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Management Matters: Continuing Analysis and Surveillance System

CASS is the acronym for continuing analysis and surveillance system; its primary role is to help air carriers put an airworthy aircraft on the gate each and every time. Like the safety management system (SMS), CASS uses a systems approach – it is a system, not a program.

Today, there is a “new” CASS, however, the initial regulation has not changed. The “new” CASS can help air carriers realize a positive return on investment (ROI) from the maintenance dollars spent.

The reader might ask: Why worry about the “new” CASS if the actual rule of CASS has not been changed? First, as noted above, an effective CASS can provide a positive ROI. Second, for the last five plus years, more than 1,000 FAA aviation safety inspectors have been trained in the new CASS. CASS training is planned to continue until all ASIs have been exposed to the “new” CASS. The FAA’s expectation of what CASS should look like and do has changed.  It is natural to expect that some air carrier’s CASS might need revision.

The rule of CASS was created in 1964 and is mandated by the FAA for Part 121 and Part 135 (10 seats or more) air carriers. The legal basis for CASS is the regulation: 14 CFR §§ 121.373 or 135.431. CASS is a three paragraph regulation and paragraph (a) is explicit to air carriers: “(a) Each certificate holder shall establish and maintain a system for the continuing analysis and surveillance of the performance and effectiveness of its inspection program and the program covering other maintenance, preventive maintenance, and alterations and for the correction of any deficiency in those programs, regardless of whether those programs are carried out by the certificate holder or by another person.”

Most Part 121 and Part 135 (10 seats or more) air carriers have convinced themselves and their FAA inspector(s) that they are in compliance to the CASS regulation. Because there had been no clear picture of what a CASS should look like, few questioned the issue of compliance. Figure 1 reflects how some air carriers feel they are addressing the requirements of a CASS. The air carrier’s quality group accomplishes audits, both internal and external (the surveillance side of CASS) and the reliability group accomplish data collection and analysis (the analysis side of CASS).

In the last decade the picture of CASS has changed. The FAA issued two Advisory Circulars:

  • AC 120-16 (Air Carrier Maintenance Programs, Rev. D on 03/20/2003 and Rev. E on 09/11/2008), and
  • AC 120-79 (Developing and Implementing a Continuing Analysis and Surveillance System (Original on 04/21/2003 and Rev. A on 09/07/2010). 

AC 120-16 (as revised) explains what a maintenance program is. For some people, this is quite a new definition. In essence, there are 10 elements that comprise an air carrier’s maintenance program. Some of those elements are the maintenance schedule, records, training, the manual, RII, and CASS.

AC 120-79 (as revised) advises that CASS is responsible for looking over an air carrier’s entire maintenance program (as defined by AC 120-16), not just the traditional operational data and audits. Examples of other items under the “new” CASS umbrella would include all 10 elements of the maintenance program, daily briefings, voluntary self-disclosures, pilot write-ups, non-routine write-ups, SDRs, and human factors. Figure 2 more closely resembles what can be covered by an air carrier’s “new” CASS.

Within the new guidance material for CASS, four major activities are identified that are inherent to any CASS, regardless the size, culture, or complexity of the air carrier. Those four major activities are surveillance, analysis of data, corrective action (when applicable), and follow-up (to corrective action). Most air carriers do the first three activities well. Very few air carriers accomplish the fourth activity well if at all, i.e., follow-up to determine if the corrective action(s) implemented are providing the desired/expected results. Figure 3 reflects the four major activities of a CASS.

A key expectation related in the new CASS guidance Advisory Circular is that air carriers will periodically report status on each of the 10 elements of the air carrier’s maintenance program.  This means not just meeting and talking about delay and cancellations, air turn backs, the number of pilot reports, or nonroutine write-ups generated during a planned maintenance visit.  Maintenance training should be reported on and discussed – is the training being provided, effective; how is effectiveness being measured? Is the air carrier’s tool and test equipment program working as designed, what is being discovered when quality assurance does its audits?  Are the air carrier’s manuals up-to-date, if not, why not? What are the hurdles and what is being done to remove those hurdles? Who is responsible? All 10 elements of the maintenance program do not necessarily have to be reported on every month, but all 10 elements (their status, their health, the successes, and failures) should be accounted for throughout the year.

Deficiencies in the maintenance program, their corrective actions and follow-up plans should be inherent to each CASS board or senior leadership team meeting.

Some indications that an air carrier’s CASS might need some attention are: Is the air carrier’s reliability program (FAA approved or not) subservient to CASS? If not, it should be. Does the air carrier have periodic CASS board meetings or reliability board meetings? Does the air carrier have a CASS manager and/or CASS director, or does it have a reliability manager and/or director?  CASS is mandated; reliability programs are not. Is the air carrier accomplishing genuine root cause analysis, which includes human factor considerations, or is a “Band-aid” approach to corrective actions being used? When corrective actions are implemented, do they have follow-up plans to determine if the corrective actions were effective?

CASS has been around since 1964 and SMS, as a rule, is within sight. Both CASS and SMS have some common traits. For example, CASS is expected to reflect the size and complexity of each air carrier, there is not one CASS model that is good for all. The same goes for SMS, each SMS will be designed to reflect the air carrier’s size, culture, and complexity. CASS was created to help enhance safety; the same can be said for SMS. If air carriers take a close look at what an effective CASS should be and make it so, it is not inconceivable that their “new” CASS could serve as a primary maintenance feed to the overall organization’s SMS. This is another good reason for an air carrier to have an effective CASS – when SMS becomes law, many air carriers’ maintenance organizations may be able to achieve compliance using their CASS as the foundation.

The CASS regulation mandates continuous surveillance and measurement of both performance (is the air carrier doing things right?) and effectiveness (is the air carrier doing the right things?). Determination of performance and effectiveness for each of the 10 elements that comprise the maintenance program can help the air carrier realize a positive ROI from its CASS.

Lastly, it should noted that while CASS is mandated for certain U.S. air carriers, any organization can benefit from an effective CASS. Guidance provided in Advisory Circular 120-79 (as revised) can be used to help develop a very effective and beneficial business plan. Not only will it provide a higher awareness to safety, but it will also provide a more effective means to manage the organization’s economics.

Dave Nakata is vice president, Consulting Services for EmpowerMX. He has been with EmpowerMX since 2002; prior to that he was with two major U.S. air carriers for a total of 35 years. The FAA recognized Nakata as a CASS subject matter expert; he was selected to help train FAA ASIs in CASS, maintenance programs, reliability programs, and MSG-3. EmpowerMX (www.EmpowerMX.com) provides aircraft maintenance software and maintenance/engineering consulting services to the air transport industry. You can contact Nakata at dave.nakata@empowermx.com or (612) 239-6671.