2
Role of the Aircraft Certification Service (AIR)

AIR (the Aircraft Certification Service) is the department within the FAA that develops and administers safety standards for aircraft and related products that are manufactured in the United States or are used by operators of aircraft registered in the United States. Related products include engines, propellers, equipment, and replacement parts. This chapter provides background information that is necessary to understand the recommended safety management process and other findings and recommendations that appear in Chapters 4 through 7 of this report. Readers who are already knowledgeable about AIR's roles and processes may wish to skip this chapter.

AIR's functions include issuing initial and amended type certificates for designs for new aircraft, issuing supplemental type certificates (STCs) for designs of modifications to existing aircraft, issuing production certificates to certify a manufacturer's ability to build an aircraft in accordance with an approved design, and issuing airworthiness certificates to verify that individual aircraft have been manufactured in accordance with approved designs and are in safe operating condition. AIR is also responsible for overseeing the continued operational safety of manufacturers and aircraft. AIR issues airworthiness directives (ADs) to correct unsafe conditions when they are detected in aircraft that have previously been issued an airworthiness certificate. AIR is not responsible for oversight of pilots, airlines, or other facets of aviation operations that are the purview of the FAA's Flight Standards Service. Additional information on AIR's activities and how they apply to engines, spare parts, etc. appears in the section on Specific Regulatory Actions near the end of this chapter.

AIR's mission priorities are as follows (FAA, 1998):

  1. continued airworthiness and other activities related to continued operational safety

  2. rulemaking and policy development

  3. certification

Continued airworthiness activities are the highest stated priority because they have the greatest immediate impact on the safety of operating aircraft and because they promote the continued satisfactory performance of approved systems, such as manufacturers' approved quality control systems. Rulemaking and policy development are considered to be a higher priority than issuing new certificates because the integrity of the certification program depends on the currency of applicable rules and policies.

HISTORY AND STATUTORY AUTHORITY

No person may lawfully operate a civil aircraft in the United States unless it has an airworthiness certificate. The requirement for certificating civil aircraft dates back to enactment of the Air Commerce Act of 1926 (Komons, 1978), which is the origin of the FAA's current process for aircraft certification and continued airworthiness. The Air Commerce Act of 1926 also established an Aeronautics Branch within the Department of Commerce. The Aeronautics Branch subsequently evolved into the FAA, which is organizationally within the Department of Transportation.

During the early years of U.S. aviation, the government did not play a formal role in promoting the safety of civil aircraft. The Aeronautics Branch issued the first civil aviation safety regulations, the "Air Commerce Regulations," which became effective on December 31, 1926. The Air Commerce Regulations included the first standards for licensing (certification) of aircraft. On March 29, 1927, the Aeronautics Branch first certificated a civil aircraft: the Buhl-Verville Model J-4 Airster, an open cockpit, single engine, bi-wing aircraft also known as the model C-3A. The Air Commerce Regulations thus became the cornerstone of the U.S. airworthiness standards. Those standards, and the processes used to implement them, have evolved over the past 72 years through legislative and regulatory changes, reorganizations among executive branch departments, and reorganizations of individual agencies. This evolution has been driven by the following factors:



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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service 2 Role of the Aircraft Certification Service (AIR) AIR (the Aircraft Certification Service) is the department within the FAA that develops and administers safety standards for aircraft and related products that are manufactured in the United States or are used by operators of aircraft registered in the United States. Related products include engines, propellers, equipment, and replacement parts. This chapter provides background information that is necessary to understand the recommended safety management process and other findings and recommendations that appear in Chapters 4 through 7 of this report. Readers who are already knowledgeable about AIR's roles and processes may wish to skip this chapter. AIR's functions include issuing initial and amended type certificates for designs for new aircraft, issuing supplemental type certificates (STCs) for designs of modifications to existing aircraft, issuing production certificates to certify a manufacturer's ability to build an aircraft in accordance with an approved design, and issuing airworthiness certificates to verify that individual aircraft have been manufactured in accordance with approved designs and are in safe operating condition. AIR is also responsible for overseeing the continued operational safety of manufacturers and aircraft. AIR issues airworthiness directives (ADs) to correct unsafe conditions when they are detected in aircraft that have previously been issued an airworthiness certificate. AIR is not responsible for oversight of pilots, airlines, or other facets of aviation operations that are the purview of the FAA's Flight Standards Service. Additional information on AIR's activities and how they apply to engines, spare parts, etc. appears in the section on Specific Regulatory Actions near the end of this chapter. AIR's mission priorities are as follows (FAA, 1998): continued airworthiness and other activities related to continued operational safety rulemaking and policy development certification Continued airworthiness activities are the highest stated priority because they have the greatest immediate impact on the safety of operating aircraft and because they promote the continued satisfactory performance of approved systems, such as manufacturers' approved quality control systems. Rulemaking and policy development are considered to be a higher priority than issuing new certificates because the integrity of the certification program depends on the currency of applicable rules and policies. HISTORY AND STATUTORY AUTHORITY No person may lawfully operate a civil aircraft in the United States unless it has an airworthiness certificate. The requirement for certificating civil aircraft dates back to enactment of the Air Commerce Act of 1926 (Komons, 1978), which is the origin of the FAA's current process for aircraft certification and continued airworthiness. The Air Commerce Act of 1926 also established an Aeronautics Branch within the Department of Commerce. The Aeronautics Branch subsequently evolved into the FAA, which is organizationally within the Department of Transportation. During the early years of U.S. aviation, the government did not play a formal role in promoting the safety of civil aircraft. The Aeronautics Branch issued the first civil aviation safety regulations, the "Air Commerce Regulations," which became effective on December 31, 1926. The Air Commerce Regulations included the first standards for licensing (certification) of aircraft. On March 29, 1927, the Aeronautics Branch first certificated a civil aircraft: the Buhl-Verville Model J-4 Airster, an open cockpit, single engine, bi-wing aircraft also known as the model C-3A. The Air Commerce Regulations thus became the cornerstone of the U.S. airworthiness standards. Those standards, and the processes used to implement them, have evolved over the past 72 years through legislative and regulatory changes, reorganizations among executive branch departments, and reorganizations of individual agencies. This evolution has been driven by the following factors:

