{"id":"F2006B06855","name":"AD/SD3-60/12 Amdt 1 - Horizontal Stabilizer Rear Spar","slug":"ad-sd3-60-12-amdt-1-horizontal-stabilizer-rear-spar","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114731,"registerId":"commonwealth-F2006B06855-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SD3-60/12 Amdt 1 - Horizontal Stabilizer Rear Spar","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/SD3-60/12\n\nAmdt 1\n\n\nHorizontal Stabilizer Rear Spar 4/86\n\n \n\nApplicability: All model SD3-60 with S/Nos SH3601 to SH3678. Requirement:  Action in accordance with Shorts SB SD360-55-06 R1. Compliance:               Prior to 4800 hours total time in service.\n\nBackground:  The manufacturer reports instances of the existing standard blind rivets in the horizontal stabilizer becoming loose. The rivets attach the bottom skin to the rear spar. This Directive is amended to change the compliance requirement in accordance with Revision 1 of the Service Bulletin.\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 AD as amended alters the compliance requirement to align with Revision 1 of Shorts Service Bulletin SD360-55-06 R1. The text states: \"This Directive is amended to change the compliance requirement in accordance with Revision 1 of the Service Bulletin,\" and the Compliance provision requires the action \"Prior to 4800 hours total time in service.\""},"complexity_factors":["Narrow applicability limited to a defined serial-number range (SH3601–SH3678) reduces scope complexity.","Requires following an external technical document (Shorts SB SD360-55-06 R1), so compliance depends on that document’s technical detail and availability.","Fixed compliance threshold (prior to 4,800 hours TIS) creates scheduling constraints across operators.","Safety-critical aircraft structure work can require qualified maintenance personnel and specific tooling, adding implementation complexity.","Amendment changes the compliance requirement, so operators must track revisions to the SB and the AD."],"plain_english_summary":"# What this directive does\n\nThis Airworthiness Directive (AD) requires operators of certain Shorts SD3-60 aeroplanes to carry out a specific maintenance action described by the manufacturer. Mechanically, it mandates that the work set out in Shorts Service Bulletin SD360-55-06 Revision 1 (SB SD360-55-06 R1) be performed on the horizontal stabilizer rear spar before each affected aircraft reaches 4,800 hours total time in service. (See: \"Requirement: Action in accordance with Shorts SB SD360-55-06 R1\" and \"Compliance: Prior to 4800 hours total time in service\").\n\n# Who is affected\n\n- The directive applies to all SD3-60 aircraft with serial numbers SH3601 through SH3678. (See: \"Applicability: All model SD3-60 with S/Nos SH3601 to SH3678\").\n\n# Why it matters (official rationale and what the text says)\n\n- The manufacturer reported that standard blind rivets attaching the bottom skin to the horizontal stabilizer rear spar have been found to become loose. The directive implements the manufacturer’s corrective instructions. (See: \"Background: The manufacturer reports instances of the existing standard blind rivets in the horizontal stabilizer becoming loose. The rivets attach the bottom skin to the rear spar.\").\n- The AD text states it has been amended to change the compliance requirement in line with Revision 1 of the Service Bulletin. (See: last sentence of \"Background\").\n\n# Who pays and who decides\n\n- Operators/owners of the affected aircraft pay for and arrange the work required by the Service Bulletin. (Implied by \"Requirement: Action in accordance with Shorts SB SD360-55-06 R1\".)\n- The Civil Aviation Safety Authority (CASA) issues the mandatory AD; compliance must follow the manufacturer’s Service Bulletin as mandated by the AD. The maintenance provider (or operator’s engineer) decides how to carry out the mandated work, subject to the SB’s procedures and applicable maintenance standards.\n\n# Behavioural and operational effects\n\n- Operators must schedule the required inspections/repairs and complete them before each aircraft reaches 4,800 hours total time in service, which may require taking aircraft out of service for maintenance earlier than planned. (See: \"Compliance: Prior to 4800 hours total time in service\").\n- The AD directs performance of a specific technical action rather than leaving the choice of remedy open; the SB provides the technical instructions to be followed.