21L.A.174 Management system for design

DESIGN ASSURANCE SYSTEM

(a)Purpose This GM outlines some basic principles and objectives of the design assurance system.

(b)Definitions

(1)‘Design assurance system’ The design assurance system includes the organisational structure, responsibilities, procedures, and resources to ensure the proper functioning of the design organisation.

(2)‘Design assurance’ refers to all planned and systematic actions necessary to provide adequate confidence that the organisation has the capability to: design products or parts in accordance with the applicable type-certification basis and environmental protection requirements; demonstrate and verify compliance with the type-certification basis and environmental protection requirements; and demonstrate compliance to EASA.

(3)‘Type investigation’ refers to the tasks of the organisation in support of the type certificate (TC), supplemental type certificate (STC), or other design approval processes necessary to demonstrate, verify, and maintain compliance with the applicable type-certification basis and environmental protection requirements. The complete design process, starting with the type-certification basis, environmental protection requirements and product specifications, and culminating with the issuance of a type certificate (TC), is shown in the diagram in Figure 1. This identifies the relationship between the design, the type investigation and the design assurance processes.

[Figure or form omitted from this preview — available in the Avioverse workspace library.] Figure 1 — Relationship between design, design assurance and type investigation

PLANNED AND SYSTEMATIC TASKS For design organisations that carry out the certification process of products, their planned and systematic tasks should cover the following, and the related procedures should be defined accordingly.

(a)General

(1)Issue or, where applicable, supplement, or amend the documentation of the management system for design (or, if it is used, the declared design organisation exposition (DDOE)) in accordance with point 21L.A.174(d).

(2)Assure that all the procedures are adhered to.

(3)Conduct the certification process.

(4)Nominate staff as ‘compliance verification engineers’ that are responsible for approving compliance documents as defined in point (c) below.

(5)Nominate staff that belong to the airworthiness function and are responsible as defined in GM1 21L.A.174(b)(1).

(6)In the case of an applicant for an STC, obtain the agreement of the TC holder for the proposed STC to the extent that is defined in point 21L.A.86.

(7)Ensure that there is full and complete liaison between the design organisation and the related organisations that have responsibility for the products and parts that are manufactured according to the type design.

(8)Provide assurance to EASA that any prototype models and test specimens adequately conform to the type design (see points 21L.A.25(c), 21L.A.85(c) and 21L.A.206(c)).

(b)Head of the design organisation (or deputy) The head of the design organisation (HDO), or an authorised representative, should sign a declaration of compliance (see points 21L.A.25(f), 21.A.85(f) and 21L.A.206(f)) with the applicable type-certification basis and environmental protection requirements after verifying the satisfactory completion of the certification process. The signature of the HDO on the declaration of compliance confirms that the relevant procedures of the management system for design have been followed.

(c)Compliance verification

(1)Approval through the signing of all the compliance documents, including test programmes and data that are necessary for the verification of compliance with the applicable type-certification basis and environmental protection requirements, as defined in the compliance-demonstration plan.

(2)Approval of the technical content (completeness, technical accuracy, etc.), including any subsequent revisions, of the manuals to be approved by EASA (aircraft flight manual (AFM), airworthiness limitations section (ALS) of the instructions for continued airworthiness (ICAs)).

(d)Maintenance and operating instructions

(1)Ensuring the preparation and updating of all the maintenance and operating instructions (including ICAs and SBs) that are needed to maintain airworthiness (i.e. continuing airworthiness) in accordance with the relevant certification specifications (CSs).

(2)In accordance with points 21L.A.8 and 21L.A.9 and, where applicable, point 21.A.609, ensuring that those documents are made available as per point 21.A.9(c).

AIRWORTHINESS FUNCTION The following tasks are normally performed by the airworthiness function:

(a)Liaison between the design organisation and EASA with respect to all aspects of the design certification application.

(b)Preparation of the compliance-demonstration plan and obtaining its approval by EASA.

(c)Coordination internally, in the design organisation, of all compliance-demonstration activities according to the compliance-demonstration plan.

