Deep Dive into the F-35 Reliability Growth Plan

            The F-35 weapon system is being procured under a phased capability introduction strategy. Each phase is defined in the F-35 Air System Block Plan and expands the systems capability at each of the 11 Low Rate Initial Production (LRIP) batches. Currently delivering LRIP 5 aircraft, each batch or Block builds on the previous design and is intended to reach maturity by the end of LRIP 11. Key to this maturity is effective system enhancement through detailed Reliability and Maintainability (R&M) assessment.  Reliability growth during JSF Air Vehicle maturity will be achieved by the process of identifying, analyzing, and improving the Air Vehicle Mean Flight Hour Between Failure (MFHBF). This process will be implemented across the entire F-35 program with participation from Lockheed Martin, Developmental/Operational Test Teams, subcontractors, suppliers, and Operational Organizations. Performance and Maintenance data will be collected and analyzed to identifying candidates for reliability improvements.  Design improvement candidates are further evaluated to determine the best benefit versus cost to determine prioritization. Selected reliability improvement candidates have been and will continue to be recommended for incorporation into the design. This process uses an iterative, closed-loop reliability growth methodology.  This  includes testing, analyzing test failures to determine the root cause of failure, redesigning to remove the cause, implementing / incorporating the new design, and retesting to validate that the failure case has been removed (LM, 2011).

            Reliability does not improve as a result of planned changes.  Reliability grows, or improves, only as a result of incorporating effective design changes.  Once changes are incorporated, they must be validated to determine their effectiveness. The initial reliability depends on a number of factors, including product complexity, design maturity, design-to reliability guidelines and criteria, technology maturity, subsystem testing results, etc. (MIL-HDBK-189, 1981). The F-35 Program has implemented a closed-loop Failure Reporting, Analysis, and Corrective Action System (FRACAS) that includes inputs from suppliers, subcontractors, testing activities, and operational organizations.  F-35 Joint Program Office (JPO) R&M managed Joint Reliability Maintainability Evaluation Team (JRMET) is established to assist in the collecting, reporting, analyzing, and categorizing (utilizing the FRACAS application) of reliability data in support of Developmental Test and Evaluation (DT&E), Operational Test and Evaluation (OT&E) (JARMET Charter). There are two objectives of statistical analysis of this data. Firs, determine if reliability growth is being achieved according to planned growth. Second, identify the equipment failure rates and patterns to focus engineering and management activities to ensure that the contractual MFHBF values are achieved (JARMET Charter).

            Reliability growth analysis results and tracking status is reported, along with the status of reported failures and of recommended and implemented corrective actions.  Open items are highlighted for initiation of closure action.  A “Top Contributors” chart, commonly known as the R&M top 100 list, is maintained for visibility and to prioritize the corrective action process. Monthly reports summarize the results of the reliability growth tracking analysis as compared to the corresponding planned growth value. (JSF Reliability Growth Plan, 2011).

             The F-35 Reliability Growth Plan is based on a program wide data collection initiative designed to validate predicted performance as well as drive engineering chances to ensure system maturity, As stated last week, instability in aircraft design, system maturity, and performance reliability negatively impact an acquisition program. Each of these factors are even more programmatic under concurrent development programs like the F-35.    

References:

Duane, J. T., ''Learning Curve Approach To Reliability Monitoring'', IEEE Transactions on Aerospace, Vol. 2, pp. 563-566, 1964.

Kececioglu, Dimitri, B. (1991). Reliability Growth, Reliability Engineering Handbook, Ed. 4, Vol. 2, Prentice-Hall, Englewood Cliffs, New Jersey.

Joint Reliability Maintainability Evaluation Team (JRMET) and Test Data Scoring Board (TDSB) Charter. (2007, May 17). Appendix Updates:  E ~ I.

