Lockheed PHM F35

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PHM on the F-35 Fighter Dr. Neal N. McCollom

Lockheed Martin Aeronautics PO Box 748, MZ 8671 Fort Worth, TX 76101

817-935-3722 [email protected]

Edward R. Brown BAE SYSTEMS Inc.

6100 Western Place, Suite 320 Fort Worth, TX 76107

817-762-1487 [email protected]

Abstract: The F-35 Lightning II Joint Strike Fighter (JSF) Program is developing a comprehensive and industry-leading Prognostics and Health Management (PHM) system. This system, which is central to the programs Performance Based Logistics (PBL) approach, is built on incremental capability deployment and a careful balance of on-aircraft and off-board software, systems, and processes. The breadth of capability development and timing of deployment is unprecedented for a combat aviation system. The initial set of F-35 PHM capabilities is currently deployed and actively supporting the flight test program. This paper will provide a top level overview of the F-35 PHM concept and architecture, the incremental design approach, and discuss overall program status. Some specific examples of long-term system benefits, in relation to sustainment and PBL business decisions, will be discussed.

TABLE OF CONTENTS

1. INTRODUCTION ...................................................... 1 2. F-35 PHM SYSTEM DEVELOPMENT ..................... 2 2.1 PHM SYSTEM ELEMENT DISTRIBUTION ............ 2 2.2 PHM PROGRESSIVE DEVELOPMENT .................. 4 2.3 END-STATE PHM FUNCTIONALITY .................... 5 3. F-35 PHM SYSTEM OPERATION ........................... 5 3.1 PHM SYSTEM PERFORMANCE MEASURES ........ 6 3.2 PHM & SUPPLY CHAIN INTEGRATION .............. 6 3.3 PHM AND PERFORMANCE BASED LOGISTICS ... 7 4. CONCLUSION ......................................................... 7 REFERENCES ............................................................. 8 BIOGRAPHY ............................................................... 8

1. INTRODUCTION

The F-35 Lightning II program, also know as the Joint Strike Fighter (JSF) has recently deployed the initial elements of its progression of capabilities. Integrated aircraft Prognostics and Health Management (PHM) functions, in their basic form, are now in operation in the flight test program. These functions are coupling airborne and ground-based systems much earlier than for legacy programs. This early implementation demonstrates the programs unique commitment to the creation of a new form of aircraft and operational systems, with a fundamental and essential focus on two of the four program pillars Supportability and Affordability. (see Figure 1) PIRA AER200802007 2010 Lockheed Martin 2010 British Aerospace North America

LM JSF Team Program InformationNon-Technical Data Releasable to Foreign Nationals

FF--35 Program Pillars35 Program Pillars

SupportabilityLethalilty

Affordability Survivability

Cleared for public release under provisions of PIRA AER200309027

Fig. 1: F-35 Aircraft Vision The F-35 program provides three aircraft variants (see Figure 2), with a very high degree of common components and airframe structure. It also provides a complete suite of supporting functions including training, maintenance, spare parts, support equipment, and information services. In its simplest telling, the F-35 PHM system incorporates advanced technology and integrated capabilities within the Air Vehicle (AV) together with ground-based Autonomic Logistics and Global Sustainment (ALGS) systems.

Lockheed Martin Aeronautics Company DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.121905-19

Public Release

Short Take-Off andVertical Landing(STOVL)

Short TakeShort Take--Off andOff andVertical LandingVertical Landing(STOVL)(STOVL)

Carrier Variant(CV)

Carrier VariantCarrier Variant(CV)(CV)

ConventionalTake-Off and

Landing(CTOL)

ConventionalConventionalTakeTake--Off andOff and

LandingLanding(CTOL)(CTOL)