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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service continued high levels of public and congressional concerns about air transportation safety the introduction of new technologies, which have advanced the efficiency of the air transportation system and provided opportunities to improve aviation safety lessons learned from investigations of civil aviation accidents and incidents changes in international air transportation regulations and policies The Air Commerce Act of 1926 was superseded by the Civil Aeronautics Act of 1938, which in turn was superseded by the Federal Aviation Act of 1958. In July 1994, the Act of 1958 was recodified as Subtitle VII of Title 49 of the United States Code, which currently provides the FAA's regulatory authority. Airworthiness standards, known as the FARs (Federal Aviation Regulations), are separately codified in Chapter I of Title 14 of the Code of Federal Regulations.1 Among other things, FARs set forth the type certification requirements—known as ''airworthiness standards''—for aircraft designs, the requirements for manufacturers' production quality control systems, the requirements for airworthiness certification of individual aircraft, and the operations and maintenance rules for air carriers and repair facilities. Both AIR and the Flight Standards Service administer these regulations. The parts of the Code of Federal Regulations (i.e., the FARs) that are most relevant to the roles of AIR and the Flight Standards Service are listed below. Definitions and General Procedures Part 1. Definitions and abbreviations Part 11. General rulemaking procedures Part 13. Investigative and enforcement procedures FARs Administered by AIR Part 21. Certification procedures for products and parts Part 23. Airworthiness standards for normal, utility, acrobatic, and commuter category aircraft. Note: Part 23 includes certification requirements for all types of small airplanes. A design for a multi-engine, propeller-driven airplane with 19 or fewer seats (excluding seats for the flight crew) and a maximum certificated takeoff weight of 19,000 pounds or less must be type certificated as a "commuter category airplane" under FAR 23 unless it is certificated under Part 25. Part 25. Airworthiness standards for transport category airplanes. Note: Unless eligible for certification under Part 23, all airplane designs with 10 or more seats (excluding seats for the flight crew) or a maximum certificated takeoff weight of more than 12,500 pounds must be type certificated under Part 25. However, any multi-engine airplane design, regardless of size, may be type certificated as a transport category airplane if it meets the airworthiness standards of FAR 25. Part 27. Airworthiness standards for normal category rotorcraft Part 29. Airworthiness standards for transport category rotorcraft Part 33. Airworthiness standards for aircraft engines Part 35. Airworthiness standards for propellers Part 39. Airworthiness directives FARs Administered by the Flight Standards Service Part 43. Maintenance, preventive maintenance, rebuilding, and alteration Part 91. General operating and flight rules. Note: These rules are applicable to all aircraft, but general aviation aircraft are often referred to as Part 91 aircraft because they are not subject to additional operating rules under Parts 119, 121, 125, or 135. General aviation aircraft may be of any type and size, as long as they are not operated in accordance with Part 121 or scheduled operations under Part 135. General aviation operations are mostly recreational flying, but also include business aviation, flight instruction, and industrial flying, such as firefighting, aerial application of pesticides, etc. Part 119. Certification requirements for air carriers and commercial operators. Note: Part 119 defines when Parts 121, 125, and 135 are applicable. Part 121. Operating requirements for domestic, flag, and supplemental operations. Note: Part 121 generally applies to airlines operating jet airplanes or any other types of airplanes with 10 or more passenger seats or a payload capacity of 7,500 pounds or more. Aircraft used for operations covered by Part 121 usually must be certificated under Part 25 or as commuter category aircraft under Part 23. Part 125. Certification and operations for aircraft with a seating capacity of 20 or more passengers or a maximum payload capacity of 6,000 pounds or more. Note: Part 125 is primarily applicable only when common carriage is not involved, and it is not applicable to aircraft operated under Parts 121 or 135. Part 135. Operating requirements for commuter and on-demand operations. Note: Part 135 is generally applicable to rotorcraft and fixed-wing aircraft with nine or fewer passenger seats and a payload capacity of 7,500 pounds or less. Because of practical and regulatory considerations, most Part 135 aircraft are certificated under Part 23. Most Part 135 operators of large aircraft have been required to transition to Part 121 operations. Part 145. Repair stations 1    Title 49 of the United States Code is defined by federal legislation and can only be changed by new legislation. Title 14 of the Code of Federal Regulations is defined by regulations issued by federal agencies, such as the FAA, in accordance with relevant sections of the United States Code.

