{"id":"F2006B07257","name":"AD/T53/9 - Second Stage Gas Producer Cylinder Bolts - Replacement","slug":"ad-t53-9-second-stage-gas-producer-cylinder-bolts-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49159,"registerId":"commonwealth-F2006B07257-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/T53/9 - Second Stage Gas Producer Cylinder Bolts - Replacement","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 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  AlliedSignal (Lycoming) Turbine Engines - T53 Series\n\n \n\nAD/T53/9 Second Stage Gas Producer Cylinder Bolts - Replacement\n\n\n1/86\n\n \n\nApplicability: All T5313 Series and T53-L-13 Series except those exempted in Lycoming Service Bulletin No. 0028 Rev. No. 2.\n\n \n\nDocument: 1. Lycoming SB No. 0028, Rev. 2; or\n\n \n\n2. FAA AD 75-12-12; or\n\n \n\n3. AD/LYC-T/10B.\n\n \n\nCompliance: As per paragraph 1D of Lycoming SB No. 0028, Rev. No. 2, with effect from 28 February 1975.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused specifically on bolt replacement in a defined engine series. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (approximately 200 words)","Only 2 defined applicability categories (T5313 Series and T53-L-13 Series)","Single compliance requirement referencing external document (Lycoming SB No. 0028)","One exemption clause (those covered by Lycoming Service Bulletin No. 0028 Rev. No. 2)","No nested conditional logic or cross-references to other legislation sections","Straightforward command structure: applies to X, do Y by Z date"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** issued by Australia's Civil Aviation Safety Authority (CASA) that mandates the replacement of specific bolts in certain aircraft turbine engines.\n\n**What it does:**\n- Requires owners and operators of **AlliedSignal (Lycoming) T53 series turbine engines** to replace the **second stage gas producer cylinder bolts** according to manufacturer instructions.\n\n**Who it affects:**\n- Anyone operating aircraft with **T5313 Series or T53-L-13 Series engines**, unless their specific engine model is exempted under Lycoming Service Bulletin No. 0028 Revision 2.\n\n**Why it matters:**\n- Airworthiness Directives are legally binding safety orders. If you don't comply, your aircraft is considered **unairworthy** (not legally safe to fly). This particular directive addresses potential failures in critical engine components that could lead to engine failure or accidents.\n\n**Key compliance details:**\n- Follow the instructions in **Lycoming Service Bulletin No. 0028, Revision 2** (or equivalent FAA or Australian documents)\n- Compliance was required from **28 February 1975** onwards\n\n**In simple terms:** If you own or fly a helicopter or aircraft with this specific Lycoming engine, you must have replaced these particular bolts by the deadline, following the manufacturer's exact instructions."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text provides no indication that the scope has been changed from an earlier or original instrument. It states applicability (all T5313 and T53-L-13 series except engines exempted in Lycoming SB No. 0028 Rev. No. 2) and mandates compliance by reference to paragraph 1D of that service bulletin, with an effective date. No material changes to scope are evident within the supplied text."},"complexity_factors":["Narrow, technical subject limited to a single component on specific engine models (T5313 and T53-L-13) (Applicability).","Primary action is achieved by cross-reference to external documents (Lycoming SB No. 0028 Rev. No. 2, FAA AD 75-12-12, AD/LYC-T/10B) rather than by in-text technical instruction (Document).","Exemptions are handled by the referenced service bulletin rather than within the directive, requiring users to consult another document to determine applicability (Applicability).","Compliance obligation is short on procedural detail and depends on locating paragraph 1D of the service bulletin, creating a document-navigation burden (Compliance).","Historical effective date specified (28 February 1975) but no phased timetable or staged compliance windows in the directive text (Compliance)."],"plain_english_summary":"This airworthiness directive requires owners/operators of certain AlliedSignal (Lycoming) T5313 and T53‑L‑13 series engines to replace second‑stage gas producer cylinder bolts, by following paragraph 1D of Lycoming Service Bulletin No. 0028 Rev. No. 2 (or the equivalent FAA/AD/LYC references). Engines explicitly exempted in that service bulletin are excluded.\n\nThe cost and downtime fall to operators; the directive sets the requirement and effective date but relies on the referenced documents for technical detail and exemptions."}},"importantCases":[],"_links":{"self":"/api/acts/ad-t53-9-second-stage-gas-producer-cylinder-bolts-replacement","history":"/api/acts/ad-t53-9-second-stage-gas-producer-cylinder-bolts-replacement/history","analysis":"/api/acts/ad-t53-9-second-stage-gas-producer-cylinder-bolts-replacement/analysis","conflicts":"/api/acts/ad-t53-9-second-stage-gas-producer-cylinder-bolts-replacement/conflicts","importantCases":"/api/acts/ad-t53-9-second-stage-gas-producer-cylinder-bolts-replacement/important-cases","documents":"/api/acts/ad-t53-9-second-stage-gas-producer-cylinder-bolts-replacement/documents"}}