{"id":"F2006B09153","name":"AD/DHC-6/65 - Wing Strut Chafing","slug":"ad-dhc-6-65-wing-strut-chafing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52840,"registerId":"commonwealth-F2006B09153-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-6/65 - Wing Strut Chafing","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)  DHC-6 (Twin Otter) Series Aeroplanes\n\n \n\nAD/DHC-6/65 Wing Strut Chafing 4/92\n\nApplicability: All models.\n\n \n\nRequirement: Inspect for the presence of the protective nylon shield incorporated in the wing strut upper fairings by de Havilland Modification 6/1581.\n\n \n\nIf the shield is not installed, visually inspect the struts for damage in accordance with de Havilland Service Bulletin 6/342, and incorporate Modification 6/1581.\n\n \n\nNote: Transport Canada Airworthiness Directive CF-91-30 dated 8 August 1991 refers.\n\n \n\nCompliance: 1. Inspect within 25 hours time in service after 2 April 1992.\n\n \n\n2. Modify before 25 June 1992.\n\n \n\nBackground: Transport Canada’s aging aircraft review identified this as mandatory action.\n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD keeps the original scope set out in the text: it applies to all DHC-6 models and requires inspection for the presence of the protective nylon shield and, if absent, inspection for strut damage per Service Bulletin 6/342 and incorporation of Modification 6/1581. There is no indication within the AD text that the scope has been expanded or narrowed from its stated requirements. (Applicability; Requirement; Compliance; Background)"},"complexity_factors":["Limited and specific applicability (all DHC-6 models) reduces legal scope.","Single clear inspection trigger (presence of nylon shield) and a single prescriptive remedy (install Mod 6/1581) simplify required actions. (Requirement)","Short, fixed compliance deadlines create scheduling pressure for operators but do not add legal ambiguity. (Compliance)","Dependence on external technical documents (de Havilland Service Bulletin 6/342 and Modification 6/1581) introduces operational complexity because those documents contain the technical steps and possible discretionary judgements for damage assessment. (Requirement)","Potential for follow-on repairs if damage is found makes cost and downtime uncertain, creating practical complexity for operators scheduling maintenance. (Requirement)","Cross-reference to a foreign authority AD (Transport Canada) adds contextual complexity but not additional procedural steps in this AD. (Note)"],"plain_english_summary":"This AD applies to all de Havilland DHC‑6 Twin Otter aircraft and requires operators to check wing strut upper fairings for a protective nylon shield; if absent, inspect struts for damage per the referenced service bulletin and install Mod 6/1581. It affects owners, operators and maintenance providers, and stems from an aging‑aircraft review to ensure strut protection and structural safety."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused specifically on wing strut chafing in DHC-6 aircraft. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific aircraft type (DHC-6 Twin Otter)","One clear requirement chain: check for shield → if missing, inspect → then modify","Only two defined compliance deadlines","No nested exceptions or conditional logic","References only two external technical documents (Service Bulletin 6/342 and Modification 6/1581)","Total length: approximately 150 words"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order for aircraft owners and operators.\n\n**What it does:**\nOrders inspections and repairs on **de Havilland DHC-6 Twin Otter aircraft** (a twin-engine turboprop plane commonly used for regional transport and skydiving).\n\n**The safety problem:**\nThe wing struts (the structural supports connecting the wings to the fuselage) can suffer from **chafing** — wear caused by rubbing. Without a protective nylon shield, this rubbing can damage the struts, potentially compromising the aircraft's structural integrity.\n\n**Who must do what:**\n- **All DHC-6 Twin Otter operators** must check whether their aircraft have a specific protective shield (Modification 6/1581)\n- If the shield is missing: visually inspect the struts for damage, then install the protective modification\n\n**Deadlines:**\n- **Inspection:** Within 25 flight hours after 2 April 1992\n- **Modification:** Before 25 June 1992\n\n**Why it matters:**\nThis prevents potential structural failure of wing struts. The directive was triggered by Transport Canada's aging aircraft review, which identified this as a critical safety issue requiring immediate action."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-6-65-wing-strut-chafing","history":"/api/acts/ad-dhc-6-65-wing-strut-chafing/history","analysis":"/api/acts/ad-dhc-6-65-wing-strut-chafing/analysis","conflicts":"/api/acts/ad-dhc-6-65-wing-strut-chafing/conflicts","importantCases":"/api/acts/ad-dhc-6-65-wing-strut-chafing/important-cases","documents":"/api/acts/ad-dhc-6-65-wing-strut-chafing/documents"}}