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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service As indicated in this list, AIR is responsible for FARs associated with certification, airworthiness standards, and ADs; and the Flight Standards Service is responsible for FARs associated with operations and maintenance. Aircraft certification regulations (Parts 21-39) are intended to promote the airworthiness of aircraft by requiring that every aircraft, aircraft engine, and propeller is produced in conformance with an approved type design and is in safe operating condition. Aircraft certification regulations also require the development of maintenance requirements and operational limitations. One of the key goals of certification and continued air-worthiness standards is that each safety-critical system have a reliability of at least 0.999999999—"nine 9's"—per flight hour; in other words, the probability that a particular safety-critical system will fail is no more than one in a billion for each flight hour. Regulations seek to achieve this goal through a combination of requirements for design, analysis, test, inspection, maintenance, and operations. As much as possible, regulations do not constrain designers a priori by specifying details such as material properties or the design of individual structures. Instead, designers are given a free hand to incorporate new materials, structural concepts, etc., as long as they accept the responsibility for showing that systems with innovative design features meet the FAA's stringent reliability requirements. The maintenance rules of Part 43 establish performance standards for individual maintenance workers, and Part 145 establishes quality control system requirements for certificated and rated repair stations that perform maintenance. Operating rules (Parts 91,121,125, and 135) define the responsibilities of owners and operators for ensuring that aircraft are properly operated and maintained in an airworthy condition. Part 119 defines when these operating rules are applicable. Different standards are applied depending on the size and use of aircraft. For example, expected levels of safety for aircraft operated by air carriers is higher than for general aviation aircraft. Neither the "applicability" requirements of Part 23 nor Part 25 addresses the issue of operating rules, which may require that additional equipment be installed or may apply additional airworthiness standards or operating limitations. Descriptors of aircraft categories used for the purposes of type certification2 do not directly correspond to similar terms that might be used to define applicable operating rules. The descriptors used in the aircraft certification regulations only define the airworthiness standards applicable to the design of the aircraft, whereas the descriptors used in the operating rules define the specific operating rules that apply. For example, an aircraft type certificated as a "transport category airplane" under Part 25 may or may not be intended for use in air transportation service by an "air carrier" under Part 121. Similarly, an aircraft type certificated as a "commuter category airplane" under Part 23 may or may not be intended for use in ''commuter" service under Part 135. Environmental considerations were added to the aircraft certification process by the Noise Control Act of 1972 and by a 1973 amendment to the Clean Air Act. The FAA's Office of Environment and Energy, in close coordination with the Environmental Protection Agency, promulgates the regulations and policies for aircraft noise and engine emissions as required by these statutes. However, findings of compliance are made by AIR as an integral element of the basic aircraft and aircraft engine design approval (type certification) process. To summarize, the manufacturer is responsible for the original airworthiness of an aircraft, aircraft engine, or propeller; the operator is primarily responsible for maintaining the expected level of airworthiness. The operator retains full responsibility for the airworthiness of its aircraft, even if the operator uses leased aircraft or relies on outside contractors for maintenance. The aircraft certification regulations (Parts 21-39) are developed and administered by AIR, and the operating regulations (Parts 91-135) are developed and administered by the Flight Standards Service. The aircraft maintenance regulations (Parts 43 and 145) are also developed and administered by the Flight Standards Service. However, during the type certification process, the Flight Standards Service works closely with AIR to assess the operational acceptability of the product being certificated and to develop operational and maintenance documentation to facilitate the introduction of the product into service. Figure 2-1 illustrates how aircraft certification and continued airworthiness regulations are related to the current safety management process. Supreme Court Opinions Concerning FAA Statutory Responsibilities In June 1984, the U.S. Supreme Court rendered a landmark opinion concerning the FAA's tort liabilities in the certification of civil aircraft. The court's opinion concerned two cases involving FAA regulatory responsibilities under the Federal Aviation Act of 1958 and determined the extent of the FAA's liability in cases of alleged negligence. 3 The first case concerned the original type certification of a U.S.-manufactured aircraft that was operated by a foreign operator; the second case concerned FAA supplemental type certification of modifications to a small aircraft that had been manufactured in another country. In the second case, the aircraft was used in the United States for air taxi operations 2    Type certification basis is described below in the section on initial type certification. 3    United States v. S.A. Empresa de Vaicao Aerea Rio Grandense (Varig Airlines) et al. (82-1349) and United States v. United Scottish Insurance Co. et al. (82-1350). On writs of certiorari to the U.S. Court of Appeals (9th Circuit 1984). The two cases were combined, and a single opinion was issued.

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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service FIGURE 2-1 Current aircraft certification and safety management process. The safety management process recommended by the committee is shown in Figure 4-1. (i.e., in accordance with Part 135 of the FARs). The Supreme Court determined that liability claims against the FAA for alleged negligence were barred by the "discretionary function exception" of the Federal Tort Claims Act.4 Important points in the Supreme Court's opinion, which is applicable to all FAA regulatory programs, include the following: "The FAA certification process is founded upon a relatively simple notion: the duty to ensure that an aircraft conforms to FAA safety regulations lies with the manufacturer and operator, while the FAA retains the responsibility for policing compliance . . .. This premise finds ample support in the statute and regulations." "When an agency determines the extent to which it will supervise the safety procedures of private individuals, it is exercising discretionary regulatory authority of the most basic kind. Decisions as to the manner of enforcing regulations directly affect the feasibility and practicality of the Government's regulatory program; such decisions require the agency to establish priorities for the accomplishment of its policy objectives by balancing the objectives sought to be obtained against such practical considerations as staffing and funding." "It follows that the acts of FAA employees in executing the 'spot-check' program in accordance with agency directives are protected by the discretionary function exception as well." "The FAA has a statutory duty to promote safety in air transportation, not to ensure it." (Emphasis in the original.) In summary, the court's opinion clarified that the FAA's authority and duty to promote aviation safety through regulation is defined by FARs, whereas the degree to which the FAA exercises oversight authority, especially in areas such as aircraft certification and continued airworthiness, depends to a great extent on the resources allocated by Congress in annual appropriations. ORGANIZATION OF THE AIRCRAFT CERTIFICATION SERVICE (AIR) AIR is an organizational unit of the FAA that reports to the associate administrator for regulation and certification, who in turn reports to the FAA administrator. As shown in Figure 2-2, four other units report to the same associate administrator: the Flight Standards Service, the Office of Aviation Medicine, the Office of Rulemaking, and the Office of Accident Investigation. AIR has a matrix organizational structure with lines of policy direction and guidance that, in some cases, differ from those of the administrative organization. The lines of both policy direction and administrative direction begin with the director of the AIR, who is located at FAA headquarters in Washington, D.C. Technical policy responsibilities within AIR are divided among six "policy centers" (two divisions located at FAA headquarters in Washington, D.C., and four directorates located elsewhere). Each policy center is responsible for regulatory and policy development and for national oversight of its assigned area of technical responsibility. The Aircraft Engineering Division at FAA headquarters is the policy center for general type certification procedures and continued airworthiness procedures, including technical issues common to all aircraft and product types. The Production and Airworthiness Certification Division is the policy center for production and airworthiness certification. AIR's four directorates are as follows: Transport Airplane Directorate (Seattle, Washington) Small Airplane Directorate (Kansas City, Missouri) Rotorcraft Directorate (Fort Worth, Texas) Engine and Propeller Directorate (Burlington, Massachusetts) Each directorate is also assigned a geographic area that covers about one-fourth of the United States and designated areas overseas. Within its assigned area, each directorate is 4 Neither case went to trial as a result of the Supreme Court's opinion. Therefore, courts have never decided whether there was negligence on the part of the FAA in these cases.

