Par 1006 Page 39 (and 40) immediate knowledge or skill deficiency and the training may focus on one individual or a small group. You may include competency-based training in your initial or recurrent training requirements.
b. For those circumstances where you identify a competency deficiency through investigation of an event, your competency-based training should show an individual what happened, why it happened, and demonstrate, in a positive manner, how to prevent it from happening again.
c. Your competency improvement training should be oriented toward correcting personnel competence deficiencies that may be identified through your CASS.
Par 1100 Page 41 CHAPTER 11. CONTINUING ANALYSIS AND SURVEILLANCE SYSTEM (CASS) 1100. BACKGROUND OF THE CASS. Introduction of the CASS requirement resulted from an FAA-industry study of a series of maintenance-related air carrier accidents occurring during the 1950s. The study found that, in many cases, the primary causal factor of an accident was a fundamental weakness or weaknesses in the maintenance program. The study found that in some cases maintenance personnel failed to accomplish required maintenance tasks or failed to accomplish the task correctly. They simply didn’t follow the manual. In other cases, the study found that the maintenance program, even when followed as planned and documented, was not effective in preventing the situation that led to the accident. It did not produce the desired results.
a. Responding to this finding, the FAA introduced regulations (§§ 121.373 and 135.431) that require air carriers to establish and maintain a system for the continuing analysis and surveillance of the performance and effectiveness of their inspection, maintenance, preventive maintenance, and alterations programs.
b. These regulations further require that the air carrier’s CASS provide a process to correct any deficiency identified in those programs, regardless of whether the work was accomplished directly by the air carrier or by other persons.
1101. CASS IS A SAFETY MANAGEMENT TOOL. A CASS is your system for managing safety as it relates to maintenance functions. As a safety management tool, it is part of the overall structure of policies and procedures that you use to ensure operations are to the highest degree of safety. It is a structured, methodical process that helps you reach your maintenance program objectives. CASS is the only management system currently mandated by regulation. If you use it properly, your CASS becomes an inherent way of doing business for you, and helps you promote a culture of safety in your company by providing a formal process for employees to identify and correct safety discrepancies. As you will see in the following brief discussion of the structure of a CASS, the same objectives of measuring and continuously improving the performance (program execution) and effectiveness (program results) of a major function (maintenance) apply equally to all safety-related functions that must be managed by an air carrier.
1102. BASIC CASS PROCESSES.
a. Your CASS is a risk-based, closed-loop system that has four basic processes:
(1) Surveillance. An information gathering/audit process you use to collect data to measure your program execution and measure your program results.
(2) Analysis. An analysis process you use to identify any maintenance program deficiencies and any necessary corrective actions.
(3) Corrective Action. A planning process you use to ensure that your corrective actions and implementation steps are well-defined.
(4) Followup. A followup, performance measurement process you use to verify that your corrective actions are performed and are effective. This is also an information-gathering and analysis process, thereby, closing the loop.
Page 42 Par 1102
b. During the first step, surveillance, you will gather and obtain data using an audit program to support measurement of performance (program execution). Your audit program should be well-structured, based on risk assessment, and accomplished by individuals trained and skilled specifically at auditing. Consistent with the wording of the regulation, your primary type of audit should be work-in-progress audits that evaluate if the worker is following the manual.
Your auditors would also look at areas such as manuals and other maintenance technical data, aircraft condition, actual in-process maintenance practices, training, publications, and ground operations. In addition, information gathering to obtain data that will support the measurement of effectiveness (program results) is generally a collection of flight operational data such as accidents/incidents, mechanical delays and cancellations, in-flight engine shutdowns, unscheduled landings, engine performance, pilot log book write-ups, and unconfirmed components or parts removals.
c. In the second step, you will analyze the data to identify indications of maintenance program weaknesses. Your analysis should be accomplished by individuals experienced and/or trained as analysts. One of your key objectives here is to not only identify a weakness, but to determine its root cause. This is where your knowledge of human factors becomes critical.
