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RCM in the Public Domain: An Overview of the US Naval
Air Systems Command’s RCM process
By
JC
Leverette and Andres Echeverry, Anteon Corporation
Originally presented at RCM-2005 - The Reliability
Centered Maintenance Managers' Forum
You can purchase the RCM-2005 Proceedings CD and
Proceeding Book for just $99 here
Abstract
The US
Navy’s Naval Air Systems Command (NAVAIR) has been one
of the leading implementers of Reliability-Centered
Maintenance (RCM) methodologies in its efforts to
improve reliability, safety, and minimize costs
associated with the operation and maintenance of the US
Navy’s aircraft fleet. NAVAIR’s RCM methodologies have
been updated and refined with over 30 years of RCM
experience on a wide variety of complex systems. This
paper will present an overview of the NAVAIR process
including:
·
The NAVAIR
RCM process and tools, both of which are openly
available to the public
·
The
relationship between the NAVAIR RCM process and the SAE
JA1011 standard
·
Clarification of some common misconceptions about the
NAVAIR RCM process and RCM in general
·
Several
case studies of the application of NAVAIR RCM with a
focus on various execution methods.
·
Examples
of applications of NAVAIR RCM on non-aircraft equipment.
Background
The US Navy has been one of the leaders in
development and application of RCM analysis. In one of
the earliest applications of RCM principles, the US Navy
began applying Maintenance Steering Group (MSG) logic
developed by the commercial airline industry to the
P-3, S-3 and F-4 aircraft in the early 1970’s. In 1975,
NAVAIR applied an updated version of MSG-2 called the
Analytical Maintenance Program to Naval aircraft and
engine programs. In 1978 the Department of Defense (DoD)
sponsored DoD report AD-A066579, “Reliability
Centered Maintenance” by Stanley Nowlan and Howard
Heap of United Airlines. This report was based on the
principles of MSG logic and was the foundation of most
modern day RCM processes (reference 1). Throughout the
1980’s DoD issued several documents related to RCM
analysis; most notably in 1986, DoD issued MIL-STD-2173,
"RCM Requirements for Naval Aircraft, Weapons Systems
and Support Equipment". This document was the basis
of the current NAVAIR RCM Process. In 1996, MIL-STD-2173
was superseded by NAVAIR 00-25-403, “Guidelines for
the Naval Aviation Reliability-Centered Maintenance
Process”, which contains the current RCM process
described in this paper (reference 2).
The objective of this paper is to introduce
the NAVAIR RCM process; identify some of the tools and
resources available to those interested in using RCM
analysis; and demonstrate some of the lessons learned
from application of the NAVAIR RCM process. The NAVAIR
RCM process is a completely non-proprietary process that
is free and openly available to the general public. It
is the hope of the authors that exposure to this
information will encourage some people to pursue the use
of RCM who might not otherwise do so because of the
perception that a long term and expensive commitment to
a proprietary process and tools is required.
Anyone who
has been exposed to any of the public discussion
surrounding RCM knows that there are many vendors
offering RCM services. Many of the claims about these
competing processes seem to be contradictory and
confusing. Some of the information being passed around
is, at best, unsubstantiated and, at worst, inaccurate.
A secondary purpose of this paper is to address some of
the known inaccuracies, particularly those directed
towards the NAVAIR RCM process and the closely related
SAE JA1011 RCM Standard.
It is not
the intent of this paper to compare RCM processes, nor
is it the intent to suggest that the NAVAIR RCM process
is superior to any other RCM process. We will attempt to
point out where we believe the NAVIR process is unique
and how it can be effectively used in the public domain.
Many RCM vendors provide experience in specific
industries, different approaches to executing RCM
analysis, and various tools such as software that may be
beneficial to a particular user. It is the hope of the
authors that this paper can provide potential users with
a means to learn more about RCM independently and decide
for themselves what type of process best meets their
needs, before committing to one particular process or
vendor.
NAVAIR RCM and the SAE JA1011 Standard
In the early 1990’s the US DoD began a
series of initiatives to streamline the acquisition
process for military procurements. One of these
initiatives was a decision to eliminate, as much as
possible, the use of military standards in new
acquisitions, and instead, rely on commercial or
performance standards. This decision was documented in a
memorandum from Secretary of Defense William Perry dated
29 June 1994. The decision was enforced with the
systematic canceling of a large number of military
standards. One of those cancelled was MIL-STD-2173,
which documented the RCM process used by NAVAIR at the
time.