Length 51.4 ftSpan 43 ftWing Area 668 ft2Internal Fuel 19,570 lb






F 35 Variants

Fig. 2: F-35 Aircraft Variants

978-1-4244-9827-7/11/$26.00 2011 IEEE

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In combination, these elements are defined as the Enterprise that will sustain high levels of aircraft availability at significantly lower support costs in a Performance Based Logistics (PBL) environment. (see Figure 3) To achieve the F-35 PHM vision, several key characteristics are essential:

- highly capable on-aircraft (or airborne) systems providing high quality and high confidence aircraft health information and insight;

- highly integrated new technology systems on-aircraft to observe, diagnose, and report aircraft health and condition;

- aircraft health data management systems that are coupled to maintenance and to end-use supply;

- health code analysis, troubleshooting, health management and visualization systems, at aircraft, squadron, and sovereign fleet levels; and

- fully integrated Enterprise operations that engage stakeholders from suppliers to policy makers.

The F-35 business model demands favorable economic performance from the point of initial deployment which means providing a highly capable and fully integrated set of systems at time zero, with future improvements as operational insight grows to maturity.

Lockheed Martin Aeronautics Company DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.121905-41

Public Release

Autonomic Logistics Global Sustainment

Performance Based LogisticsOne Particular Business

Arrangement That Best Aligns Contractor and

Warfighter

Global Sustainment Enables Program Affordability

Global SustainmentStrategy, Partnerships and Business Arrangement That

Provides Warfighter Better Service at Lower Cost

Fig. 3: F-35 PHM Supports Performance Based Logistics PHM program objectives fall into the categories of high level of initial capability, systems and processes to achieve rapid maturity, continuous improvement, and full integration of system development with end-game business operational processes. When these act in synchronicity, they ensure key performance characteristics of increased platform availability, reduced operating costs, cooperation with external support systems and processes, and continuously improving operational sustainment. In short they are the operational pillars of Supportability and Affordability.

2. F-35 PHM SYSTEM DEVELOPMENT

The F-35 program, like many before, is a staggered incremental development effort, with on-aircraft elements generally being developed before or in parallel with ground-based systems. The F-35 program is unique, however, in developing all this under a single synchronous contractual umbrella. This enables significant performance benefits when complete, but which also generates significant levels of development pressure in technology integration, schedule, and budget. The unique system architecture and development approaches ensure the highest level of confidence of providing the PHM framework and offers a solid foundation for maturation through continuous improvement, through the fleet life cycle.

2.1 PHM SYSTEM ELEMENT DISTRIBUTION

A simplified view of the F-35 PHM Enterprise (see Figure 4) recognizes the aircraft as the definitive source of health status data, the ground-based systems as the data management and maintenance authorization source, and the Enterprise sustainment being provided through close association of the multiple service owners of the F-35 fleet.

Fig. 4: F-35 PHM Enterprise Architecture This paper will focus more closely on the airborne and ground-based systems and their interactions, but will also address some of their relationships with the sustaining Enterprise. Prior papers [1,2,4] have discussed the development of specific technologies used on the F-35, and have offered a general operating overview of the systems at maturity [3,5]. A closer look is offered here at the types of decisions which affect the development of an integrated health management system. These include new technology availability and development cost, subsystems and integrated system development cost, system operating costs and effectiveness, and system maintenance and continuous improvement costs. Of these, the latter is most closely aligned with the PBL decision and authorization practices, and so will not be considered here in depth. Those related

