPIA 

PIA 

COH 

PIA 

PIA 

SRA 

DPIA 

DSRA 

PIA 

PIA 

SRA 

DPIA 

PIA 

COH 

DPIA 

SRA 

PIA 

PIA 

DSRA 

PIA 

PIA 

SRA 

RCOH 

RCOH 

RCOH 

EOC 

IMP-24 

IMP-32 

2 4 6 8 10 12 14 16 18 20 22 

Years 

IMP 32 

IMP 24 

FIGURE 4. EOC, IMP-24 and IMP-32 Readiness 

Strategy 

EOC vs. IMP-24 

Philosophy and strategy is one thing, but with 

concept execution, the plan development process 

and details were not always as simple. In order 

to affect a transition to the IMP, several steps 

were required to satisfy technical requirements 

in-place at the time. An initial study was 

conducted identify all the requirements and 

applicable certification durations and their 

impact on the new IMP cycle; the most 

significant being the existing 5 year docking 

requirement. Those identified strategies were 

then challenged or changed to ―push‖ or ―pull‖ 

maintenance actions to fit within the new 

schedule. High cost evolutions (like dry 

docking) required a number of engineering 

changes (ship alterations) to gain technical 

justification to ―push‖ the requirement to 6 

years. Condition based assessments were 

implemented to assure appropriate monitoring, 

data collection and analysis were available to 

drive maintenance actions. 

In support of the development of the IMP, a 

phased maintenance strategy review was 

conducted. The strategy incorporated the 

following steps: 

Define a complete list of maintenance 

requirements with the number of affected 

components, equipment and systems, along 

with their required level of repair. 

Sequence maintenance actions by 

availabilities. 

EOC 

 

 

Account for the age of the ship within its life 

cycle: Modify the levels of repair based on 

age degradation calculations and apply an 

―aging factor‖ across scheduled 


Employ a time-based approach to budgeting 

while conforming to a condition based 

approach to maintenance. 

The review evaluated requirements, workload, 

manning, critical paths, testing and services. 

The work was comprehensively ―sequenced‖ 

and all the maintenance requirements level 

loaded across the ships service life. This 

―Sequencing Plan‖ approach became an integral 

building block of the shift from the EOC to IMP. 

The IMP was composed of repeating 24-month 

operating cycles with one major 6-month 

Planned Incremental Availability (PIA) 

maintenance period per cycle. Every repeating 

third cycle, the major maintenance availability 

was a 10.5-month Docking Planned Incremental 

Availability (DPIA). 

To accommodate the ―aging factor‖, budgetary 

baselines were established, and shipyard 

workload requirements were identified. Then 

the notional availabilities were divided into a 

three-tier set of notional maintenance periods 

categories based on anticipated man days due to 

the life of the ship and the expected 

requirements (Figure 5). Initial man day 

requirements were set in 1992 and have been 

modified as the IMP evolved. 

Figure 5: Notional Aircraft Carrier Life Cycle & 

Aging Factors 

Once the categories were developed, the 

shipyards that work on aircraft carriers reviewed 

them in order to determine if they were 

achievable in relation to capacity. Norfolk Naval 

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Shipyard (NNSY) and Puget Sound Naval 

Shipyard (PSNS) determined they could execute 

the first two categories of availabilities (called 

PIA1s, PIA2s, DPIA1s and DPIA2s), but that 

the third set (PIA3s and DPIA3s) exceeded 

capacity by 2,000 men per day. During the 

initial EOC timeframe (circa 1992) the shipyard 

had excess capacity (NNSY: 11,205 personnel 

and PSNS and IMF: 12,356 personnel). When 

the IMP was developed and the availability 

categories were defined, the Shipyards had 

reduced their manning significantly. By fiscal 

year (FY) 2004, NNSY had 7,778 personnel and 

PSNS and IMF was manned at 9,421 personnel. 

Mitigation strategies (such as contracting of 

additional work) were developed to compensate 

for the lack of manpower capacity to support the 

PIA3 and DPIA3’s. One strategy was to reduce 

the workload within the availability by having a 

spare available for a wholesale change out of the 

equipment, instead of using vital manpower to 

overhaul in place. The equipment would then be 

repaired during a time when the shipyard was at 

less demand. The program was called the Carrier 

Planned Equipment Replacement (CARPER) 

program. 

Today, man day requirements are continuously 

reviewed as part of the overall feedback process. 

Table 1 shows the original PIA/DPIA depot man 

day requirements and subsequent changes. 

TABLE 1: Original Depot Man day 

Requirements and Changes 

At the same period of time that the IMP was 

being developed, the carrier maintenance 

community established a process improvement 

organization called Carrier Team One (CT1), a 

knowledge sharing network developed to 

improve the execution of availabilities. Though 

not created directly as a result of the inception of 

IMP, CT1 has matured in parallel with the IMP 

and has played no small role in its success. 

Advantages of IMP-24 

The shift from the EOC strategy to IMP-24 was 

a major change in the way carrier maintenance 

had been conducted for many years, and yielded 

significant gains. The 24-month operating cycle 

(IMP-24) provided for more consistently sized 

availabilities and, as a result, produced: 

More consistent short term and long term 

readiness. 

Increased ship availability and surge 

capability. 

