{"id":"F2006B08634","name":"AD/CON/52 Amdt 1 - Crankshaft Bearing Integrity and Piston Pin Replacement","slug":"ad-con-52-amdt-1-crankshaft-bearing-integrity-and-piston-pin-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51638,"registerId":"commonwealth-F2006B08634-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CON/52 Amdt 1 - Crankshaft Bearing Integrity and Piston Pin Replacement","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)  \nTeledyne Continental Motors Piston Engines\n\nAD/CON/52\n\nAmdt 1\n\n  \n\nCrankshaft Bearing Integrity and Piston Pin Replacement\n\n  \n8/88\n\nApplicability: TSIO-520BE engines, S/N 528001 through 528337, and TSIO-520CE engines S/N 530001 through 530140.\n\nRequirement: Action in accordance with TCM SB's M87-25 and M87-26 as applicable.\n\nNote: FAA AD 87-26-08 Amdt 39-5883 refers.\n\nCompliance: Before further flight after 12 January 1988.\n\nBackground: This Directive has been raised following advice of 7 crankshaft and 6 piston pin failures in TSIO-520BE engines. Amendment 1 includes reference to TSIO-520CE engines as this model has parts in common with the \"BE\" and operates in a similar environment. This Directive supersedes AD/CON/48 which has been cancelled.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"Amendment 1 expanded the directive’s scope by adding TSIO-520CE engines to the list of affected units because that model shares parts and operating environment with the TSIO-520BE. The amendment also supersedes the earlier AD/CON/48 which has been cancelled, thereby altering the set of regulatory requirements that apply to these engine groups. (Background)"},"complexity_factors":["Narrow applicability defined by specific engine models and serial number ranges (Applicability)","Mandates following manufacturer service bulletins rather than prescribing technical steps directly (Requirement)","Immediate compliance deadline tying work to next flight after a specified date (Compliance)","Cross-reference to an FAA airworthiness directive (Note)","Amendment expanded affected population by adding a model with shared parts (Background)","Operational complexity largely arises from maintenance logistics (parts, labour, downtime), which are external to the text"],"plain_english_summary":"### What this directive does\n- Applies to Teledyne Continental Motors (TCM) piston engines TSIO-520BE (serial numbers 528001–528337) and TSIO-520CE (serial numbers 530001–530140). (Applicability)\n- Requires operators to carry out the work described in TCM Service Bulletins M87-25 and M87-26, as applicable. (Requirement)\n- Must be complied with before the next flight after 12 January 1988. (Compliance)\n- It replaces an earlier directive (AD/CON/48) and adds the TSIO-520CE model because it shares parts and operating conditions with the TSIO-520BE. (Background)\n\n### Who pays and who decides\n- Aircraft owners/operators are responsible for arranging and paying for the inspections and any replacement or repair work required by the TCM service bulletins. (Requirement; Compliance)\n- Maintenance providers or certificated mechanics will apply the specific procedures in the TCM service bulletins when performing the work; the Civil Aviation Safety Authority (CASA) enforces the requirement by issuing the directive. (Requirement)\n\n### How it works mechanically\n- The directive does not itself prescribe technical steps; it mandates compliance with the manufacturer’s service bulletins M87-25 and M87-26, which contain the technical instructions for inspection and replacement actions. The AD therefore converts those manufacturer procedures into a mandatory regulatory requirement for the listed engines. (Requirement)\n\n### Stated reason for the directive\n- CASA issued the directive after being advised of seven crankshaft failures and six piston pin failures in TSIO-520BE engines. By extension, the TSIO-520CE was included because it shares parts and operates in a similar environment. (Background)\n- The directive also notes a related FAA airworthiness directive. (Note)\n\n### Practical effects, incentives and trade-offs\n- Immediate grounding risk: Because compliance is required before the next flight after the specified date, affected aircraft may be grounded until the work is done, creating direct time and operational costs for operators. (Compliance)\n- Direct costs fall on owners/operators: costs include labour, replacement parts, and any downtime for maintenance facilities. (Requirement; Compliance)\n- Dependence on manufacturer documentation: The AD delegates