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to development of new technology and its general cost to acquire, stabilize, and deploy have been elsewhere described to a level suitable for this discussion. It is the balance of on- and off-board systems and techniques that have most affected the initial developmental operation of the F-35 PHM systems. On the F-35 program, as described in [1] and [3], aircraft subsystem providers were assigned specific and aggressive capability targets for self detection of component failures and life consumption. These benchmarks have been combined with the integrating PHM software to provide a common framework of basic diagnostic functions health reporting, life data collection, and failure event data collection to support off-board analysis and learning. One of the central successes of the F-35 program is the operation of the basic diagnostics services early in the development program. This has been confirmed using data collected from initial flight operations, and with PHM system operation early in the flight test program. Early implementation of the PHM system has offered an opportunity to detect component and system design errors and enforce corrective action very early in the program. Similarly, off-board data systems have been developed to act on the data received from aircraft beginning with the initial operations of the first flying vehicle. This has allowed for early detection and correction of anomalies in on- and off-board system integration issues. From a classic aviation development program standpoint, this could appear as increased development cost and time. However, this early integration with on- and off-board systems will reduce the overall F-35 life cycle costs to a significant degree. Each major subsystem on the F-35 vehicle contains sensors, software, and processing capability (or has off-board processing available) to detect faults. These subsystems will also report key data points that can be used to deduce or infer consumed life. Many systems, especially those that are deemed safety critical or that provide subsystem redundancy, also have an integrating layer of software that can provide additional failure or degradation information. Reasoning on this information is accomplished through classic redundancy management schemes or by comparing actual performance to modeled desired behavior. Finally, the unique status reports from all of the components or subsystems are compiled into a common structured health indication by the PHM software. This constitutes the heart of F-35s basic diagnostics. The health reporting is augmented with additional indicators for major aircraft mode changes, for time subsystem alignment or synchronization, and with environmental data captured for each health report. This latter data is most useful for improving PHM system capability over time, as well as for post-flight troubleshooting of events that are not readily resolved at the time of occurrence. On-aircraft basic diagnostics functions are augmented with enhanced reasoning models that improve the capability of determining the root cause failure in the presence of

multiple subsystem failures. Alternate approaches vary by the class of system being managed. The F-35 approach is discussed in more detail in [5]. The enhanced diagnostics that this approach brings replaces or overrides the multiple basic diagnostics reports, and in many cases successfully isolates the root cause failure, leading to more efficient sustainment tasks and significantly improved availability. By indicating the single component, or even by reducing the candidate set to a few items, the total on-ground maintenance time is minimized. Even when ambiguity remains, the information provided from the aircraft allows for intelligent selection and structuring of troubleshooting processes to minimize the maintenance delay prior to successful isolation and resolution of the failure. The off-board systems provide a small set of closely related, highly coupled services. First, the vehicle health indications are consolidated, captured locally, and distributed to the appropriate processing and information systems. These systems, from the above-mentioned intelligent troubleshooting, to maintenance management systems, to archiving and distribution of supporting information, serve as an enabler for future product analysis and improvement opportunities. The basic diagnostics and data collection functions on the aircraft serve as data sources for the receiving ground-based systems and data stores. The off-board systems provide the human-machine interfaces to the maintenance and life management systems, the intelligent decision support for minimal troubleshooting and for maintenance authorization. All systems are inter-related, with carefully defined interfaces with the air vehicle data source and with the other data systems. The information architecture supports evolutionary improvement or replacement of system elements as technology advances and especially important consideration given that ground-based systems can benefit early and regularly from rapid advances in information technology. This approach ensures that the medium-term maturation and long-term continuous improvement can be executed with minimal development and deployment costs, and with very little re-training of the end-user communities. The economics of determining what functions to implement on the aircraft essentially reduce to a few points:

- sole opportunity to capture fault indications; - economic advantage of consolidating all vehicle

data to a common forma and onto a common source;

- best opportunity to capture salient data or supporting information;

- best opportunity to deduce root cause of the fault, failure, or event in the operating environment versus off-line;

- economic advantage of identifying root-cause of fault or failure events early (i.e., early identification of probable repair or replacement

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resources).

Opposing factors include: - the cost and complexity of embedding non flight

essential processing on-aircraft; - the difficulty of implementing changes to fixed

configuration assets; - the cost of re-qualifying airborne products (at the

component level through the aircraft or vehicle level); and

- the cost and difficulty of deploying changes to supplied products after closure of development contracts.

