{"id":"F2006B09502","name":"AD/EMB-120/13 Amdt 1 - Wing Rib to Skin Fitting Angles","slug":"ad-emb-120-13-amdt-1-wing-rib-to-skin-fitting-angles","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54049,"registerId":"commonwealth-F2006B09502-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/EMB-120/13 Amdt 1 - Wing Rib to Skin Fitting Angles","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Embraer EMB-120 (Brasilia) Series Aeroplanes\n\n \n\nAD/EMB-120/13\n\nAmdt 1\n\n\nWing Rib to Skin Fitting Angles 12/95\n\n \n\nApplicability: All Model EMB-120 aircraft.\n\n \n\nRequirement: Action in accordance with the technical requirements of CTA AD 95-05-01R1 Amdt 39-746.\n\n \n\nCompliance: As specified in the requirement document.\n\n \n\nThe original issue of this directive became effective on 20 July 1995.\n\n \n\nBackground: The Brazilian CTA received reports of cracks in the wing rib to skin fitting angles (shear clips) in both the upper and lower wing skins.\n\n \n\nAmendment 1 is issued in response to a revision of the Requirement Document which requires a final corrective action.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Yes. The amendment revises the Requirement Document so that the AD now requires a \"final corrective action\" rather than only the actions in the original issue. The AD therefore changes from its original form (effective 20 July 1995) by mandating the corrective step specified in the revised CTA document. (Amendment 1; original issue note; Requirement)"},"complexity_factors":["References an external technical document (CTA AD 95-05-01R1 Amdt 39-746) for all technical detail, so compliance complexity depends on that document (Requirement).","Applies to every Model EMB-120 aircraft, creating potentially large aggregate operational and scheduling impacts for multiple operators (Applicability).","Amendment introduces a \"final corrective action\", changing the nature of required work from interim inspections to a terminating modification or repair; exact content and timing are delegated to the Requirement Document (Amendment 1; Requirement).","The AD text itself contains no timing, methods, or acceptance criteria — those are in the Requirement Document, increasing the need for operators to obtain and interpret an external instrument (Compliance).","Potentially involves physical repair or replacement of wing rib-to-skin fitting angles (shear clips), which can require parts, certified maintenance capability and aircraft downtime (Background; Requirement).","Enforcement/compliance relies on matching work to the CTA document; any ambiguity or variation in implementation raises operational and regulatory risk (Requirement; Compliance)."],"plain_english_summary":"This AD makes compliance with CTA AD 95-05-01R1 Amdt 39-746 mandatory for all Embraer EMB-120 operators in Australia: inspect and carry out the corrective work it specifies to address reported cracks in wing rib‑to‑skin fitting (shear clip) angles. Amendment 1 updates the referenced CTA requirement to add a final corrective action. Owners/operators (and their maintenance providers) bear the inspection, repair and downtime costs."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment remains tightly scoped to its original purpose: addressing wing rib cracks in EMB-120 aircraft. Amendment 1 simply updates the technical requirements to mandate final corrective action rather than ongoing inspections, without expanding to other aircraft types or structural issues."},"complexity_factors":["Very short document (under 200 words)","Only 1 defined applicability criterion (all Model EMB-120 aircraft)","Single technical requirement referencing an external document (CTA AD 95-05-01R1)","No nested conditions, exceptions, or cross-references within the instrument itself","Straightforward compliance structure (follow the external document's timeline)"],"plain_english_summary":"This is an **Airworthiness Directive** (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires aircraft owners and operators to fix a specific safety problem.\n\n**What it does:**\n- Requires inspection and repair of **cracks in wing rib to skin fitting angles** (also called \"shear clips\") on Embraer EMB-120 \"Brasilia\" aircraft\n- These are small metal brackets that connect the wing's internal ribs to the outer skin\n- Cracks were found in both the upper and lower wing surfaces\n\n**Who it affects:**\n- All owners and operators of **Embraer EMB-120 series aircraft** in Australia\n- Maintenance organisations servicing these planes\n\n**Why it matters:**\n- Cracks in wing structure can lead to **structural failure** and potentially catastrophic accidents\n- This directive makes the repairs **legally mandatory**, not optional\n- \"Amendment 1\" updates the original 1995 order to require **final corrective action** (permanent fix) rather than just repeated inspections\n\n**What must be done:**\n- Follow the technical instructions in the referenced Brazilian aviation document (CTA AD 95-05-01R1)\n- Compliance deadlines are set out in that technical document"}},"importantCases":[],"_links":{"self":"/api/acts/ad-emb-120-13-amdt-1-wing-rib-to-skin-fitting-angles","history":"/api/acts/ad-emb-120-13-amdt-1-wing-rib-to-skin-fitting-angles/history","analysis":"/api/acts/ad-emb-120-13-amdt-1-wing-rib-to-skin-fitting-angles/analysis","conflicts":"/api/acts/ad-emb-120-13-amdt-1-wing-rib-to-skin-fitting-angles/conflicts","importantCases":"/api/acts/ad-emb-120-13-amdt-1-wing-rib-to-skin-fitting-angles/important-cases","documents":"/api/acts/ad-emb-120-13-amdt-1-wing-rib-to-skin-fitting-angles/documents"}}