{"id":"F2006B09501","name":"AD/EMB-120/12 Amdt 1 - Aileron Upper Channel Fairings","slug":"ad-emb-120-12-amdt-1-aileron-upper-channel-fairings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54047,"registerId":"commonwealth-F2006B09501-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/EMB-120/12 Amdt 1 - Aileron Upper Channel Fairings","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nEmbraer EMB-120 (Brasilia) Series Aeroplanes\n\nAD/EMB-120/12\n\nAmdt 1\n\n  \nAileron Upper Channel Fairings 7/96\n\nApplicability: Model EMB-120 aircraft with serial numbers listed in Embraer Service Bulletin 120- 57-0021 Revision 2.\n\nRequirement: Action in accordance with Embraer Service Bulletin 120-57-0021 Revision 2.\n\nNote: CTA AD 95-01-01 R2 refers.\n\nCompliance: Unless already accomplished in accordance with initial issue of this Directive, before 20 September 1996.\n\nBackground: There have been several reported instances of stiffness in the aileron control system. An investigation revealed that the cause was ice forming between the aileron upper channel fairings (kevlar strips), and the aileron leading edge surface. This Directive requires the removal and discarding of the upper channel fairings plus other rework action.\n\nAmendment 1 is issued in response to revisions of the Requirement Document and CTA AD, which add new material information plus dimension and instruction changes.\n\nThe original issue of this Airworthiness Directive became effective on 23 March 1995.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted airworthiness directive addressing a specific mechanical defect in a specific aircraft type. Amendment 1 remains within the original scope—updating technical requirements based on revised manufacturer guidance. There is no scope creep; it is a routine technical amendment to an existing safety directive."},"complexity_factors":["Very short document (under 300 words)","Only 1 defined applicability criterion (specific aircraft serial numbers)","Single requirement referencing an external technical document (Embraer Service Bulletin)","No nested conditional logic or exceptions","Straightforward compliance deadline with single carve-out (already accomplished work)","Minimal cross-referencing (one note to Brazilian CTA AD, one reference to manufacturer's bulletin)"],"plain_english_summary":"This safety order requires owners, operators, and maintenance organisations of certain Embraer EMB-120 Brasilia aircraft (those listed in Embraer Service Bulletin 120-57-0021 Rev 2) to remove specified upper channel fairings and perform related work to prevent ice buildup that can stiffen aileron controls. It addresses a serious control-impairment risk and mandates compliance by 20 September 1996 (unless already done). Amendment 1 updates the directive with new dimensions and revised manufacturer/regulator instructions."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 modifies the required technical work by updating the Requirement Document (service bulletin) and the referenced CTA AD to add new material information and change dimensions and instructions. The Directive continues to require removal/discard of the aileron upper channel fairings but the amendment changes the specific instructions and dimensions operators must follow."},"complexity_factors":["Applicability limited to specific EMB-120 serial numbers (external parts count and aircraft tracking required).","Requirement depends on an external document: Embraer Service Bulletin 120-57-0021 Revision 2 (operator must obtain and follow that SB).","Amendment revises the Requirement Document and CTA AD, adding material information and changing dimensions/instructions (technical detail changes to maintenance work).","Mandated removal and discarding of parts (disposal and parts-replacement logistics).","Fixed compliance deadline (scheduling, aircraft downtime and maintenance planning).","Cross-reference to CTA AD 95-01-01 R2 (regulatory linkage requiring cross-checking).","Need to verify whether action was already accomplished for a given aircraft (record checks)."],"plain_english_summary":"This Airworthiness Directive requires operators of specified Embraer EMB-120 aircraft to remove and discard the aileron upper channel fairings (Kevlar strips) and carry out related rework by following Embraer Service Bulletin 120-57-0021 Revision 2. The action addresses reported aileron stiffness caused by ice forming between the fairings and the aileron leading edge. Compliance was required by 20 September 1996 unless already done; Amendment 1 updates the service instructions and dimensions."}},"importantCases":[],"_links":{"self":"/api/acts/ad-emb-120-12-amdt-1-aileron-upper-channel-fairings","history":"/api/acts/ad-emb-120-12-amdt-1-aileron-upper-channel-fairings/history","analysis":"/api/acts/ad-emb-120-12-amdt-1-aileron-upper-channel-fairings/analysis","conflicts":"/api/acts/ad-emb-120-12-amdt-1-aileron-upper-channel-fairings/conflicts","importantCases":"/api/acts/ad-emb-120-12-amdt-1-aileron-upper-channel-fairings/important-cases","documents":"/api/acts/ad-emb-120-12-amdt-1-aileron-upper-channel-fairings/documents"}}