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Production and Maintenance The manufacture of modern jet transport aircraft is an organizational tour-de-force. Components of the air- craft--wings, tail and landing gear assemblies, fuselage sections, doors and latches, avionic and radio equip- ment--arrive at the assembly plant from all over the world. In hangars the size of several football fields, work crews tow the airplanes through a dozen or more positions on the production line, until each finished airplane eases from the hangar ready for testing and ap- proval for flights. Once an airplane is in service, the airline performs myriad maintenance operations on it--daily checks, peri- odically scheduled maintenance, major overhauls, repairs of unexpected damage and replacement of failed compo- nents. The number of aircraft in daily service for each air carrier, the complexity of the airplane, the distan- ces between centers of operations, and the variations in procedures and practices among airlines all figure into a maze of maintenance operations in which millions of actions are performed by thousands of individuals. As a consequence, there are many opportunities for assuring that each aircraft is built and maintained to established safety standards. With careful workmanship, failures are preventable. By alert examination, errors are detectable. Carelessness and inattention, by con- trast, often lead to mistakes and mishaps. 49
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IMPROVING AIRCRAFT SAFETY/50 Quality Assurance in Production For each new type of aircraft, a manufacturer must obtain a Production Certificate from the FAA. Prior to awarding the certificate, a team of specialists from the FAA regional office, constituted as a Production Certi- fication Board, reviews and evaluates the applicant's proposed manufacturing and quality control procedures. The review is intended to make sure that each aircraft produced conforms to the design specifications of the Type Certificate. Once the Production Certificate is awarded, government oversight of production is main- tained by a system that couples direct FAA review by assigned inspectors with the work of delegated company- employed Designated Manufacturing Inspection Representa- tives (DMIRs). The job of assuring that the aircraft meets the design specification rests with the manufacturer's qual- ity control organization. It reviews all aspects of the production process, including the materials, parts, tools, and equipment; the methods of operations and the sequence in which these are performed; in-process and final inspections and tests; and the qualifications and training of all production personnel. Inspections are performed by company employees who are required to verify by formal record that the product meets the established standards. The record signifies that the inspector stands behind the proper performance of the work. Articles are tagged or stamped with marks that identify the individual inspector and ensure that only inspected and accepted items are used in the fin- ished product. For example, suitable "acceptance," "rework," or "rejection" stamps are placed on articles subjected to heat-treatment, welding, riveting, solder- ing, hardness tests, laboratory analysis, and other tests. Responsibility for the continuous review and moni- toring of the quality control system on a daily basis resides with the FAA Principal Inspector assigned to the facility. The inspector supervises the work of and is assisted by a staff of FAA inspectors and the Designated Manufacturing Inspection Representatives. The designees certify on behalf of the FAA that aircraft are consis- tent with the approved design and specifications. FAA inspectors provide surveillance of the entire production
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51/Production and Maintenance and quality control system. They also participate in FAA enforcement actions, a function specifically exclud- ed from the designee's authority. Designees are company employees with many years' experience in manufacturing or special processes and in inspection, all gained with the same firm, generally. They are nominated by the company and approved by the FAA in a manner analogous to the appointment for design review of the Designated Engineering Representatives. Their responsibilities include: (i) the witnessing and verification of tests; (ii) issuance of Aitrworthi- ness Certificates (a certificate that the individual aircraft meets the design specifications of the Type Certificate and has been flown, either by FAA or company test pilots on behalf of the FAA, and has been found in compliance with applicable standards) and export approv- als; and (iii) performance of conformity inspections. In the last instance, they provide a second assurance that the product conforms to its design, not by repeat- ing the work of the company inspector, but by performing an audit of what was done to the product. They also work on behalf of the FAA during type certification to determine whether or not prototype articles conform to design data. Designees accomplish the audit primarily by reviewing the paperwork and process documents. They also make spot checks of the inspections at selected points. Once an error is detected by a designee, he is charged with seeing that it is corrected, but not neces- sarily with reporting the error to the FAA. The FAA inspector is charged with the broader re- sponsibility of ensuring that the entire quality control system is carried out in accordance with the plan sub- mitted to the FAA and approved by its Production Certi- fication Board--a procedure called "Certificate Manage- ment." The FAA inspector's concern extends to the tools or equipment used, the sequence of operations, the training of the individual performing the work, and the steps taken by the company's quality control organiza- tion. The processes that go into producing aircraft have increased in number and complexity over the years. At present, according to company representatives, quality control activities represent approximately 15 percent of the total cost of an aircraft. To verify that the mul- tiple tasks are consistent with established procedures, .