In support of this acquisition streamlining
effort, a group called the Reliability, Maintainability
and Supportability (RMS) Partnership, began coordinating
the efforts of various other organizations involved in
developing standards related to reliability,
maintainability and supportability. Through the RMS
Partnership, the Society of Automotive Engineers (SAE)
was asked to lead the development of an RCM Standard to
replace the various Military RCM standards being
cancelled since no equivalent commercial standard
existed at the time.
SAE chartered a sub-committee to begin
development of an RCM standard under its G-11
Supportability Committee. The RCM subcommittee initially
consisted of representatives from the US Navy and
various DoD contractors. It was noted that the
development of a “commercial” standard was being
performed almost exclusively by personnel associated
with DoD.
The group
started down several different paths in development of
this standard, including one directed by “higher-ups” in
SAE that the sub-committee develop a “preventive
maintenance” standard because they didn’t think there
would be enough interest in RCM. The actual quote from
an email is presented for its humor value: "We [the
SAE Supportability Committee] are not interested in an
'RCM spec'. We want a 'scheduled maintenance spec'. An
'RCM spec' would be too narrow in scope. There's not
enough general interest in RCM to justify SAE
involvement in such a spec.”
The group
also found itself, at various times, trying to correct
known or perceived deficiencies in current processes but
could not always agree on how to correct them. After
several of these false starts the group concluded that
there was no “standard” RCM process and that a
“standard” was not the place to develop new and untried
procedures. They also decided to ignore the directive to
create a preventive maintenance standard. The group
began to settle on the idea of creating a set of
criteria with which to compare existing processes to
ensure a given process was conforming to the original
tenets of RCM as defined by Nowlan and Heap.
The group
made further efforts to seek out additional experience
from commercial industry. In late 1997, the
well-respected John Moubray and a few users of the RCM2™
process became involved. With new participation and a
clearer direction in place, despite some lively debate,
the group was able to complete the SAE JA1011 Standard
in 1999. The group also continued work on SAE JA1012,
which was intended to “provide additional clarification
and amplification for some of the key concepts and terms
in JA1011”[i]
(references 3 and 4).
At about the same time the SAE effort was
started, NAVAIR started an effort to retain their RCM
process information in a format that would not be viewed
as objectionable as a “standard”. The effort also was
intended to capture the many lessons learned and
improvements identified from significant RCM efforts
performed after the release of MIL-STD-2173 in 1986. The
result of this effort was the NAVAIR manual, NAVAIR
00-25-403. Many of the participants in this effort were
also participants in the SAE JA1011 development effort
including the author of this paper who participated in
both efforts.
At this point it is worth discussing
how DoD uses standards. In what may be a gross
oversimplification, DoD uses standards to ensure it
knows what it is getting when it buys a product or
process. While there is an assumption that a standard
referenced in a procurement satisfies the exact
requirements of the procuring activity, solicitations
often encourage vendors to provide alternative solutions
as long as they can be proven to meet all relevant
requirements and are advantageous in some manner. In the
opinion of this author, SAE JA1011 was intended to be
used the same way; as a reference to ensure a potential
user of a particular RCM process understood what they
were getting relative to the original RCM concept as
proposed by Nowlan and Heap. It was not intended to
conclude that this was the only process to determine
maintenance requirements or even the best process for
every situation. In other words, it is the
responsibility of the user of a process to decide
whether or not a process complies partially or
completely with JA1011 and whether it even matters.
Finally it is also worth noting that there
seems to be a notion in some camps that SAE JA1011 was
primarily developed from the RCM2™ process. In fact, SAE
JA1011 was heavily influenced by users of both the RCM2™
and the NAVAIR RCM processes. However, as noted above,
much work was accomplished prior to the involvement of
Mr. Moubray. In the opinion of this author, as a
participant in its development, SAE JA1011 was an
impartial assessment of the original tenets of RCM and
was as unbiased by any particular personal or business
agenda as was humanly possible. Any of the dozen or more
people involved will attest that debate was lively and
no one person or group got everything they wanted in the
document.
NAVAIR RCM Process Description
The NAVAIR RCM process has been evolving
ever since the first applications of MSG-2 logic on US
Navy aircraft in the 1970’s. The RCM logic, analytical
tools, and associated execution and implementation
processes have been refined and improved over the years
based on the experience and lessons learned from many
applications of the process under a variety of
circumstances.
