{"id":"F2006B07269","name":"AD/TB 200/2 - Exhaust System","slug":"ad-tb-200-2-exhaust-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49194,"registerId":"commonwealth-F2006B07269-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TB 200/2 - Exhaust System","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAerospatiale (Socata) TB 200 Series Aeroplanes\n\nAD/TB 200/2 Exhaust System 10/99\n\nApplicability: TB200 aircraft serial numbers 1 through 1619 not incorporating the requirements of SOCATA Service Bulletin SB 10-074 78, Amendment 1.\n\nRequirement: To prevent the failure of the exhaust system; modify the exhaust system in accordance with the requirements of SOCATA Service Bulletin SB 10-074 78, Amendment 1.\n\nNote: DGAC Airworthiness Directive 94-067 (A) R1 refers.\n\nCompliance: Within 50 hours time in service from the effective date of this directive.\n\nThis Airworthiness Directive becomes effective on 7 October 1999.\n\nBackground: This directive has been issued to require the replacement of double plain nut locking of the exhaust pipe connections with single self locking nuts and the replacement of the cylinder exhaust mount stud plain nuts and lock washers with self locking nuts. The requirement reflects reports of the original exhaust system coming loose in service.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive requires the specific replacement of exhaust-system fastenings for TB200 serials 1–1619 not already modified (Applicability; Requirement). The Background states the same objective—to prevent exhaust system failure by addressing nuts and mount hardware that have come loose—so the scope as imposed (hardware replacement for those serials) aligns with the stated original intent (Background)."},"complexity_factors":["Narrow applicability limited to TB200 serial numbers 1–1619 not already modified","Single, narrowly defined mechanical modification (nuts and lock washers) to follow a manufacturer service bulletin","Short compliance window of 50 hours time in service creates scheduling and operational pressure","Requirement depends on availability and use of SOCATA Service Bulletin SB 10-074 78, Amendment 1 (external document reliance)","Administrative task to verify prior incorporation of the service bulletin for each aircraft"],"plain_english_summary":"What this instrument changes mechanically\n\n- It requires a specific change to the exhaust hardware on certain Aerospatiale (SOCATA) TB 200 series aeroplanes: replace existing double plain nut locking at exhaust pipe connections with single self-locking nuts, and replace plain nuts and lock washers on the cylinder exhaust mount stud with self-locking nuts (Requirement; Background).\n\nWho it applies to\n\n- It applies to TB200 aircraft with serial numbers 1 through 1619 that have not already had SOCATA Service Bulletin SB 10-074 78, Amendment 1 incorporated (Applicability).\n\nWhat the regulator says the purpose is\n\n- The directive states its purpose is to prevent failure of the exhaust system, based on reports that the original exhaust hardware had come loose in service (Background). That purpose is explicitly linked to the mechanical changes required (Requirement).\n\nKey compliance rules and timing\n\n- Operators/owners must carry out the modification in accordance with SOCATA Service Bulletin SB 10-074 78, Amendment 1 (Requirement).\n- The modification must be completed within 50 hours time in service from the directive’s effective date (Compliance).\n- The directive became effective on 7 October 1999 (header).\n\nWho pays, who decides, and what behaviour changes\n\n- Who pays: aircraft owners/operators of the affected TB200 serial numbers must provide parts and labour to perform the modification. The text makes the requirement mandatory for those aircraft (Applicability; Requirement).\n- Who decides: the Civil Aviation Safety Authority issued the airworthiness directive and sets the compliance requirement (header; Compliance).\n- Behaviour changes: affected owners/operators must schedule and carry out the specified hardware replacements within the stated 50-hour window and use the service bulletin as the method (Requirement; Compliance).\n\nCosts, incentives, trade-offs and implementation issues (source-grounded)\n\n- Direct costs: the action requires purchasing replacement self-locking nuts and associated parts and paying for installation (Requirement). Those costs are borne by the affected owners/operators (Applicability; Requirement).\n- Time and operational cost: the aircraft will require maintenance time and may be out of service while the modification is performed; compliance must occur within 50 hours time in service, which creates a scheduling constraint (Compliance).