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IMPROVING AIRCRAFT SAFETY/5 2 even oy reviewing the system on a spot check basis, is beyond the daily capabilities of the few FAA inspectors and manufacturing designees who work in production. For instance, early in 1980, the FAA indicated that there were only about 21 inspectors and 36 manufacturing designees working in the production facilities of the three major manufacturers. Most of the FAA staff had other assignments. Accordingly, the routine surveillance of the manu- facturers' production and quality assurance systems by FAA inspectors is augmented by special FAA teams who periodically perform a Quality Assurance Systems Analy- sis Review (QASAR) of the systems. Such in-depth audits involve, primarily, a detailed examination of documents and records. Little specific attention is given to hardware. The committee found the relationship between the FAA principal inspectors and company designees to be one of mutual respect. _ _ _ , ~ _ _ , In comparing the two groups, it con- cluded that the basic minimum requirements for training and inspection experience were similar. Accumulated ex- perience levels are about the same, as are basic salary ranges, although the FAA offers a higher maximum salary to its most senior inspectors.20 al actions only for the FAA. Some differences exist among companies in how the designees are used. At two companies, they are assigned to the quality assurance organization, report to the FAA Principal inspector, and Perform inspections and approv At the third company, the same functions are performed, although some functions in addition to their FAA tasks are required at the direc- tion of their employer. The FAA regional office staffs view the work of the designees as essential and of excellent quality. Simi- larly, each of the companies describes the designee function as necessary to demonstrating compliance with the regulations. The committee is satisfied that FAA manufacturing inspectors relate to their counterparts essentially on a peer basis. The committee also found that the team approach to auditing quality assurance is well conceived, but that the typical intervals between audit visits are too long, often as much as three years. While the manufacturers' quality control systems and the quality of the FAA inspectors appear generally to be
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53/Production and Maintenance good, there have been nevertheless a number of lapses that raise warning flags. Examples are such production failures as the faulty cargo door latch that caused the Turkish Airlines DC-10 accident outside Paris21 and the discovery in the course of an inspection, after the Chicago accident of loose, failed, and missing pylon spar web fasteners on another aircraft.22 Materials used in aircraft production also may present quality problems. In the absence of extremely alert quality control PerSonnel' flaws can enter the manufacturing cycle before they are identified. In connection with the need for alertness, the com- mittee observed that the FAA inspection personnel are tied to their offices too much. It would be more valu- able if inspectors were to establish their presence on the production floor with greater frequency, observing first-hand the manufacturer's fabrication and inspection activities. While recognizing that it is not the FAA's function to inspect and approve specific hardware and operations, as the company inspectors must do, it is the committee's view that an understanding of and judgments about the total process are enhanced by greater famili- arity with the hardware being produced, by observing the manufacturing and inspection operations, and by talking with the individuals performing the work. Considering all of these matters, the committee recommends that the FAA increase its emphasis on quality ossuronoe in aZZ phoses of the production process by in- oreasing the frequency of Quality Assurance Systems Analysis and Review team visits to aZZ Production Certi- ficote holders, and by expanding the responsibilities of FAA inspectors and quality ossuranoe teams to inoZude the observation of aotuaZ hardcore. Maintenance Surveillance Once a new aircraft leaves the manufacturerls plant for use in service by a carrier, the responsibility for maintaining it in compliance with applicable FAA regula- tions devolves upon the airline. At the same time, the day-to-day FAA responsibility shifts from the manufac- turing review staff of the regional office to air carri- er inspectors in the respective district offices, locat- ed near the principal airports of the country.