d. Based on the results of your analysis, the third step is for you to develop a corrective action, if necessary, again taking into account human factors so that your corrective action is likely to be successful. Once you determine what the corrective action is, you will develop and implement a corrective action plan.
e. To close the loop, the fourth step of your CASS will have you conduct a followup measurement process using surveillance and analysis to verify that your corrective action was implemented properly and completely and that it has effectively corrected the deficiency you identified. You can design this followup data gathering process specifically for the issue of interest, or you can make it a part of your continuing surveillance that is the first step of your CASS. Determining if a special information gathering is needed is part of your analysis that you accomplished in step three.
f. Note that both the initial and followup surveillance can and should have proactive and reactive aspects to them. In the case of audits, by auditing systems and procedures, as well as specific transactions, the analysis of audit results can identify weaknesses in a process.
Correcting these weaknesses before a problem results is a proactive approach. An audit also may uncover a missed or improper maintenance action. Investigating this finding and correcting the immediate problem is a reactive process. Developing and implementing a corrective action to prevent a similar future event is equally important for improving the maintenance program, and it is required by the regulations. Similarly, your analysis of operational performance data from a systems point of view can result in identification of a system’s weakness before a specific unwanted event, such as a cancellation, occurs, which is a proactive process. Investigating and correcting an undesirable operational event related to the maintenance program after it has occurred, though reactive, also is a necessary and desirable procedure.
1103. RISK-BASED DECISIONS. All effective CASS take into account the need to manage risk to an acceptable level, as well as the practical limitations that must be faced when addressing deficiencies. Consequently, you must set priorities and make choices for planning audits and
Par 1103 Page 43 other information gathering activities, analyzing data, and selecting and implementing corrective actions. You should tie setting such priorities directly to a risk assessment process, so the resulting maintenance program achieves its objectives.
1104. SCOPE OF CASS. CASS monitors all 10 elements of your maintenance program:
• Airworthiness responsibility,
• Air carrier maintenance manual,
• Air carrier maintenance organization,
• Accomplishment and approval of maintenance and alterations,
• Maintenance schedule,
• RII,
• Maintenance recordkeeping system,
• Contract maintenance,
• Personnel training, and
• CASS.
1105. CASS DESIGN PRINCIPLES.
a. The following are attributes of system safety:
(1) Clear authority,
(2) Clear responsibility,
(3) Specific written procedures,
(4) Effective controls,
(5) Performance measures, and
(6) Well-defined interfaces.
b. These six system safety attributes should be the starting point for the design of your CASS. It should be clear who in your organization is responsible for and who has authority over the CASS. You should not divide responsibility/ authority into two or more parts due to the likely possibility that activity such as auditing and operations data analysis are poorly coordinated. Typically, in addition to an individual with overall CASS responsibility, you should have a management board or committee to ensure good communications and coordination of all
Page 44 Par 1105 CASS functions and to maintain regular senior level management involvement. This oversight group also can provide a form of control over critical aspects of your CASS operation and measure the performance and effectiveness of the CASS itself.
c. In addition to the many elements within your maintenance organization, there are many interfaces between the CASS and functions or organizational elements of a typical air carrier that are outside maintenance. Some of the more obvious examples are engineering, flight operations, purchasing, safety, and the FAA. It also is important to ensure the CASS relationships to your other programs (if they exist) such as internal evaluation programs, Flight Operations Quality Assurance programs, voluntary disclosures, and Aviation Safety Action Programs, are welldefined and coordinated 1106. CASS PERSONNEL REQUIREMENTS.
a. An effective CASS requires certain skills that may not be readily available within a maintenance organization. For example, auditing skills are not automatically inherent in those skilled in maintenance. Analysis capability, particularly related to root cause determination, risk analysis, and consideration of human factors is specialized and generally requires specific training and experience.
b. For all operators, but particularly for the smaller ones, required personnel can be shared, functions can be performed part-time, and some functions can be accomplished under contract.
However, it is essential that you recognize the need for knowledge and skills that do not necessarily coincide with those resulting from many years of maintenance experience repairing airplanes.
