全球智库信息集成服务系统

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.