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IMPROVING A I RCRAFT SAFETY/ 5 4 Prior to operating a particular aircraft in revenue service, the individual air carrier has to develop and submit a maintenance program to its assigned FAA Princi- pal Maintenance Inspector for approval. The program in- cludes a combination of maintenance operations specifi- cations and a manual of instructions for accomplishing maintenance and inspection, as well as a means for their administration. In practice, preparation of the initial maintenance program for a specific type of aircraft is begun early in the design stage. The FAA review is ac- complished during the type and production certification period. An industry committee, called the Maintenance Steering Group (MSG), representing relevant airlines, other operators who expect to purchase the airplane, and the manufacturer, provides advice during its preparation. Once the manufacturer has presented the initial mainte- nance program and manual for approval to the FAA, the document is reviewed in the regional office by a Mainte- nance Review Board (MRB). The Board, an FAA committee of specialists, including engineers and representative maintenance and avionics inspectors, prepares a Mainte- nance Review Board Report to approve the maintenance program. In the normal course of events, each carrier modi- fies the initial maintenance program, subject to review and approval by the FAA's assigned maintenance or avion- ics inspectors, in light of the carrier's particular maintenance practices and the experience gained from maintaining the aircraft in service. The maintenance program is also changed in response to Airworthiness Directives (FAA regulations prescribing mandatory inspec- tion and/or repair), manufacturers' service bulletins, and relevant maintenance reports of other carriers The process of revising both the manufacturer's maintenance manual and the program in actual use by the carriers is one of considerable magnitude. A major car- rier visited by the committee includes in its mainte- nance manual all engineering and maintenance policies, procedures, specifications, and job instructions. Its manual has 200,000 pages, in which some 300,000 pages of revisions--some revised several times--were made during one year.23 It is likely that two airplanes produced one after the other on the same production line will be subject, after a period of use by different carriers, to quite
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55/Production and Maintenance different maintenance operations. The particular route and operation of each airline call for differences in the type and frequency of the work required. Even so, each carrier's program of maintenance bears the approval of the FAA. The FAA's primary means for effecting the surveil- lance of the carriers' maintenance program is the as- signment of Principal Maintenance (and Avionics) Inspec- tors and their staffs at locations adjacent to the car ~ These officials are responsible for assuring that the carriers to which they are assigned maintain the airplanes in compliance with the regulations. They do so primarily by reviewing the airline's maintenance system and checking its mainte- nance job records. Depending upon the workload and in- clination of the respective inspectors, they may review or spot-check actual work done or in progress. This system of surveillance is supported by three back-up activities: (i) FAA inspectors at other airport facilities along the carrier's route perform ramp checks to evaluate the apparent condition and routine servicing of the aircraft; (ii) audit-type inspections, called situation monitorings--analogous to the system of audits performed for manufacturing by quality assurance teams, though not so regular--are conducted in limited cases, especially where the regional office becomes aware of specific safety problems; and, (iii) a formal system for reporting and reviewing accidents, incidents, and ser- vice difficulties. Boeing, Douglas, and Lockheed all have product support departments that play important roles in their respective operations. One has 1,440 product support nersonnel;24 another has an even larger staff. These units monitor the use of their products and provide as- sistance to the owners, no matter how often the equip- ment changes hands, because, as they view it, the per- formance of one aircraft reflects on all others from a manufacturer. Typically, company representatives are assigned to an airline 30 days in advance of the de- livery of a new type of aircraft. They assist the cus- tomer, on request, with engineering and maintenance ad- vice, provide specialized training as the need arises, and, in general, become the carrier's instant point of contact with the manufacturer. The company representa- tives also gather and report home to their companies all racers' principal maintenance bases.