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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service FIGURE 2-2 Partial organizational diagram of the FAA and AIR. Source: FAA.

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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service responsible for all administrative aspects of the aircraft certification and continued airworthiness process. For example, the Transport Airplane Directorate in Seattle is the primary point of contact for all six AIR divisions and directorates for domestic organizations located in 18 western states and for foreign organizations located anywhere in the Asia-Pacific region. Within each directorate's geographic area of responsibility is an infrastructure of aircraft certification offices (ACOs) and manufacturing inspection district offices (MIDOs), to which the majority of AIR's engineers, flight test pilots, and manufacturing inspectors are assigned. Each ACO and MIDO has a defined geographic area of responsibility within its directorate's geographic region. The ACOs work directly with applicants for design approvals for all types of new aircraft, engines, and propellers; aircraft and system modifications; new materials; and spare parts. Similarly, MIDOs work directly with applicants for and holders of production certificates (manufacturers) for all types of regulated products, primarily with regard to the approval and oversight of production quality control systems. MIDOs are also responsible for issuing airworthiness certificates for individual new aircraft and for approving the airworthiness of engines, propellers, spare parts, etc. Both the ACOs and the MIDOs have continued operational safety functions that involve reviewing service difficulty reports, participating in accident and incident investigations, developing draft ADs, and enforcing regulations. The ACOs and MIDOs work under the administrative supervision of the directorate with responsibility for their geographic area and receive policy direction and guidance from all other policy centers regarding the product types and technology areas for which each center is responsible. Making this system work effectively requires that all six policy centers work in close cooperation with each other, and AIR has established the Aircraft Certification Management Team for this purpose. AIR employs a cadre of national resource specialists as technical specialists in key disciplines, such as flight loads and aeroelasticity, nondestructive evaluation, flight management, and human factors. These positions were established to increase AIR's technical expertise in designated areas; national resource specialists work, as needed, on projects throughout AIR. In accordance with FAR Part 183, AIR also makes extensive use of highly knowledgeable industry personnel designated as "representatives of the administrator." Delegated individuals include designated engineering representatives, designated airworthiness representatives, and designated manufacturing inspection representatives. The FAA relies on these individuals to act on its behalf in reviewing and approving specified actions proposed by their companies. These representatives allow FAA engineers and inspectors to devote more of their attention to more critical areas. Organizational delegations, which are similar to individual delegations, include holders of delegation option authorizations, holders of designated alteration station authorizations, and organizational designated airworthiness representatives. SPECIFIC REGULATORY ACTIONS Airworthiness Certification Airworthiness certificates, which are issued for individual aircraft, are the cornerstone of AIR's overall certification process. Part 91 prohibits the operation of civil aircraft without an airworthiness certificate, in violation of any term of the applicable airworthiness certificate, or in violation of any applicable FARs. The FAA issues both "standard" and "special" airworthiness certificates. Special airworthiness certificates include primary, restricted, limited, provisional, and experimental airworthiness certificates and may be associated with special flight permits that do not meet the international certification standards of the International Civil Aviation Organization (ICAO) in the Convention on International Civil Aviation, to which the United States is a signatory.5 For a civil aircraft to receive an airworthiness certificate, the FAA must determine that the aircraft conforms in detail to an FAA-approved type design and is in safe operating condition. Similar requirements exist for engines, propellers, and certain materials, parts, and equipment installed on certificated aircraft. As part of this process, AIR issues several kinds of type certifications and production approvals, which are discussed below. Type Certification Type certification includes FAA approvals for new and modified designs of aircraft, aircraft engines, and propellers. Aircraft engines and propellers are issued type certificates separately from the aircraft on which they are installed. One requirement for type certification of an aircraft design is that the designs of the engine and propeller(s), if applicable, have appropriate type certificates. The type certification process also encompasses design approvals for materials, spare parts, and other equipment to be installed on type-certificated aircraft, aircraft engines, and propellers. Initial Type Certification When the FAA receives an application for type certification of the design of a new product (aircraft, engine, or propeller), the first step is to establish the type certification basis for the product. The type certification basis is the body of applicable regulations designated in accordance with the procedural regulations of FAR 21.17. Generally speaking, the type certification basis for a product includes the following: 5   Commonly known as the Chicago Convention of 1944.