Leveled the profile of the maintenance and 

related budget spikes by incrementally 

executing the work throughout the carrier’s 

service life. 

Provided ships with the right capabilities as 

a result of focusing on condition based 

maintenance and modernization. 

Unnecessary maintenance under the 

antiquated time based maintenance plan left 

too much variability for effective planning. 

Level loaded the maintenance industrial 

base by comprehensively listing and 

sequencing all the maintenance requirements 

by shop and trade skill. 

 

More accurate and predictable schedules and 

maintenance workload forecasts. 

COMNAVSEASYSCOM letter of June 91 

applied an ―Aging Factor‖ to account for the 

effects of aging on ship system repairs. 

 

Reduced the number of docking 

availabilities (EDSRA vs. DPIA) by four, 

resulting in: 

o 

o 

o 

Increased carrier service life operational 

availability (A O ) by 18 months. 

Reduced the number of maintenance 

man days by 985,000 man days per 

carrier over its 50 year service life 

(Note: The majority of these man day 

reductions were associated with services 

(project management, dry dock support) 

rather then ―wrench turning‖ work. 

Ensured all ―wrench turning‖ work 

reductions were the result of 

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modernization design changes or 

Technical Warrant Holder (TWH) 

approved study recommendations. 

New strategies were developed for components 

with periodic inspections (flex hoses, 

pressurized cylinders, tanks, voids, and wire 

ropes, among others). Availability durations, 

critical paths, trade skill demands and spare part 

requirements were all evaluated to optimize 

successful maintenance period execution. The 

total effect resulted in a ―Sequencing Plan‖ that 

reapportioned maintenance man days and 

workloads across the entire carrier life cycle and 

industrial infrastructure. The Sequencing Plan 

included the deletion of inefficient SLEP 

availabilities. Although not always tied directly 

to the IMP effort, the carrier maintenance 

community leadership had introduced specific 

system upgrades (ship alterations) to extend the 

service life of systems determined to be in 

jeopardy beyond 30 years (e.g., changing 90/10 

firemain piping to 70/30 copper nickel). 

Additionally, original design infrastructure and 

distributive system service margins (electrical 

power, fiber optic cable plant status, chill water 

capacity, firemain, etc.) were closely monitored 

using a program called the Ships System Status 

Program (SSSP). 

The IMP was officially approved as the CVN 

68’s Class Maintenance Plan in 1994 and the 

first PIA was executed in FY97. As IMP 

availabilities were completed, the entire IMP 

approach was validated. A Carrier unique 

Project Management College (PMC) was 

instituted under the leadership of the newly 

established CT1. Post availability ―Hot 

Washes‖ were reviewed, and the planning and 

execution successes and failures and 

―knowledge sharing‖ elements of CT1 all 

contributed to the overall positive validation 

process. 

EVOLUTION OF THE IMP 

When the IMP was first established, 

―maintenance‖ was scheduled based upon a 

consistent and predictable 24-month operational 

cycle of ―heel-to-toe‖ deployments. In 2001, 

operational demands associated with the events 

following September 11, 2001 resulted in an 

increase in the average length between IMP 

availabilities from 24-months to 27-months as 

allowed by OPNAVNOTE 4700 tolerances. 

IMP-24 vs. IMP-27 vs. IMP-32 

In 2004, the operational cycle for a CVN 68 

Class Aircraft Carrier was officially modified 

and recognized in the OPNAVNOTE 4700 of 

June 2004 as 27 months. Adoption of a 

27-month cycle resulted in a reduction of the 

total number of depot availability opportunities 

executed and the elimination of approximately 

400,000 man days of life cycle maintenance. 

The most significant factor related to the 2004 

transition to a 27-month operational cycle was 

the determination to not adjust or modify 

programmed notional man days to account for 

the two (2) deleted PIAs, one during each half of 

the ship’s life (12 months of depot time). 

Because of the heavily condition based IMP, as 

well as the usage of better materials and 

preservation systems, it was assessed there 

would be negligible impact on material 

readiness in extending the operational cycle by 

three months. 

Concurrently in 2004, in an effort to provide 

even more operational availability to fleet 

commanders, Commander, NAVSEA requested 

PMS 312, under PEO Carriers, evaluate the 

technical feasibility of increasing the length 

between availabilities from 27-months to 

32-months. This technical review by all 

maintenance stakeholders, coincident with 

technical approval to extend the dry-docking 

interval for the Nimitz Class to 8 years, 

concluded that there were no technical 

impediments to extending the time between 

depot availabilities to 32-months. The dry-dock 

interval extension–from 6 years to 8 years— 

required a full technical review which validated 

the extension, represented an acceptable and 

manageable level of risk, and was approved by 

the Technical Warrant Holders (TWH) as 

outlined in PEO Carriers letter of March 2005. 

The major 32 month/8 year docking Study 

concluded in 2006 with the approval of the 32- 

5 


DPIA3 

DPIA3 

DPIA3 

PIA3 

CIA 3 

PIA3 

CIA 3 

CIA 3 

PIA3 

CIA 3 

PIA3 

CIA 3 

CIA 2 

PIA2 

CIA 2 

PIA2 

CIA 2 

CIA 3 

PIA3 

CIA 3 

PIA3 

CIA 3 

CIA 2 

PIA2 

PIA2 

DPIA2 

CIA 1 

PIA1 

PIA1 

CIA 2 

CIA 2 

CIA 1 

CIA 1 

month operating cycle (IMP-32). This last 

iteration has had the following additional 

benefits to the Navy and the Fleet: 

An additional reduction in the number of 

CNO availabilities by four; two PIAs and 

two DPIAs (totaling 33 months of depot 

time over the lifecycle of each aircraft 

carrier). 