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IMPROVING AI RCRAFT SAFETY/5 6 data on component repair, routine operational data, and other matters of technical significance. Manufacturers regularly issue service bulletins to their customers concerning recommendations related to product improvement or reliability. One kind, called an Alert Service Bulletin, which also is sent routinely by the manufacturer to its FAA regional office, concerns significant problems in which safety is considered an issue. While many airlines may make changes immediately in response to an Alert Service Bulletin, they are not legally required to do so unless the PAA incorporates the bulletin into an Airworthiness Directive (AD). Carriers also are not required to report the completion of work in response to service bulletins to either the FAA or the manufacturer. Service bulletins may or may not be reviewed by the FAA maintenance inspector as part of the examination of the airline's maintenance documents. However, the pro- ject engineer in the regional office often considers the Alert Bulletins for possible issuance of a mandatory Airworthiness Directive. . . . The differences in maintenance organizations and practices lead the FAA, in turn, terpretations of the regulations _ inspectors. The lack of consistency from one office to another is an inevitable and reasonable consequence of the diversity of users' needs and not a shortcoming to be eliminated. There are, however, wide differences in the prac- tices of FAA inspectors, especially the frequency of their direct observation of the aircraft, the level of their maintenance inspection activity, and their general assertiveness. While the regulations make inspectors responsible for approving the maintenance program and any changes in it, the committee sees the system as allowing and even encouraging them to view their res- ponsibility as a passive one. Because of the importance of maintenance to the safe operation of aircraft, the FAA needs to do all it can to encourage its inspectors to be more assertive, and to take full advantage of the opportunities to detect and correct conditions they con- sider to be unacceptable. As in the case of manufac- turing inspectors, the committee found that, while FAA maintenance inspectors now acquire information princi- pally by reviewing documents, it is important that the - to varying local in- bY its air carrier
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57/Production and Maintenance inspectors acquire first-hand familiarity with the carriers' extensive maintenance activities that go on around the clock. One way of enabling inspectors to observe mainte- nance events is to provide them with better tools and knowledge about their work--e.g., access to carriers' service computers and to their own computer systems, more and better training about new aircraft, and annual conferences on matters of wide concern. Periodic tele- phone conferences linking inspectors to each other and to regional project engineers would provide greater understanding of the findings of other inspectors and the possible implications of those findings. FAA inspectors also should be encouraged to observe more strategically, acting, for instance, on the natural "cues" that the system provides. Cues are to be found in Airworthiness Directives, individual aircraft main- tenance records, manufacturers' service bulletins, gov- ernment and industry trend analyses, and statistical data. The manufacturer's issuance of an Alert Service Bulletin, for instance, provides an opportunity for the FAA inspector to gain insights on how the carrier per- ceives a particular safety problem. While there is a clear value to be gained by in- creasing the awareness of the maintenance and avionics inspectors to ongoing maintenance activities, as well as their knowledge of other operations, the total amount of activity and information generated will nonetheless ex- ceed their day-to-day grasp and capabilities. Their reach could be extended by reinstituting the systematic deployment of the FAA's former Systemworthiness Aircraft Program (SWAP) maintenance auditing teams to supplement the work of the assigned inspectors. This program was "reoriented" recently to the less regular "situation monitoring" inspections,25 which are conducted in res- ponse to known problem conditions. With proper preparation, members of the reinstituted teams could provide checks of the carriers' maintenance systems from broadly based experience. They could be specifically prepared to investigate individual areas of concern prompted by analyses of reported problems, and could be in a position to conduct spot reviews of air- craft hardware to assure that Airworthiness Directives are implemented and that other changes are made to safe- guard the condition of the aircraft. By not giving
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IMPROVING AI RCRAFT SAFETY/5 8 advance notification of an audit, the team could obtain a candid picture of the actual circumstances of the op- erator's maintenance program. Such team visits would have an additional advantage of assuring that the per- formance of the resident FAA inspection staff lives up to expectations. Because of the importance of maintenance to the continued airworthiness of the carriers' aircraft, the committee recommends that the FAA inoreose its surveiZ- Zanoe of airline mointenonoe operations, making use of team approach for frequent and unannounced inspections, and encouraging its air carrier inspectors to give high- er priority to strategioaZZy selected on-site visits and hardware observation, both random by during aZZ shifts, and for specific maintenance procedures that they deem espeoiaZZy oritioaZ or important. Licensing of Maintenance Personnel With the exception of the flight crew, no group has a greater effect on aircraft safety than the maintenance workers at the airlines. It stands to reason that the skill levels of mechanics and inspectors should be of high quality and appropriate to the type and complexity of the particular aircraft on which they are working. The FAA certificates aircraft mechanics by awarding Airframe and Powerplant (A&P) licenses after an indivi- dual has passed written tests covering the construction and maintenance of aircraft appropriate to the rating sought.26 The FAA requires that all maintenance work be signed off by an individual holding an appropriate license. Under the present arrangement, an individual obtains such ratings and remains perpetually licensed, irrespective of the extent or kind of subsequent work experience, training, or qualifications. The development of increasingly complex, modern jet transport over the past 30 years has led to rapid chang- es in the level of skills and knowledge necessary to maintain aircraft in airworthy condition. When the con- cept of licensing or certificating U.S. airline mainte- nance personnel was originally developed in the late 1920's, the aircraft and the air transportation system