Obviously the specific cost decisions vary significantly depending on the system(s) under consideration. The approach that is most viable for the F-35 might not be optimal for rotorcraft, less so for large marine platforms, and even less so for ground based systems or infrastructure. The general criteria outlined above are readily generalized for these and other classes of systems. But even within a system such as the F-35, there may still be significant variation in approach, given other technical or business factors such as availability of process capacity, effectiveness and reliability of supporting information technologies, and the ever-present budgetary pressure during large-scale development programs. However, the broad guidelines readily lend themselves to the general architecture described above.

2.2 PHM PROGRESSIVE DEVELOPMENT

A key aspect to the successful deployment of a complex integrated system such as the F-35 PHM is the progressive implementation of capabilities and features. The overall system architecture described above allows for the appropriate placement of complexity within the on-aircraft and off-board system functions. In general, the on-aircraft basic diagnostics, off-board health management, and initial maintenance management functions are developed and deployed first, to drive earliest maturity into these core capabilities. The next phase is to incorporate enhanced diagnostics on-aircraft and enhanced decision systems off-board, covering troubleshooting and system life decisions. As the overall system is maturing, all the on- and off-board elements are in a Continuous Improvement cycle, while the Enterprise systems are fully described and implemented. (See Figure 5)

Fig. 5: F-35 PHM Progressive Development This last phase brings the advantages (and the inherent difficulties) of distributed operation and decision making across the user/provider/supplier areas of interest, and is generally driven by economics. The tendency to make locally optimal but system-wide sub-optimal economic decisions is managed through the evolving ground rules of the PBL environment. The deep involvement of suppliers, especially for those providing highly integrated or highly complex functions, is dependent upon new technology which is both necessary and highly sensitive. Add the further dimension of multiple service owners of the fleet, it will be apparent to the reader that this is an area that will ripe for discussion for some time to come. Focusing instead on the near-term achievable objectives, the F-35 PHM program has already developed and deployed the initial elements of basic diagnostics and the supporting off-board systems. This offered both proof-of-concept for the F-35 PHM approach, and an opportunity to capture improvements from observed effects of the installed system. Thus the health management systems are now both operating and improving in conjunction with the flight test program, driving corrective action and improvement prioritization across the development life cycle phases. Additional data recording is added to the basic diagnostics on-aircraft, so that there is ample supporting data for both troubleshooting and maintenance in the early development period, and so that initial life consumption algorithms (Prognostics) can be developed and improved. While maintenance decisions in the earliest periods of F-35 operations are dominated by traditional failure-driven criteria and by classic reliability predictions, this early capture and monitoring time allows for high-confidence decisions earlier. This in turn leads to on-condition maintenance as a replacement for time-based or scheduled maintenance. One of the key goals for the F-35 program is to minimize time-based maintenance (e.g., replace part X after 1000 hours of operation). Instead maintenance is based on an assessed component condition on failure when it occurs, but also on life condition when the usage