The NAVAIR
RCM process is fully described in NAVAIR 00-25-403. This
manual provides information on the following topics:
·
RCM
analysis planning and preparation
·
RCM
Training and certification
·
Failure
Modes, Effects, and Criticality Analysis (FMECA)
·
The RCM
analysis decision logic process
·
Implementation of analysis results
·
Sustaining
the maintenance program through RCM analysis
·
Assessing
RCM effectiveness
Figure 1
shows the overall NAVAIR RCM process, which includes
four major steps: planning and preparation, the
analysis, implementation of results, and sustaining the
program. It can be seen from this process overview that
the NAVAIR RCM process provides a comprehensive RCM
program that addresses not just the analysis process but
also the preliminary effort and follow-on efforts
necessary to ensure the RCM effort achieves the desired
results.
Figure 1.
Figure 2 is
the NAVAIR RCM logic diagram. The NAVAIR RCM logic has
many similarities and a few noteworthy differences from
many of the earlier processes. Like many other logic
charts, it differentiates safety and non-safety and
hidden and evident failures. It also addresses
environmental consequences in the safety branches.
Applicable task types and other outcomes depend on which
branch of the logic tree the failure mode falls into.
One of the most noticeable differences from other logic
diagrams is the lack of a preferential order in the
review of each task type. Most RCM processes assume a
preferred order in the selection of a maintenance task,
e.g. on-condition first, time-directed or hard-time
second, etc. In these processes, if one of the tasks is
deemed to be applicable and effective, it is selected
and the analysis continues with the next failure mode.
The NAVAIR RCM process encourages consideration of all
applicable failure management strategies for a given
failure mode and provides comparison methods to help
select the most effective of all applicable solutions.
Figure 2.
While it
is not the intent of this paper to provide a complete
description of the NAVAIR RCM process, there are few
additional points about the NAVAIR RCM process worth
mentioning:
·
The
process provides analytical methods for task interval
determination. However, the process does not
require them to be used. Users are free to use
whatever means they choose for task interval
determination.
·
The
process provides specific data collection tasks called
Age Exploration tasks for use where the analysis may
have been based on assumptions that warrant further
analysis when better data is available. The use of these
tasks is also optional.
·
The
process contains provisions to develop specific
non-maintenance solutions called “Other Actions” to
address failure modes. These Other Actions can include
design changes, operating restrictions, operator
training, equipment replacement, procedural changes,
etc. The analysis contains procedures to assess the
relative benefits of these actions compared to other
applicable preventive maintenance options and
run-to-failure.
·
The
process does not require any specific execution
strategy. It has been used with facilitated teams, as
well as by dedicated RCM analysts. Guidance is provided
for both methods. Additional discussion on this issue is
provided below.
·
The
process has been applied to many types of equipment
including industrial equipment, power generation, and
facilities.
·
The
process provides guidance for application on a limited
basis based on user determined priorities when resources
do not allow a full application.
·
The
process provides guidance for developing a living RCM
program.
·
The
process considers both physical and automated
inspections to be on-condition maintenance and
emphasizes the need to justify implementation of
integrated sensing technologies on the same basis as
other RCM options.
·
The
process provides information on grouping maintenance
tasks to gain additional efficiencies.
Execution Strategies
Unlike many other RCM processes, the NAVIR
process does not promote one particular execution
strategy over another. Additionally, users of the NAVAIR
process have employed many of the techniques other
processes use as reasons to claim their processes are
better, faster, or more efficient.
For
discussion purposes, we will discuss three main types of
execution strategy (with the acknowledgement that there
could be any number of others that we are unaware of):
·
Formal
facilitated groups: One of the most widely accepted
methods of performing RCM today is the use of an RCM
“facilitator” to lead the analysis of a system in a
meeting setting using a group of system experts that
include maintainers and operators.
·
Dedicated
analysts: The analysis is performed by one or more RCM
analysts who gather information from all relevant
sources including system experts, operators and
maintainers. Typically the analyst is an RCM expert with
anywhere from some to extensive knowledge of the
equipment he or she is analyzing.
·
Informal
facilitated analysis: Analysis is performed by one or
more facilitators using one to a few key subject matter
experts in informal settings gathering additional data
from other sources as needed. This could be considered a
combination of the other two approaches.