An increase in a carrier’s service life A O by 

an additional 11 months from IMP-24 to 

IMP-32. 

Although providing more A O , the loss of these 

availabilities resulted in the removal of 1.12M 

man days of original depot level work. 

Approximately half of these man days are 

associated with items such as test programs and 

docking costs (services) that are completely 

eliminated and result in actual cost avoidances. 

The remaining half is actual maintenance 

requirements that must be accounted for and 

reprogrammed into the updated class 

maintenance plan. A Continuous Maintenance 

(CM) strategy was developed using Carrier 

Incremental Availabilities (CIAs) to incorporate 

a portion of the missed requirements. Another 

change was the increase in size of some DPIAs 

by one category (e.g., DPIA1 to DPIA2). The 

latest IMP strategy increases platform 

availability to the operator in support of a Fleet 

Response Plan (FRP) 6 available aircraft carriers 

plus 1 in docking (6+1) philosophy and includes 

the CM Strategy. 

In order to account for the displaced 433,000 

―wrench turning‖ maintenance man days 

removed by the reduction of maintenance 

availabilities, every maintenance opportunity has 

been utilized, including a reprogramming of the 

―wrench turning‖ man days into the remaining 

DPIAs and newly established CIAs, depicted in 

Figure 6. 

53.1k MDs 

Over DPIA1 

20.6 k 

MDs Btwn 

Each Avail 

32-Month Operational Cycle Continuous 

Maintenance 

24.2 k MDs 

Btwn Each 

Avail 

47.7k MDs 

Over DPIA2 

27.8 k MDs 

Btwn Each 

Avail 

24.2 k MDs 

Btwn Each 

Avail 

148.5k Mandays Redistributed 

47.7k MDs 

Over DPIA2 

27.8k MDs 

Btwn Each 

Avail 

FIGURE 6. 32-Month Operational Cycle with 

Continuous Maintenance 

The evolution of the IMP from its inception has 

resulted in a total 937,300 maintenance man 

days reduction per ship over its 50 year service 

life by removing services associated with 6 

fewer availabilities. 

RESULTS—ADVANTAGES OF 

IMP OVER EOC 

Since implementing IMP-24 the aircraft carrier 

maintenance community has continued to 

challenge maintenance requirements as part of 

ongoing total ownership cost improvement 

initiatives. This evolution has resulted in 

improved benefits that include: 

Fleet Benefits 

o Increased platform readiness (Ao) 

o Material ready assets 

o Assets with the right capabilities at the 

right time 

o Improved confidence in Budget 

Requirements and Schedules 

TYCOM Benefits 

o Reduced maintenance costs 

o Improved maintenance forecasting 

capability 

o Levelized funding - easily defendable. 

Maintenance Providers Benefits 

o Improved maintenance forecasting 

o Levelized shipyard loading; including at 

the shop and trade skill levels 

Ships Force Benefits 

o Better able to maintain qualification 

proficiency 

o More predictable schedules 

6 


K-Man-days 

Deviation from OPNAV Completion (Days) 

Deviation From OPNAV Completion (Days) 

The evolution of the IMP provides critical 

short-term (current) readiness to support 

post-9/11 FRP surge requirements, while 

accommodating long-term (future) readiness by 

minimizing infrastructure and distributive 

system deterioration ―gaps‖ to ensure full 

service life at a significantly reduced cost. 

400 

350 

300 

250 

200 

150 

100 

50 

CVN68 CL Depot Availability Duration History - EOC 

Figure 7 illustrates the ―step down‖ in total 

maintenance man day costs resulting from the 

sequential move from EOC to the IMP-32. The 

seven per cent (7%) increase in man days from 

the 1994 IMP-24 to the 2002 IMP-24 is a result 

of quality of life (QOL) initiatives which shifted 

work traditionally accomplished by ships force 

(such as fire watches) to maintenance providers. 

0 

(50) 

(100) 

1982 1984 1986 1988 1990 1992 1994 1996 1998 

FIGURE 8. EOC Availability Duration History – 

EOC 

400 

350 

300 

250 

CVN68 CL Depot Availability Duration History - IMP 

7000 

200 

150 

6000 

100 

5000 

- 22 % 

+ 7 % 

- 6 % 

- 14 % 

50 

0 

4000 

(50) 

(100) 

1994 1996 1998 2000 2002 2004 2006 2008 2010 

3000 

2000 

FIGURE 9. Depot Availability Duration History - 

IMP 

1000 

0 

1992 EOC 1994 IMP-24 2002 IMP-24 2004 IMP-27 2006 IMP-32 

FIGURE 7. Comparison of Carrier Life Cycle 

Man day Totals 

Based on Programs of Record, there has been a 

reduction of approximately 2 million man days 

per carrier over its 50 year service life 

(excluding Shipbuilding and Conversion, Navy 

(SCN) funded RCOH), equating to roughly $1B 

cost avoidance per carrier. 

