{"id":"F2006B11282","name":"AD/ML-M4/13 - Horizontal Tail to Fuselage Front Attach Tubes - Inspection and Modification","slug":"ad-ml-m4-13-horizontal-tail-to-fuselage-front-attach-tubes-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57093,"registerId":"commonwealth-F2006B11282-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/ML-M4/13 - Horizontal Tail to Fuselage Front Attach Tubes - Inspection and 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)  Maule M-4 Series Aeroplanes\n\n \n\nAD/ML-M4/13 Horizontal Tail to Fuselage Front Attach\n\nTubes - Inspection and Modification\n\n\n3/80\n\n \n\nApplicability: All M-4 series with S/Nos. as referenced in Maule Aircraft Corporation SB No. 1. Document:               Maule Aircraft Corporation SB No. 1.\n\nCompliance: Unless already accomplished, within 100 hours time in service after 31 October 1979.\n\n \n\nBackground:  There is a possibility that the fuselage tube attaching the front attach point of the horizontal tail may be cracked.\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":2,"scope_assessment":{"changed":false,"description":"The text presents a single, time‑limited requirement applying to M‑4 series aircraft listed in the referenced manufacturer’s service bulletin and cites a specific compliance deadline. The document does not indicate any amendment, expansion, or narrowing from a prior instrument within the text provided, so there is no evidence here that the AD’s scope has changed from an earlier intent."},"complexity_factors":["Narrow technical scope: limited to the fuselage tube at the front attach point of the horizontal tail (Background sentence).","Limited applicability requires cross‑reference to an external document (\"S/Nos. as referenced in Maule Aircraft Corporation SB No. 1\"), which adds a step to determine whether a given aircraft is affected.","Short, specific compliance window (\"within 100 hours time in service after 31 October 1979\") imposes scheduling requirements but is straightforward to calculate.","Technical methods are not reproduced in the AD; implementers must obtain and follow the manufacturer’s service bulletin (Document reference), creating dependency on that external source for execution.","Minimal procedural or regulatory complexity in the AD text itself — no multiple options, repetitive inspections, or conditional branching within the directive."],"plain_english_summary":"The Civil Aviation Safety Authority’s Part 39 directive requires owners/operators of specified Maule M‑4 serial numbers to inspect and carry out the modification in Maule Aircraft Corporation Service Bulletin No. 1 on the fuselage front attach tube that supports the horizontal tail, within 100 hours TIS after 31 October 1979 (unless already done).  \n\nIt affects those M‑4 owners/operators, shifts cost and scheduling burden to them, and aims to mitigate the risk of a potentially cracked attach tube."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive remains tightly focused on its original purpose: addressing a specific structural defect in a particular aircraft model. It has not expanded beyond the original safety concern regarding cracked fuselage attachment tubes."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 defined references (Service Bulletin No. 1 and the aircraft serial numbers)","Single compliance condition with straightforward deadline","No nested exceptions or conditional logic","No cross-references to other legislation or regulations beyond the enabling Civil Aviation Regulations 1998","Simple cause-and-effect structure: identified defect → mandatory action → deadline"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\n- Requires owners and operators of **Maule M-4 series aeroplanes** to inspect and potentially modify a specific structural component — the tubes that attach the horizontal tail (the small wings at the back of the plane) to the main body (fuselage).\n\n**Who it affects:**\n- Anyone who owns or operates a Maule M-4 series aircraft with specific serial numbers listed in **Maule Aircraft Corporation Service Bulletin No. 1**.\n\n**Why it matters:**\n- The front attachment tubes for the horizontal tail may have **cracks**. If these cracks go undetected, the tail could fail in flight — with potentially catastrophic consequences. This directive ensures the problem is found and fixed before that can happen.\n\n**What must be done:**\n- Unless the work has already been completed, the inspection and modification must be done **within 100 hours of flight time** after **31 October 1979**.\n\n**Key document to follow:**\n- **Maule Aircraft Corporation Service Bulletin No. 1** — this contains the technical instructions for the inspection and modification."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ml-m4-13-horizontal-tail-to-fuselage-front-attach-tubes-inspection-and-modification","history":"/api/acts/ad-ml-m4-13-horizontal-tail-to-fuselage-front-attach-tubes-inspection-and-modification/history","analysis":"/api/acts/ad-ml-m4-13-horizontal-tail-to-fuselage-front-attach-tubes-inspection-and-modification/analysis","conflicts":"/api/acts/ad-ml-m4-13-horizontal-tail-to-fuselage-front-attach-tubes-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-ml-m4-13-horizontal-tail-to-fuselage-front-attach-tubes-inspection-and-modification/important-cases","documents":"/api/acts/ad-ml-m4-13-horizontal-tail-to-fuselage-front-attach-tubes-inspection-and-modification/documents"}}