Quality assurance

March 1, 1999

Quality Assurance

By Brian Whitehead

March 1999

Brian Whitehead is chief, policy development for the Aircraft Maintenance & Manufacturing branch in Ottawa. E-mail questions or comments to [email protected].

Procedures to ensure that maintenance tasks are completed correctly, have been an integral part of organized maintenance activities for many years.

When civil aviation activity recommenced following WWII, the larger maintenance operations typically assigned selected members of their technical staff to inspect and release the work performed by the production team. Variations of this technique are still with us today, the most common example being the Required Inspection Items (RII) of FAR 121. This process of examining a finished product for compliance is generally referred to as Quality Control (QC).

In recent years, with the growing complexity of aircraft systems and enhanced insight into the psychological and physiological aspects of maintenance (the "human factors"), it has become clear that quality control alone is not enough. For one thing, many processes are susceptible to errors that are difficult, if not impossible, to find by direct inspection. Computer programming, composite repair, and welding are good examples of this. Also, the very knowledge that an inspection will be done, and that the inspector will assume responsibility for the work, can in some cases lead to a sense of complacency that defeats the object.

Even without these problems, the rejection of work in its final stages is an inefficient and expensive way to ensure quality. All these factors have lead to the increasing use of a more comprehensive approach, generally referred to as Quality Assurance (QA). The Continuing Analysis and Surveillance system required by FAR 121 is one example of a QA application.

For the purposes of this article, QA can be considered to be the sum of all actions taken to provide assurance that the desired outputs will be attained. Instead of concentrating on the finished product, QA takes into account all aspects of a process, from planning to completion, and identifies weak points that could be prone to the introduction of errors. While inspection of the final product remains an essential part of the QA process, there are three significant differences between this and a QC final inspection.

First, the primary purpose is not to find defects per se (although, of course, if faulty items are found, they will be rejected). Rather, the finished product is inspected as one means of confirming the satisfactory operation of the system as a whole. Secondly, the QA inspector does not sign the release for the work. I will return to this point later. Finally, QA inspections are generally done by sampling, rather than looking at 100 percent of the items involved.

Unlike the U.S. FARs, the Canadian Aviation Regulations (CARs) do not require Air Operators or Approved Maintenance Organizations (AMOs) to have a QC system. There are several reasons for this, the primary one being that, under the Canadian system, every maintenance task can be considered an RII, as each is subject to a maintenance release, and the person signing that release assumes full responsibility. The fact that only a representative sample of each task is subject to QA inspection further underlines the AMEs' responsibilities, as they will be aware that, most of the time, theirs is the final inspection.

Both Air Operators and AMOs however, must have a QA system. In the case of the Air Operator, the system is required by 706.07 Evaluation Program. For an AMO, the system is required by 573.09 Quality Assurance Program. It is the latter system that I refer to here.

An AMO's QA system must be independent of all aspects of production. That is, the persons involved in QA must have no involvement in the planning, performance, recording, or certifying of the work inspected. Isolating QA personnel from responsibility for the items they inspect avoids any potential conflict of interest, and emphasizes the fact that the inspection is centered upon the performance of the system as a whole, not merely on its results. QA inspectors are simply critics, who identify existing or potential defects, and bring them to the attention of the parties responsible.

To further illustrate this point, QA inspectors should not propose any corrective action for the deficiencies they find. To do so could detract from their independence, giving them a vested interest in the success of the proposal. This could make them less objective in any future inspection of the modified system. In effect, they could become part of the problem, instead of being part of the solution.

While QA personnel are not involved in any corrective action, they are required to analyze the deficiencies they find, and identify the probable cause or causes.

This is the real strength of QA. Instead of simply acting as a final filter for the rejection of faulty work, QA is a proactive technique that identifies weaknesses before harm can result. QA findings must be formally reported to the person responsible for maintenance (i.e., the Director of Maintenance or equivalent position) who is responsible for taking appropriate corrective action. They must also be made available to the certificate holder, who has final authority for all activities performed under the authority of the AMO certificate.

Because the QA analysis looks at the entire process, corrective action may be applied anywhere in the system, often far removed from the event that prompted the finding. Typical responses could include a change in procedures, improvements in equipment, better lighting, changes to the training program, or modification of a component, to name just a few. Often, a combination of actions will be indicated. Where appropriate, both immediate and long-term corrective actions must be addressed. All action taken must be documented, and the QA department notified. Future QA inspections will then track the results of the corrective action, to verify its effectiveness.

The Approved Maintenance Organization Standards include details of acceptable methods for complying with the QA program requirements. Among the chief requirements is an initial self-audit of all aspects of the AMO's technical activities within 12 months following the initial issue of the AMO certificate (This is additional to the ongoing QA inspection functions). Thereafter, a recurring cycle of further audits must be carried out at intervals established in the approved Maintenance Policy Manual.

The adoption of Quality Assurance techniques is one more example of the maturity of the aircraft maintenance industry. By no longer taking a purely reactive approach to quality, AMOs can look ahead and manage this critical aspect of their operations using the same professional business strategies that they apply to the commercial side of their operations.