The IMP strategy to develop precisely planned 

availabilities, tailored to accommodate shipyard 

shop and trade skill capabilities, combined with 

CT1 project management initiatives have 

resulted in significantly improved availability 

execution. Figure 8 depicts the deviation from 

OPNAV established maintenance duration the 

carrier community experienced under the EOC. 

Figure 9 is a similar scatter gram reflecting 

availabilities after implementation of the IMP 

and shows a significant improvement of 

schedule adherence. 

A comparison of the notional data indicates that 

depot time under the EOC was 33% of a carrier 

life cycle versus only 20% under the IMP-32. It 

should be noted that the data excludes RCOH 

and Post-RCOH Post Shakedown Availability 

(PSA)/SRA timelines. 

IMP FUNCTIONALITY 

The IMP gains its functionality from the 

foundation by which it was built. Clearly 

identified and articulated technical requirements 

are the cornerstones while hard lessons learned 

from historical challenges provide the structural 

strength. Inputs to the IMP are (1) Core 

technical requirements and (2) Historical 

feedback requirements (Figure 10 (Note: The 

information flow is BI-DIRECTIONAL for all 

these functions except for historical feedback 

(which by definition is unidirectional)). 

Requirements, Budgets, Workload Forecasting 

and Baseline Availability Work Package 

(BAWP) development are iteratively updated as 

feedback information validates (or invalidates) 

7 


and refines the information contained in the 

IMP. 

FIGURE 10. Functions of the IMP 

Requirements: The IMP serves as the single 

authoritative repository of all ―off ship‖ 

technical maintenance requirements defined by 

higher order documents such as Naval Ship 

Technical Manuals (NSTM’s), General 

Specifications for Overhaul (GSO), Steam and 

Electric Plant Manual, etc. The key 

organizations (not all inclusive), which set the 

requirements are: OPNAV, SEA 05, SEA 08, 

Naval Air Systems Command (NAVAIR), 

Naval Surface Warfare Center (NSWC), 

Commander Naval Air Forces (CNAF), etc. ―On 

ship‖ technical maintenance requirements are 

managed through the Preventative Maintenance 

Schedule (PMS). 

Feedback: The IMP serves as the repository of 

historical execution feedback from the Naval 

Supervising Authority (NSA), In-Service 

Engineering Agents (ISEAs), etc. required to 

continuously validate and improve the plan 

itself. 

The key Output functions of the IMP are: 

To develop notional budgets for OPNAV 

and the Program Objective Memorandum 

(POM) process. 

To develop the Material Unit Cost (MUC) 

rates for COMNAVAIRFOR. This MUC is 

used to convert expected Material demands 

to a man day rate in order to budget under 

the same units. 

To develop workload forecasts for SEA 04 

in order to project the industrial base 

workload for future years. 

To develop BAWPs for the Naval Aviation 

Enterprise (NAE). 

To serve as the single authoritative data 

repository for ―off ship‖ maintenance 

requirements and financial information to 

enable ―war gaming/what if‖ data calls. An 

example of this was the ability to generate a 

2,600 page ―cradle to grave‖ forecast of 

Baseline Availability Work Package 

(BAWP) technical requirements for a 

―generic‖ aircraft carrier over its entire 50 

year in-service life. This package was used 

by OPNAV during POM12 to show that the 

notional allowances being requested were 

based on known and required work. 

Through ongoing review and continuous update 

of the IMP, the Carrier Planning Activity (CPA) 

(PMS 312C) accomplishes: 

Workload and financial notional reviews. 

Validation or improvements to the 

assessment plans. 

Availability work package growth analysis. 

IMP Flexibility – Double Deployments 

Under the IMP-24 there was only one 

deployment between maintenance periods. Table 

2, shows the IMP-32 flexibility to increased 

deployments when required, e.g., to date five (5) 

carriers have ―double deployed‖ between their 

maintenance periods. Review of maintenance 

data shows no significant increase in the Job 

Control Numbers (JCNs) the ―double deployed‖ 

ships reported versus JCNs reported by the end 

of their single deployment operational cycles. 

8 


SRA 

SRA 

SRA 

SRA 

SRA 

SRA 

SRA 

SRA 

Carrier Action Date Start Date End 

CVN 68 PIA2 03/01/2006 08/30/2006 

Deploy 04/02/2007 09/30/2007 

Deploy 01/24/2008 06/03/2008 

PIA2 06/16/2008 12/16/2008 

CVN 69 PIA2 01/22/2008 07/23/2008 

Deploy 02/21/2009 07/30/2009 

Deploy 01/04/2010 Est. 07/2010 

PIA2 09/01/2010 02/28/2011 

CVN 70 PIA3 04/01/2002 08/30/2002 

Deploy 02/07/2003 09/18/2003 

Deploy 01/13/2005 07/13/2005 

RCOH 11/10/2005 07/11/2009 

CVN 72 DPIA2 06/23/2003 06/07/2004 

Deploy 10/15/2004 03/05/2005 

Deploy 02/27/2006 08/08/2006 

PIA3 09/05/2006 06/30/2007 

CVN 76 PIA1 05/01/2007 10/30/2007 

Deploy 05/19/2008 11/25/2008 

Deploy 05/28/2009 10/21/2009 

PIA1 11/09/2009 05/09/2010 

TABLE 2. ―Double Deploying‖ Carriers 

IMP Flexibility – Forward Deployed 

Naval Force (FDNF) Aircraft Carrier 

In 2008 a Nimitz Class aircraft carrier, USS 

George Washington (CVN 73), replaced USS 

Kitty Hawk (CV 63) as the Forward Deployed 

Naval Forces (FDNF) carrier in Yokosuka, 

Japan. This is the first time a nuclear powered 

vessel has been systematically maintained 

outside of the United States in a tethered 

forward deployed status. 