Other
techniques for expediting the analysis include the use
of analysis templates that contain partially completed
analysis from similar equipment, limiting the analysis
to address only existing preventive maintenance tasks,
and limiting either the systems or failure modes
addressed in the analysis. The NAVAIR RCM process has
been applied using some form of all of these approaches.
Tools
and Resources
The NAVAIR RCM process is supported by some
excellent tools and resources. These tools are again
openly available to the public at no charge. These
include technical documentation, software, analytical
tools, and process improvement forums.
Software
The primary software tool used by NAVAIR for
RCM analysis is the Integrated Reliability-Centered
Maintenance System (IRCMS). IRCMS is a stand-alone
software tool designed to assist in the analysis process
as well as provide a repository for analysis decisions
that are easily reviewed as needed. IRCMS is a public
domain tool developed for the US Navy and is available
via the World Wide Web at the sites listed below. IRCMS
has been used on aircraft and related systems as well as
industrial equipment and in commercial settings.
The current version available at the time of
writing of this paper is version 6.2.5. The current
version was written for the military aircraft
environment but was easily adaptable to commercial
organizations by redefining a few aviation and military
terms such as “flight hours” to mean “operating hours.
However, version 6.3 is due to be released within the
next few weeks and was written to address most of these
differences. Version 6.3 also has some new advanced
features such as the addition of a pre and post RCM
hazard risk index assignment.
IRCMS is relatively easy to use; however
experience has shown that a full understanding of its
features and capabilities is best accomplished through
hands on training via another experienced user, or
through readily available formal training. IRCMS was
designed to be very open to process changes and
therefore does not restrict the analysis with an overly
rigid decision logic. As a result, a thorough
understanding of an RCM process is required to
effectively use IRCMS. Although we are unaware of anyone
trying this, there is no reason IRCMS couldn’t be used
with any RCM process that closely follows the
requirements in SAE JA1011. Software offered by vendors
may prove better for a given application, but IRCMS can
provide a means to explore the process and provide a
frame of reference for available capabilities for those
considering an RCM project.
Documentation and other tools
As
mentioned throughout this paper, the NAVAIR 00-25-403
manual is the primary guidance document for the NAVAIR
process. It is available for download at the websites
listed below along with several other guidance and
program documents. Also available, although not on the
website, is an Excel spreadsheet that provides
analytical methods for determining maintenance task
intervals based on the methods described in NAVAIR
00-25-403.
Process
Improvement
Since the
mid 1990’s NAVAIR has had an officially chartered
committee dedicated to improving the NAVAIR RCM process
and tools. The NAVAIR RCM Steering Committee provides a
forum to receive feedback on the NAVAIR RCM process and
tools. Among other functions, the RCM Steering committee
is charged with: coordinating the development,
distribution, maintenance, and update of the IRCMS
software; coordinating training and certification
requirements; and maintaining and disseminating
knowledge of advancements in RCM related technologies
and processes among other services, industry, and
academia. The RCM Steering Committee appreciates
feedback from all sources on NAVAIR’s RCM processes and
tools. This feedback can be provided via the below
NAVAIR web site.
Resources
Nearly all of the tools and resources
mentioned in this paper are available at no charge from
the following websites.
-
NAVAIR RCM website:
http://logistics.navair.navy.mil/rcm/index.cfm
-
Anteon
website:
http://www.anteon-rcm.com
RCM Myths
As mentioned previously, there seems to be a
tremendous amount of controversy over what RCM is and
what constitutes “proper” RCM analysis. Of course, much
of this is driven by competition in the market place and
the need for vendors to differentiate their products and
services from that of another. Unfortunately some have
taken this a bit far by making claims about other
processes that cannot be substantiated. Other
inaccuracies are misunderstandings or misperceptions
that have been perpetuated over time through various
forums. In this section of this paper we will attempt to
clarify some of the existing misinformation as it
applies to NAVAIR, or other military versions of RCM,
and the SAE JA1011 Standard. This discussion is intended
only to address some of the more often heard
inaccuracies. These issues are not universally discussed
nor is the discussion here comprehensive.
Myth #1:
RCM, especially “classical” RCM, is cumbersome, time
consuming, and expensive.
