{"id":"F2006B11370","name":"AD/MU-2/4 Amdt 1 - Integral Fuel Tank Sealing - Inspection","slug":"ad-mu-2-4-amdt-1-integral-fuel-tank-sealing-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57269,"registerId":"commonwealth-F2006B11370-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/MU-2/4 Amdt 1 - Integral Fuel Tank Sealing - Inspection","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)  Mitsubishi MU-2 Series Aeroplanes\n\n \n\nAD/MU-2/4\n\nAmdt 1\n\n\nIntegral Fuel Tank Sealing - Inspection 3/72\n\n \n\nApplicability: As detailed in the requirement document. Document: Mitsubishi SB No. 143B.\n\nCompliance: As detailed in the requirement document.\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\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"The instrument is labelled \"Amdt 1\" (AD/MU-2/4 Amdt 1), indicating it is an amendment to a previously issued AD. The AD text supplied replaces or updates requirements by mandating the actions set out in Mitsubishi Service Bulletin No. 143B for the Mitsubishi MU-2 series. The instrument itself does not describe the prior text or the precise nature of the change from the original AD; it only shows that an amendment has been issued and that applicability and compliance are to be determined by the referenced service bulletin."},"complexity_factors":["Incorporation by reference of an external technical document (Mitsubishi SB No. 143B) rather than stating technical requirements in the AD itself","Vague wording in the AD as supplied: \"Applicability: As detailed in the requirement document\" and \"Compliance: As detailed in the requirement document\" (requires cross-reference to know scope and timing)","Technical subject matter (integral fuel tank sealing) requires specialist maintenance knowledge to implement and assess","Regulatory enforcement sits with CASA under Civil Aviation Regulations 1998 (Part 39), creating legal obligations tied to a manufacturer document","The instrument is presented as an amendment (Amdt 1), implying a change from an earlier AD and adding retrospective or altered compliance obligations that must be reconciled by operators"],"plain_english_summary":"This CASA airworthiness directive (AD/MU-2/4 Amdt 1) makes the inspection and any required corrective work on integral fuel tank sealing mandatory for Mitsubishi MU-2 aeroplanes covered by Mitsubishi Service Bulletin No. 143B. It affects owners/operators and maintenance organisations, who must arrange and fund the inspections and repairs; CASA enforces compliance under Part 39. The AD incorporates SB No. 143B by reference, so the specific procedures, intervals and burdens are set out in that service bulletin."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive format that has not expanded beyond its original purpose. ADs are designed to be brief instruments that incorporate external technical documents by reference. The scope remains precisely targeted: mandatory inspection of fuel tank sealing on a specific aircraft type."},"complexity_factors":["Extremely short document (under 200 words)","No defined terms section — relies entirely on external reference document","No conditional logic or nested exceptions within the text itself","Single cross-reference to Mitsubishi SB No. 143B (external technical document)","Minimal structural elements: applicability, document reference, and compliance placeholder only"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order — issued by Australia's Civil Aviation Safety Authority (CASA) for **Mitsubishi MU-2 series aeroplanes**.\n\n**What it does:**\n- Requires operators to inspect the **integral fuel tank sealing** (the seals built into the aircraft's fuel tanks, not removable tanks) on these specific aircraft.\n- The actual technical details of what to inspect, how, and when are contained in **Mitsubishi Service Bulletin No. 143B** — the AD simply makes compliance with that bulletin legally mandatory.\n\n**Who it affects:**\n- Owners and operators of Mitsubishi MU-2 series aircraft registered in Australia.\n- Maintenance organisations servicing these aircraft.\n\n**Why it matters:**\nFuel tank seal failures can lead to fuel leaks, which create fire hazards and can cause engine failure. This AD ensures Australian-registered MU-2 aircraft meet the same safety standards as those addressed by the manufacturer's service bulletin. The \"Amdt 1\" indicates this is an amended version of an earlier directive, suggesting the requirements have been updated based on new safety information or operational experience."}},"importantCases":[],"_links":{"self":"/api/acts/ad-mu-2-4-amdt-1-integral-fuel-tank-sealing-inspection","history":"/api/acts/ad-mu-2-4-amdt-1-integral-fuel-tank-sealing-inspection/history","analysis":"/api/acts/ad-mu-2-4-amdt-1-integral-fuel-tank-sealing-inspection/analysis","conflicts":"/api/acts/ad-mu-2-4-amdt-1-integral-fuel-tank-sealing-inspection/conflicts","importantCases":"/api/acts/ad-mu-2-4-amdt-1-integral-fuel-tank-sealing-inspection/important-cases","documents":"/api/acts/ad-mu-2-4-amdt-1-integral-fuel-tank-sealing-inspection/documents"}}