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profile and performance data indicates. This is a major contributor to the affordability pillar of the F-35. Enhanced diagnostics are the next PHM technology to be integrated into the development program, with a complementary decision support system off-board added at the same time. The aircraft provides root-cause failure indicators, allowing the off-board system to recognize but not take unnecessary action on symptomatic faults. An example was described in [5]. Implementation is now well underway, and initial testing of these capabilities will begin at the same time as basic diagnostic functions. To support them, an advanced maintenance aid has been developed to serve as an advisory and instructional system to the maintainer. This computer-aided system will also provide an alternate method to move data between the aircraft and the ground-based systems. This device will first see operation with the basic diagnostics capable vehicles, but will also gradually increase in capability as systems and capabilities are added to the aircraft. The ultimate vision is to fully isolate all failures on the aircraft which will be achieved for many faults, but there will always be some number of system failures that cannot be completely resolved without outside assessment. The Anomaly and Failure Resolution System (AFRS), will allow the ground-based systems to provide the best options or approaches to troubleshooting such cases, and so reduce the time to return a failed system to a fully capable state. In short, when there is an inevitable maintenance delay time, the Operational Availability (AO) impact will be minimized. In the completed system, the on-aircraft data collection, basic and enhanced diagnostics, and supporting systems are implemented and deployed to cover all installed systems. The Enterprise systems are developed to support continuous improvement, the execution of PBL, and the emphasis on economically-driven change. This also involves the archival and advanced technology for data mining for hidden relationships or for non-obvious trending and the development of future prognostic algorithms. One significant advantage to this phased or progressive implementation approach is that the system developers can develop the capabilities that are of core value first. They will then add on the planned enhancements in a naturally staged manner, and build the infrastructure to support known but as-yet-unspecified expansions and improvements. This may all be accomplished while maintaining a development cost focus. This allows the program to build increasing capability in a just-in-time manner, minimizing the impact of uncertainty or missing information until it has the chance to be resolved through early operational experience. Another advantage is the ability to focus contractual improvements with the suppliers systems and components while their developmental experience is still engaged, and improvements to the integrating health management functions.

2.3 END-STATE PHM FUNCTIONALITY

The total F-35 PHM system performance uses a balance of on-aircraft capabilities, off-board systems, and Enterprise processes; and it builds progressively from basic diagnostics and simple maintenance management, to a state of fully integrated advanced PHM under a continuously improving Enterprise. The long term benefits to the maturing global organization are both operational and economic increased AO and decreased Life Cycle Costs. This relates back to the pillars of Supportability and Affordability. But it also supports or even enables increased efficiencies in the Supply Chain, from demand-driven spares quantity and placement, to opportunistic maintenance supporting predictive end-life proximity and the consequential improvements to both AO (again) and to product flow through and lead-time planning for the Supply Chain. The mature Enterprise can take advantage of the information and decision support that comes from the fully capable PHM system. And both the end user and the providers can realize the economic and financial advantages inherent in a modern PBL relationship. (See Figure 6)

9Use or disclosure of the information contained herein is subject to the restrictions on the Cover Page

F-35 Program InformationNon Export Controlled Information Releasable to Foreign Persons

Autonomic Logistics Information System

Decision Support Information Integration

Fleet Management Activities

Off Board PHM Diagnostic Tools Failure Resolution Assess Material Condition Prognostic Algorithms

Unit Level Maintenance Effective Fault Isolation Condition Based

Suppliers and OEMs

Prognostics & Health ManagementImproves Aircraft Availability

Customer Support

PMDAir Vehicle PHM

Enhanced Diagnostics / BIT Fault Corroboration Information Fusion Health Management Reports

Downlink

PMA

PHM Supports Performance Based Logistics within the ALGS

Fig. 6: PHM Supports the Enterprise

3. F-35 PHM SYSTEM OPERATION

The advantages of the F-35 PHM System can perhaps best be considered by comparing the total system reaction to a few closely related but differently scaled scenarios. In the first, aircraft are operating normally, with no exceptional issues arising. In the second, a fielded aircraft experiences a failure on a certain component call it System Z. In the third, a local trend is observed, where System Z faults are now noted across several vehicles, at a rate above what would normally be expected. And in the fourth, a much larger trend is observed, with the failures in System Z occurring across the fleet at a higher than predicted rate. First, though, an introduction to some of the PHM related metrics are in order.