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59/Production and Maintenance were far simpler. That was a period in which materials and structures were less complex and reciprocating in- ternal combustion engines and simple electric circuits were the most important items affecting airworthiness. The term "avionics," which combines modern aircraft electrical, electronic, navigation and communication systems, had not been coined. Today's maintenance staff is required to bring great competence to aircraft func- tions requiring avionics skills in operation and flight control systems, protection and warning systems, commun- ication and navigation components, instrumentation and cockpit displays, and passenger support and safety equipment. Such maintenance functions require knowledge of complex equipment and circuits, and complex test equipment. However, mechanics dealing with avionics do not have special credentials under the present system. By regulation, responsibility for the adequate training of maintenance personnel lies with the car- rier. It must provide "a training program to ensure that each person who determines the adequacy of work done is fully informed about procedures and techniques and new equipment in use and is competent to perform his duties. 27 In the committee's judgment, the FAA's current licensing and training requirements for airline maintenance personnel are, unhappily, of limited effec- tiveness. There is no stringent standard, comparable, for instance, to that for flight crews, for initially estab- lishing or periodically upgrading the skills of mechan- ics who repair or service commercial aircraft. In 1977, the FAA proposed an amendment to the regulation cited above, observing that "no minimum standard exists today to ensure that airline maintenance personnel have ade- quate initial and recurrent training."28 This is still the case. The change proposed in 1977 (but not yet adopted) addressed only the requirement of certifica- tion and training for supervisory personnel--i.e., the persons who determine the adequacy of work perform- ed.29 At present, there is no regulation that effec- tively prevents an airline from assigning persons with little relevant training and/or qualification to the performance of critical maintenance tasks, as long as someone who is certificated signs off the work. (The committee has made no evaluation to determine if such assignments are actually made in practice.) -
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IMPROVING AIRCRAFT SAFETY/6 2 operation is the ultimate test. Accordingly, it is largely through knowledge gained in operational experi- ence that changes in maintenance procedures, and modifi- cations to design, are made. The manufacturer's experience in analyzing mainten- ance operations and manufacturing changes is not always sought, however, before maintenance programs or designs are modified . While the designer participates directly in the preparation of the initial maintenance program, once the carrier begins to alter it, the FAA does not require that the manufacturer holding the Type Certifi- cate be consulted before changes are made. Further, the FAA personnel or offices responsible for approving such changes are not necessarily those who originally approved the maintenance procedures during the certification of the aircraft. It is possible that some changes or modifications will degrade the safety of the airplane in subtle ways that only the aircraft designer is likely to discern. Aircraft safety may be eroded by unusual procedures for removing and reattaching major components, different aircraft jacking or towing conditions, or changes in liquids and gases used for servicing, purging, or clean- ing. The modification of a fuselage to accommodate a larger cargo loading door could result in changes to load paths and the consequent overloading of another critical part of the fuselage structure. In some cases, the manufacturer will have more detailed knowledge than the carrier about the strength of structures and sensi- tivity to damage of the aircraft and its major compo- nents. A requirement for seeking formal review by the manufacturer, as well as the FAA, of a proposed signifi- cant modification or variation in maintenance procedure could improve the likelihood of early warnings of any dangers. In some cases, particularly as an aircraft puts on many flight hours in operation and major component re- placements are necessary, or as an airplane is modifi- ed, the air carriers purchase parts and assemblies from vendors other than the original manufacturer and either make their own alterations or have the work done at a Designated Alteration Station (DAS), a repair facility whose work procedures have been approved by a regional office of the FAA. In either case, the operator must have received a Supplemental Type Certificate (STC) from
