Industry Viewpoint: Is CASS Telling Us What We Need to Know?

Evaluating maintenance programs

Since the early 1960s, all air carriers have been required by the Federal Aviation Regulations (FARs) to conduct continuous evaluations of their maintenance programs. These evaluations form the basis for the Continuous Analysis and Surveillance System (CASS). Air carriers are required by the FARs to maintain CASS programs which are a structured process to analyze the performance and effectiveness of their inspection, maintenance, preventive maintenance and alteration programs and to find and correct deficiencies in those programs. The phenomenally low air carrier accident rate is a testament to the general effectiveness of these programs to spot and correct problems.

CASS programs at most airlines do a good job of ensuring that the manuals are available and up-to-date, that inspection programs are adequate and that, in general, the process for controlling and performing maintenance and inspections is appropriate. Process is of critical importance in maintenance and CASS programs are generally good at ensuring that an air carrier’s processes and procedures are complied with.

While the success of CASS programs over the years has been undeniable, a troubling series of recent news reports from Texas have underscored potential deficiencies in the programs. Recent investigative news reports have described unqualified maintenance personnel performing maintenance at repair stations in the United States used by multiple major airlines. These reports are troubling for a number of reasons but they may highlight a problem with air carrier CASS programs. Were the airlines using these repair stations aware of the reported lack of qualifications of these workers, including their reported lack of proficiency in English? Should CASS have been able to ferret out what some inquisitive reporters were able to find?


The present CASS systems’ emphasis is based on sampling process and paperwork may not be adequate to test the actual qualifications of employees, and may not always assess whether repair station employees performing specific maintenance tasks are actually capable of performing those tasks properly.

CASS was developed at a time when most airline maintenance was performed by the airlines themselves using certificated mechanics. Now, more and more maintenance is outsourced to repair stations that frequently use uncertificated mechanics working under the supervision of certificated mechanics. While this is perfectly legal under the FARs, the use of uncertificated workers means that their actual qualifications to perform an airline’s maintenance needs to be evaluated in a structured and ongoing manner by both the repair station employer and the airline customer.

CASS programs today are not generally set up to do those detailed evaluations of a repair station’s hiring practices. But they could be. Several years ago, a major airline performed a special audit — separate and apart from its CASS program, although using CASS auditors — of its outsourced maintenance providers to determine the qualifications of employees performing maintenance functions. It found that a number of people were not in fact qualified to do the work they were assigned. The air carrier immediately instituted a special emphasis program to ensure that everyone who worked on their aircraft was properly qualified. While this airline chose not to include this audit as part of its CASS program, I believe it could and should be.

Afterall, there is nothing more critical to the performance of maintenance than the qualifications of those who do the work.

John Goglia has 40 years experience in the aviation industry. He was the first NTSB board member to hold an FAA aircraft mechanic's certificate. He can be reached at

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