\n\n# Costs, trade-offs and implementation risks (concrete mechanisms)\n\n- Direct costs: operators incur labour and parts costs to perform the SB work. The AD does not specify parts or time, so costs depend on the SB’s procedures, parts required and local labour rates. (See: \"Requirement: Action in accordance with Shorts SB SD360-55-06 R1\").\n- Scheduling and availability: complying before 4,800 hours may force operators to reallocate maintenance slots and aircraft utilisation; this is an opportunity cost in flight hours deferred.\n- Dependency on SB content: the AD requires compliance with a document external to the AD (Shorts SB SD360-55-06 R1). Operators must obtain and follow that SB; the AD’s practical effect depends on the SB’s technical detail and parts availability.\n- Implementation risk: if the SB requires replacement or specialized workmanship (for example, replacing rivets or re-fastening skins), that work needs appropriately qualified maintenance personnel and facilities; incorrect execution could leave the underlying issue unaddressed.\n- Enforcement and discretion: CASA sets the compliance deadline; operators have limited discretion about when and where to perform the SB work, provided it is done before 4,800 hours TIS and in accordance with the SB.\n\n# Concrete citation of the source statements\n\n- Applicability and serial numbers: \"Applicability: All model SD3-60 with S/Nos SH3601 to SH3678.\" \n- Required action: \"Requirement: Action in accordance with Shorts SB SD360-55-06 R1.\" \n- Timing: \"Compliance: Prior to 4800 hours total time in service.\" \n- Reason given by manufacturer: \"The manufacturer reports instances of the existing standard blind rivets in the horizontal stabilizer becoming loose. The rivets attach the bottom skin to the rear spar.\" \n- Amendment note: \"This Directive is amended to change the compliance requirement in accordance with Revision 1 of the Service Bulletin.\"\n"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive addressing a specific mechanical defect in a specific aircraft model. The amendment (Amdt 1) merely updates the compliance timing to match a revised manufacturer service bulletin — it does not expand the scope beyond the original safety purpose."},"complexity_factors":["Extremely short document (under 200 words)","Only 4 operative provisions: applicability, requirement, compliance, and background","No defined terms section — all language is technical but self-explanatory to aviation professionals","Single cross-reference to external manufacturer document (Service Bulletin)","No conditional logic, exceptions, or nested provisions","Straightforward command structure: identify aircraft → do this action → by this deadline"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires aircraft owners or operators to fix a specific mechanical problem.\n\n**What it does:**\n- **Targets:** Short SD3-60 series aeroplanes (a type of regional turboprop aircraft) with serial numbers SH3601 through SH3678\n- **The problem:** The manufacturer found that blind rivets holding the bottom skin to the rear spar of the horizontal stabilizer (the tail wing that keeps the plane level) were becoming loose — a potential safety risk\n- **The fix:** Owners must follow the manufacturer's Service Bulletin (Shorts SB SD360-55-06 R1) to address the rivet issue\n- **Deadline:** Before the aircraft reaches 4,800 total flight hours\n\n**Why it matters:** Loose rivets in a critical flight control surface could lead to structural failure. This directive makes the repair legally mandatory rather than optional. The \"Amdt 1\" indicates this is an updated version that changes when the fix must be completed based on revised manufacturer guidance.\n\n**Who must comply:** Anyone operating or maintaining these specific Short SD3-60 aircraft in Australia."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sd3-60-12-amdt-1-horizontal-stabilizer-rear-spar","history":"/api/acts/ad-sd3-60-12-amdt-1-horizontal-stabilizer-rear-spar/history","analysis":"/api/acts/ad-sd3-60-12-amdt-1-horizontal-stabilizer-rear-spar/analysis","conflicts":"/api/acts/ad-sd3-60-12-amdt-1-horizontal-stabilizer-rear-spar/conflicts","importantCases":"/api/acts/ad-sd3-60-12-amdt-1-horizontal-stabilizer-rear-spar/important-cases","documents":"/api/acts/ad-sd3-60-12-amdt-1-horizontal-stabilizer-rear-spar/documents"}}