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63/Production and Maintenance the FAA prior to making the change. The application for a certificate is handled by the regional office where the carrier or repair facility is located, which, in most instances, is not the same office that deals with the manufacturer. Just as with variations to the maintenance program, changes can be introduced and even approved by a desig- nee (subject to subsequent FAA approval) in cases where the manufacturer-designer is best able to judge whether or not unacceptable degradation to safety margins might result. In this case, the designee could be a Consul- tant Designated Engineering Representative, and not an experienced employee of the original manufacturer. Because the committee did not examine the matter of consultant designees, it cannot extend its previous favorable recommendation to anyone other than designees employed by an aircraft maker. With such considerations in mind, the committee recommends that the FAA assure that the manufacturer (type Certificate holder) have Continuing knowledge of an operator's mointenonoe procedures by obtaining the monufaoturer's formoZ review prior to authorizing any significant deviation from the approved mointenanoe program. SimiZorZy, it recommends that the FAA assure that the manufacturer be made onshore of on operator's appZioation for a SuppZementaZ Type Certificate by obtaining the monufaot~rer's forma Z review prior to authorizing any significant deviation from the approved design. The committee recognizes that this recommendation introduces the need to define "significant" in a way that will make it clear which items require a review by the manufacturer-designer. Such items should be con- fined strictly to those involving the continuing inte- grity and safety of the design. One way to accomplish this would be to require the Type Certificate holder to identify all structural and functional system items es- sential to safety by marking their location clearly on a diagram associated with the maintenance program. In carrying out this recommendation, the FAA needs to take care that small and/or independent businesses do not unjustly lose contracts as a result of the manufac- turer's review, or that innovative improvements to air- craft are not discouraged. The purpose of the recommen- dation is to assure that safety is maintained by seeking
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IMPROVING AIRCRAFT SAFETY/64 the guidance~of those responsible for the original design, not to provide a power of approval or veto to the manufacturer or imply that only it or a major repair facility is capable of satisfactorily performing the work. Information System The maintenance and operation activities of all air carriers produce vast numbers of reports and service data. Manufacturers, carriers, and the FAA collect, organize, and transmit much of the available data and information via their own systems. These systems, some of which interconnect and overlap, are intended to keep track of what is occurring with respect to the various aircraft, to permit analyses that help identify trends or predict future trouble spots, and, generally, to provide information and advice to carriers and manu- facturers that can be used in future improvements and contributions to safety. In addition to sharing the results of the FAA's formal reporting and disseminating mechanisms, manu- facturers receive information from their customer ser- vice representatives stationed at the airlines as well as from the carriers directly. They scrutinize all such material to identify trends in the use of their equip- ment that may suggest the need for a change in the de- sign, manufacture or recommended maintenance, or that may indicate significant operational occurrences. They communicate their findings to the carriers by a variety of means including regular newsletters and service bulletins. Each carrier is required to have a system for the "continuing analysis and surveillance of the performance and effectiveness" of its maintenance program.30 Specific records are to be maintained and monitored on failures and other significant events. The carriers collect data on maintenance and reliability character- istics from a number of internal information systems-- e.g., unusual flight incident reports, flight log reports of malfunctions, aircraft maintenance infor- mation systems, daily operations reports, flight log monitoring systems pertaining to engine reports, monthly summaries of flight delays and cancellations, monthly premature removal reports, and shop cost records.
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65/Production and Maintenance Many of the larger air carriers keep computerized maintenance records on each of their airplanes. Such records portray the aircraft's complete maintenance history--the date and nature of all work performed and the status of any deferred items, and the planned future maintenance schedule. They also can call special atten- tion to any unanticipated failures. Some airlines con- duct a daily telephone conference with their various repair stations across the country to receive and share information concerning current failures and service dif- ficulties. A few carriers also make sampling inspection techniques a part of their maintenance programs to ensure the monitoring of the aging process in their equipment. The airlines must submit daily Mechanical Relia- bility Reports (MRR) to their assigned FAA maintenance inspectors concerning the occurrence of 16 specified types of aircraft failure, malfunction, or defect. Thirteen of these involve events occurring in flight-- defined as "the period from the moment the aircraft leaves the surface of the earth on takeoff until it touches down on landing,"31 and widely interpreted to exclude from the reporting requirements any incident oc- curring while the plane is taxiing or otherwise on the ground, including during maintenance. Carriers also are required to submit Mechanical Interruption Summaries (MIS), listing the causes of all mechanical difficulties that result in the delay or can- cellation of a flight.32 These are submitted approxi- mately every 10 days and are reviewed for any unusual trends by the Principal Maintenance Inspector. All "major" alterations must be reported as well.* FAA inspectors convert some of the information ac- quired to Service Difficulty Reports (SDRs) and forward these to the FAA Maintenance Analysis Center in Oklahoma City. The center incorporates them into its data bank together with all other reports it receives. The data are analyzed to help identify problems and trends in various categories of aircraft, components, and assem- blies. The staff at the center examines the information *The distinction between "major" and "minor" damage is discussed on pages 68-69.