\n- Reliance on a manufacturer document: the directive makes compliance conditional on following SOCATA Service Bulletin SB 10-074 78, Amendment 1, which delegates specification of the technical steps to the manufacturer’s bulletin (Requirement). That creates dependence on the bulletin’s availability and on technicians able to follow it.\n- Verification burden: owners/operators must establish whether their aircraft already ‘‘incorporates the requirements’’ of the referenced service bulletin; those that have already done so are excluded from the requirement (Applicability), which requires administrative verification of maintenance records.\n- Enforcement and certainty: the directive is explicit and time-limited (50 hours), so the compliance obligation is clear; the regulator prescribes the remedy rather than leaving it to operator judgement (Requirement; Compliance).\n\nOpportunity costs and effects on private choice and businesses\n\n- The owners/operators face a choice between scheduling the mandated modification promptly (at their cost) or being non‑compliant and subject to regulatory consequences. The directive reduces operator discretion over how to address the reported loosening problem by mandating specific hardware and a service-bulletin-based method (Requirement).\n- Independent maintenance providers can perform the prescribed work, subject to access to the service bulletin and appropriate skills; the directive does not prescribe a single provider (Requirement), but does require conformity with the manufacturer’s bulletin.\n\nImplementation risks and trade-offs\n\n- If the modification is not performed correctly per the service bulletin, the exhaust loosening problem may persist; correct compliance depends on adequate parts, skilled labour and following the bulletin (Requirement; Background).\n- A short compliance window (50 hours time in service) raises the risk of operational disruption if owners cannot schedule the work promptly (Compliance).\n\nSummary of alignment between stated purpose and the mechanical change\n\n- The directive’s mechanical requirement (replace plain nuts/lock washers with self-locking nuts at specified locations) is directly framed as the remedy for reported exhaust components coming loose (Requirement; Background). The instrument ties the stated safety objective to a concrete hardware change and a compliance deadline (Requirement; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft model. It has not expanded beyond its original purpose of mandating exhaust system modifications."},"complexity_factors":["Single, specific applicability criterion (serial number range with one exclusion)","One clear mechanical requirement referencing an external technical document","Simple compliance condition (50 hours time in service)","No defined terms section, no cross-references to other legislation beyond a single note","Straightforward background explanation in plain language","Total length: approximately 150 words"],"plain_english_summary":"This is a **safety order for specific aircraft** that mandates a mechanical fix to prevent engine exhaust systems from failing in flight.\n\n**What it does:**\n- Requires owners/operators of certain **Socata TB200 aeroplanes** (serial numbers 1 through 1619) to modify their exhaust systems\n- The fix involves replacing standard nuts with **self-locking nuts** on exhaust pipe connections and cylinder exhaust mount studs\n\n**Who it affects:**\n- Owners and operators of TB200 aircraft with serial numbers 1–1619\n- Specifically excludes aircraft that have already been modified under a manufacturer service bulletin (SB 10-074 78, Amendment 1)\n\n**Why it matters:**\n- The original design used \"double plain nut locking\" (two standard nuts tightened against each other) and plain nuts with lock washers\n- These were **coming loose during flight**, creating a serious safety risk\n- The directive prevents potential in-flight exhaust system failure, which could cause loss of engine power, fire, or carbon monoxide entering the cabin\n\n**Compliance deadline:**\n- Must be completed within **50 flight hours** after 7 October 1999\n\n**Key terms explained:**\n- **Airworthiness Directive (AD):** A mandatory safety order issued by aviation regulators requiring fixes to unsafe aircraft conditions\n- **Time in service:** Actual flight hours (not calendar time)\n- **Service Bulletin:** Manufacturer-issued instructions for maintenance or modifications"}},"importantCases":[],"_links":{"self":"/api/acts/ad-tb-200-2-exhaust-system","history":"/api/acts/ad-tb-200-2-exhaust-system/history","analysis":"/api/acts/ad-tb-200-2-exhaust-system/analysis","conflicts":"/api/acts/ad-tb-200-2-exhaust-system/conflicts","importantCases":"/api/acts/ad-tb-200-2-exhaust-system/important-cases","documents":"/api/acts/ad-tb-200-2-exhaust-system/documents"}}