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3.1 PHM SYSTEM PERFORMANCE MEASURES

It is important to consider what the F-35 PHM program measures in order to ensure robust operation. First and foremost, there are the classic indications of Fault Detection and Fault Isolation (FD/FI) comparing the designed or theoretical levels of performance against the very-long term trend of observed performance. FD is just what it appears the automatic self-observation and reporting of faults in the system. In nearly all cases this is the primary indication of one or more failed components. FI is the correct indication of the root cause fault that is causing numerous symptoms. An example of this is considered in [3] and [5], using the example of a cooling system fault causing numerous cooled symptoms to also report failures. FD/FI are generally presented in terms of percentage of ideal coverage, but can also be assessed in terms of operating time between failures. A second key measure is False Alarm (FA) rate where maintenance action is taken that is not necessary, or which does not correctly resolve the root cause. The latter condition must carefully consider the cases where one fault masks a second. FA metrics must consider the difference between reporting that causes the pilot (or other operator) to take compensating action, versus those that cause a remove-and-replace action at the vehicle. One problem that arises is that the fault can not be duplicated by the supplier. This could indicate that either the part was actually good and not failed or that the failure could not be duplicated as the conditions where the failure occurred can not be replicated on the ground. These conditions suggest that multiple measures are needed, and that they consider the entire component migration through the maintenance loop of the Supply Chain. Long term trending is also a crucial measure, especially for indication of either improvement or degradation, for subsystems and components, for vehicles, and for groupings up the to enterprise fleet level. Maturity curves that forecast progressive improvements (as well as down-stepping where usage changes, or where new elements or new technology is introduced) serve as targets for the observed measures of merit; a trend of deviation below the target provides evidence of the need for either modified usage or for investment in product improvement. Long term trending is also useful in assessing aggregates of design life consumption, across varying groups of similar and similarly used elements from components to squadrons. The fundamental metric that directly supports the PBL operation, is AO (see Figure 7). Ideal availability, independent of local and supply chain logistics delay, can be calculated as a theoretical target, but requires significant assumptions (e.g., zero administrative delay, or unconstrained supply of spares and consumables) that quickly break down in the presence of actual operations. While AO can be used as a target for financial incentive, it is equally useful as an indication or variation in the Enterprise processes, across fleets, aircraft types, or component

sources. It is also useful as an indication of increasing maturity of the PHM system, and is a useful supplement to the data driving PHM system improvement decisions.

Fig. 7: Example of Operational Availability The central concept is to provide appropriate visibility into the material condition of the component, system, or fleet being assessed, so that decisions can be made at the policy-appropriate level.

3.2 PHM & SUPPLY CHAIN INTEGRATION

Turning now to the example introduced above, we envision four simple cases: first System Z is free of fault or defect, and the aircraft is operating normally; second there is a singleton occurrence of a System Z fault, requiring maintenance action; third there is a local cluster of System Z faults occurring within an operating squadron or group; and fourth there is a notable trend of System Z faults happening ahead of the reliability forecast rate. The first case is fundamentally uninteresting, with two exceptions. One is the continuous capture of life usage information from the various aircraft, and the low-rate transmission of that data into the Enterprise archives. Note that this data can accumulate to a fairly significant size when combined with other usage data from other systems on each aircraft, flying multiple sorties per day over a multi-day deployment. Tens of megabytes of data per aircraft over such a deployment rate would not be unexpected. Fortunately there is not a demand for instantaneous access to this data, in the general failure-free case. The other point of interest is the experience and frame of reference, or set of expectations, that is being established within the local maintenance community. Since System Z is not experiencing any significant problems, there would be little attention given to it, other than its contribution to over all aircraft health and life. But the data systems are accumulating experience, and are settling on a typical range of performance effectively setting control bounds on the expected performance for this type of system at this level of