CVN 73 was under the CVN 68 Class IMP, and 

transitioned as the FDNF carrier to a modified 

IMP strategy utilizing annual 120-day SRAs in 

lieu of the 32/8 strategy detailed above. The 32/8 

CVN 68 Class IMP maintenance approach was 

considered for the forward deployed 

environment. Due to the unique forward 

deployed operational requirements of the FDNF, 

the 32/8 strategy did not support six consecutive 

months with the assigned carrier in a 

maintenance status. Two other availability 

scheduling options previously applied to the 

conventionally-powered aircraft carriers in 

Yokosuka were given primary consideration. 

Those two options were: 

Two annual 70-day availabilities and 

notional 15-day upkeep. 

Single annual 120-day availability and 

notional 30-day upkeep. 

The strategy involving the annual 120-day SRA 

(Figure 11) was selected primarily due to the 

following advantages: 

Consistent with FDNF Operational 

requirements. 

One availability start-up period and one test 

program per year vice two. 

Increased capability to accomplish more 

significant repairs/modernization during the 

longer maintenance period. 

Reduced overlap between planning of a 

follow-on availability and the execution of 

an ongoing availability. 

More efficient scheduling and execution of 

required work during the longer 


2007 

FDNF Maintenance Schedule 

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 

DPIA PIA PIA RCOH 

IMP Maintenance Schedule 

FIGURE 11. Comparison of FDNF and IMP 

Maintenance Schedules 

Building on both technical requirements and 

historical lessons learned, the scheduling of 

discrete ―work packages‖, and appropriately 

fitting the FDNF maintenance profile was both 

efficient and effective. The flexibility and 

functionality of the IMP was again proven. 

Managing the Plan (IMP) 

As can be seen by its evolution to date, the plan 

(IMP) has never been static, and has resulted in 

improved benefits as it moved from IMP-24 to 

IMP-27 to the current IMP-32 and IMP-FDNF. 

The carrier maintenance community is 

constantly challenging the plan and its 

underpinning requirements, and incorporating 

new strategies and tools to handle emerging 

issues and maintenance problem areas. 

Through teaming with Submarine Maintenance 

Engineering Planning and Procurement Activity 

(SUBMEPP) and the Surface Ship Life Cycle 

Management (SSCLM) Activity, and by 

identifying and using best practices and tools of 

other maintenance communities, NAE has been 

able to accelerate their efforts to increase the 

RCOH 

9 


efficiency of the IMP. Their involvement in 

organizations that make a difference to the base 

requirements, such as the Common Maintenance 

Plan Working Group (CMPWG) and 

Cumbersome Work Practice Group (CWP) are 

all important parts of managing the plan. The 

following are the major strategies and tools that 

orchestrate the Aircraft Carrier Class 

Maintenance Plan (ACCMP): 

ACCMP Manual: The ACCMP manual (PEO 

Aircraft Carriers 2006 and annual updates since) 

is the Program of Record that provides the 

overarching maintenance strategy and processes 

used to execute and manage life cycle 

maintenance for all aircraft carriers. The 

composition of life cycle maintenance is 

constantly evolving as strategies are affected by 

modernization, Reliability Centered 

Maintenance (RCM) analysis, maintenance 

process improvements and technical innovation. 

While the IMP provides the notional estimates 

for material costs, manpower costs in labor, 

engineering and overhead, the ACCMP 

integrates the technical requirements managed in 

the IMP into execution strategies to optimize 

when, where, and how the maintenance will be 

done. Current maintenance strategies include: 

Freeboard/Topside Maintenance, Tank 

Maintenance, and CVN 68 Class Non-Nuclear 

Cognizant Air Circuit Breaker Maintenance. 

Such a structured approach improves safety, 

maintenance effectiveness, reduces cost, and 

increases overall operational reliability through a 

carrier’s entire service life. 

Through the utilization of the CT1 Availability 

Work Package Development Process, the 

ACCMP maintenance strategies and 

requirements are meshed with modernization, 

deferred maintenance, ship’s force work items, 

and repair actions to define all significant “Life 

Cycle Work” required for a specific aircraft 

carrier’s 32-month operational cycle. The 

planning that results from executing the 

ACCMP supports carrier notional availability 

budget projections which are developed through 

the use of historical maintenance data, coupled 

with a continual review and challenging of 

requirements. This provides technical rigor to 

the process. 

Maintenance & Ship Work Planning 

(M&SWP) tool: In the past, the IMP was 

maintained in a CPA ―in-house‖ database. 

Through its efforts to identify best practices 

from the other maintenance communities they 

became aware of SUBMEPP’s M&SWP tool. 

