{"id":"F2006B06262","name":"AD/PL 12/16 Amdt 1 - Engine Mount Tube","slug":"ad-pl-12-16-amdt-1-engine-mount-tube","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47261,"registerId":"commonwealth-F2006B06262-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PL 12/16 Amdt 1 - Engine Mount Tube","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)  Transavia PL 12 Series Aeroplanes\n\n \n\nAD/PL 12/16\n\nAmdt 1\n\n\nEngine Mount Tube 2/89\n\n \n\nApplicability: PL 12 and PL 12U with S/Nos prior to 1249 and G351. Requirement:  Action in accordance with Transavia SL No. 21.\n\nCompliance: Within 100 hours time in service unless already accomplished.\n\n \n\nBackground:  This Amendment deletes “All models” from the “Applicability” and reflects design and manufacturing improvements to later model aircraft.\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\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":true,"description":"The amendment narrows the original scope. The original AD/PL 12/16 applied to 'All models' of the PL 12 series. Amendment 1 restricts applicability to specific serial number ranges (prior to 1249 and G351), reflecting that later production aircraft incorporated design improvements. This is a scope reduction rather than expansion."},"complexity_factors":["Extremely short document (under 200 words)","Only 2 defined applicability criteria (model type and serial number ranges)","Single compliance action referencing an external document (Transavia SL No. 21)","No nested conditions, exceptions, or cross-references to other legislation","Plain language background explanation included","Amendment logic is straightforward (deletion of 'All models', addition of specific serial number cutoffs)"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) issued by Australia's Civil Aviation Safety Authority for a specific type of light aircraft: the **Transavia PL 12 series**.\n\n**What it does:**\n- Requires owners and operators of certain PL 12 aircraft to inspect or fix a problem with the **engine mount tube** (the structural component that attaches the engine to the airframe).\n- The work must follow instructions in **Transavia Service Letter No. 21** (a manufacturer bulletin).\n\n**Who it affects:**\n- Owners of **PL 12 and PL 12U aircraft** with **serial numbers below 1249 and G351**.\n- This amendment **narrows** the original directive by removing \"All models\" — newer aircraft (serial 1249/G351 and above) are now exempt because the manufacturer fixed the design flaw in production.\n\n**Why it matters:**\n- Engine mount failures can cause the engine to detach in flight — obviously catastrophic.\n- This update reflects that newer planes don't need the fix, saving those owners unnecessary maintenance costs while keeping older planes safe.\n\n**Compliance deadline:** Within **100 hours of flight time** (unless already done)."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"Yes. The amendment narrows the AD’s scope by removing the prior phrase 'All models' and limits applicability to PL 12 and PL 12U aircraft with serial numbers prior to 1249 and G351. The background states this change reflects design and manufacturing improvements to later model aircraft. (Background; Applicability)"},"complexity_factors":["Narrow, specific applicability based on model and serial-number cutoffs (requires checking aircraft serial numbers). (Applicability)","Mandates action by reference to an external document (Transavia SL No. 21) rather than listing technical steps in the AD itself. (Requirement)","Short, defined compliance window (100 hours time in service), which requires operational scheduling. (Compliance)","Amendment changes previous scope (deletion of 'All models'), so historical records and older AD versions may need comparison. (Background)"],"plain_english_summary":"What this instrument does\n\n- This is an airworthiness directive (AD) addressed to operators of Transavia PL 12 series aeroplanes. It requires specific corrective action on the engine mount tube for certain aircraft (see Applicability and Requirement below).\n\nWho it affects\n\n- Owners/operators of Transavia PL 12 and PL 12U aeroplanes with serial numbers prior to 1249 and G351. (Applicability)\n\nWhat it requires and how it works mechanically\n\n- The AD directs affected operators to carry out the actions set out in Transavia Service Letter No. 21. (Requirement)\n- Those actions must be completed within 100 hours time in service from the AD’s effect unless they have already been done. (Compliance)\n\nWhy it matters (official rationale and practical implications)\n\n- The published background says the amendment narrows the applicability by deleting the previous “All models” description and reflects design and manufacturing improvements in later production aircraft. (Background)\n- Mechanically, the AD imposes an obligation on the operator/owner: obtain Transavia SL No. 21 and implement the procedures it prescribes on each affected airframe within the 100-hour window. (Requirement; Compliance)\n\nWho pays and who decides\n\n- The operator/owner of each affected aeroplane is the party responsible for complying with the AD and therefore will bear any direct costs (labour, parts, maintenance facility time) required by Transavia SL No. 21. (Requirement; Compliance)\n- The Civil Aviation Safety Authority issued the AD as the regulatory instrument; the specific technical remedy is specified by Transavia in Service Letter No. 21. (Requirement)\n\nIncentives, trade-offs and implementation notes\n\n- The AD concentrates obligations on owners/operators of older serial-numbered airframes; later serial-numbered aircraft are excluded because of later design/manufacturing changes. (Applicability; Background)\n- The AD refers to an external manufacturer document (Transavia SL No. 21). Operators must obtain and follow that document to comply, which creates an administrative step and potential cost for parts/labour. (Requirement)\n- The compliance window (100 hours time in service) creates a short-term operational scheduling requirement: affected operators will need to plan maintenance within that time, which can produce downtime or the need to reallocate flying hours. (Compliance)\n\nConcrete trade-offs and risks (mechanisms, not judgments)\n\n- Benefit mechanism claimed by the source: narrowing applicability recognises and relies on later design/manufacturing improvements to exclude newer serial-numbered aircraft from this mandatory action. (Background)\n- Cost mechanism: affected operators must implement whatever inspections/repairs/modifications SL No. 21 requires within the prescribed time, incurring labour, parts and opportunity costs of aircraft out of service. (Requirement; Compliance)\n- Administrative mechanism: compliance depends on the content of Transavia SL No. 21; the AD does not itself list technical steps. Operators must secure and follow that external technical document to meet the regulatory requirement. (Requirement)\n\nSource citations\n\n- Applicability: \"PL 12 and PL 12U with S/Nos prior to 1249 and G351.\" (Applicability)\n- Requirement: \"Action in accordance with Transavia SL No. 21.\" (Requirement)\n- Compliance: \"Within 100 hours time in service unless already accomplished.\" (Compliance)\n- Background: \"This Amendment deletes 'All models' from the 'Applicability' and reflects design and manufacturing improvements to later model aircraft.\" (Background)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-pl-12-16-amdt-1-engine-mount-tube","history":"/api/acts/ad-pl-12-16-amdt-1-engine-mount-tube/history","analysis":"/api/acts/ad-pl-12-16-amdt-1-engine-mount-tube/analysis","conflicts":"/api/acts/ad-pl-12-16-amdt-1-engine-mount-tube/conflicts","importantCases":"/api/acts/ad-pl-12-16-amdt-1-engine-mount-tube/important-cases","documents":"/api/acts/ad-pl-12-16-amdt-1-engine-mount-tube/documents"}}