{"id":"F2006B06800","name":"AD/SC7/26 Amdt 2 - Wing Attachment Bushes in Fuselage Front and Rear Spar Frames","slug":"ad-sc7-26-amdt-2-wing-attachment-bushes-in-fuselage-front-and-rear-spar-frames","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114657,"registerId":"commonwealth-F2006B06800-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SC7/26 Amdt 2 - Wing Attachment Bushes in Fuselage Front and Rear Spar Frames","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)  \nShort SC7 (Skyvan) Series Aeroplanes\n\nAD/SC7/26\n\nAmdt 2\n\n  \n\nWing Attachment Bushes in Fuselage Front and Rear Spar Frames\n\n  \n9/99\n\nApplicability: All model SC7 aircraft.\n\nRequirement: Inspect in accordance with Shorts Mandatory Service Bulletin 53-68 Revision 3.\n\nNote: UK CAA AD 009-01-96 refers.\n\nCompliance: Unless the initial inspection is already accomplished, inspect within 50 flights after 31 December 1998, and thereafter at the intervals specified in the Requirement Document.\n\nThe initial compliance of the previous issue of this Directive remains unchanged. This Amendment becomes effective on 9 September 1999.\n\nBackground: Reports were received of bush migration in the fuselage rear spar frame. This Directive requires bushes in the front and rear spars to be inspected, and where necessary, oversize bushes to be installed. Amendment 1 introduced changes to the repeat inspection interval times.\n\nAmendment 2 is issued in response to a revision of the Requirement Document which amends the text for repeat inspection requirements.\n\nAmendment 1 of this Airworthiness Directive became effective on 31 December 1998.\n\nThe original issue of this Airworthiness Directive became effective on 10 October 1996.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose — ensuring inspection of wing attachment bushes in SC7 aircraft. Amendment 2 makes only technical wording changes to repeat inspection intervals without expanding the aircraft covered, the components affected, or the nature of the required action."},"complexity_factors":["Short, single-purpose safety directive under 300 words","Only 2 defined references (Shorts Mandatory Service Bulletin 53-68 Revision 3, UK CAA AD 009-01-96)","Simple conditional structure: one applicability clause, one requirement, one compliance deadline with a single exception clause","No nested definitions or cross-references to other legislation","Clear, chronological amendment history provided for context"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspections and corrective action on all SC7 (Short Skyvan) aircraft after discovery of migrating metal bushes in wing spar frames that can weaken wing attachments. Operators must inspect and, where required, fit oversize bushes per the manufacturer’s service bulletin to prevent catastrophic failure. Amendment 2 only revises the wording on repeat inspection intervals; it does not change the initial inspection requirement."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive's applicability remains 'All model SC7 aircraft' and the core requirement—to inspect front and rear spar frame bushes and install oversize bushes if necessary—remains unchanged. Amendment 2 only revises the wording for repeat inspection requirements in the Requirement Document rather than expanding the set of aircraft or introducing new types of mandatory corrective action (Background; Amendment 2)."},"complexity_factors":["Cross-reference to an external Requirement Document (Shorts Mandatory Service Bulletin 53-68 Revision 3) sets technical detail outside the AD, creating dependency on another document for compliance (Requirement).","Applicability is broad—'All model SC7 aircraft'—so the directive affects every operator of that type rather than a subset (Applicability).","Timing rule uses a flight-count trigger ('within 50 flights after 31 December 1998 unless the initial inspection is already accomplished'), which requires operators to track flight cycles and maintenance history precisely (Compliance).","Repeat inspection intervals are not stated in the AD text but delegated to the Requirement Document, producing operational ambiguity unless the service bulletin is consulted (Requirement; Amendment 2).","Remedial action may require fitting oversize bushes where necessary, imposing parts procurement, fitting labour and potential aircraft downtime (Background; Requirement).","Historical amendments: the AD has prior issues and earlier changes to repeat intervals (original AD 1996; Amendment 1 effective 31 December 1998), so operators must reconcile prior compliance with amended wording (Background).","Reference to a foreign authority (UK CAA AD 009-01-96) indicates alignment with another regulator but may create additional compliance-watch requirements for operators and maintainers (Note)."],"plain_english_summary":"This Directive requires owners/operators of all Short SC7 aeroplanes to inspect the wing‑attachment bushes in the fuselage front and rear spar frames following Shorts Mandatory Service Bulletin 53‑68 Revision 3 and to fit oversize bushes where necessary.\n\nThe initial inspection is required within 50 flights after 31 December 1998 unless already done, with repeat inspections at intervals set out in the Requirement Document. It responds to reported bush migration and therefore imposes inspection, parts and downtime costs on operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sc7-26-amdt-2-wing-attachment-bushes-in-fuselage-front-and-rear-spar-frames","history":"/api/acts/ad-sc7-26-amdt-2-wing-attachment-bushes-in-fuselage-front-and-rear-spar-frames/history","analysis":"/api/acts/ad-sc7-26-amdt-2-wing-attachment-bushes-in-fuselage-front-and-rear-spar-frames/analysis","conflicts":"/api/acts/ad-sc7-26-amdt-2-wing-attachment-bushes-in-fuselage-front-and-rear-spar-frames/conflicts","importantCases":"/api/acts/ad-sc7-26-amdt-2-wing-attachment-bushes-in-fuselage-front-and-rear-spar-frames/important-cases","documents":"/api/acts/ad-sc7-26-amdt-2-wing-attachment-bushes-in-fuselage-front-and-rear-spar-frames/documents"}}