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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service applicable airworthiness standards (e.g., FAR Part 25 for transport category airplanes) in effect on the date of application special conditions that have been developed to address novel and unusual design features of the product that are not adequately covered by the basic airworthiness standards standards for fuel venting and emissions (Parts 34 and 36) exemptions to the above standards that have been issued in the public interest6 The type certification basis may be amended during the type certification process for a number of reasons. However, once the type certificate is issued, the type certification basis is fixed and becomes part of the type certificate. Throughout the production life of a particular product, manufacturers make design changes to improve performance or producibility. Most of these changes are not intended to improve safety. For example, aircraft modifications may be intended to improve dispatch reliability, to reduce maintenance and operating costs, or to improve passenger comfort. As defined by Part 21, these changes are classified as either "minor" or "major" changes. The FAA evaluates each minor change against the original type certification basis and the body of relevant ADs and, if appropriate, approves it as an amendment to the type design.7 Approval is required before products built in accordance with the modified design will be issued an airworthiness certificate or approval. Major changes usually involve the holder of a type certificate who plans to introduce a derivative model of an existing product. The term "derivative" is not defined by regulation but is traditionally used to denote a major change to a previously approved type design. For example, the Douglas DC-9-30 is one of several derivative aircraft designs based on the original DC-9 type design (the DC-9-10). The type certification basis for a derivative type design is the type certification basis for the original type design, as modified by special conditions issued to address novel and unusual design features in the derivative design that are not adequately addressed by the original type certification basis. Changes to the original type design mandated by ADs must be built into the design of the derivative model, as applicable. Analyses and tests conducted during type certification of the original type design are not repeated if they remain applicable to the derivative design. At the conclusion of the process, the original type certificate is amended to include the derivative model. This process may be repeated to add any number of derivative models to an original type certificate.8 Supplemental Type Certification Manufacturers frequently recommend that owners and operators modify existing products to improve performance, reliability, safety, etc. Typically, these design changes are developed by the manufacturer and are promulgated as service bulletins. Aircraft modification centers and others also design product improvements, such as new navigation and communications installations, upgraded crew and passenger accommodations, modified propulsion systems, and conversions to transform passenger aircraft to all-cargo configurations (complete with large cargo-loading doors and structural reinforcements). In some cases—most commonly with old aircraft—operators must rely on third parties (someone other than the original manufacturer) to design aircraft modifications either because the manufacturer is no longer in business or because the manufacturer is unable to develop the required safety modifications. All of the changes listed above require FAA approval. This approval takes the form of an STC (supplemental type certificate) when someone other than the holder of the type certificate (the original manufacturer) asks the FAA to approve the design for a major change in a product. As in the case of a derivative aircraft or other product, the type certification basis for an STC is the product's original type certification basis, with new special conditions, as appropriate. To protect the proprietary rights of the type certificate holder, the FAA does not disclose type certification data owned by the type certificate holder without its permission. This permission is often not granted for competitive reasons or because of concerns about product liability. For example, operators may decide to have existing aircraft modified as an alternative to buying new aircraft from the original manufacturer, or the modifications may be intended to compete with similar modifications available from the original manufacturer. If the original manufacturer does not grant access to a product's basic engineering data, an STC applicant may reverse engineer the product design or conduct independent tests to develop the basic product data to proceed with an STC project. For example, if the original strength or functionality of a component to be modified under an STC is established by independent tests and analyses, the STC applicant may then show that the modified component retains at least the same strength or functionality as the original. However, lack of access to the manufacturer's data 6   Part 11 requires, among other things, that the petitioner for an exemption explain why it would not adversely affect safety or how the petitioner would provide a level of safety equal to the level provided by the rule from which the exemption is sought. Notifications of petitions for exemptions are published in the Federal Register and are subject to public comment before they are granted or denied. 7   In most cases, manufacturers' designated engineering representatives approve minor changes to type designs. 8   See Chapter 4 for additional information on the type certification of derivative aircraft, engines, and propellers.

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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service sometimes prevents applicants from formulating an acceptable STC application.9 Other approval documents used for type certification include technical standard order authorizations (TSOAs) for the designs of certain materials, parts, and equipment and parts manufacturing approvals (PMAs) for the designs of spare and replacement parts not otherwise approved under a type certificate, STC, or TSOA. Production Approvals The FAA issues several types of production approvals: production certificates, production inspection system letters, PMAs, and TSOAs. Production certificates are issued after the FAA examines a manufacturer's production quality control system to verify that the manufacturer has the ability to produce products that conform to the approved type design and are in a condition for safe operation. Production certificates are issued for specific products, and only for products for which a type certificate has already been approved. Approved production inspection system letters, which are similar to production certificates, may be issued to small manufacturers of aircraft, engines, or propellers in lieu of production certificates. The production quality control systems of manufacturers that hold a TSOA or PMA are approved as an integral part of those authorizations. In other words, TSOAs and PMAs are, in effect, combined design and production quality control system approvals. For all production approvals, the manufacturer's production quality control system is viewed as incorporating the quality control systems of all its suppliers.10 Thus, each holder of a production approval is responsible for ensuring that its suppliers at all levels perform in accordance with the details of the holder's FAA-approved production quality control system. In the event of a breakdown in a supplier's quality control system, including a breakdown by a subtler supplier, enforcement action by the FAA would be directed at the production approval holder—not the supplier. Thus, although the FAA inspects suppliers, the primary purpose of those inspections is to verify that holders of production approvals are meeting their own oversight responsibilities. Promoting Continued Airworthiness AIR monitors the safety performance of aircraft in service, manufacturers' production quality control systems, and representatives of the administrator (designees) to determine if they are maintaining expected levels of safety and to verify they are complying with the terms of certifications or delegations they hold. In effect, the type certification, production approval, and airworthiness certification processes described above never end. If expected levels of safety are not maintained or compliance problems are found, AIR takes corrective action, usually by issuing an AD or taking regulatory enforcement action. The FAA uses feedback from manufacturers and operators (including pilots and maintenance personnel), as well as its own safety investigations, to determine when corrective action is needed to prevent or correct unsafe conditions. However, the terms "safe" and "unsafe" are hard to quantify. Therefore, the FAA's own measure of public confidence, often manifested by political pressures, can become a factor in the decision making process. For example, ADs have been issued to restore public confidence even before technical investigations have been completed or an agreement has been reached on the cause of an accident or reported safety problem. AIR's activities to promote the continued airworthiness of the operational fleet of civil aircraft include the following: participating in accident and incident investigations reviewing and analyzing reports of in-service difficulties that might reveal the existence of unsafe conditions reviewing safety recommendations made by the National Transportation Safety Board (NTSB) that relate to aircraft certification reinvestigating design approvals for compliance with design certification standards, as necessary auditing production quality control systems to verify continued compliance with the terms of production certificates and approvals initiating enforcement actions, which may include civil penalties and/or suspending or revoking certificates issuing ADs (see below and the section on Risk Management/Action in Chapter 4) ADs are issued as amendments to FAR 39. Aircraft owners or operators have primary responsibility for determining if their aircraft are in compliance with all applicable ADs. ADs may specify modifications that must be made within a certain time, special inspections that must be conducted, and/ or special operating limitations with which the aircraft must comply. Thus, ADs essentially serve as required changes to previously certificated type designs. Most ADs refer to the detailed instructions in manufacturers' service bulletins or other documents. However, FAA procedural regulations allow the FAA to issue an AD first and then direct the manufacturer of the affected product to submit design changes for FAA approval. 11 After approval, this information is provided to operators. This procedure has been done in a few cases when a manufacturer, for whatever 9   See Chapter 4 for additional information on STCs. 10   Some parts suppliers obtain their own production approvals so they can legally market their products to customers other than the prime manufacturers that have designated them as approved suppliers. 11   Such an AD would, in objective terms, require correction of a stated problem within a specified time.

