The type certification ceremony for the SAAB 2000 aeroplane, which was held in Linköping 31st of March 1994, was the culmination of almost 5 years of intense work by Saab Aircraft AB and its partners but also by the Aviation Authorities that participated in the type certification process. This paper gives a short description of the certification process, which probably is not well know to the passengers that benefit from the safe operation of the airliners today.
ICAO standards are very general minimum rules and need to be complemented by detailed requirements. Large aviation countries such as the USA, United Kingdom and the former USSR have developed such detailed codes (FAR 25, BCAR and NLG); other countries have referred to these with more or less additions and changes. Each ICAO member state is obliged to declare which detailed code that is applicable for aircraft on its register. 24 European countries cooperating through the Joint Aviation Authorities, "JAA", have now agreed a common standard for large aeroplanes in the form of JAR-25.The Airworthiness Certificate issued with reference to the declared code is the entry ticket to the international airspace.
"Airworthy" can be defined as "meeting accepted standard for safe flight". The Swedish Aviation Law has the following definition: "An aircraft is airworthy if it is designed, manufactured, equipped and maintained and has such performance that safety is ensured".
a) Type certification, approval of a certain aircraft type.
b) Manufacturing certification, approval of the manufacturer's process to produce aircraft.
c) Individual certification, approval of individual aircraft
ICAO does not require type certification but it has been found practical first to verify the type in relation to the detailed certification code by the issuance of a TYPE CERTIFICATE. Each aircraft, which is built in conformity with this certificate, can then receive an AIRWORTHINESS CERTIFICATE by means of a simplified approval process.
Manufacturing certification is manifested by the issuance of a PRODUCTION CERTIFICATE when working methods, processes and quality assurance system used by the manufacturer have been found satisfactory. The Authority can then rely on the manufacturer's statement and only make random checks before issuance of the airworthiness certificate.
A fourth form of certification, not directly related to safety, is environmental certification with regard to noise (external) and engine emissions. Agreed standard for this is defined in Annex 16 to the Chicago convention
• Concorde U.K / France
• SAAB SF340A 10 JAA countries
• Airbus A320 France / Germany / U.K. / The Netherlands
It should be remembered that the SAAB SF340A certification was a trial of working jointly which has been of great importance for the development of joint procedures for the JAA. Also the certification of the SAAB 340B, which was performed "in the spirit of Future Airworthiness Procedures" gave valuable experience and resulted in a joint certification by 11 Authorities.
The purpose of joint certification is a) that Type Certificates can be issued after a common evaluation and b) Airworthiness Certificates for export can be issued by the Aviation Authority of the manufacturer without additional dealings with the importing state. The joint certification should also give a less total workload on the Authorities, resulting in reduced cost for the industry, compared with a situation where each Authority has to perform its own certification.
The present system used by the JAA is by means of a team that performs the evaluation on behalf of all Authorities. The team is led by a Project Certification Manager (PCM) and a number of specialists for various technical disciplines. These are:
1.Flight testing
2.Performance
3.Structure
4.Mechanical and hydraulic systems
5.Electrical systems
6.Avionics
7.Propulsion systems
8.Environmental systems (Air conditioning, ice protection, oxygen)
9.External noise
Each discipline normally has 2 members of which one comes from the Authority of the state of the manufacturer and the other member comes from another Authority. Additional specialists may be added to the team to cover certain specialities e.g. computer software verification and composite structure. Flight testing is performed by a pilot and a flight test engineer working together, therefore this discipline normally has four members.
All team members are formally working as individuals in the team and are not reporting to their home Authorities but to the PCM. All Authorities have an insight in the process by means of a national coordinator who receives information from the team and has to agree certain steps in the certification.
In the end the PCM presents a final report to the Authorities. The report is scrutinized by the JAA Certification Committee (a group of senior airworthiness experts) after which a letter with a recommendation for certification is sent to all Authorities. Each JAA member still has to issue the legal document, the Type Certificate, to verify national acceptance of the aeroplane, since JAA is not an Authority.
A fundamental principle is established regarding the relationship Authority- Manufacturer.
•It is the manufacturer´s responsibility to demonstrate that the design meets the requirements.
•The team has to be satisfied that enough has been done by the manufacturer to show that the design meets the requirements.
Possible non-compliances with the requirements, that are detected after certification, have to be corrected by the manufacturer by design changes.
It is an impossible task for the Authority to check everything during the certification of a transport category aircraft. Therefore reliance must be put on the manufacturer. Sweden, like several other countries, has required the manufacturer to have a design reviewer organization, which is independent from the engineering part of the company. This organization has to check and verify the content of all compliance documents before they are sent to the certification team for approval.
•Establishment of the team
•Definition of the applicable requirements
•Evaluation of preliminary design concept
•Participation in / witnessing of ground- and flight tests
•Evaluation of final design details through drawings and reports from the manufacturer
The definition of applicable requirements has during recent years been a major task for the team because a clear definition acceptable to all Authorities has not been available. As a starting point JAR-25 with the status of the date of application for certification was used. However, the basic code had to be complemented by 16 additions, so called "Special Conditions", which were actually proposed changes to the JAR-25, not yet finalized, but which the Authorities felt were of such importance that they should be applied. This led to a form of negotiation which was sometimes difficult for the team and the manufacturer.
The team flight evaluation concentrates upon the aircraft behaviour, performance and handling qualities, after the loss of power from one engine. Other important items are the cockpit layout with regard to crew workload aspects and emergency procedures which have to be defined and presented in the Aeroplane Flight Manual. Towards the end of the certification one aeroplane has to be flown in airline-like operations with scheduled flights including normal maintenance and also carrying passengers.
A limited number of meetings where the whole team has been present have been arranged but normally each discipline has had their own meetings. The team´s work is documented by minutes from meetings, "Certification Review Item" papers that normally are used to define the certification requirements and by a "Compliance Question Book" which contains discussions regarding certain problems experienced by the team. 359 such questions were raised in the process.
The engine and the propeller are also subject to type certification by separate procedures.
In total the SAAB 2000 certification team spent nearly 25000 manhours before the PCM final report could be presented.
The Authority in the state of the manufacturer has a special responsibility to enable continued airworthiness through definition of design- and procedure changes and inspections when operation of the aircraft has uncovered airworthiness related problems. These are mandated by the issuance of Airworthiness Directives which are distributed to all states with aeroplanes of the type on their register.