This life cycle management planning tool was 

far more robust and versatile than CPA’s. As a 

result, CPA developed a Memorandum of 

Agreement (MOA) with SUBMEPP, and has 

modified M&SWP to accommodate CVN 68 

Class maintenance requirements. M&SWP 

provides a single database for management of 

Non-Nuclear ―off ship‖ Class Maintenance Plan 

(CMP) requirements, linked to configuration and 

historical completion data at the component 

level. 

The CPA has completed conversion from the old 

database and now the CVN 68 ACCMP ―off 

ship‖ requirements are housed in M&SWP. 

Since NAE’s adaptation of M&SWP, the Fleet 

has endorsed it under their Maintenance Figure 

of Merit (MFoM) initiative as the Program of 

Record and the SSLCM Activity has begun its 

transition to it as well. 

Corrosion Control Information Management 

System (CCIMS): CCIMS provides a single 

database containing the current detailed status of 

corrosion in aircraft carrier tanks, voids and 

plenums. CCIMS evolved from the Carrier Life 

Enhancing Repairs (CLER) program. The 

CCIMS database provides condition based 

scheduled inspection and work requirements and 

is a direct feed into M&SWP used for 

development of the BAWP. Since its inception 

in 2003, CCIMS has been the mechanism the 

Carrier community used to reduce the unknown 

tank coating conditions from 45% to 5%. Better 

management of the tank life cycle process has 

allowed the CPA to provide more accurate 

BAWP tank packages and budgets projections, 

which assists the executing activates in their 

ability to plan and execute. Additionally, the 

information derived from CCIMS resulted in 

successfully challenging and changing both 

inspection and preservation requirements 

resulting in a substantial cost avoidance. 

10 


CCIMS has been selected as the Program of 

Record for management of corrosion across the 

entire fleet and is utilized by all three Naval 

Enterprises. 

Requirements Review: There is a new and 

revitalized focus on challenging the core 

requirements with a TOC perspective. 

Baselining the CMPs: In response to a 

tasking from Commander, United States 

Fleet Forces Command, Class Maintenance 

Plan maintenance requirement Zero-Based- 

Reviews (ZBR) were conducted by a crossenterprise 

working group (eventually 

evolving into the CMPWG), chaired by 

NAVSEA 04RM and having members from 

ship maintenance planning organizations, 

ship life cycle managers, fleet 

representatives and technical managers. The 

ZBR validated that the maintenance plan 

requirements were derived from RCM based 

requirements, a higher-level technical 

requirement, or a regulatory directive. The 

outcome of the review resulted in 97% of 

the Aircraft Carrier requirements being 

validated; 1% deleted; and the remaining 2% 

have under gone reviews since to resolve. 

CMPWG: The CPA is a founding member 

of the CMPWG which is central to 

continuously challenging requirements and 

is in alignment with the Surface and 

Submarine Enterprises. The CMPWG was 

established in June 2006 consisting of 

NAVSEA 04RM, Naval Sea Logistics 

Center (NSLC), SUBMEPP and CPA. The 

Working Group operates as a cross platform 

cooperative group to achieve common 

maintenance requirements and associated 

best practices and to determine the right 

maintenance requirements across platforms. 

The ultimate purpose of the CMPWG is to 

optimize maintenance requirements and 

procedures across platforms and establish a 

culture of continuous improvement and 

knowledge sharing for developing 

maintenance requirements. This requires 

establishing the most applicable and 

effective requirements possible while 

institutionalizing periodic formal reviews of 

all maintenance requirements. 

 

NAE Knowledge Sharing Network: Over 

the last several years, the NAE has taken 

great effort in establishing a culture that 

aligns its various activities along the 

Personnel, Equipment, Supply, Training and 

Ordinance (PESTO) pillars. Under the ―E‖ 

pillar various teams including the Life Cycle 

Management Group (LCMG), Cost 

Optimized Readiness E-Pillar (COR-E), 

Cost Wise Readiness Team (CWRT) and 

Ready for Tasking – Equipment (RFT-E) 

have been established. The LCMG focuses 

on current and future mission requirements 

in support of the aircraft carrier’s 50 year 

in-service life. Current platform, system and 

equipment concerns are identified and 

mitigation strategies explored to improve 

today’s readiness (Ao) and costs. Future 

requirements (Joint Strike Fighter 

integration, interoperability issues, etc.) are 

addressed through modernization and 

technology upgrades. To execute these 

responsibilities and support rigorous fact 

based and informed decisions, in 2006 the 

LCMG chartered the COR-E Cross 

Functional Team (CFT). 

The COR-E (Current Readiness, 2010) 

aligns resources across the carrier 

maintenance community through the 

identification, prioritization, analysis and 

mitigation of critical deckplate problems. 

The Team identifies equipment readiness 

and cost drivers, and provides a forum for 

knowledge management and transparency. 

The basic work of COR-E is divided into 

five (5) main Sub-Groups at the Working 

Group Level: Aircraft Launch and recovery 

(ALRE); Propulsion; Command, Control, 

Communication, Computer, and Combat 

System (C5I); Hull, Mechanical and 

Electrical (HM&E), and Logistics. Each of 

the Sub-Groups has its own Lead/Co-Lead 

and is in itself a CFT with membership from 

appropriate Systems Commands, Ships, 

TYCOM, Program Offices, etc. Members 

bring with them the inherent authority, 

responsibility and perspective of their parent 

organizations. COR-E’s taps into key 

maintenance community activities (not just 

organizations) to assure complete visibility 

11 


and transparency for all maintenance related 

issues. 

