{"id":"F2006B09055","name":"AD/DHC-2/7 - Aileron Differential Mount - Modification","slug":"ad-dhc-2-7-aileron-differential-mount-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52785,"registerId":"commonwealth-F2006B09055-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-2/7 - Aileron Differential Mount - 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)  DHC-2 (Beaver) Series Aeroplanes\n\n \n\nAD/DHC-2/7 Aileron Differential Mount - Modification 4/63\n\nApplicability: All models.\n\n \n\nDocument: De Havilland and Canada Engineering Bulletin Series \"B\" No. 28. Compliance: Forthwith.\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":2,"scope_assessment":{"changed":false,"description":"The text does not indicate any change of scope from an earlier or original instrument. It states applicability as 'All models' and prescribes compliance with a specified engineering bulletin 'Forthwith.' No amendment, exception, or narrowing of scope is present in the provided text."},"complexity_factors":["Very brief text that mandates a single modification (low structural complexity).","Broad applicability to all models increases practical reach but does not add legal complexity (Applicability: All models).","Immediate compliance requirement ('Forthwith') raises operational urgency for affected parties.","Technical details are deferred to an external document (De Havilland and Canada Engineering Bulletin Series 'B' No. 28), which creates dependence on that bulletin for implementation complexity.","Lack of expressly stated cost allocation, certification procedure, or enforcement detail in the AD increases contextual uncertainty for implementers."],"plain_english_summary":"This AD mandates immediate modification of the aileron differential mount on all DHC‑2 (Beaver) aircraft, requiring compliance forthwith with the technical instructions in De Havilland and Canada Engineering Bulletin Series “B” No. 28. It creates a legal obligation for every owner, operator and maintenance organisation of the type and matters because the AD compels action while delegating the technical method to the referenced bulletin."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1963 (indicated by the \"4/63\" suffix). It has not expanded beyond its original purpose of mandating a specific safety modification to the aileron differential mount on DHC-2 aircraft. The scope remains precisely as intended: a targeted technical fix for a defined aircraft type."},"complexity_factors":["Extremely short document (under 200 words)","Only one substantive requirement (perform the modification)","Single cross-reference to an external technical document (Engineering Bulletin B/28)","No defined terms section","No conditional logic or exceptions","Simple applicability clause (\"All models\")","Minimal legislative machinery — essentially a safety order referencing manufacturer instructions"],"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) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of **De Havilland Canada DHC-2 \"Beaver\" aircraft** (all models) to carry out a specific modification to the **aileron differential mount**. The ailerons are the hinged panels on the wings that make the plane roll left or right; the \"differential mount\" is part of the mechanism that controls how much each aileron moves. This modification was needed to fix a safety issue.\n\n**Who must comply:** Anyone who owns or operates a DHC-2 Beaver aircraft in Australia.\n\n**When:** **\"Forthwith\"** — meaning immediately, without delay. This is the most urgent compliance timing CASA can set.\n\n**How to comply:** Follow the technical instructions in **De Havilland Canada Engineering Bulletin Series \"B\" No. 28**.\n\n**Why it matters:** Airworthiness Directives are legally binding safety orders. Ignoring this directive means the aircraft cannot legally fly in Australian airspace. The modification addresses a potential structural or control-system defect that could affect the aircraft's ability to maneuver safely."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-2-7-aileron-differential-mount-modification","history":"/api/acts/ad-dhc-2-7-aileron-differential-mount-modification/history","analysis":"/api/acts/ad-dhc-2-7-aileron-differential-mount-modification/analysis","conflicts":"/api/acts/ad-dhc-2-7-aileron-differential-mount-modification/conflicts","importantCases":"/api/acts/ad-dhc-2-7-aileron-differential-mount-modification/important-cases","documents":"/api/acts/ad-dhc-2-7-aileron-differential-mount-modification/documents"}}