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life consumption. The second case is somewhat more interesting. When the aircraft experiences the fault in System Z, as well as any sympathetic failures or faults that are induced, the root cause is isolated to System Z, and a maintenance procedure to replace (or repair in place, if viable) is initiated once the vehicle returns to a maintenance-capable facility. This stimulates several areas of the PHM system. The fault detection is noted and recorded, as is the operating environment information surrounding the time of the fault observation. This data is captured locally for use during troubleshooting (if required) and also archived for future trend or anomaly analyses. The life consumed is also noted, and the life tracking initiated for the new (or repaired) unit. If it was not repaired in place, the faulty unit is returned to the supplier for repair and eventual return, or is scrapped if not economically repairable. The third case follows the same sequence as the second, at least regarding the response to the individual fault. However, the local maintenance management notes that the number of System Z failures is now significant and beyond the typically expected quantity or density of faults. So at a local level, the maintenance management and staff will investigate for common cause increased level of life consumed as expected due to the particular types of usage (e.g., mission mix); or common local maintenance issues (e.g., need for additional training, or for revised procedures uniquely adapted to the maintenance location); or other common cause. Fleet management would likely be informed if not actively engaged, with the objective of gathering similar observations at other sites or fleets and applying any corrective action or refinement that had been already proven successful. The supplier would also likely be informed particularly if the usage or duty cycle for the device differs from the design-to standard. The supplier would reasonably be expected to take more aggressive action in maintaining the Supply Chain, since there is now a local trend that has steadily consumed and possibly diminished the available spares supply. Diversion of unused spares from other pre-positions storage would be preferred over manufacture of additional replacement units and the inherent increase in total operational cost. The fourth case takes the case one significant step farther in that the local trend is also observed at a more global level. It may be interesting to note that this fourth case may also be stimulated by a distribution of locally unique failures, but which aggregate at a fleet level. In addition to the increased maintenance demand at the various locales, there is also an increased pressure on the Supply Chain. This is more likely to drive both near-term and long-term corrective action, which could span from providing additional units as spares, to initiating a product improvement redesign. The supplier would request access to the applicable usage data, to help determine what usage and loads the failed System Z components had experienced. The trigger now is explicitly

improvement to AO, as the increasing number of unexpected maintenance events is driving increased down time and maintenance workload. If the trend has a large enough economic impact, it could also drive changes to the Enterprise procedures for this system, and even end user policy on aircraft usage. The most extreme cases could involve grounding aircraft for safety considerations which would have a very clear and unfavorable impact on availability a decision that is not made lightly, given the economic and readiness repercussions. Although these scenario summaries do not detail the topology or interface between the affected systems, it should be clear from the PHM system descriptions throughout this paper that the more extensive the distribution of faults, the more the stresses on the Enterprise and Supply Chain. Corrective action will tend to be done at the most economically viable level, with compensation within the ground-based PHM and Enterprise systems tending to be preferred, at least for short-term reaction.

3.3 PHM AND PERFORMANCE BASED LOGISTICS

The primary driving metric that supports the PBL operation is Operational Availability (AO). It is the trigger to determine when the total Enterprise system is working properly, and when it is not. When AO measures approach the theoretical reliability maxima, the system is stable and improving. When deviations persist or when degradations are observed, there is a clear need for intervention and corrective action. A secondary benefit is the secondary focus on Supply Chain efficiency. If the absolute minimum material is cycled through the Supply Chain for repair and restocking, then PBL operation performance will be driven largely by component reliability. And since reliability improvement programs are a well understood and widely used technique to get secondary affect on Supply Chain performance, PBL decisions will drive additional PHM capability on- or off-board, in supplier product, or in processes and policies.

4. CONCLUSION

Looking forward, the F-35 PHM system at maturity exhibits the characteristics of a continuously improving operation. The integrated on-aircraft elements have been validated and enhanced, and improvements made to the subsystems and components. The classic FD/FI measures show that the aircraft systems have reached a highly capable and stable level of operation. Any changes will now being driven by other considerations from diminishing manufacturing sources and availability of new technology, especially for electronics, to product improvement for enhanced performance, to the addition of new elements and components into the aircraft. Event-driven and performance monitoring data are being successfully captured and stored for off-board analysis and life trending.

