For nearly six decades, the FAA has required all air carriers to conduct continuous evaluations of their maintenance programs. Specifically, regulations require air carriers and commercial operators—both Part 121 and 135 (for aircraft with more than 10 passenger seats)—to establish a continuing analysis and surveillance system (CASS) to monitor, analyze, and optimize the performance and effectiveness of their maintenance and inspection programs.
The regulations (CFR 14 121.373 and 135.431) that define CASS are performance-based. According to FAA AC 120-79A, a performance-based regulation is a regulatory approach that focuses on measurable outcomes, rather than prescriptive processes, techniques, or procedures. This perspective leads to defined results without a specific direction or instruction in the regulation regarding how to obtain those results.
CASS is an element of a continuous airworthiness program (CAP). The FAA introduced CAP in 1964 as a response to safety concerns and “discoveries of weaknesses” in air carrier maintenance programs revealed during accident investigations and FAA surveillance. A goal of CASS is to establish the highest possible degree of safety through data collection, corrective actions, and follow-up.
As defined, CASS is a quality assurance system and must consist of the following functions: surveillance, controls, analysis, corrective action, and follow-up. Combined, these functions create a closed-loop system to manage risk in aircraft maintenance much like a safety management system (SMS).
Established using performance-based regulations, a CASS is scalable and provides flexibility to meet the needs of different air carriers or commercial operators. As an example, a large Part 121 airline with more than 500 aircraft may leverage many different resources across its entire enterprise, whereas a smaller Part 135 charter operator with only 20 aircraft may adopt a simpler model that effectively accomplishes the same tasks.
CASS, as a quality assurance program, has demonstrated that it not only improves safety but can make a meaningful contribution to improving operational efficiencies; thus Part 91 or 125 operators may also benefit from CASS implementation.
Managing a mix of safety programs for both maintenance and flight operations for the business aviation operator can be a daunting task. Many of these safety systems and programs—all designed to improve safety by reducing risk—operate independently of each other with different software tools and workflows with little opportunity for “cross-talk” or overall system improvement.
Breaking down Silos
Recently, Wyvern, the Nashua, New Hampshire-based aviation safety and risk management specialist, added a robust CASS module to its Quality and Safety Management (QSMS) software. Wyvern CEO Sonnie Bates understands the importance of integrating CASS within an SMS. “The FAA requires Part 121 and Part 135 operators with aircraft that have 10 or more passenger seats to implement a CASS. Through CASS, the operator is expected to identify aircraft technical issues, monitor and track those issues while looking for trends, and then apply mitigation strategies to correct the problems. They are also expected to follow up to make sure these corrective actions are effective. This is essentially what SMS does, but in a broader sense, capturing safety issues related to any aviation-related activity,” Bates said. “By integrating CASS and SMS, efficiencies are realized, complexity is reduced, simplicity increased, and workload optimized.”
The CASS module within Wyvern’s QSMS software is feature rich and was tailor-made to meet specific client needs. Alec Blume, Wyvern's assistant v-p of risk management systems, is the architect of the new CASS module. “Like all QSMS functionality, the CASS feature was developed and grown organically, in response to the real-world needs of our busy clientele,” Blume said. “This feature, like all others, continues to evolve in unison with our operators’ systems.”
Blume further explained that by design, the CASS module functionally supports all elements of a CASS. “The methodologies that comprise QSMS workflows are perfectly suited to fulfill the requirements and expectations associated with CASS given that the same basic functional loop is being employed—surveillance, analysis, correction, and follow-up. It is the same idea.”
Wyvern’s QSMS software is comprised of two portals: an administrative portal and a user portal. The user portal is available on mobile devices and is designed to promote employee reporting and risk assessments by frontline employees. The admin portal is used to support administrative functions, such as analysis, assessments, remediation, follow-up processes, and reporting. Reporting features can be exported to both internal and external stakeholders (such as vendors or FAA). The system utilizes multiple dashboards to visually present information to stakeholders.
QSMS/CASS in action
To better understand the workflow of the CASS module and the integration within the QSMS software we’ll review a typical aircraft maintenance activity at a business aviation flight department.
In this example, a large business aircraft during its initial descent experienced a “generator fault.” The crew performed the QRH procedure that directed the crew to reset (OFF then ON) the affected generator. The crew was unable to reset the generator, so per the QRH they disconnected the integrated drive generator (IDG) and started the APU (for a second source of electrical power).
After landing, with the aircraft secured, the pilot entered the maintenance item in the post-flight briefing workflow within the QSMS/CASS software. The maintenance write-up was then emailed instantly to maintenance personnel (a maintenance controller in this case) and the IDG was deferred per the MEL (tagged by ATA code) with operations procedures, operational limitations, and maintenance procedures assigned to that aircraft. This deferral was now a permanent record within CASS.
Of importance, for this operator, the FAA allows the flight crew to use the QSMS software (in lieu of a paper aircraft maintenance logbook) and maintenance control interacts with the actual logbook. This is a huge benefit since maintenance now has a consistent, standardized, and legible record. Plus, this removes a step in the workflow where a technician or clerk would have to transcribe the write-up into a digital format.
Prior to the next flight, the flight crew completed a pre-flight flight risk assessment, and the MEL information automatically populated with any restrictions that may have affected that flight. In this case, the operational limitation required the APU to be operated continuously, which increased the fuel burn and limited the maximum allowable cruise altitude. The flight crew then coordinated with its dispatcher for additional fuel to compensate for the flight at a lower altitude and APU fuel burn.
Through the CASS surveillance process, an analyst discovered an increase in unscheduled maintenance items on this aircraft type. Further investigation, using the QSMS software (using an ATA code/registration number search) revealed an increase in IDG failures. The analyst then worked with the quality assurance department and determined that these IDGs were overhauled by the same vendor. The vendor determined that the wrong oil seal was used on the IDG during the overhaul process—a corrective action was taken—and the operator continued to monitor IDG reliability as a follow-on activity.
The value, in this case, was that using one software platform—the Wyvern QSMS/CASS module— the operator was able to provide useful information across its entire safety enterprise to include flight ops, maintenance, and quality assurance personnel to reduce risk, improve efficiencies, and potentially save money.
Wyvern’s Blume added, “Our aim is always to provide intuitive, useful functionality to maximize the safety professional’s time and effectiveness. By integrating SMS and CASS—utilizing common tools and techniques for both—we benefit from streamlined workflows as well as provide for the normalizing of data across features, which translates to efficiently and accurately arriving at actionable conclusions.”
A feature of the QSMS software is the risk management module (RMM) that allows an operator to determine root cause and practice “what if” planning scenarios to reduce operational risk. Blume said, “The RMM component at the heart of QSMS provides for a standardized workflow no matter where the risk is detected. The integrated Risk Visualization Tool allows the aviation professional to construct a graphical chain of events, facilitating determination of root cause and causal factors as well as capturing multiple threads of realized and potential consequence.”
In summary, Wyvern’s Bates said, “One way the CASS/SMS integration improves safety is by making the MEL process more transparent and ensuring close-looped communications between the functional areas (dispatch, aircraft maintenance, pilots). This integration keeps all these functional areas on the same sheet, negating the risk of dispatching an aircraft with an unknown anomaly.” He continued, “There are also cost and time savings elements to the integration since the SMS facilitates and enables all the CASS functions, which results in less training required, less software cost, and less time managing issues in different locations.”