This myth is typically perpetuated by those
who use processes that they espouse to be much faster
than “traditional” RCM. Early applications of MSG and
RCM were very rigorous and highly detailed, and were
therefore time consuming. Users began to look for ways
to shorten the process. Some looked to change the
process itself to make it shorter. For discussion
purposes we’ll call these “abbreviated” or “derivative”
processes. Implied in the “abbreviated process” view is
that the “abbreviated processes” will yield the exact
same results as a more detailed analysis. Others looked
to improve the way they performed the process with only
minor changes to the process itself. We’ll call these
“classical” RCM. In general, the “classical” processes
try to abide by the original tenets of Nowlan and Heap’s
process, and are therefore more likely to be compliant
with SAE JA1011. As with any undertaking, people learn
how to do things faster and better with experience, so
both approaches should yield a faster analysis than the
earlier applications of RCM.
Fact #1a: Any RCM process is
no more than a set of steps. The basic steps are very
simple. The amount of effort put into each step is
completely up to the user of the process. The time spent
on these steps ultimately depends on the equipment level
the analysis is performed at, the amount of information
examined and included in the analysis, and how much
detailed analytical processing is performed on the data.
Basic answers to the process steps can often be
completed in a matter of minutes. The only real way to
shorten the process is to reduce the information
considered or to become more experienced and efficient
at processing that information.
As
mentioned above, the NAVAIR RCM process not only
includes a set of steps very similar to those described
in SAE JA1011, but also includes some analytical tools
for interval determination, and cost and availability
assessment of maintenance tasks. The extent to which
these tools are used on each individual failure mode or
maintenance task is at the sole discretion of the user.
Recent applications of the NAVAIR RCM process range from
years for some aircraft applications to days for some
commercial plant systems. Our opinion:
Applied appropriately, any SAE JA1011 compliant process
(including the NAVAIR RCM process) should require nearly
the same effort as an appropriately applied
“abbreviated process”.
Fact #1b:
There have been no comprehensive independent studies of
various RCM processes to determine if any are in fact
faster than others. There has been at least one study
(reference 5) that compared the results of a “classical”
process and an “abbreviated” process on two identical
systems at different locations. This study demonstrated
that, at least in this one case, the two different
analysis processes applied on similar systems, did not
produce similar results. The results are summarized as
follows:
Output[ii]
Classical
Abbreviated
Number of
Functions
6 2
Number of
Functional Failures
14 2
Number of
Components in the System Boundaries
13 3
Number of
Failure Modes Analyzed
130 8
Hidden
Failure Modes
88 0
Number of
Critical Failure Modes
73 5
Number of
PM Tasks Specified (incl. RTF)
141 8
Number of
“Items of Interest” (IOI’s)
49 0
Myth #2:
RCM must be performed in facilitated teams to give the
best, or even valid, results. Variations: NAVAIR RCM and
other processes that use independent RCM analysts do not
include proper mechanisms for obtaining maintainer and
operator input
The
argument goes something like this: Including experts
from various elements of an organization in the analysis
process will extract as much relevant information from
as many sources as possible. In addition, the group
analysis process will promote “buy-in” from the
participants through development of consensus in the
analysis results. It is argued that the RCM results are
much more likely to be implemented and therefore the RCM
more likely to be successful because affected parties
participated in and agreed with the analysis.
The
facilitated group method is an excellent method of
performing RCM analysis in many cases. However, some
proponents of this method would have you believe that
using any other method, ever, is inefficient,
ineffective, or even dangerous. Reasons cited include:
·
Other
methods fail to include relevant maintainer, operator,
or subject matter expert knowledge
·
Other
methods are likely to fail because they do not get
maintainer buy-in to the requirements generated by the
analysis.
·
Other
methods take longer due to getting bogged down in
unnecessary detailed analysis of data
·
Other
methods do not disseminate the information developed in
team meetings as well
Fact #2a:
RCM has been successfully and efficiently executed, and
the results implemented, using several different
execution strategies.
Fact #2b:
There are situations where the facilitated team
advantages may not apply or where other approaches may
be better overall, considering that the facilitated team
approach requires participants to all be trained in RCM
and away from their regular jobs while participating in
the analysis effort. Remember, any valid approach will
still be required to obtain necessary information from
operators and maintainers.
·
Contracted
maintenance: Some contract maintenance situations may
make it impossible to include relevant maintainers. For
example, in some facility maintenance environments,
maintenance may be performed on an on-call basis. The
same maintenance personnel or even the same company may
not perform the same task each time.