(d)Regular reporting to EASA about the progress of compliance-demonstration activities and coordination of EASA investigations. These include the necessary arrangements for the physical inspection and assessment of the aircraft and the critical design review, in accordance with point 21L.A.241(c)(2), and the first-article inspection, in accordance with point 21L.B.46.

(e)Establishing the compliance checklist and updating it with any changes, as necessary.

(f)Checking that all the compliance documents that are necessary to demonstrate compliance with the applicable type-certification basis and the applicable environmental protection requirements, as well as for completeness, are prepared and signing the documents for release.

(g)Providing verification to the head of the design organisation that all the activities required for a type investigation have been properly completed.

(h)Endorsing the classification of changes and repairs in accordance with point 21L.A.63 and 21L.A.203 respectively.

(i)Ensuring the initiation of activities as a response to an occurrence report and providing information to EASA if the airworthiness is impaired.

(j)Advising EASA on the issuing of airworthiness directives (ADs) in general based on service bulletins (SBs).

(k)Monitoring significant events on other aeronautical products, as far as they are relevant, to determine their effect on the airworthiness of the products designed by the design organisation.

(l)Ensuring that there is cooperation in preparing SBs and any subsequent revisions, with special attention being given to the manner in which the contents affect airworthiness and environmental protection aspects.

INDEPENDENT VERIFICATION FUNCTION OF THE DEMONSTRATION OF COMPLIANCE

(a)The independent verification function of the demonstration of compliance is normally carried out by a person that did not create the compliance data. Such a person may work in conjunction with the individuals that prepare compliance data.

(b)The verification is normally shown by signing all compliance documents, including test programmes and data that are necessary for the demonstration of compliance with the applicable type-certification basis and the applicable environmental protection requirements as defined in the compliance-demonstration plan.

(c)For a product, there is normally only one compliance-verification engineer that is nominated for each relevant technical discipline. The relevant procedures would normally describe the way of action in case of non-availability of the nominated persons and their replacement, when necessary.

(d)For STC cases, when compliance statements and associated documentation are produced by the TC holder, and when this data is approved under the system of the authority of the TC holder, then the STC applicant does not need to provide, within its own DDO, the independent verification function that is required by point 21L.A.124(b)(2) for that data.

PARTNERS AND SUBCONTRACTORS Examples of elements that the process to control partners and subcontractors should normally address are: the identification of the work to be subcontracted (e.g. design of parts, drafting drawings, stress analysis, laboratory testing); the selection of a subcontractor based on its capability to perform the identified work (criteria (e.g. facilities, knowledge and experience) and the selection process); the working arrangement (e.g. purchase technical specifications, statement of work); this may cover technical requirements (for parts to be design or tasks to be performed) and process requirements (e.g. procedures to be followed by the subcontractor); and the control of the work performed by the subcontractor; this control would not only cover the deliverables provided by the partners and subcontractors but also the monitoring function required under point 21L.A.174(c), and, if relevant, the independent function to verify the demonstration of compliance required under 21L.A.174(b)(2). If a partner or subcontractor holds a design organisation approval (DOA), then the declared design organisation may take this into account for the effective integration of that partner or subcontractor (e.g. simplifying the selection process when the scope of work of the respective subcontractor’s DOA is similar with the scope of the subcontracted work). The declared design organisation maintains a list of all selected partners and subcontractors, including their respective scope of subcontracted work. If the independent function to verify the demonstration of compliance required under point 21L.A.174(b)(2) is subcontracted, the declared design organisation should normally identify in its own documentation the authorised staff of the partner or subcontractor performing this function.

