{"id":"F2006B11205","name":"AD/LYC/80 - Turbocharger Oil Inlet Adaptor Bushing","slug":"ad-lyc-80-turbocharger-oil-inlet-adaptor-bushing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56918,"registerId":"commonwealth-F2006B11205-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LYC/80 - Turbocharger Oil Inlet Adaptor Bushing","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nLycoming Piston Engines\n\nAD/LYC/80 Turbocharger Oil Inlet Adaptor Bushing 3/87\n\nApplicability: All TIO, LTIO-540 Engines.\n\nRequirement: Replace the turbocharger oil inlet adaptor bushing if made of brass or bronze material, with a steel bushing.\n\nNote: Bushing P/N STD 1932 is an acceptable replacement.\n\nCompliance: Unless already accomplished, prior to the issue of the next Maintenance Release after 12 March 1987: and;\n\nAt each overhaul period ensure a bushing of acceptable steel material is fitted.\n\nBackground: Airworthiness Directive, AD/LYC/43, was cancelled in December 1985, the intent of which is now re-issued in response to an incident involving a Piper Navajo during flight. Loss of power and oil pressure resulted from the failure of the turbocharger oil inlet bushing made of brass material.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive restates the prior safety intent (previously in AD/LYC/43) and targets the same technical issue: replacing non-steel turbocharger oil inlet adaptor bushings on TIO and LTIO-540 engines with steel equivalents. The operative scope — which engines are covered and that brass/bronze bushings must be replaced with steel — is consistent with that stated intent and is not expanded in this text (Applicability; Requirement; Background)."},"complexity_factors":["Narrow applicability (only All TIO and LTIO-540 engines) (Applicability)","Single, well-defined mechanical action (replace brass/bronze bushing with steel) (Requirement)","Clear compliance timeline (before next Maintenance Release after 12 March 1987) plus recurring obligation at each overhaul (Compliance)","Presence of an acceptable replacement part number (P/N STD 1932) reducing technical ambiguity (Note)","Lack of detailed technical specifications for steel grade or inspection methods increases minor implementation uncertainty (Requirement; Note)","Reference to a prior cancelled AD and re-issuance of intent adds a small historical/administrative layer (Background)"],"plain_english_summary":"What this directive changes (mechanically)\n\n- It requires that the turbocharger oil inlet adaptor bushing on certain Lycoming piston engines be replaced if the existing bushing is made of brass or bronze. The replacement must be a steel bushing (Requirement). An example acceptable replacement part is bushing P/N STD 1932 (Note).\n\nWho and what is affected\n\n- Applicability: the rule applies to all TIO and LTIO-540 Lycoming piston engines (Applicability).\n- Timing: if the replacement has not already been done, it must be completed before the issue of the next Maintenance Release after 12 March 1987. After that, at each engine overhaul the bushing fitted must be of an acceptable steel material (Compliance).\n\nOfficial reason given\n\n- The directive states it is re-issuing the intent of a previously cancelled AD (AD/LYC/43) in response to an in-flight incident involving a Piper Navajo. The incident is described as a loss of power and oil pressure caused by failure of a turbocharger oil inlet bushing that was made of brass (Background). This is presented in the AD as the operational safety rationale for mandating steel bushings.\n\nPractical effects, incentives and costs (source-linked)\n\n- Who pays: Owners/operators of affected aircraft bear the direct cost of parts and labour to replace brass/bronze bushings with steel ones, since the requirement applies to those engines (Applicability; Requirement; Compliance).\n- Behaviour change required: Maintenance organisations and mechanics must inspect the turbocharger oil inlet adaptor bushing material and replace brass/bronze bushings with steel before the next Maintenance Release (if not already done) and ensure steel bushings at each overhaul (Requirement; Compliance).\n- Ongoing compliance burden: After the initial required replacement, the recurring obligation is to confirm steel material at each overhaul. The AD sets clear, simple inspection/replacement milestones rather than continuous monitoring (Compliance).