Equipment/system readiness trends are 

monitored by RFT-E Data, consisting of 

Impaired Days and Out of Commission 

(OOC) Days identified by ship’s force. The 

formal stand-up of COR-E has had a 

measureable impact. In FY09, the ―Top 

Five‖ Critical Shipboard Systems monitored 

by RFT-E data had their ―Impaired Days‖ 

reduced by over 80 per cent. OOC 

equipment trend data shows a decline of 

approximately 45 per cent over a two and a 

half year span. 

The CWRT collects data for trending costs 

on both the findings of the CMPWG and the 

efforts of COR-E as they pertain to aircraft 

carriers and: 

Provides information to allow decisionmakers 

to provide the same readiness at 

reduced cost. 

Allows carrier community to better 

understand TOC. 

Promotes CWR decisions. 

Metrics assess benefits of CWR 

decisions and actions. 

Captures requirement changes that 

should be reflected during the ―9-Step‖ 

development process. 

Captures and tracks all of the initiatives 

that affect the cost of aircraft carriers for 

the carrier maintenance community. 

Technical Foundation Papers (TFPs): The 

CPA, along with SUBMEPP and SSLCM 

Activity for their respective enterprises, 

maintain a TFP for each ship class that 

documents how the technical requirements 

contained in the CMP are expressed as 

budgetary requirements. The TFP provides the 

background, rational and basis for the CNO 

availability notionals, both for labor, in man 

days, and material, in dollars, required to 

execute the ACCMP. These CNO availability 

notional allowances are documented in 

OPNAVNOTE 4700 which is issued annually to 

support the POM/PR budget process. 

Availability notional allowances are used as a 

tool to project long range budget requirements. 

The TFP also documents the business rules and 

processes used by NAE to refine the OPNAV 

Notional class allowances used for long range 

forecasting into a ship specific allowance for 

near term budget requirements. All three 

Enterprises use the Fleet managed ―9-Step‖ 

Process to submit their budget requirements. 

These submissions are not only utilized in the 

budget process but also by the Public Shipyards 

in the development of their workload capacity 

plans. 

Bottom Line: These elements combined, 

including the ACCMP, IMP, maintenance 

strategies, requirements reviews, CMPWG, 

M&SWP, TFPs, and the proactive involvement 

of the Carrier maintenance community provide 

for an agile, flexible and properly aligned 

approach to an engineered strategy in support of 

affordable assets available to the Fleet for 

tasking. A recent audit of the CPA’s CMP 

Management Processes by the Board of 

Inspection and Survey (INSURV) to determine 

the effectiveness of the CMP maintenance 

processes for the USS Abraham Lincoln (CVN 

72) showed: 96% of the CMP requirements have 

Known Last Accomplished Dates, only 4.4% of 

the CMP Scheduled maintenance requirements 

were overdue; and that 100% of the past due 

requirements will be technically adjudicated by 

the official close out of the availability. 

Additionally, a recent internal requirements 

review of the 32-month operation/maintenance 

cycle, in-place since 2006, has shown no 

decrease in the ships material readiness since the 

latest iteration of the IMP was implemented. 

This was verified by a review of: 

Current Ship Maintenance Project (CSMP) 

trends. 

INSURV results. 

NAE, LCMG, COR-E Team efforts, and its 

RFT-E data trends. 

Comparison of level of readiness and 

material condition to previous (IMP- 

24/IMP-27) operational cycles. 

CPA’s Life Cycle Analysis. 

12 


Continued low level (

Maintenance, the IMP contributed to a legacy of 

on-time availability completions. 

Future challenges exist, both known (integration 

of CVN 78, JSF, etc.) and unknown (changing 

world environment), but the IMP strategy has 

proven highly adaptable and flexible to address 

whatever over the horizon events present. 

REFERENCES 

COMNAVSEASYSCOM ltr 4700/CV/CVN 

OPR PMS 312E/785 Ser 00/0656 of 4 Jun 91, 

Maintenance and Modernization Strategy for the 

CV/CVN and AVT Force 

Current Readiness & Enterprise AIRSpeed 

Newsletter; Volume 8, Issue 2, March 2010 

Manvel, T., M. Knight, K. A. Dieter, and L. R. 

Dutton, ―Incremental Maintenance for USS 

Nimitz (CVN68) Class Aircraft Carriers,‖ 

Technical Proceedings, Fleet Maintenance 

Symposium, October 1993. 

OPNAVNOTE 4700 ser N431H/4U741235 of 

30 Jun 04, Representative Intervals, Durations, 

Maintenance Cycles, and Repair Mandays for 

Depot Level Maintenance Availabilities of U.S. 