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IMPROVING AIRCRAFT SAFETY/66 and sends it on to the regional offices and to manufac- turing inspectors. The FAA also receives the National Transportation Safety Board's aircraft accident reports and the reports of special studies that the board conducts on recurrent problems or trends noted from its knowledge of accidents and incidents. Additionally, the FAA can request speci- al computer runs of the Safety Board's accident data bank to identify problems and failure trends in aircraft. The information-gathering mechanisms presently used by the FAA are a collection of individual systems that have come into being at different times in response to the identification of particular problems. In the past, the Congress and the General Accounting Office33 have found that the FAA's data base and communications system are inadequate both in scope and practice for the modern aviation system. The individual systems have little or no common basis for cross-correlation of information. Consequently, information in these data systems is often not available in timely fashion, not able to be cross- referenced, and not presented in a format that can be easily used. Recognizing this problem, the FAA has requested the Department of Transportation's Transportation Systems Center in Cambridge, Massachusetts, to develop a modern, comprehensive information and data-processing system. The committee was pleased to learn of this plan; how- ever, we view the five years contemplated for its devel- opment, testing, and implementation to be excessive. Hence, the committee recommends that the FAA aooeZerate its deveZopment of on effective info~mation-gathering and data system. This system shouZd include assess to the appropriate eZements of the monufaoturers' and worriers' records. A properly employed information system is indispens- able to providing clues to, and early warning of, poten- tial accidents. Critical to the effectiveness of such a system are the following elements: . . Information should be gathered and processed quickly, and the system should be capable of highlighting those items having possible consequences for safety. Additional information, beyond what is now available, should be obtained, wherever possible. The FAA needs to devote more
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67/Production and Maintenance attention to the safety information passing between and among the airlines and manufac- turers that is now largely outside its purview. The manufacturers should draft service bulle- tins so as to provide the carriers with more complete descriptions of the events or conse- quences that the bulletins are intended to pre- vent. By the same token, the carriers should provide more details to the manufacturer identi- fying the circumstances that led carriers to request maintenance or alteration assistance. Analysis of the data should be made by well- qualified users. The users of the system must be disciplined to determine the cause of every incident, fail- ure, or accident, to require that corrective action be taken, and to provide feedback to all concerned parties. An example of a potentially effective information system is the experimental Aviation Safety Reporting System (ASRS), a project developed at the request of the FAA by NASA. The committee was impressed, from the briefing it received from NhSA, that this project is already making a major contribution to safety, largely because of the painstaking and detailed analysis of the data that NASA is providing. Since 1975, NASA has developed and operated the safety reporting system, which permits confidential reporting of safety problems and violations of pro- cedures within the aviation system, including infor- mation on human error. Anyone is permitted to file a confidential report of observed or experienced safety problems but, to date, pilots and air traffic control- lers have been the principal reporting sources. In all, more than 22,000 incidents have been reported. NASA has published quarterly reports containing both the statis- tical grouping of items and analyses of the more signif- icant ones. In addition, special studies are conducted at the request of the FAA or other parties. An adequate statistical base now permits some trend studies to be undertaken. Importantly, in the NASA system, no single report is regarded as trivial. Indeed, some seemingly trivial but recurring items have turned out to be far from trivial.