\n- Supply/implementation considerations: The AD identifies an acceptable replacement part number (P/N STD 1932), which reduces ambiguity about what satisfies the requirement but may concentrate demand on suppliers of that part (Note).\n- Trade-offs and opportunity costs: The immediate trade-off is cost and downtime for replacement versus reduced risk of bushing-related failure. The AD does not quantify costs or required labour time (Requirement; Compliance).\n- Bureaucratic discretion and clarity: The directive is prescriptive about the material change (to steel) and provides a compliance deadline; it leaves little administrative discretion about whether to comply but does not specify testing methods or exact steel specification beyond an acceptable replacement part number (Requirement; Note).\n\nWhat the source does not specify\n\n- The AD does not set a precise steel grade or technical performance standard in the text (it only cites an acceptable P/N), nor does it provide cost estimates, approved labour procedures, or inspection protocols beyond the timing requirements (Requirement; Note; Compliance).\n\nBottom line (mechanical and operational):\n\n- For all TIO and LTIO-540 Lycoming engines, any turbocharger oil inlet adaptor bushing made of brass or bronze must be replaced with a steel bushing (acceptable example P/N STD 1932). The replacement deadline is before the next Maintenance Release after 12 March 1987 if not already done, and operators must ensure steel bushings are fitted at each overhaul thereafter (Applicability; Requirement; Compliance). The AD bases the mandate on a reported in-flight failure linked to a brass bushing (Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope — addressing a specific material failure mode in a defined engine component. The background note references a cancelled earlier directive, but this does not represent scope creep; rather, it confirms the directive remains tightly focused on the original safety issue (brass/bronze bushing failure) without expanding to cover unrelated engine systems or broader operational requirements."},"complexity_factors":["Single, specific mechanical component addressed","Clear applicability limited to two engine model families (TIO, LTIO-540)","Simple binary compliance test: brass/bronze = replace, steel = acceptable","One defined part number (STD 1932) provided as acceptable alternative","Straightforward deadline structure (next Maintenance Release after fixed date)","No nested exceptions, conditional clauses, or cross-references to other legislation beyond the cancelled AD/LYC/43 mentioned in background","Total length under 200 words"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires aircraft owners and mechanics to fix a specific mechanical problem.\n\n**What it does:**\nOrders the replacement of a small but critical engine part — the **turbocharger oil inlet adaptor bushing** — on certain Lycoming aircraft engines. If the existing bushing is made of **brass or bronze**, it must be swapped for a **steel** version.\n\n**Who it affects:**\nAnyone who owns, operates, or maintains aircraft with **TIO or LTIO-540 model Lycoming piston engines** (these are turbocharged six-cylinder engines commonly used in light aircraft like the Piper Navajo).\n\n**Why it matters:**\nA brass or bronze bushing can fail in flight, causing **catastrophic engine damage** — loss of power and oil pressure. This actually happened to a Piper Navajo, prompting this safety order. The steel replacement won't fail in the same way.\n\n**What must be done:**\n- **By when:** Before the aircraft's next **Maintenance Release** (a formal certificate saying the plane is safe to fly) issued after 12 March 1987.\n- **Ongoing:** At every engine overhaul, mechanics must check that a steel bushing is installed.\n- **Approved part:** Bushing part number **STD 1932** is acceptable.\n\n**Background:** This replaces an earlier cancelled directive (AD/LYC/43) after a real incident proved the danger was still present."}},"importantCases":[],"_links":{"self":"/api/acts/ad-lyc-80-turbocharger-oil-inlet-adaptor-bushing","history":"/api/acts/ad-lyc-80-turbocharger-oil-inlet-adaptor-bushing/history","analysis":"/api/acts/ad-lyc-80-turbocharger-oil-inlet-adaptor-bushing/analysis","conflicts":"/api/acts/ad-lyc-80-turbocharger-oil-inlet-adaptor-bushing/conflicts","importantCases":"/api/acts/ad-lyc-80-turbocharger-oil-inlet-adaptor-bushing/important-cases","documents":"/api/acts/ad-lyc-80-turbocharger-oil-inlet-adaptor-bushing/documents"}}