Navy Ships 

PEO Carriers (PMS 312) ltr 4790 PMS312 Ser 

05-337 of 4 Mar 2005, Aircraft Carrier 

Drydocking Interval 

PEO Aircraft Carriers ltr 4700 PEO Ser 06-1203 

of 6 September 2006, Aircraft Carrier Class 

Maintenance Plan (ACCMP) (Rev 3 - Jan 2010) 

ACKNOWLEDGEMENTS 

Capt. Talbot Manvel, USN (Ret) is an Adjunct 

Master Instructor of Naval Architecture at the 

United States Naval Academy. A 1972 graduate 

of the US Naval Academy with a B.S. in Ocean 

Engineering, he retired from the U.S. Navy as an 

Engineering Duty Officer after 28 years of 

service. He served on three aircraft carriers, 

assisted in the supervision of the construction of 

two nuclear carriers, lead the development of 

the Incremental Maintenance Plan for the 

NIMITZ Class and the design development of 

the FORD Class. 

Bradley A. Toncray is the Chief Engineer and 

Engineering Division Manager for PEO 

Carriers PMS312C Carrier Planning Activity 

(CPA). Mr. Toncray holds a bachelors degree 

in Mechanical Engineering from the Georgia 

Institute of Technology. He began his career in 

1990 at Norfolk Naval Shipyard Engineering 

and Planning Department’s Propulsion 

Machinery Branch, working as a waterfront 

trouble-desk engineer, special-projects engineer, 

Project Engineering and Planning Manager 

(PEPM) and eventually as the acting branch 

head for the propulsion machinery branch. He 

transferred to the CPA Life Cycle Systems 

Engineering Branch as the Propulsion System 

Specialist and Aircraft Carrier Vibration 

Machinery Condition Analysis Program 

Manager in 1998. Mr. Toncray has represented 

the aircraft carrier community on several major 

life-cycle maintenance initiatives including the 

Common Class Maintenance Working Group 

(CMPWG), Material Assessment Cross 

Functional Team (MACFT) and the CVN 65 

Main Feed Pump Life Cycle Maintenance 

Engineering Task Force. Mr. Toncray was 

awarded the Department of the Navy 

Meritorious Civilian Service Award for his 

service to PEO Aircraft Carriers. 

Randal L. Harrington is the Life Cycle 

Engineering Division Manager for PEO 

Carriers PMS 312C Carrier Planning Activity. 

Mr. Harrington holds a bachelors degree in 

Mechanical Engineering from Michigan 

Technological University. He was recruited 

directly from college by Norfolk Naval Shipyard 

(NNSY) and began his career in the Engineering 

and Planning Department as a Planning Yard 

Design Engineer specializing in Heating, 

Ventilation and Air Conditioning (HVAC). Mr. 

Harrington’s career at NNSY included 

assignments as a design engineer; waterfront 

trouble desk engineer; branch head for several 

modernization and maintenance engineering 

codes; and concluded as the Project 

Engineering and Planning Manager (PEPM) for 

several ship availabilities. He has been with 

14 


CPA since 2000 serving as the Branch Head 

responsible for both the hull modernization plan 

and the class maintenance plan. Mr. 

Harrington is the co-author and a presenter of 

“Breaking the “Unique” Paradigm: Using 

Common Best Practices to Improve Navy 

Maintenance” presented at the 2007 ASNE 

conference. 

maintenance, processes and Reliability Centered 

Maintenance (RCM) issues. Since retirement 

Mr. Newton has worked as a consultant for PRC 

Inc. and American Management Systems Inc. 

(AMS). He has been with AMSEC LLC, a 

subsidiary of Northrop Grumman Corporation, 

since 2002, and has supported the CPA since 

2004. 

Nicholas D’Amato is a Senior Strategic 

Planning Manager with AMSEC LLC 

supporting PMS 312 and PEO Carriers. He 

retired in 2008 as the Carrier Planning Activity 

Deputy after 38 years Government service. Mr. 

D’Amato holds a bachelors degree in 

Mechanical Engineering from Newark College 

of Engineering. His career began in 1969 at 

Norfolk Naval Shipyard in the Engineering 

Department’s Propulsion Machinery Branch. 

Career advancements included Propulsion 

Branch Head and 20 years as Assistant Chief 

Engineer. As a special assignment, Mr. 

D’Amato was technical lead for the CVN-68 

Class conversion from an Engineered Operating 

Cycle (EOC) to an Incremental Maintenance 

Plan (IMP). He was selected Deputy/Chief 

Engineer of the Carrier Planning Office at 

SUPSHIP Newport News in 1998. In 2006 the 

Carrier Planning Activity was realigned under 

the Aircraft Carrier Programs Office. With the 

introduction of Enterprise concept, Mr. 

D’Amato became a member of the NAE’s 

Carrier Readiness Team as (then) Co-Lead 

CAPT Tom Moore’s Action Officer. He joined 

AMSEC LLC, a subsidiary of Northrop 

Grumman Corporation, in January 2008 and 

continues to support the NAE, CRT and 

PMS-312. 

Jeffrey P. Newton is a Program Manager with 

AMSEC LLC. He graduated from Excelsior 

College with a bachelors degree in Liberal Arts 

and holds masters degrees in Public 

Administration and Human Resources 

Management from Troy University. He retired 

from the U.S. Navy as a LCDR (SWO) with over 

25 years of service in 1993. Mr. Newton was a 

participating member of the CVN 65 Main Feed 

Pump Life Cycle Maintenance Engineering Task 

Force and supports PMS 312C Carrier 

Planning Activity as a consultant for life cycle 

15

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