{"id":"F2006B09154","name":"AD/DHC-6/66 - Stabiliser Attachment Fittings","slug":"ad-dhc-6-66-stabiliser-attachment-fittings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52844,"registerId":"commonwealth-F2006B09154-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-6/66 - Stabiliser Attachment Fittings","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-6/66 Stabiliser Attachment Fittings 6/92\n\nApplicability: Model DHC-6 series, with serial numbers 3 through 820.\n\n \n\nRequirement: Action in accordance with the technical requirements of Transport Canada AD CF-92-04.\n\n \n\nNote: de Havilland SB 6/438 Rev.D and SB 6/513 refer.\n\n \n\nCompliance: As specified in the Requirement Document with a revised effective date of 21 May 1992 for Australian registered aircraft.\n\n \n\nBackground: Loose horizontal stabilizer forward and aft attachment fittings have been reported on several aircraft. This Directive is issued to align with the above referenced Transport Canada AD which supersedes AD CF-83-21 (AD/DHC-6/53) and AD CF-85-10 (AD/DHC-6/59).\n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This Australian AD aligns domestic obligations with Transport Canada AD CF-92-04 and, in doing so, supersedes earlier related ADs (CF-83-21 / AD/DHC-6/53 and CF-85-10 / AD/DHC-6/59) as stated in the Background. The directive therefore updates the operative technical requirement for the affected DHC-6 serial numbers and sets a revised effective date of 21 May 1992 for Australian-registered aircraft, replacing the earlier AD requirements. (Background; Compliance)"},"complexity_factors":["Directive delegates technical specifics to an external document (Transport Canada AD CF-92-04) rather than setting them out in full","Cross-reference to manufacturer service bulletins (de Havilland SB 6/438 Rev.D and SB 6/513) increases number of documents practitioners must consult","Applicability limited by aircraft serial number range (3–820), so implementers must identify affected airframes","Effective date is revised for Australian-registered aircraft, creating a jurisdiction-specific compliance timeline","Supersession of prior ADs (CF-83-21 and CF-85-10) requires checking historical directives for changes in obligations"],"plain_english_summary":"This AD makes compliance with Transport Canada AD CF‑92‑04 (and the de Havilland service bulletins) a legal requirement for Australian-registered de Havilland DHC‑6 aircraft serial numbers 3–820 to address reported loose horizontal‑stabilizer attachment fittings, effective 21 May 1992. Affected operators and their maintenance organisations must obtain and carry out the referenced inspections/repairs at their own cost to meet the Australian safety obligation."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft type. It supersedes two earlier directives on the same subject matter, representing an update rather than scope expansion. The document maintains its original narrow purpose: ensuring airworthiness of stabiliser attachment fittings."},"complexity_factors":["Single, clearly defined applicability (specific aircraft model and serial number range)","Single requirement referencing an external technical document (Transport Canada AD)","No defined terms section","No nested conditional logic or exceptions","Minimal cross-referencing (only two service bulletins and two superseded directives)","Short document (approximately 150 words of substantive content)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order for aircraft owners and operators.\n\n**What it does:**\n- Requires owners of specific **de Havilland DHC-6 Twin Otter aircraft** (serial numbers 3 through 820) to inspect and fix potential problems with the **horizontal stabiliser attachment fittings** — the metal brackets that connect the tail's horizontal wing to the aircraft body.\n\n**Why it matters:**\n- Loose attachment fittings have been found on several aircraft. If these fittings fail, the horizontal stabiliser (which controls the aircraft's pitch and stability) could detach or malfunction, potentially causing loss of control.\n- This directive replaces two earlier safety orders (from 1983 and 1985) with updated requirements from **Transport Canada** (Canada's aviation safety regulator).\n\n**Who must comply:**\n- Australian operators of affected DHC-6 Twin Otter aircraft.\n\n**What they must do:**\n- Follow the technical instructions in **Transport Canada AD CF-92-04**.\n- Check two specific service bulletins from the manufacturer: **SB 6/438 Rev.D** and **SB 6/513**.\n- Complete the work by **21 May 1992** (for Australian-registered aircraft)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-6-66-stabiliser-attachment-fittings","history":"/api/acts/ad-dhc-6-66-stabiliser-attachment-fittings/history","analysis":"/api/acts/ad-dhc-6-66-stabiliser-attachment-fittings/analysis","conflicts":"/api/acts/ad-dhc-6-66-stabiliser-attachment-fittings/conflicts","importantCases":"/api/acts/ad-dhc-6-66-stabiliser-attachment-fittings/important-cases","documents":"/api/acts/ad-dhc-6-66-stabiliser-attachment-fittings/documents"}}