{"id":"F2006B06882","name":"AD/SD3-60/37 - Horizontal Stabiliser Attachment Lugs","slug":"ad-sd3-60-37-horizontal-stabiliser-attachment-lugs","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114762,"registerId":"commonwealth-F2006B06882-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SD3-60/37 - Horizontal Stabiliser Attachment Lugs","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)  Short SD3-60 Series Aeroplanes\n\n \n\nAD/SD3-60/37 Horizontal Stabiliser Attachment Lugs 6/93\n\nApplicability: All SD3-60 aircraft with tailplanes which have accumulated 20,000 or more flights.\n\n \n\nRequirement: Modify the aircraft and ultrasonically inspect the forward and aft tailplane attachment lugs, upper and lower surfaces, in accordance with SB SD360-55-19.\n\n \n\nNote: SB SD360-55-19 has been classified mandatory by the UK CAA.\n\n \n\nCompliance: Before 29 July 1993. Reinspect at intervals of not more than 4000 flights.\n\n \n\nBackground:  The manufacturer has determined by continued testing that additional inspections are required on the horizontal stabiliser attachment lugs.\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\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The directive imposes a new mandatory technical requirement for SD3-60 aircraft whose tailplanes have accumulated 20,000 or more flights: aircraft must be modified and the forward and aft horizontal stabiliser attachment lugs ultrasonically inspected (upper and lower surfaces) in accordance with SB SD360-55-19, with initial compliance before 29 July 1993 and reinspections at intervals not exceeding 4,000 flights. The directive records that the manufacturer determined additional inspections were required (Background) and makes the SB mandatory for compliance (Requirement; Note)."},"complexity_factors":["Technical inspection method required: ultrasonic inspection of specific attachment lugs (Requirement).","Reference to an external Service Bulletin (SB SD360-55-19) for procedural detail (Requirement; Note).","Applicability threshold based on accumulated flights (>= 20,000 flights) which requires operators to check aircraft flight counts (Applicability).","Recurring inspection interval (every 4,000 flights) creates an ongoing maintenance schedule to track (Compliance).","Fixed initial compliance date (before 29 July 1993) imposes a one‑off deadline in addition to recurring tasks (Compliance)."],"plain_english_summary":"## Scope and Applicability\n\n- Who this applies to: All Short SD3-60 series aeroplanes (SD3-60) whose tailplanes have accumulated 20,000 or more flights. (Applicability)\n- Who issued it: Civil Aviation Safety Authority as an Airworthiness Directive under Part 39. (header)\n\n## Technical Requirements\n\n- What must be done: Modify the aircraft and perform an ultrasonic inspection of the horizontal (forward and aft) stabiliser attachment lugs on both upper and lower surfaces. The inspection and modification must be carried out in accordance with Service Bulletin SB SD360-55-19. (Requirement)\n- Referenced material: The directive relies on SB SD360-55-19 for the precise modification and inspection procedure. The directive notes that SB SD360-55-19 has been classified mandatory by the UK CAA. (Note)\n\n## Compliance Timeline\n\n- Initial compliance: The required modification and inspection must be completed before 29 July 1993. (Compliance)\n- Ongoing inspections: After the initial action, reinspect the specified attachment lugs at intervals of not more than 4,000 flights. (Compliance)\n\n## Regulatory Basis and Rationale\n\n- Stated reason: The manufacturer determined through continued testing that additional inspections of the horizontal stabiliser attachment lugs are required. This is recorded as the background rationale in the directive. (Background)\n\n## Who pays, who decides, and what behaviour changes\n\n- Who decides: The Civil Aviation Safety Authority issued the directive; the Service Bulletin specified by the directive (SB SD360-55-19) sets the technical method. (header; Requirement)\n- Who pays: Aircraft owners/operators are responsible for carrying out the modification and inspections required by the directive (Requirement). The directive itself specifies the actions to be taken but does not allocate funding. (Requirement)\n- Behaviour changes required: Operators must modify the aircraft as specified and carry out an ultrasonic inspection of the forward and aft tailplane attachment lugs (upper and lower surfaces) before the stated date, and then perform reinspections at intervals of no more than 4,000 flights. (Requirement; Compliance)\n\n## Practical notes\n\n- The directive ties mandatory compliance to a specific service bulletin for procedural detail; operators must follow SB SD360-55-19 to meet the directive's requirements. (Requirement; Note)\n- The directive applies only to aircraft meeting the flight-count threshold of 20,000 flights. (Applicability)\n"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused specifically on horizontal stabiliser attachment lugs for one aircraft type. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific applicability criterion (20,000+ flights)","Only one technical requirement referencing an external document (Service Bulletin SD360-55-19)","Simple compliance structure: one deadline plus recurring interval","No defined terms section","No cross-references to other legislation beyond the enabling regulations (Civil Aviation Regulations 1998, Part 39)","No conditional logic or exceptions","Extremely short document (approximately 150 words of substantive content)"],"plain_english_summary":"This is an **Airworthiness Directive** — a legally binding safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations.\n\n**What it does:**\nOrders owners and operators of **Short SD3-60 Series aircraft** (a type of regional turboprop plane) to carry out specific safety modifications and inspections on the **horizontal stabiliser attachment lugs** — the metal fittings that connect the tailplane (the small wings at the back of the aircraft) to the fuselage.\n\n**Who it affects:**\n- All operators of SD3-60 aircraft whose tailplanes have logged **20,000 or more flights**\n- Maintenance organisations servicing these aircraft\n\n**What must be done:**\n- **Modify** the aircraft structure\n- **Ultrasonically inspect** (using sound waves to detect cracks or flaws) the forward and aft attachment lugs on both upper and lower surfaces\n- Follow the procedures in **Service Bulletin SD360-55-19** (a technical instruction from the manufacturer that the UK aviation regulator has declared mandatory)\n\n**When:**\n- Initial compliance required **before 29 July 1993**\n- **Repeat inspections** every **4,000 flights** thereafter\n\n**Why it matters:**\nThe manufacturer discovered through ongoing testing that these critical structural components need extra scrutiny to prevent potential failure. The horizontal stabiliser is essential for controlling the aircraft's pitch (nose up/down movement). If attachment lugs fail, the tailplane could separate with catastrophic consequences."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sd3-60-37-horizontal-stabiliser-attachment-lugs","history":"/api/acts/ad-sd3-60-37-horizontal-stabiliser-attachment-lugs/history","analysis":"/api/acts/ad-sd3-60-37-horizontal-stabiliser-attachment-lugs/analysis","conflicts":"/api/acts/ad-sd3-60-37-horizontal-stabiliser-attachment-lugs/conflicts","importantCases":"/api/acts/ad-sd3-60-37-horizontal-stabiliser-attachment-lugs/important-cases","documents":"/api/acts/ad-sd3-60-37-horizontal-stabiliser-attachment-lugs/documents"}}