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The Potential for Savings from Parts Manufacturer Approval (PMA) Parts and Designated Engineering Representative (DER) Repairs

• For the commercial-derivative case-study engines analyzed (the CF6-50 and CFM56-2), the authors found a large number of parts that could be suitable from PMA suppliers and DER repairs.
• Engine overhaul costs for the CF6-50 engine have been reduced by 20–25 percent through the use of PMA parts and DER repairs. PMA parts and DER repairs have been used only occasionally for the CFM56-2, but when they have been, there have been significant savings as a percentage of the original part or repair.

Comparing Air Force and Commercial Source Approval Processes

• Commercial airlines solicit the supply base in a cooperative fashion — for example, share usage and part failure data with potential suppliers — whereas such cooperative relationships are rare or absent in the Air Force.
• Commercial airlines consider Federal Aviation Administration (FAA) certification of PMA parts and DER repairs to be important, whereas Air Force reviewers tend to discount FAA certification as being relevant only to commercial usage.
• Commercial airlines supplement FAA certification with their own engineering capability to assess PMA parts and DER repairs, whereas the Air Force does not devote the same level of engineering capability to such assessment.

Real and Perceived Risks of Greater Use of PMA Parts and DER Repairs

• One persistent perceived risk is that PMA parts are more likely to fail. Commercial carriers manage this concern by retaining a robust engineering capability to evaluate the approval and use of third-party parts.
• A second risk is the response of original equipment manufacturers (OEMs) to non-OEM vendors and operators who use non-OEM parts and repairs.
• A third perceived risk is that the FAA's certification of FMA parts and DER repairs is not valid in military usage. The authors did not find sufficient evidence to support this concern.

Parts Manufacturer Approval (PMA) parts and designated engineering representative (DER) repairs are parts and repairs that are provided by third-party companies and certified by the Federal Aviation Administration to be airworthy and interchangeable with original equipment manufacturer (OEM) parts or repairs. Currently, all major U.S. carriers use PMA parts and DER repairs in their own fleets so they can introduce competition, save costs, and maintain a more robust supply chain of parts and repairs. The Department of Defense (DoD) is interested in increasing its use of similar kinds of alternate parts and repairs.

This report assesses the feasibility and extent to which DoD might decrease its aircraft operating and support costs without a loss of safety or reliability through the increase in the use of non-OEM parts and repairs. The authors performed case studies on two engines used by the Air Force and the Navy; conducted a literature review; interviewed subject matter experts, engineers, and contracting personnel; and mined PMA and DoD data to analyze parts commonality among DoD engines. The authors find substantial evidence of cost savings where the Air Force and Navy have used PMA parts and DER repairs; however, they also find large differences in how, and how aggressively, the military services pursue the use of these practices in comparison with commercial airlines. The authors offer recommendations on how DoD and the services can revise their processes to realize greater benefits from PMA parts and DER repairs.

• Chapter One

  Introduction

• Chapter Two

  Case Study Engines

• Chapter Three

  PMA Parts and DER Repairs

• Chapter Four

  Actual and Potential Cost Savings Associated with Alternate Sources of Parts and Repairs on Case Study Engines

• Chapter Five

  Categorization of Real and Perceived Risks of Greater Use of PMA Parts and DER Repairs

• Chapter Six

  Source Approval Request Processes for PMA Parts and DER Repairs

• Chapter Seven

  Synthesis and Recommendations

• Appendix A

  Engine OEMs as PMA Part Holders

• Appendix B

  F117 Engine Support

• Appendix C

  Primary Data Sources Accessed and Mined

• Appendix D

  Description of a Turbofan Engine

• Appendix E

  Cost Analyses

• Appendix F

  Air Force Source Approval Request Documentation Required for New Sources of Manufacturing