Appendix 3
g. Visual comparison or prototype with type design part.
h. Fit-check comparison with type design part.
i. Weight comparison with type design parts.
j. Part marking review.
4. Project Implementation including:
• Define procurement requirements (for example, special quality clauses);
• Supplier selection and approval; and
• Delivery of first articles and conformity inspections.
Appendix 4 APPENDIX 4. CONTINUED OPERATIONAL SAFETY
1. Continued Operational Safety is a closed-loop technical and logistical support system that ensures the continued safety of a part and subsequently the product on which it is installed, throughout its lifetime. This support system includes three fundamental elements:
• Prevention;
• Data collection and monitoring; and
• Response and resolution.
2. The closed-loop system and the relationship between the three fundamental elements are shown in figure A4.1 below:
Figure A4.1: Fundamental Elements of Continued Operational Safety Prevention Data Collection and Monitoring Response and Resolution Design, Certification & Manufacturing Service Reliability, Trending, Usage & Part Failures Lessons Learned Feedback Loop Investigation, Analysis, Risk Mitigation, Corrective Action
3. The prevention element is intended to preclude in-service problems before they have a chance to occur. The prevention element includes those activities and processes that are applied during the part design, certification, and manufacturing stage to ensure the design is adequate;
the certification is thorough; and the manufacturing is controlled. PMA applicants establishing a COS plan should include procedures that address the following:
a. Internal Audits. Internal audits are used to monitor compliance with required airworthiness standards and procedures to ensure production of airworthy components. The audit must include detailed reviews of all Aircraft Certification Systems Evaluation Program (ACSEP) and Principal Inspector (PI) audit results and any reports made to satisfy § 21.3. The auditing procedures should have a feedback reporting system to ensure that proper and timely 158
Appendix 4 corrective action is taken in response to reports resulting from the independent audits. Another organization or person with appropriate technical knowledge and experience is often used to conduct the audit.
b. Part Field Experience. The following sources are available to evaluate part field experience:
• Service difficulty reports (SDRs) (located at: http://av-info.faa.gov/sdrx/);
• Pertinent airworthiness directives (ADs); and
• Available ICA (including overhaul instructions, illustrated parts catalogs, and service bulletins (SB)) should also be reviewed.
(1) Operators and maintenance providers may also have service experience with the part, next higher assembly, or both. Surveying these operators and maintenance providers may be useful to confirm the findings of any SDR, Alert SB, SB, or AD review.
c. Design Review and Safety Analysis Process. The safety analysis process is a systematic review of a design at appropriate stages. The process can identify any potential failure, malfunction, or defect and considers the impact on the part, the next higher assembly, interface features, airworthiness characteristics, manufacturing controls, and inspection plans.
This information can be used to establish preventative action. The process also evaluates the effectiveness of the preventative action through follow-on reviews. Participants in these reviews should include representatives of functions concerned with the design under review. Records of review and subsequent actions must be maintained and should include:
• A review of the available ICA and service history evaluation; and
• A safety assessment of the PMA part.
d. Part Development Planning Process. For critical and complex parts, the process focuses on structuring the design effort into significant elements to ensure part safety and reliability. The elements include:
(1) A design and development plan;
(2) A review, verification, and validation process appropriate to each design and development stage;
(3) The responsibilities and authorities for design and development;
(4) A means to record project communication; and
(5) Recording of design and development inputs related to part requirements (inputs should include functional and performance aspects, statutory and regulatory requirements, and information gathered from similar designs).
Appendix 4
e. Manufacturing Process Change Control and Substantiation. To ensure part safety and reliability, applicants utilizing a COS plan should consider a system to control manufacturing processes. Such a system requires that each process be performed by qualified personnel in accordance with approved specifications containing definitive quality standards. Certain parts may need engineering source approval (controlled or frozen manufacturing processes) of changes to the manufacturing process or inspection system, or both. Substantiation for a proposed process change may include functional or destructive testing, or both.