Lockheed Martin (LM). (2011, March 30). JSF Reliability Growth Plan. Internal Doc. No. 2ZZA00026

MIL-HDBK-189. (1981, February 13). Reliability Growth Management. Retrieved from: http://www.barringer1.com/mil_files/MIL-HDBK-189.pdf

F-35 Sustainment Management Strategy

The largest acquisition program in the Department of Defense history is attempting to leverage aggressive procurement strategies. In September of 2001 the Department of Defense mandated Performance Based Logistics (PBL) model for future acquisition programs (ALGS) . The Joint Strike Fighter is the first Air System to implement this plan across the entire platform. Other military aircraft programs have successfully adopted the PBL concept but at the sub-system or component level. Acquisition programs such as aircraft modernization or component improving initiatives have proven to be beneficial to the Government. However, introducing PBL with the complexity,  scale, and evolutionary acquisition strategy of the F-35 program has resulted in frustration to multiple U.S. and foreign participants. 

Performance Based Logistics is a life cycle sustainment plan that reduces the total ownership cost by finding efficiencies by minimizing the logistics footprint. For example, sharing resources between all organizations that operate the same type of aircraft at a particular location would eliminate excess. Take this approach across an enterprise and you find additional optimization at the theater or even global level. Sharing or "pooling" assets such as spare parts and support equipment as a global sustainment level requires a well defined resource management plan. Key to such a plan would be stability in the aircraft design, system maturity, and performance reliability. Unfortunately,  the F-35 has yet to achieve any of these key attributes.

To date more than 100 aircraft have been delivered to the US Air Force, US Marine Corp, Australia, United Kingdom, and the Netherlands prior to completion of Operational Test and Evaluation. This is not by accident,  the F-35 procurement plan was designed as a phased approach with incremental development at each step. Each phase introduces additional capability essentially freezing the production configuration and sustainment solutions as defined in the F-35 Air System Block Plan ( Lockheed Martin).  More traditional aircraft acquisition programs would complete Developmental Testing before transitioning to capabilities validation through Operational Testing followed by formal entry into Full Rate Production and delivering a mature, stable system to the first operational organization. The F-35 program is performing all these activates simultaneously which compounds the sustainment instability. 

The F-35 Spares Management Plan relies heavily on modeling and simulation to predict the spares allocation requirements. Along with other complex algorithms, each participant established a Performance Based Agreement with Lockheed Martin, identifying the specific capabilities for that particular Service. This and other factors such as primary mission, number of aircraft assigned, Number of sorties, flight hours, and aircraft availability requirements all feed the model which establishes the required spares allocation for sustainment support. The accuracy of this model is dependent on Reliability and Maintainability (R&M) data for validation. The F-35 program established an R&M maturity threshold of 50,000 flight hours per variant (F-35A, F-35B, F-35C) or 200,000 across all variants.  Currently the total flight hours across all variants is approximately 15,000.  

Based on growing concern on 28 October, 2013, the Under Secretary of Defense, Frank Kendall signed an Acquisition Decision Memorandum directing a review of the factors affecting program readiness. In a follow-on memorandum dated 29 May, 2014, Mr. Kendall highlighted the R&M criteria and established a reliability improvement program to influence changes to achieve performance objectives. This enables R&M engineering and analysts to target improvements in 2015 which is well ahead of the 50,000 or 2000,000 flight hour threshold. This will be very challenging and may introduces new risks. Consider the ripple effect of driving changes to a component based on minimal data. This could negatively impact production upstream at the vender level as they too are building capability based on the current procurement plan. Not to mention the impacts if the analysis that drove the change request is incorrect.  

Supply Chain Management under Performance Based Logistics strives to deliver the right part to the right place at the right time to minimize logistics footprint and is heavily dependent on accurate utilization data. Developing a Spares Management Plan based on predicted performance is extremely challenging. Using substantiated R&M data to validate the modeling and simulation tools is key to effective PBL strategy. Instability in aircraft design, system maturity, and performance reliability negatively impact an acquisition program. Each of these factors are even more programmatic under concurrent development programs like the F-35.