·
Highly
specialized equipment: Equipment such as gas-turbines,
aircraft structure subject to fatigue, or other highly
complex equipment may require detailed engineering
analysis of failure mechanisms and associated task
intervals. While maintainer and operator input may still
be useful, it may make no sense to subject them to the
details of such analysis.
·
Highly
stressed or lightly manned operations: Some
organizations simply cannot afford to remove key players
from their primary responsibilities long enough to
perform the analysis in meetings over days or weeks. Or,
it may be more cost effective to outsource the analysis
effort. Again, any outsourced effort should ensure
appropriate means of collecting relevant information
from key sources and ensurinfg organizational buy-in to
results are employed.
·
Highly
regulated industries: In cases where maintenance is
regulated and closely monitored such as aircraft,
nuclear power, etc., the consideration of buy-in from
maintainers is likely moot. The tasks get done or
someone gets fired or goes to jail.
·
New
acquisitions or new technology: The majority of
available data may be engineering or test data that
might be most efficiently analyzed by one or two
technical specialists.
The bottom
line is that there are more ways to get information into
an analysis than by having a group sit in a room and
talk about it. There may be times when that is the most
effective way and others when it is not.
Myth #3:
The Military/aviation environment is so different from
the industrial environment that analytical processes for
one do not apply to the other
This general myth can be broken down into several
similar misperceptions that most likely come from a
misunderstanding of military and aviation environments:
Myth #3a:
Military and aviation deal mainly with highly critical
failures that warrant detailed analysis.
Fact #3a:
Military equipment, especially aviation, designers have
spent years and invested huge resources designing in
redundancy and designing out critical failures. Most
failures of aircraft components are economic or
operational in nature. Critical failure is simply
unacceptable from a design standpoint.
Myth#3b:
Military applications are more concerned with safety and
operations than cost and have large amounts of money to
throw at things like RCM.
Fact #3b:
The US Military has been faced with declining budgets
and aging equipment since the end of the Cold War. Most
of the impetus for RCM in the US Military is to maintain
an acceptable state of operational availability while
reducing the cost of operations and maintenance.
Myth#3c:
Military versions of RCM require large amounts of data
including previously performed FMECAs.
Fact #3b:
The NAVAIR RCM process contains the same methods for
determining failure modes and effects as other RCM
processes. Previously or independently performed FMECAs
are often used as source data for analysis, but when
available, are often performed at lower equipment
indenture levels that make them unusable as a direct
input to RCM analysis. Other data is used in much the
same way it is in other industries.
Myth #4:
The
RCM process only applies to new designs
This myth, whose origins are unknown, most
likely came about because RCM was originally developed
from the MSG-2 process, which was developed for new
commercial aircraft.
Fact #4:
The RCM process developed by
Nowlan and Heap was developed for DoD to apply to new
and in-service aircraft. In fact, Nowlan and Heap has a
section dedicated specifically to application to
in-service aircraft. MSG Logic was
originally developed for new commercial aircraft[iii].
Most recent applications of RCM to equipment in DoD by
far have been to equipment that has been in-service for
a significant portion of its life cycle.
Myth #5:
RCM must be a zero based analysis
Fact #5:
RCM can be performed as a zero based analysis or using
an existing maintenance as a starting point. Many NAVAIR
RCM applications have effectively used the existing
maintenance program as a starting point as will be
demonstrated in examples below. NAVAIR 00-25-403
provides guidance on limiting the scope of analysis by
limiting the source of failure modes considered.
Analyzing all failure modes would be at one end of the
extreme and analyzing only new failure modes as they
occur would be at the other. Most NAVAIR applications of
RCM fall somewhere in the middle of this range.
Myth #6:
NAVAIR RCM is not SAE JA1011 compliant
This is probably the most absurd of the
inaccuracies in the public domain, given the histories
and relationship of SAE JA1011 and NAVAIR RCM. It
probably hasn’t been widely distributed, but it seems to
persist in certain circles. Most of the claims made in
this argument were based on outdated or inaccurate
information about the NAVAIR process, for example from
NAVAIR training materials that pre-dated SAE JA1011.
Fact #6:
The NAVAIR RCM process is fully compliant with the
spirit and intent of all provisions of SAE JA1011, as
many of the participants in its development were also
authors of NAVAIR 00-25-403. Reference (6) explores this
issue in great detail. This paper is available on the
websites previously listed.