INDEPENDENT MONITORING FUNCTION The scope of the independent monitoring function is to ensure that: the management system for design remains compliant with the applicable requirements of the Part 21 Light and with any additional requirements as established by the organisation; the staff of the design organisation follow the documented procedures of the management system when performing their tasks; and the management system for design is adequate and enables the organisation through the use of its procedures to provide assurance that the designed products, changes and repairs are compliant with the applicable type-certification basis and the applicable environmental protection requirements. An objective review of the complete set of design-management-related activities is provided through independent monitoring activities, such as audits, inspections, reviews. The independence of the monitoring activities is established by always ensuring that those activities are performed by staff that are not involved in the function, procedure or products they monitor, and that are independent from the operating managers of the function(s) being monitored; however, this should not exclude support by domain experts during monitoring. The monitoring is usually performed based on a monitoring plan. This plan is established to show when and how often the activities required by Part 21 Light will be audited. This plan normally includes, in a defined period of time, all the elements of the management system, including all subcontractors. The defined period of time for the audit planning typically does not exceed 24 months. When a non-compliance is found, the root cause(s) and contributing factor(s) should be identified and corrective actions should be defined and followed up. When providing feedback, the compliance-monitoring function should define who is required to address any non-compliance in each particular case, and the procedure to be followed if the corrective action is not completed within the defined time frame. Also, as required in point 21L.A.174(c), feedback has to be regularly provided to the head of the design organisation on the overall status of the compliance and adequacy of the management system for design, including main issues identified and cases where corrective actions have not been satisfactorily implemented. Staff that perform an independent monitoring function should have access to all the parts of the design organisation and, as necessary, to any subcontracted organisations.

DOCUMENTATION Point 21L.A.174(d) requires the declared design organisation to document its processes and procedures. In order to do so, the declared design organisation may consider to establish a declared design organisation exposition (DDOE). The purpose of a DDOE is to set forth in a concise document format the organisational relationships, responsibilities, terms of reference, and the associated authority, procedures, means and methods of the organisation. If utilised, the DDOE typically contains the following:

(a)a statement signed by the head of the design organisation confirming that the DDOE and any associated manuals, procedures and instructions that define the organisation’s compliance with this Subpart will be complied with at all times;

(b)the title(s) and name(s) of the person(s) nominated in accordance with point 21L.A.175(b);

(c)the duties and responsibilities of the head of the design organisation and the person(s) as specified by point 21L.A.175(b), including matters on which they may deal directly with EASA on behalf of the organisation;

(d)an organisational chart showing the associated chains of responsibility of the managers as required by point 21L.A.175(e);

(e)the list of authorised staff that perform the independent function of verifying the demonstration of compliance as referred to in point 21L.A.174(b)(2);

(f)the nomination procedure for key personnel and authorised staff;

(g)a general description of manpower;

(h)a general description of the facilities located at each address specified in the declaration of design capability;

(i)a general description of the declared design organisation’s scope of work as defined in the declaration of design capability (see also point 21L.A.176);

(j)the procedure for the notification of organisational changes to EASA according to point 21L.A.178;

(k)the procedure for the amendment of the DDOE;

(l)the independent system monitoring procedure;

(m)the subcontracting procedure and the list of partners and subcontractors;

(n)the procedure for identification and issuance of type design documentation and configuration control;

(o)the procedure(s) followed and forms used for type certification and supplemental type certification;

(p)the procedures for design changes;

(q)the procedure for design of repairs;

(r)the continued-airworthiness procedures (including reporting system and data in support of the issuance of airworthiness directives);

(s)the procedures for the collaboration between design and production organisations (including transfer of design data and approval of production concessions or non-conformities);

(t)the record-keeping procedure;

(u)the procedure for marking products and parts;

(v)the procedures for the issuance of manuals and instructions for continued airworthiness (ICAs);

(w)the procedures for the interface with EASA (supporting EASA investigations and answering to findings and observations). The DDOE may be produced and distributed in paper or electronic format. If the above information is documented in separate procedures and instructions, the DDOE may include a summary of the information and an appropriate cross reference. When changes to the organisation occur, the DDOE should be kept up to date. Changes to the organisation shall be notified to EASA as required by point 21L.A.178. If the organisation holds one or more additional organisation certificates within the scope of Regulation (EU) 2018/1139 and the delegated and implementing acts that are adopted on the basis thereof (DOA, POA, etc.), so that the organisation is required to establish another exposition, the organisation may combine the documents by producing a separate manual or supplement that covers the differences between the DDOE and the other exposition. In that case, the manual or supplement should identify where in the other exposition the remaining information on the declared design organisation is covered. That remaining information then formally becomes part of the exposition.