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Off-board systems are successfully managing the aircraft health data, enabling the maintenance end users to make informed best-value decisions on aircraft maintenance and life management. The systems also allow fleet managers to optimize use of the aircraft for their intended missions, and to manage the overall life of the fleet. The integration of information from numerous systems deployed across the user services lets the development and integration contractor to investigate and rapidly resolve anomalous situations that do arise. The Enterprise is operating smoothly, with essential information moving near real time from fielded vehicles to the local management systems to the complete fleet management center. Detailed event-driven data and information is routed to decision centers and to suppliers as needed, to assist in the quick turn-around of failed or damaged components. Suppliers, service providers, and end users work in concert to keep vehicles in service as long as they safely can, scheduling maintenance and service on or ahead of condition, with decreasing numbers of failure-driven service. A mature PHM system fulfills the core sustainment tenets the program operational pillars of Affordability and Supportability. It does so through the full realization of the architectural vision, involving complete integration of the development cycle, the product deployment cycle, and the complete Supply Chain operation. The system is continuously improving itself, making advantageous use of new technology where there is economic benefit. It is being matured early and is applying corrective change back on itself from the earliest stages of development. In doing so, it applies the lessons learned from its numerous legacy programs develop early, mature early, stabilize early. The F-35 PHM system brings unique new technology to fruition, but gains its maximum advantage through the early and complete integration of the many systems and organizations involved. In this sense more than any other, the F-35 approach is readily adaptable to other aviation platforms, aerospace platforms, land based and marine systems, and to many other applications mobile or fixed. The effort is formidable, but manageable. The necessary integration is complex, but achievable. And ultimately the end-game advantages are realized when the operation reaches maturity and stability, yielding the envisioned operational and economic benefit.

REFERENCES

[1] Engel S, Gilmartin B, Bongort K, Hess A., Prognostics, The Real Issues Associated With Predicting Life Remaining, March 2000 IEEE Conference

[2] Calvello G., Dabney T., Hess A. PHM a Key Enabler for the JSF Autonomic Logistics Support Concept, paper # 1601, 2004 IEEE Conference, March 2004.

[3] Hess A. and Fila L. Prognostics, from the Need to Reality from the Fleet Users and PHM System Designer / Developers Perspectives, paper #116, 2002 IEEE Conference, March 2002.

[4] Hess A., Frith P., Calvello G. Challenges, Issues, and Lessons Learned Chasing the Big P: Real Prognostics Part 1, paper # 1595, 2005 IEEE Conference, March 2005.

[5] Brown, E., McCollom, N., Moore, E., Hess A. Prognostics and Health Management: A Data Driven Approach to Supporting the F-35 Lightning II, paper # 1597, 2007 IEEE Conference, March 2007.

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BIOGRAPHY

Neal N. McCollom has been the PHM Integrator for the F-35 Autonomic Logistics Global Sustainment (ALGS) organization since shortly after contract award. His main task is to provide an interface between the ALGS development and the on-aircraft PHM development to ensure that the on-aircraft capabilities are properly integrated into the ALGS processes and products. He has many years of experience in software/systems development, knowledge-based systems, and manufacturing shop floor systems. Neal received his PhD in Industrial Engineering from Texas A&M University, a BS and MIE in Industrial Engineering and Management from Oklahoma State University. He is a registered Professional Engineer in Texas. Edward R. Brown is Senior Manager for F-35 Lightning II Prognostics and Health Management, responsible for PHM product development and integration for all F-35 aircraft systems, across the JSF Lockheed Martin / Northrop Grumman / BAE SYSTEMS team. Ed, an employee of BAE SYSTEMS Inc., has held leadership roles in the JSF program since the contract was awarded in October 2001, and prior to that was part of the Collier Award winning X-35 STOVL Propulsion Lift System team. He has worked aviation control and diagnostic systems since the early 1980s, including commercial and military Digital Engine Controls, V-22 and C-17 Flight Control Systems, and rotary and fixed wing research and experimental vehicle control systems from X-Wing to the X-35. Ed has a BS in Mathematics from the University of Hartford.

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