4. The data collection and monitoring element includes those activities and processes focused on the collection, assimilation, and interpretation of data related to in-service part performance, for example, reliability, trending and usage. It consists of the following procedures:
a. Closed Loop Process for all Field Inquiries. This process is used to review, evaluate, and respond to inquiries or notifications of potential service problems from aircraft operators, maintenance service providers, or the FAA. This process includes a list of individuals or organizations within the company with defined responsibilities for responding to all inquiries and notifications. The process is used to identify appropriate methods and resources to investigate service problems, identify the cause of any service difficulties, develop corrective actions, and implement those actions in a timely manner. The process is also used to define how the resolution and corrective action would be transmitted to the reporting entity, other entities potentially impacted, and the FAA.
b. Part-Specific Performance Data Trend Analysis. The data trend analysis process is based on part-specific performance. This process is for a PMA part that is determined during the design phase to have a potential adverse effect on the operational safety of the product if it does not perform as intended. This process should include a means for the PMA holder to track its parts, and receive inspection and qualitative feedback from the part user after the part is removed from service for any reason, including routine maintenance. When possible, input from the product operator regarding part performance relative to the design assumptions should be sought.
c. Part Delivery Statistics. This process records the quantity of parts shipped, the shipping date and customer. The records should also contain sufficient information to accurately link each shipped part to its lot number or to a manufacturing order.
d. Continuing ICA Review. Continuing ICA review is a procedure to review all available new and revised TC holder’s maintenance instructions and service bulletins, as well as ADs that pertain to each TC holder’s part replaced by a PMA part. This procedure may use periodic searches of new or revised TC holder ICAs for referencing a TC holder part number replaced by a PMA part number. This procedure should include a list of qualified individuals or organizations within the company that can determine if any new or revised ICA could potentially affect the performance of their PMA part. The procedure should define the steps needed when it is determined the PMA part is affected by new or revised ICA.
5. The COS plan response and resolution element must include those activities and processes that focus on investigating and analyzing part failures, both actual and precursor; assessing the risks associated with continued operation; identifying and implementing any actions necessary 160
Appendix 4 to mitigate an unsafe condition; and implementing corrective actions necessary to restore part safety. These activities and processes are:
a. Reporting required under § 21.3. Applicants already have this requirement within their FAA-approved fabrication inspection system. AC 21-9A, “Manufacturers Reporting Failures, Malfunctions, or Defects,” and AC 21-1B, “Production Certificates” provide further guidance for reporting under § 21.3.
b. Customer Notification Process. This process should include a procedure for the release and control of technical information issued to ensure all necessary parties are aware of a field problem. The notification system may include FAA review. The notification system should include detailed technical instructions for the end user to complete the necessary corrective action.
c. Ability to Identify, Develop, and Implement Field Corrective Action Plans. This activity should direct the development and implementation of corrective action plans to address unsafe conditions associated with the part failure. This activity should include a process to communicate with the supply chain and customers so that issues can be tracked and corrective actions implemented. A good reference for this process is AC 39-8, “Continued Airworthiness Assessments of Powerplant and Auxiliary Power Unit Installations of Transport Category Airplanes.”
d. Failure Analysis Capability. The PMA holder should be capable of providing a failure analysis of any in-service or manufacturing difficulty. Failure analysis capability demonstrates the applicant understands the part, its interaction with mating parts, its manufacturing processes, and the product and engine. The company should have a policy that demonstrates its understanding of who should complete the failure analysis and how it is disseminated and presented to the FAA, if required.
e. Customer Support. The applicant should have the ability to source and manufacture replacement parts to ensure that reliability and safety issues are satisfactorily managed.
f. Feedback into Preventative Systems and Procedures. The final step in resolving service difficulties pertains to the lessons learned. We recommend applicants establish feedback to the existing engineering, quality, manufacturing, and safety systems. The objective of feedback is to prevent recurrence of these and similar problems, and, at a minimum, resolve them before an unsafe condition occurs. Feedback can occur through means such as a lessons learned library, training activities, continuous monitoring, and refinement of company processes. The applicant’s management, engineering, manufacturing, and quality departments should be aware of service information that requires changes regardless of the level of safety impacted. The key is to develop, implement, and monitor solutions to resolve problems and prevent future ones from occurring.