Case Studies
The case studies present in this section
will probably be from a slightly different perspective
than a traditional case study format. Rather than
provide a detailed review of one specific application of
the NAVAIR RCM process, we will present higher level
overviews of several RCM projects. We believe this will
better serve the audience by demonstrating the
flexibility of implementing the NAVAIR RCM process
rather than showing more examples that claim some
quantitative savings in some metric that is only
meaningful to the organization performing the analysis.
It is also believed that some of these implementation
approaches could be used with other RCM processes as
well. We will, however, present the results of a study
that tries to demonstrate quantitatively, at a high
level, the improvements made by RCM in reliability,
availability, and maintenance cost across the NAVAIR
organization.
 A-7
Corsair Aircraft
The A-7
Corsair is a carrier based attack aircraft fielded in
the 1960’s and retired by the US Navy in 1992. It is
discussed here because it is good example of a limited
analysis approach. An MSG-2 style analysis was performed
early in the aircraft program’s life but it was not kept
up to date. Changes were made to the maintenance program
over time with little documented analysis. As a result,
the aircraft maintenance program and its initial
analysis diverged significantly. Late in the life of the
program a decision was made to re-implement RCM analysis
with NAVAIR’s newer process. Based on the fact that the
existing maintenance program had some basis in analysis,
and the late stage of the life of the program, a
decision was made to go straight to a living RCM program
with no initial analysis. Any changes to the maintenance
program from that point on would be through RCM
analysis, but no up-front analysis of existing tasks or
failure modes would occur. System performance trending
was used to identify systems that might benefit from an
RCM review and RCM analysis was performed only when a
system began to perform poorly. Failures deemed to be
“important” were also analyzed as they occurred. The
trend monitoring and RCM analysis was performed by
full-time RCM experts acting as independent analysts who
were also experienced maintainers on the aircraft.
The A-7
RCM Program was thought of as one of the best at the
time and demonstrates one possible scenario for
application of RCM. If a system has a maintenance
program that is thought to be fairly good to start with
or there is little life remaining in an existing system
it may be worthwhile to start RCM from a sustaining
perspective rather than starting with a large initial
analysis effort.
 E-6
Mercury Aircraft
The
E-6 Mercury aircraft is a strategic communications
platform operated by the US Navy. It is based on a
modified Boeing 707 commercial airframe. The original
maintenance program was developed from a review of
existing tasks on its predecessor the EC-130, the 707
Boeing recommended maintenance program, and the US Air
Force E-3 aircraft that was also based on the Boeing 707
airframe. A sustaining RCM program was put into place
much like that on the A-7. Recently an effort was
started to update the existing maintenance program with
RCM. The aircraft was already very reliable, but it was
felt the existing maintenance was negatively impacting
the operational availability of the aircraft. The
approach taken was to analyze, at least initially, only
failure modes being addressed by existing maintenance
tasks. A team of dedicated contractor and US Navy
analysts were employed. To complicate matters it was
decided to perform the analysis by maintenance package
(e.g. 56 day requirements, 600 flight hour requirements,
etc.) This required the analysis to address each system
multiple times and resulted in significant redundancy of
effort. It did, however, also allow significant benefits
from the analysis to be implemented much more quickly
than other approaches. Whole maintenance packages could
be extended and modified at once, whereas a
system-by-system analysis approach would require the
complete analysis to be done before major changes could
be incorporated, or individual tasks would have to be
updated piece-meal. The RCM effort is still ongoing, but
significant savings in maintenance man-hours and
increased availability have already been realized.
F/A-18
Hornet Aircraft
The F/A-18
"Hornet" is a carrier-based, supersonic, twin engine,
all weather, combined fighter and attack aircraft. The
Hornet replaced the F-4 Phantom, A-7 Corsair, and the
A-6 Intruder as they were phased out in the in the 1980s
and 1990s. Like some other US Navy aircraft, the RCM was
performed by the prime contractor during the initial
design of the aircraft. Also like many other aircraft,
the analysis was maintained sporadically during many
years of operation. Similar to our other examples, a
decision was made to revisit the RCM program. Because
only one year of funding was allotted initially, the
decision to pursue a maintenance package analysis
strategy like that on the E-6 was made to show return on
investment as soon as possible to justify continued
funding of the effort. However, unlike the E-6, after
one maintenance package was analyzed and the benefit
demonstrated, the analysis would return to a more
efficient system-by-system approach taking into account
all significant failures, not just those covered by
existing maintenance tasks. Again, this effort is still
ongoing but significant returns on investment have
already been realized.
