Throughout the service life of a military aviation product (aircraft, engine or propeller), degradation (damage) of the systems/structures supporting safe flight and certification may be compromised through direct (accidental impact and battle damage) overload, normal wear and tear, or insidious (fatigue, corrosion, moisture ingress, dis-bond, ultraviolet light etc.) environmental sources. Repairs are those actions developed and implemented to restore damaged products to the minimum airworthy state dictated by their respective Type Certification Basis (or equivalent) established at Initial Certification (or as supplemented/tailored over time).
The approval process ensures that the product the repair applies to will be returned to the risk inherent in the Type Certification Basis (or equivalent) as a result of the repair’s incorporation. The scenarios under which repair data can be used and under which repairs are designed, approved and embodied can vary significantly depending on the organisations fulfilling the respective roles in the repair process. However, in terms of repair design approval, the fundamental principles applied to safety assurance considerations are the same regardless of the organisation performing them.
Data to be used in repairs may come through a repair design approval process where DASA is the certifying Authority (either approved by DASA or by an appropriately privileged organisation), or through a process where the recognition framework is used. The overarching DASRs governing the design development, approval and associated obligations as they relate to repairs to Australian Military Aviation Product are:
DASR 21 Subpart M: This Subpart establishes the procedure for the approval and classification of a repair design of a product, part or appliance, and establishes the rights and obligations of the applicants for, and holders of, those approvals.
DASR 21 Subpart J: A Military Design Organisation (MDO) complies with the requirements ofDASR 21 Subpart J. The DASR presents eligibility criteria, requirements for a design assurance system, terms of approval, candidate privileges (approved at DASA’s discretion), and obligations. It also specifically requires the organisation to establish and maintain a Safety Management System (SMS), in accordance with DASR.SMS
DASR M Subpart C: This Subpart at Section M.A.304 provides requirements for data to be used in repairs. DASR M.A.304(a) and (b) allow data to be used that has been approved by DASA, and by a Design Organisation approved under DASR 21 Subpart J. In each of these cases, DASA is the certifying Authority and the requirements of DASR 21 Subpart M are applicable.
Approved by DASA: Notification of an intended major11 repair requiring DASA approval can be made using a DASR Form 31– Notification of Major Change/Major Repair. Submission of a DASR Form 31 initiates dialogue that enables DASA to guide the applicant through the major repair approval process
A submission for a major repair must include a Certification Programme (CP) containing among other elements;
a description of the damage and repair design identifying the configuration of the type design upon which the repair is made
an identification of all areas of the type design that are changed/affected by the repair, and
an identification of any reinvestigations necessary to demonstrate compliance of the repair design with the Type Certification Basis (or equivalent)
The requirement for a detailed CP is determined in consultation with DASA. In the case of major repairs, if long and complex compliance demonstration activities are deemed to not be required, the CP can be submitted in simplified form as part of the application. Application for approval of a major repair design should be made using a DASR Form 31b. (Refer to DASR 21.A.432C for details)
Approved by a privileged organisation: An organisation awarded a privilege by DASA to approve repairs will execute those privileges within the constraints of the scope and limitations defined by DASA in the MDO Terms of Approval. The relevant procedures are defined in the MDO’s Design Organisation Handbook (DOH). (Refer to DASR 21.A.263 for details).
Holder obligations apply to applications from (or on behalf of) Commonwealth organisations awarded the authorisation, or DASR 21J MDOA organisations making approvals under privilege. Responsibilities of a holder are presented at DASR 21.A.451(a) and (b) for a major repair and minor repair respectively. Amongst other things, the holder is required to:
establish a system for reporting failures, malfunctions and defects of major repairs
propose to DASA corrective actions, where those failures, malfunctions and defects of major repairs constitute an Unsafe Condition being subject to an Airworthiness Directive (AD)
ensure collaboration between the design organisation and the production organisation as necessary
provide at least one complete set of those changes to the instructions for continuing airworthiness which result from the design of the repair (or any subsequent update to the repair), to any operator of the affected product incorporating the repair.
retain all relevant repair design information at the disposal of DASA and in order to provide the information necessary to ensure the continued airworthiness of the repaired product.
Once a repair design is approved by DASA or an appropriately privileged organisation, DASA compliance assurance is achieved through Oversight and Enforcement activities as they relate to holder obligations and the ongoing safety of individual repair designs. These two aspects effectively are encompassed by:
periodic compliance assurance of MDOA organisations and MTCH organisations, either through on site visits or remote assessments to gain confidence in the effectiveness of the systems in place to meet the requirements of DASR 21.A.451
DASA safety assurance of Reported Occurrences as they pertain to approved repair designs
DASA’s oversight processes are contained in the DASA Instructions, DASA(I) SAPO 01-002, DASA Oversight (On-Site and Remote),DASA(I) 01-009, DASR Findings and DASA(I) IINV 03-001 (Assurance of Reportable Occurrences) Available on the DASA intranet site.