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IMPROVING AI RCRAFT SAFETY/68 Examples of such problems, subsequently corrected, in- clude ambiguous and hard-to-read approach chart infor- mation for high density major airports, and taxiway/ runway near misses. The system also reveals altitude assignment violations and ambiguous or contradictory controller instructions. Information of this kind--largely subjective and anecdotal--is valuable and not available in the data systems operated by the FAA. It should be included in the proposed new data system. Although mechanics and other ground personnel have not made use of the NASA system so far, and there are some distinguishing or identifying features in the data that would be submit- ted that would make the confidentiality of such sources difficult to preserve, the committee urges that the system be extended to the reporting of maintenance errors related to airworthiness concerns. Damage to Primary Structure The efficacy of the FAA's information and data system depends in large part on its dependability for reporting damage to the aircraft structure and associ- ated repairs. Under Present regulations and Guidelines. damage to aircraft structure is reported in different ways depending on: the consequence of the occurrence, where it occurred (flight or ground), what structure was involved, the repair involved, interpretations of degree of damage (e.g., significant or not significant), inter- pretations of the type of repair (e.g., major or minor), and, to a degree, a combination of these matters. Depending on the descriptor, the requirements for reporting and approval vary widely, thus increasing the possibility that the FAA and the industry may fail to identify an unsafe condition. An example of the con- fusion existing in the present system involves the dis- tinction between major and minor repairs. "Major" is generally understood to refer to primary structure, i.e., the principal load-carrying members, such as the main wing beams. FAA regulations, however, are ambigu- ous in distinguishing major and minor. The regulations call for reporting the condition of the aircraft's structure. The procedure for preparing and submitting Alteration Reports and Repair Reports ~ ~ ~ ~ - ~:7 ~, ~_ i, ` a,
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69/Production and Maintenance requires that: "Each certificate holder shall, promptly, upon its completion, prepare a report of each major al- teration or major repair of an airframe, aircraft en- gine, propeller, or appliance of an aircraft operated by it."34 Copies of reports concerning major alterations are to be submitted to the FAA representative, while copies of reports about major repairs are to be kept available for inspection by the same representative.35 In another part of the regulations, the terms "major repair" and "minor repair" are defined as follows: "Major repair means a repair: "1. That, if improperly done, might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight charac- teristics, or other qualities affecting airworthiness; or "2. That is not done according to ac- cepted practices or cannot be done by elementary operations. "Minor repair means a repair other than a major repair.~36 In yet another place in major repairs are defined as "strengthening, reinforcing, the regulations, airframe those involving the splicing, and manufac- tur~ng ot primary structural members or their replace- ment, when replacement is by fabrication such as rivet- ing or welding."37 The application of these definitions requires con- siderable interpretation by many individuals of variable experience to determine whether or not to initiate a re- pair report and thus enter the condition into the FAA's information system. Such judgments, concerning whether a major repair is reportable, and if so to whom, include where the damage has occurred on the aircraft and, in the case of structural damage, whether the aircraft was in flight, or on the ground with engines operating. It appears to the committee that some important occurrences of structural damages may not be--indeed are not likely to be--promptly and effectively reported and reviewed by the FAA. For instance, the damage to the aft pylon bulkhead, caused by a faulty maintenance pro- cedure by Continental Airlines prior to the American ..
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IMPRoVING AIRCRAFT SAFETY/70 Airlines Chicago accident,* involved damage to a load- carrying structure, but apparently was not a candidate for reporting. According to the FAA Western Region, the existing reporting system does not call for reporting nonservice-related occurrences; therefore, the pylon damage did not have to be reported. Arguably, if it had been clear to Continental that such damage should have been reported, the subsequent American Airlines acci- dent might have been prevented. It is obvious that these confusing requirements for reporting accidents, incidents, occurrences, and repairs of structural damage or deterioration need to be revised to provide a clearer and more direct decision process concerning what, when, and where to report. According- ly, the committee recommends that the FAA require that any damage to the primary structure of on aircraft, re- gordZess of box the damage was caused, be reported. This recommendation requires a commonly accepted de- finition of primary structures, which are the principal load-carrying members, as known by the designer. Iden- tification of primary structures by maintenance personnel would be made easier by requiring the manufacturer to include sketches of the aircraft structural skeleton, which are normally produced during the aircraft design stage, in the maintenance manual. should be clearly marked. *See Appendix B. Primary structures
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Representative terms from entire chapter: