Maintenance and Certification
- The International Context for Aircraft Certification
- Elevator Trim Rigging Anomalies on Cessna 208
- A New Accountability Framework for Aeronautical Product Certification
The Aircraft Certification Branch is responsible for the development and implementation of the regulations, standards and guidance for the type certification of aeronautical products, including any mandatory corrective action required during the service life of the products. But what does this mean, and what are the international responsibilities that we have?
The first of the two main groups of products that we certify are those that originate in Canada. They include the aircraft manufactured by Bombardier, Bell Helicopter, Eurocopter, Diamond Aircraft, Found Aircraft, Zenair, Conair, Convair, Symphony, Fantasy and Sundance, and the engines manufactured by Pratt &Whitney Canada and Orenda. In addition to the basic aircraft and engines, we certify the design changes and repairs made by the operators, maintainers and modifiers, as well as certain equipment installed on aircraft. Many of these certified products, design changes, or repairs are destined for use in other countries, and it is our responsibility to certify them in a manner that will make them readily acceptable to our foreign counterparts. Once the certification work is accepted, we have an ongoing international responsibility to the countries that have accepted our certification work to take corrective action in response to significant in-service difficulties.
The second group of products that we certify arc those that originate in foreign countries and are to be operated in Canada. In this case, we rely heavily on our foreign counterparts in the same way that they rely on us for the certification of Canadian products.
Over the years, the international exchange of aeronautical products has driven the need for those products to be certified to common standards. Long before the Airworthiness Manual was established, Canada accepted products certified to both the U.K. British Civil Airworthiness Requirements (BCARs) and the U.S. Federal Aviation Regulations(FARs), to the extent that some aircraft types had two acceptable configurations; one for each set of regulations. The Airworthiness Manual introduced the Canadian standards based on the U.S. FARs. The evolution of the Joint Aviation Authorities (JAA) in Europe led to greater efforts to harmonize the European and North American design standards. Transport Canada has played, and continues to play, an active role in the harmonization of many of the design standards. The current differences in the design standards between the U.S., Europe, and Canada are minimal, which, in the majority of instances, allows products to be certified in a common configuration that satisfies the U.S. Federal Aviation Administration (FAA), the European Aviation Safety Agency (EASA), and Transport Canada.
Internationally-aligned type certification procedures
As the degree of harmonization of the design standards increased, so did pressure from the international industry to achieve greater commonality of the certification procedures. Transport Canada has also been actively engaged in the development of internationally-harmonized certification procedures, and although there remain some differences, the degree of commonality is today at a very high level.
The effort put into the harmonization activities over the years has formed a good basis for our international agreements. The existing Bilateral Air Safety Agreement (BASA) with the U.S. relics heavily on the mutual acceptance by both countries of the standards and procedures related to type certification. Our past relationship with the JAA in Europe and our evolving relationship with EASA have both been built on a similar basis.
Maintaining and implementing a harmonized regulatory framework
The harmonization of the standards and procedures along with the international agreements are important, and they all need to be maintained to respond to the changes in industry and the aviation environment. The experience of implementing the framework generates a need for dialogue between the authorities to support the smooth flow of products while respecting our safety mandate.
Transport Canada continues to be active in a number of forums to support these international responsibilities.
Harmonization of the standards and procedures
The U.S. and Europe sponsor numerous rule-making activities for which they are committed to consultation and harmonized solutions.Transport Canada certification specialists are involved in many of these activities with the focus being on those areas with the most relevance to Canadian certification projects.
Participation in the Joint FAA/EASA Certification Management Team
The FAA and EASA directors of Aircraft Certification meet twice a year to oversee their mutual acceptance of aeronautical products. Transport Canada is permitted to participate in these meetings, as there are often agenda items of common interest.
Annual meetings with the FAA Aircraft Certification Management Team
Transport Canada, Aircraft Certification managers meet annually with their FAA counterparts to provide update briefings and to discuss current issues.The discussions often lead to enhanced BASA implementation procedures.
Annual meetings with the key FAA certification offices
The flow of Canadian products to the U.S. is primarily through the New York Aircraft Certification Office (ACO), with rotorcraft being handled by the Rotorcraft Directorate in Fort Worth, Texas, and engines and propellers being handled by the Engine and Propeller Directorate in Burlington, Massachusetts. Annual meetings are held with the New York ACO and Rotorcraft Directorate offices to deal with the day-to-day procedures and any issues that may arise.
Annual meetings with the EASA certification office
As we develop a formal relationship with the relatively new EASA organization, we intend to establish annual meetings similar to those in place with the FAA to ensure that our working relationship is effective and relevant.
Contact with other foreign authorities
The export and import of aeronautical products requires that we deal with many authorities worldwide. Although we do not necessarily have the structured agreements with these authorities that are in place with Europe and the U.S., we often conduct business in a similar manner. Where the level of exchange of products is significant, we would, in the long term, expect to develop agreements with those authorities.
Our primary international responsibility is for the basic certification and on-going continued airworthiness support of aeronautical products originating from Canada. Our primary national responsibility is for the safety of the products operating in Canada. Each of these responsibilities requires that we establish and maintain strong relationships with our international counterparts.
Two Transport Canada Aircraft Maintenance and Manufacturing inspectors carrying out ramp inspections at airfields in the Prairie and Northern Region (PNR) this past fall, came across several Cessna 208 (Caravan) aircraft that had anomalies in the elevator trim rigging.
The aircraft had not all been maintained by the same organization, which led them to believe that the issue they found may be more widespread than just the aircraft they inspected.
The area of concern was the connection of the elevator trim control pushrods to the elevator trim tab horns. It was noticed that in some instances, washers had been added to the bolt/bushing stack-up (highlighted in beige in Figure 1), which removed the required endplay on the assembly.
The lack of endplay bound the pushrods to the trim tab horns, stopping them from pivoting freely, which could lead to eventual failure of the horns or pushrods.
Discussion with approved maintenance organization (AMO) personnel on site revealed that adding washers was an attempt to remove the "slop" (side play) in the assembly.
When properly installed, as per the manufacturer's instructions, each pushrod will have approximately 1/8 in. side play on the trim tab horn.
Figure 1: Artist's impression of original technical diagram
In this instance, as elsewhere, the pertinent manufacturer's instructions should always be consulted for the identification of required parts, and their proper assembly.
Over the years, the Aircraft Certification Branch has built a strong partnership with the Canadian aviation industry to effectively make use of Ministerial Delegation of Authority as specified in the Aeronautics Act.The development of our delegation framework originated in 1968 with "Notice to Aircraft Maintenance Engineers and Aircraft Owners N-AME-AO 45/68," which introduced the design approval representative (DAR) system. Based on recommendations of the Dubin Commission in the 1980s, the Aeronautics Act was amended in 1985 to provide for authorization, by the Minister, of persons engaged in the field of airworthiness. Airworthiness standards were then developed in Airworthiness Manual Chapter 505, and the DAR system was expanded to include two new categories of corporate delegate: the airworthiness engineering organization (AEO), and the design approval organization (DAO).
In light of the strategic direction of Transport Canada Civil Aviation (TCCA), as specified in Flight 2005 and Flight 2010, the need to improve the current delegation system within the Aircraft Certification Branch was identified. The current framework confuses the obligations and weakens the accountabilities of the applicants and holders of design approvals by focusing only on the role of the Minister and delegate in the certification process, which leads to the Minister often assuming certain obligations that should be assumed by the applicant or holder.
The Aircraft Certification Branch has taken steps to improve this situation by proposing the new Civil Aviation Regulation (CAR), Part V, Subpart 21 (CAR 521), which more clearly delineates the roles and obligations of the applicant and holder. However, CAR 521 is not placing enough emphasis on the obligations of the applicant and the holder. In the course of CAR 521 discussions, industry supported the concept of recognizing a design organization's capability without necessarily granting an organizational delegation. These discussions led to the development of the new accountability framework.
In the new framework, accountability would be clearly placed on the applicant of the design approval having an obligation to develop a safe and compliant design, and the holder having the obligation to maintain a safe and compliant design. As a condition of eligibility to apply for, or to hold, a design approval, the applicant and holders would be required to have demonstrated knowledge of the certification process and technical capability, including adequate design assurance system, to design products that comply with the applicable airworthiness and environmental standards. Applicants and holders would demonstrate their knowledge and technical capability by being certified, under the current proposal, as either an approved design organization (ADO) or an approved design individual (ADI).
The Aircraft Certification Branch is moving towards an approach whereby the applicant or holder has to demonstrate the capability of controlling the design and showing compliance with a high degree of assurance. The demonstrated capability would then be backed up by a design validation process, whereby individuals not having been directly involved in the design activities would conduct independent verification of compliance, followed by a declaration of compliance made by the applicant. It is important to note that Transport Canada would continue to maintain an appropriate oversight role through appropriate levels of certification and surveillance activities.
The Minister would continue to delegate specific functions, limited to the issuance of certain types of certificates and approvals after having confirmed compliance with specific elements of the certification process. With a well-structured design assurance process addressing the demonstration, validation, and declaration of compliance, the need for making individual findings of compliance against each applicable airworthiness and environmental standards becomes redundant and, therefore, delegated functions would no longer include making findings of compliance.
Given that certificate holders have an obligation to maintain a safe and compliant design, the recognition of technical capabilities would take considerations beyond the design and certification process by including the need to have appropriate systems in place to support continued operational safety and continued airworthiness throughout the life cycle of the aeronautical product.
In summary, these changes will greatly clarify the roles, obligations, and accountabilities of the various parties involved in the aeronautical product certification process, while providing a better framework that will facilitate the implementation of a proactive approach to aviation safety, including safety management systems (SMS).
The Aircraft Certification Branch will soon commence the development of the required regulatory amendments to introduce the new accountability framework to the Canadian Aviation Regulations Advisory Council (CARAC) Part V (Aircraft Certification) technical committee in 2007, with full implementation scheduled for 2010.
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