{"id":"F2006B11364","name":"AD/MU-2/34 - Engine Air Intake Bleed Air Tubing Coupling Nut Retorque, Inspection, Modification","slug":"ad-mu-2-34-engine-air-intake-bleed-air-tubing-coupling-nut-retorque-inspection-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57263,"registerId":"commonwealth-F2006B11364-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/MU-2/34 - Engine Air Intake Bleed Air Tubing Coupling Nut Retorque, Inspection, Modification","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-2/34 Engine Air Intake Bleed Air Tubing Coupling Nut\n\nRetorque, Inspection, Modification\n\n\n7/84\n\n \n\nApplicability: All models MU-2B/-10/-15/-20/-25/-26 with S/Nos. 008 to 347 (except S/Nos. 313SA and 321SA) and MU-2B-30/-35/ -36 with S/Nos. 501 to 696 (except S/Nos. 652SA and 661SA).\n\n \n\nDocument: Mitsubishi SB No. 196 Rev A.\n\n \n\nNote: JCAB AD No. TCD-2342-84 refers.\n\n \n\nCompliance: Before further flight after 31 July 1984.\n\n \n\nBackground: Loss of engine bleed air at the intake anti-ice coupling nut can cause malfunction of the engine air intake anti-ice system. The manufacturer has therefore introduced an inspection and a minor modification to ensure permanent security of the coupling nut.\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":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of ensuring the security of engine air intake bleed air tubing coupling nuts."},"complexity_factors":["Single, unambiguous compliance requirement (retorque, inspect, modify)","Clear applicability section with specific serial number ranges and explicit exceptions","Single external reference to manufacturer service bulletin (SB No. 196 Rev A)","No defined terms section, no cross-references to other legislation, no conditional logic","Fixed deadline compliance ('before further flight after 31 July 1984')","Background explanation provided in plain language"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific Mitsubishi MU-2 aircraft.\n\n**What it requires:** Owners and operators of affected Mitsubishi MU-2 aeroplanes must perform a specific maintenance task before flying after 31 July 1984. The task involves:\n- **Retorquing** (tightening to a specific tension) the coupling nut on the engine air intake bleed air tubing\n- **Inspecting** the component for security\n- **Modifying** it to ensure the coupling nut stays tight permanently\n\n**Who it affects:** Specific Mitsubishi MU-2 models with particular serial numbers — essentially most MU-2B variants and early MU-2B-30/-35/-36 models built between certain serial numbers, with two specific aircraft excluded from each group.\n\n**Why it matters:** If the coupling nut loosens, the engine's bleed air system can fail. This air is used for the **intake anti-ice system** — which prevents ice from forming in the engine intake during flight. Ice buildup can severely restrict airflow to the engine, causing power loss or engine failure. This directive prevents a potentially catastrophic in-flight emergency.\n\n**The bottom line:** This is a one-time, mandatory safety fix. You cannot legally fly these aircraft after the deadline without completing this work."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD enacts the manufacturer's inspection and minor modification for the listed MU-2 serial numbers to secure the coupling nut. The text limits action to the specified aircraft and tasks and does not expand scope beyond the manufacturer's bulletin and stated applicability."},"complexity_factors":["Narrow, specific applicability by model and serial number (Applicability).","Single, immediate compliance deadline: before further flight after 31 July 1984 (Compliance).","Prescribes three straightforward tasks: retorque, inspect and minor modification following Mitsubishi SB No.196 Rev A (Document; Background).","Includes explicit serial-number exceptions, requiring careful fleet screening (Applicability).","Compliance cost and operational downtime fall to aircraft owners/operators (Compliance; Background)."],"plain_english_summary":"**What it does:** Requires operators of specified Mitsubishi MU-2 aircraft (listed models and serial numbers) to retorque, inspect and apply a minor modification to the engine air‑intake bleed‑air coupling nut per Mitsubishi SB No.196 Rev A to prevent loss of bleed air.\n\n**Who pays/decides:** Compliance is mandatory before further flight after 31 July 1984; aircraft owners/operators must arrange and pay for the work; enforced under the Civil Aviation Safety Authority. (Applicability; Document; Compliance; Background)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-mu-2-34-engine-air-intake-bleed-air-tubing-coupling-nut-retorque-inspection-modification","history":"/api/acts/ad-mu-2-34-engine-air-intake-bleed-air-tubing-coupling-nut-retorque-inspection-modification/history","analysis":"/api/acts/ad-mu-2-34-engine-air-intake-bleed-air-tubing-coupling-nut-retorque-inspection-modification/analysis","conflicts":"/api/acts/ad-mu-2-34-engine-air-intake-bleed-air-tubing-coupling-nut-retorque-inspection-modification/conflicts","importantCases":"/api/acts/ad-mu-2-34-engine-air-intake-bleed-air-tubing-coupling-nut-retorque-inspection-modification/important-cases","documents":"/api/acts/ad-mu-2-34-engine-air-intake-bleed-air-tubing-coupling-nut-retorque-inspection-modification/documents"}}