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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service reason, has been reluctant to develop corrective design changes and make the necessary service information available to operators. In all cases, operators also have the option of proposing corrective action to the FAA. If a manufacturer is no longer in business or refuses to propose acceptable corrective action, the burden falls on the operators to propose corrective action for FAA approval. Otherwise, affected aircraft cannot be legally operated after the compliance date specified in the AD. Ultimately, if an unsafe condition is determined to exist and there is no known corrective action, the FAA may revoke the airworthiness certificates of the affected aircraft, thus "grounding" them. In addition to ADs, the FAA has statutory authority to reexamine already certificated aircraft designs and order amendments, suspensions, or revocations of certificates, as necessary to correct unsafe conditions. These reexaminations are especially important for promoting the continued airworthiness of aircraft that are operated much longer than was originally anticipated by their manufacturers. In addition, ADs may be issued or the operating rules (e.g., FAR Parts 91, 121, 125, and 135) may be amended to require operators to install special equipment or to make other modifications to maintain the safety of their aircraft. Examples of such requirements include the requirement that a wide-body transport airplane be able to sustain a large hole in the side of the fuselage; requirements to modify passenger cabins to improve post-crash survivability; and requirements to install collision avoidance systems, ground proximity warning systems, and windshear warning systems. The FAA has jurisdiction only over operators of U.S.-registered aircraft (i.e., aircraft included in the U.S. Civil Aircraft Registry). However, the airworthiness authorities of most other countries issue either their own orders based on FAA ADs or permanent regulations that require operators in their jurisdiction to comply with FAA ADs as they are issued. The FAA issues type certificates for many aircraft that are built by foreign manufactures and operated by U.S. operators. ADs issued by the FAA for these aircraft, like ADs issued for aircraft manufactured in the United States, typically refer to the manufacturer's service bulletins for detailed instructions. In most cases, the airworthiness authority in the country of manufacture has already issued the equivalent of an AD under its own regulatory system. However, to require compliance by U.S. operators of those aircraft, the FAA must issue its own AD—in accordance with the U.S. government's normal rulemaking procedures—because the FAA does not have the statutory authority to delegate its rule-making responsibilities or otherwise subject parties under its regulatory purview to regulations by foreign airworthiness authorities. In some cases, service experience indicates either to the FAA or to the holder of a type certificate that changes in the type design would improve the safety of the aircraft, even though an unsafe condition does not exist. In those cases, the holder of the type certificate may submit appropriate design changes for FAA approval. Upon approval, the manufacturer makes relevant service information available to operators. In these cases, ADs are not issued, and compliance with the manufacturer's service instructions is at the discretion of the aircraft owner or operator. Rulemaking Process12 The FAA uses a public rulemaking process to comply with its legislative mandate to develop and promulgate minimum safety standards for civil aviation.13 The FAA also promulgates procedural regulations for administering the application of those standards. AIR develops and issues advisory circulars and internal directives, including handbooks, orders, and notices, to provide guidance on how to implement its policies and procedures. The rulemaking process is simple in concept. First, the need for a regulatory change is identified. Next, a proposed rule change is developed and published in the form of a notice of proposed rule making (NPRM). Then, public comments in response to the NPRM are evaluated, and a final rule is written, approved, published, and implemented. The FAA's rulemaking process is structured to comply with applicable procedural requirements, as specified in numerous statues, White House executive orders, Department of Transportation orders and regulations, and the Convention on International Civil Aviation. Whenever the FAA proposes a new regulation, an amendment to existing regulations, or any other rulemaking action, it must cite a relevant statutory authority. If such authority does not exist, the FAA must seek enabling legislation before proceeding. Legislation may also direct the FAA to promulgate specific regulations. For example, the requirement to install collision avoidance systems in most passenger aircraft was the result of legislation that directed the FAA to make appropriate changes to the FARs. Rulemaking projects may by triggered externally—by public petitions, NTSB recommendations, executive orders, or congressional statutes. Projects may also be triggered internally—by the Office of the Secretary of Transportation, the FAA administrator, the Office of the Chief Counsel, or individual FAA offices, such as AIR. Based on the subject matter of the proposed rulemaking activity, an "office of primary responsibility" is then designated to determine if a project should be initiated and, if so, whether it will be assigned to the FAA's Aviation Rulemaking Advisory Committee (ARAC) or staffed in house by the responsible office. 12   Rulemaking is also discussed in Chapter 6. 13   All regulations issued by a federal agency, including the FAA, must be promulgated through a public rulemaking process in accordance with U.S. Code Title 5, Chapter 5, commonly called the Administrative Procedure Act. This act is implemented by the FAA in accordance with FAR Part 11, General Rulemaking Procedures.