the technical decision-making to the procedures in TCM SB M87-25 and M87-26. Operators must follow those SBs to meet the AD, so the clarity and completeness of those SBs affect implementation risk and compliance burden. (Requirement)\n- Supply and capacity risk: If many engines are affected, availability of parts and maintenance slots could delay compliance and increase costs. The directive text does not address parts supply or staging. (Requirement; Background)\n- Regulatory cross-reference: The AD cites an FAA directive, which may affect how operators and maintenance organisations coordinate compliance with international guidance. (Note)\n- Scope adjustment: Amendment 1 expanded the set of affected engines to include another model that shares parts and operating environment with the originally listed engines. This increases the population that must comply and therefore increases aggregate compliance costs. (Background)\n\n### Implementation risks and administrative details\n- Responsibility for correct identification rests with operators to determine whether an engine’s serial number falls within the listed ranges. (Applicability)\n- The AD converts manufacturer service bulletins into mandatory actions; any ambiguity or variation in the SBs could create enforcement or interpretation issues for CASA and operators. (Requirement)\n\n(Sections cited in parentheses: Applicability; Requirement; Compliance; Background; Note.)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment slightly expands the original scope by adding TSIO-520CE engines to the existing TSIO-520BE coverage. This is a minor technical expansion based on shared parts and operating environments, not a fundamental shift in purpose. The directive remains tightly focused on addressing specific mechanical failures in specific engine models."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 defined applicability ranges (specific engine serial numbers)","Single compliance requirement with reference to external technical documents (service bulletins)","No nested exceptions or conditional logic","No cross-references to other legislation beyond the cancelled predecessor directive","Straightforward cause-and-effect: identified failures → mandatory action → specific deadline"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it as a \"recall notice\" for aircraft engines, but with legal force.\n\n**What it does:**\n- Requires owners and operators of specific **Teledyne Continental Motors (TCM) piston engines** to inspect and replace certain parts before flying again.\n- Specifically targets **crankshaft bearings** (the parts that let the crankshaft spin smoothly) and **piston pins** (the metal rods connecting pistons to the crankshaft).\n\n**Who it affects:**\n- Owners and operators of aircraft with **TSIO-520BE engines** (serial numbers 528001 through 528337) and **TSIO-520CE engines** (serial numbers 530001 through 530140).\n- These are typically used in light aircraft like the Beechcraft Bonanza or similar general aviation planes.\n\n**Why it matters:**\n- **Safety critical:** Seven crankshaft failures and six piston pin failures had already occurred in these engines. These parts breaking in flight can cause catastrophic engine failure.\n- **Mandatory compliance:** Aircraft cannot legally fly until the required work is done (\"Before further flight after 12 January 1988\").\n- **Updated coverage:** This amendment expands the original directive to include the TSIO-520CE model because it shares parts with the BE model and operates under similar conditions.\n\n**What must be done:**\n- Follow the manufacturer's service bulletins **TCM SB M87-25 and M87-26** (technical instructions from the engine maker on how to fix the problem).\n\n**Key point:** This directive replaces and cancels an earlier one (AD/CON/48), showing how safety requirements evolve as new information emerges."}},"importantCases":[],"_links":{"self":"/api/acts/ad-con-52-amdt-1-crankshaft-bearing-integrity-and-piston-pin-replacement","history":"/api/acts/ad-con-52-amdt-1-crankshaft-bearing-integrity-and-piston-pin-replacement/history","analysis":"/api/acts/ad-con-52-amdt-1-crankshaft-bearing-integrity-and-piston-pin-replacement/analysis","conflicts":"/api/acts/ad-con-52-amdt-1-crankshaft-bearing-integrity-and-piston-pin-replacement/conflicts","importantCases":"/api/acts/ad-con-52-amdt-1-crankshaft-bearing-integrity-and-piston-pin-replacement/important-cases","documents":"/api/acts/ad-con-52-amdt-1-crankshaft-bearing-integrity-and-piston-pin-replacement/documents"}}