NOTE: You can find more detailed information concerning developing and implementing a CASS in AC 120-79, Developing and Implementing a Continuing Analysis and Surveillance System.
Par 1200 Page 45 CHAPTER 12. ADMINISTRATIVE 1200. REGULATORY REFERENCES. The regulations that underlie this AC are found in 14 CFR. A summary of specific regulatory sections follows:
a. Scope of Regulatory Applicability, §§ 119.1(c), 121.1(b), 135.1(a)(2);
b. Air Carriers’ Responsibility for Airworthiness, and for Performing Maintenance, §§ 121.363 and 135.413;
c. Air Carrier Maintenance Programs, §§ 119.5, 119.49, 121.133, 121.367, or 135.21;
d. Maintenance Program Manual, §§ 121.133, 121.137, 121.367, 121.369, 135.21, and
135.427;
e. Maintenance Organization, §§ 119.65, 119.67, 119.69, 119.71, 121.365, and 135.423;
f. Maintenance Time Limitations, §§ 119.49, 121.135, and 135.23;
g. Performance and Approval of Maintenance and Alterations, §§ 119.1(c), 121.1(b),
121.379, 135.1(a)(2), and 135.437;
h. Performance and Approval of Maintenance and Alterations Performed by Other Persons, §§ 119.1(c), 121.1(b), 121.379, 135.1(a)(2), and 135.437;
i. Continuing Analysis and Surveillance System, §§ 121.373 and 135.431;
j. Personnel Training, §§ 121.367(c), 121.375 and 135.433;
k. Maintenance Recordkeeping and Reports, part 121, subpart V; §§ 121.369, 121.380;
135.415, 135.417, 135.427, and 135.439(b);
l. Maintenance Log, §§ 121.563, 121.701, 121.709, and 135.65;
m. Service Difficulty Reports, §§ 121.703 and 135.415;
n. Required Inspection Items, §§ 121.365, 121.369, 121.371, 135.427, and 135.429;
o. Mechanical Interruption Reports, 14 CFR §§ 121.705 and 135.417; and
p. Alteration and Repair Reports, §§ 43.9(b), 121.707, and 135.439(a)(2)(vi).
1201. OTHER RELATED LEGAL AND GUIDANCE MATERIAL. For more information, consult current editions:
a. 14 CFR parts 43, 91, 119, 121, and 135;
b. 49 U.S.C. § 46310, Reporting and Recordkeeping Violations;
Page 46 Par 1201
c. AC 120-79, Developing and Implementing a Continuing Analysis and Surveillance System;
d. FAA Order 8900.1, Flight Standards Information Management System (FSIMS);
e. Air Transport Association (ATA) MSG–3, Operator/Manufacturer Scheduled Maintenance Development; and
f. Report number AD-A066-579, Reliability-Centered Maintenance.
1202. OBTAINING REFERENCE MATERIAL.
a. You can get the CFRs and those ACs for which there is a fee from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402. You can access current regulations online at http://www.access.gpo.gov/ecfr/. You can access the United States Code online at http://www.gpoaccess.gov/uscode/index.html.
b. You can be placed on FAA’s mailing list for free ACs by contacting the U.S.
Department of Transportation, SVC-121.21, Washington, DC 20590.
c. You can request free ACs from the U.S. Department of Transportation Subsequent Distribution Office, SVC-121.23, Ardmore East Business Center, 3341 Q 75th Avenue, Landover, MD 20785.
d. You can request MSG–3 information from the Air Transport Association of America;
1301 Pennsylvania Ave., NW, Suite 1100, Washington, D.C. 20004. You can also contact ATA online at http://www.airlines.org/products/pubs/.
e. You can get Report Number AD-A066-579, Reliability-Centered Maintenance, from the U.S. Department of Commerce, National Technical Information Service, Springfield, VA, 22161. http://www.ntis.gov/ Sales Desk: 1-800-553-6847 or 703-605-6000, 8 a.m.-6 p.m.;
EST, Mon-Fri.