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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service Recently approved changes to the rulemaking process specify that a Rulemaking Management Council will participate in this decision and other management functions throughout the rulemaking process. The ARAC and its industry working groups, which operate in accordance with the Federal Advisory Committee Act, facilitate the rulemaking process. Participants in ARAC working groups come from all elements of the commercial aviation industry and the regulatory authorities of many foreign countries. The ARAC provides a vehicle for private individuals and nongovernment organizations to participate officially in the drafting of NPRMs, reviews of public comments, and the drafting of final rules. NPRMs, which are published in the Federal Register, contain the complete draft of a proposed rule and provide interested parties the opportunity to submit data, opinions, or arguments for or against the rule in writing. (See the section on Rulemaking in Chapter 6 for more information on the ARAC.) Proposed rules must be assessed in terms of their ability to improve safety and their economic impact, including their impact on international trade. A copy of the cost-benefit analysis must be submitted to the Congress before a new rule can take effect. To show that the economic effects are acceptable, the FAA is required by executive order to compare the industry-wide cost of implementing the action with the value (in dollars) of the human lives that the action is expected to save. The Department of Transportation specifies the value (currently, $2.7 million per life) that the FAA must use. The requirement that the FAA provide economic justification for rulemaking actions could prevent the FAA from implementing some NTSB recommendations because the NTSB is not required to screen its recommendations based on economic impact. The FAA's Office of Rulemaking reports to the associate administrator for regulation and certification. The directors of AIR and other program offices are responsible for the technical substance of proposed regulations; the Office of the Chief Counsel is responsible for the legality and form of proposed regulations; and the Office of Aviation Policies and Plans (which reports to the assistant administrator of policy and international aviation) is responsible for verifying compliance with executive orders that require cost-benefit or regulatory analyses. Rulemaking procedures, as authorized by legislative mandate and implemented by FAR Part 11, generally take a long time to complete. The FAA often provides 120 days or more for public comments in response to an NPRM. In addition, final rules must be published in the Federal Register at least 30 days prior to their effective date, and many final rules specify compliance dates beyond the effective date of the rule. However, the FAA may issue a regulation without an NPRM or a 30-day period for public notice if it determines that these would be impractical, unnecessary, or contrary to the public interest—and explains why in the final rule (for example, in the case of an emergency involving safety or security). The preamble of each final rule summarizes all public comments received and explains how and why the FAA reacted to those comments. The FAA also uses the Airworthiness Concern Coordination Process (better known as the lead airline concept) to obtain operational insight regarding potential airworthiness problems and proposed solutions. This process comes into play when the FAA needs to interact with the Air Transport Association (an association of major U.S. airlines) in developing ADs or other actions relevant to a specific aircraft model. Under this process, which seems to be working well, the Air Transport Association has designated a specific airline for each aircraft model to take the lead in working with the FAA. AIR works with the JAA (the Joint Aviation Authorities, an organization comprised of European regulatory authorities) and individual regulatory authorities of other foreign countries to promote international harmonization of aircraft certification regulations, policies, and practices. In fact, many rulemaking projects are triggered by efforts to harmonize specific regulations between the United States and Europe. The authority to issue NPRMs related to aircraft certification has been delegated to the AIR director. With some exceptions, final rules are issued by the FAA administrator. Exceptions include the approval of ADs and special exemptions from the airworthiness standards that would normally apply to the type certification of particular products. The authority to issue final rules in these areas has been delegated to the managers of AIR's four directorates in their areas of responsibility. Final rules that may have a significant economic impact or may generate significant public (or political) interest must obtain concurrence from the Office of the Secretary of Transportation and the Office of Management and Budget (OMB) before they are issued. In some cases, concurrence is required even before an NPRM can be issued. Resources and Level of Activity AIR's budget for fiscal year 1998 was $101 million. At the end of fiscal year 1997, AIR had 1,010 full-time permanent employees, including 678 nonsupervisory technical personnel (aviation safety engineers, aviation safety inspectors, and flight test pilots), 94 managers, and 238 support personnel. This staff was distributed over 34 geographical locations. Activities completed by AIR during fiscal year 1997 included the following: 25 type certificates approving the designs of new aircraft, aircraft engines, and propellers 110 amendments to existing type certificates approving the designs of new derivative models of aircraft, aircraft engines, and propellers 1,011 new STCs approving designs for modifications to products approved by preexisting type certificates

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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service 530 amendments to existing STCs 5,715 lesser design approvals (such as TSOAs and PMAs) 2,473 production certificates and other production quality control system approvals 1,840 original airworthiness certificates issued to newly manufactured aircraft 341 ADs to correct safety problems in existing aircraft 790 appointments of new designees to act as "representatives of the administrator" for design approvals and airworthiness certifications final action in response to 31 petitions for exemption final action in response to 14 petitions for rulemaking The FAA as a whole published 19 NPRMs and issued 29 final rules. RELATED ACTIVITIES Unapproved Parts Unapproved parts are parts that have not been approved under applicable FARs or have lost their approval status because of a change in condition caused by damage, wear, etc. Unapproved parts are created primarily in the following ways: Parts are manufactured by individuals who do not seek FAA approval because they are unaware of relevant requirements. Parts from overruns produced by suppliers to prime manufacturers find their way into the marketplace without undergoing the required quality control inspections to determine their conformity or condition. Surplus military parts are sold as scrap and then introduced into the marketplace for civil aircraft parts with false documents misrepresenting them as serviceable parts. Counterfeit parts are produced by unknown sources and falsely marked, packaged, or otherwise misrepresented as parts manufactured by an approved manufacturer. Parts that are approved by foreign governments for installation on aircraft on their registry find their way into the U.S. marketplace without FAA approval for installation on U.S.-registered aircraft. Previously approved used parts are reintroduced into the marketplace with bogus, falsified, or altered maintenance records even though the parts have outlived their safe life, have been inappropriately repaired, and/ or have been reconditioned to look serviceable even though they are not. This group may include parts taken from aircraft that were involved in accidents. Thus, an unapproved part may be functionally identical in all respects to an approved part but lack the proper documentation or authorization. Although using this kind of unapproved part does not present a safety problem, per se, it is often difficult to distinguish an undocumented but fully functional part from a close copy that appears to be fully functional but, in fact, is not. Thus, the practice of using unapproved parts degrades safety. Because many approved parts cost much more than similar unapproved parts, there is a strong financial incentive for dishonest vendors or repair facilities to market or use unapproved parts knowingly. For example, in one well publicized case, an unapproved bearing spacer was detected by a repair facility conducting maintenance on the engines of a large transport airplane. The unapproved spacers, which were commercially available for other applications, could be purchased for about $40, whereas the genuine, approved part cost $500. The unapproved part would disintegrate after 600 hours in flight, resulting in complete engine failure, whereas the approved part had a 20,000 hour replacement life. The FAA issued an AD to inspect engines with the same part, and more than 30 unapproved parts were found on in-service aircraft. There are documented cases that unapproved parts have caused fatal accidents. One involved a transport category aircraft airplane and resulted in 55 fatalities. That particular accident occurred in Denmark, but the aircraft involved was manufactured in the United States. One of the cause factors for the accident was the use of unapproved and substandard parts, some of which were reportedly supplied by a company located in the United States. In another case, the failure of a helicopter tail rotor in New Zealand caused two fatalities. This accident was also caused by an unapproved part supplied by a U.S. company. FAA action to police this problem is complicated by the large number of parts suppliers, which are not required to be registered with or approved by the FAA. It is the responsibility of the individuals and companies that perform maintenance to ensure that they use only approved parts, but this can be a difficult task if a parts supplier knowingly provides unapproved parts. To address the risk posed by unapproved parts, the FAA has established an office dedicated to this problem. This office has established procedures applicable to AIR personnel, the Flight Standards Service, and other FAA offices involved in the unapproved parts problem. The FAA has also recognized self-governing approval processes established by two groups, the Society of Automotive Engineers and the Airplane Suppliers Association, to facilitate "accreditation" of qualified parts suppliers that have lacked formal approval. The committee believes the FAA should continue its current efforts to address the unapproved parts problem, including industry education, investigation, and appropriate regulatory action. Aging Aircraft The aging aircraft initiatives carried out by the FAA, overseas authorities, airlines, and manufacturers have been very successful in addressing the structural problems of aging

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Improving the Continued Airworthiness of Civil Aircraft: A Strategy for the FAA's Aircraft Certification Service aircraft, which were highlighted by the 1988 accident of an Aloha Airlines Boeing 737. Since then, all major jet transport airplanes have been subject to extensive, mandatory structural inspections and modifications. Aging aircraft programs, however, have not yet fully addressed issues associated with widespread fatigue damage criteria and repairs. The FAA's aging aircraft program evaluates aircraft structures in accordance with damage tolerance principles. These evaluations, however, do not consider the effects of structural repairs of the airworthiness integrity of the aircraft. The committee believes existing repairs and repair procedures should be reassessed using damage tolerance concepts. The FAA's ARAC has recommended a special FAR that would require operators to review repairs on airplane pressure cabins. In addition, major manufacturers have prepared repair assessment guidelines. The program is under way on a voluntary basis, but regulatory action, which may take several more years to complete, is required to mandate compliance by all operators. The committee believes the FAA should expedite action in this area. In early 1997, the White House Commission on Aviation Safety and Security recommended expanding the FAA's aging aircraft program to include nonstructural systems. However, there are comprehensive maintenance and overhaul procedures for nonstructural systems, and it is not clear if an aging problem does in fact exist in areas other than the structure. The committee believes it would be worthwhile for the FAA to initiate a cooperative study on aging of nonstructural systems to evaluate the need for expanding aging aircraft initiatives in this area. REFERENCES FAA (Federal Aviation Administration). 1998. Aircraft Certification Mission Statement. Federal Aviation Administration. Online. Aircraft Certification Service (AIR) Headquarters Office Home Page. Available: http://www.faa.gov/avr/air/hq/mission.htm. February 10, 1998. Komons, N.A. 1978. Bonfires to Beacons: Federal Civil Aviation Policy under the Air Commerce Act, 1926-1938. Washington, D.C.: Federal Aviation Administration. White House Commission on Aviation Safety and Security. Vice President A1 Gore, Chairman. February 12, 1997. Final Report to President Clinton. Washington, D.C.: White House Commission on Aviation Safety and Security.