High
Pressure Shop and Instrument Air System 
RCM
analysis was performed on several industrial equipment
systems at a large DoD industrial facility. This was one
of the first applications of the NAVAIR RCM process on
purely industrial equipment. The RCM project was driven
by the purchase of some new Predictive Maintenance (PdM)
equipment including vibration testers and infrared
cameras. The existing maintenance program was informal
and largely undocumented. The purpose of the RCM
analysis was performed to maximize equipment
availability on a production critical asset and ensure
longevity of the equipment by developing a comprehensive
preventive maintenance program. The RCM approach was to
analyze all “significant” failure modes identified
through operator and maintainer experience and work
order data. The analysis was performed by one contractor
analyst over a period of a few months. This case study
demonstrates a more traditional, complete top-down
analysis approach on industrial type equipment. A
summary of the outcome is shown in Figure 3. No
comparison was made to a previous maintenance program as
none was documented.
Impact of RCM
Given that
the primary focus of RCM is the prescription of an
optimal maintenance program, upon implementation its
effects will be first seen in a lean preventive
maintenance requirement package. Depending on the state
of the previous maintenance approach, the extent of
changes in preventive maintenance requirements from
application of RCM will vary. Typically on aircraft,
maintenance programs that were not initially
analytically based are more conservative. When RCM is
applied, preventive maintenance is usually, but not
always, reduced. The following table summarizes the
impact of RCM analysis on 3 recent NAVAIR projects.
These numbers represent changes to only the preventive
maintenance requirements addressed via RCM.
A proper
sustainment effort is essential to delivering the full
benefits of RCM. An optimal maintenance approach should
yield decreases in one or more of the following: failure
rates, corrective elapsed maintenance time, and
corrective maintenance man-hours due to the application
of the correct type of maintenance for each failure
mode. A study carried out for NAVAIR on the expected
results of such benefits is summarized in the following
table[iv]:
Conclusions
RCM is a relatively simple process, but its
implementation presents many different issues. RCM is
mostly an application of “common sense” using some basic
physical and reliability principals. Detailed analytical
methods have a place, but not universally. The best
approach to executing an RCM program will be based on
the goals, resources (time, fiscal, manpower, and
technical), and commitment of the organization
attempting to perform RCM. The most common trait in
successful implementations of RCM is good leadership
from those seeking to implement it. Good leadership will
result in buy-in from the rest of the organization.
Many of the RCM variations in the market
place have strong points and weak points. There is
probably no one best process for all situations. Be wary
of claims that suggest otherwise. Many of the
differences in RCM vendors are as much about style,
approach, and personality than technical process.
However, these can also be important in the ultimate
success of a project. Learn as much as you can before
committing to a process and make sure you are
comfortable with the approach you select. The NAVAIR
process and resources can be a valuable asset to learn
more about RCM even if you ultimately settle on another
process.
References
1.
Nowlan F.S.
and Heap, H.F., “Reliability-Centered Maintenance”,
DoD report AD-A066579, December 1978
2.
NAVAIR
Manual 00-25-403, Guidelines for the Naval Aviation
Reliability-Centered Maintenance Process. March 2003
3.
Society of
Automotive Engineers Standard JA1011, Evaluation
Criteria for Reliability-Centered Maintenance Processes,
August 1999
4.
Society of
Automotive Engineers Standard JA1012, A Guide to the
Reliability-Centered Maintenance Standard, January
2002
5.
Hefner,
Rod and Smith, A.M., “The Application of RCM to
Optimizing a Coal Pulverizer Preventive Maintenance
Program”, Proceedings of the SMRP 10th
Annual Conference, October 2002.
6.
Echeverry,
J.A. and Leverette, J.C., “NAVAIR Reliability
Centered Maintenance Compliance with SAE JA1011”,
July 2004
Acknowledgments
The authors would like to acknowledge the
contributions of Craig Paylor of the NAVAIR DEPOT,
Cherry Point, NC and Daryl Hoffman of the NAVAIR DEPOT
Jacksonville, FL for their contributions in reviewing
and providing valuable input to this paper. A | 
