{"id":"F2006B04184","name":"AD/BEECH 76/9 Amdt 1 - Engine Mount Assembly","slug":"ad-beech-76-9-amdt-1-engine-mount-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43937,"registerId":"commonwealth-F2006B04184-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 76/9 Amdt 1 - Engine Mount Assembly","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)  Beechcraft 76 (Duchess) Series Aeroplanes\n\n \n\nAD/BEECH 76/9\n\nAmdt 1\n\n\nEngine Mount Assembly 7/82\n\n \n\nApplicability: All models 76 with S/Nos. ME 1 to ME-415. Requirement:  Action in accordance with Beechcraft SI No. 1147 R1. Compliance:               As per Requirement Document.\n\nBackground: Cracks may develop in the lower tubes of the engine mount assembly. Amdt. 1 is issued to extend aircraft serial number effectivity.\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":3,"scope_assessment":{"changed":true,"description":"The amendment (Amdt. 1) extends the range of affected aircraft serial numbers. The AD as presented applies to all Model 76 aircraft with serial numbers ME 1 to ME-415 (Applicability), and the document states the purpose of the amendment is to extend aircraft serial number effectivity (Background). This constitutes a change in scope from the prior effectivity (not reproduced here) to the stated expanded serial-number range."},"complexity_factors":["References an external technical document (Beechcraft SI No. 1147 R1) rather than containing technical steps in the AD itself, requiring operators to obtain and follow that document (Requirement).","Applies to a defined serial-number range (ME 1 to ME-415) so operators must check aircraft identity against the applicability list (Applicability).","Technical subject matter (engine-mount cracking) requires qualified maintenance personnel to assess and remediate, creating operational and logistical complexity despite a short AD text (Background; Requirement).","The AD text does not state timing, frequencies, or costs; those details are in the Requirement Document, which increases practical complexity for compliance planning (Compliance).","Amendment alters scope by extending serial-number effectivity; tracing which aircraft were newly included requires record checks (Background)."],"plain_english_summary":"What this instrument does\n\n- This airworthiness directive (AD/BEECH 76/9 Amdt 1) orders owners/operators of Beechcraft Model 76 (Duchess) aeroplanes to take action about the engine mount assembly because cracks can form in the lower tubes (Background). (Civil Aviation Safety Authority; Schedule of Airworthiness Directives.)\n\nWho it affects\n\n- Owners, operators and maintenance organisations responsible for any Beechcraft 76 with serial numbers ME 1 through ME-415 (Applicability).\n\nWhat it requires, mechanically\n\n- The AD requires the specified action to be taken in accordance with Beechcraft Service Instruction No. 1147 Revision 1 (Requirement: Action in accordance with Beechcraft SI No. 1147 R1).\n- Compliance must be carried out as described in the Requirement Document (Compliance).\n\nWhy it matters (claim made in the document)\n\n- The document states the AD is needed because cracks may develop in the lower tubes of the engine mount assembly (Background). The amendment (Amdt. 1) is said to extend the range of affected aircraft serial numbers (Background).\n\nHow this works in practice (who pays, who decides, behaviour change and burdens)\n\n- Who pays: owners/operators are the parties expected to carry out the inspection/repair/replace actions required by the referenced Service Instruction; costs of parts, labour and any aircraft downtime fall to them (Requirement; Compliance).\n- Who decides: the Civil Aviation Safety Authority issues the AD; the manufacturer’s Service Instruction (Beechcraft SI No. 1147 R1) specifies the technical steps to be performed (Requirement).\n- Behaviour change required: affected aircraft must be inspected and any remedial work performed in the manner and within the schedule set out in the Service Instruction (Requirement; Compliance).\n- Compliance burden and implementation risk: the AD refers to an external technical document (Beechcraft SI No. 1147 R1). Operators must obtain and follow that document; the AD does not set out detailed actions, frequencies or costs within the text itself (Requirement; Compliance). Availability of the Service Instruction, access to qualified maintenance personnel, parts lead times and aircraft downtime are practical factors operators must manage.\n\nTrade-offs, incentives and effects on private choice\n\n- The stated purpose (preventing failures from cracked lower engine-mount tubes) increases maintenance obligations for affected aircraft. Owners/operators face direct costs and operational disruption in order to meet the safety action specified by the Service Instruction (Background; Requirement; Compliance).\n- The directive concentrates costs on the owners/operators of the specified serial-numbered aircraft, while the safety benefit accrues to aircraft occupants and to third parties who might be affected by an in-flight failure (Background).\n- The AD delegates technical detail to the manufacturer’s Service Instruction, preserving the operator’s ability to follow prescribed repair or inspection methods rather than a regulator-written technical procedure; this places practical discretion about method and timing in the hands of the referenced SI (Requirement).\n\nSpecific citation points\n\n- Applicability: “All models 76 with S/Nos. ME 1 to ME-415.” (Applicability)\n- Required action: “Action in accordance with Beechcraft SI No. 1147 R1.” (Requirement)\n- Compliance: “As per Requirement Document.” (Compliance)\n- Reason for amendment: “Amdt. 1 is issued to extend aircraft serial number effectivity.” (Background)\n- Safety concern: “Cracks may develop in the lower tubes of the engine mount assembly.” (Background)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a minor amendment (Amdt 1) that extends the serial number applicability range. The scope remains tightly focused on the original safety issue (engine mount cracks in Beechcraft 76 aircraft). No mission creep or expansion beyond the original airworthiness concern."},"complexity_factors":["Extremely short document (under 200 words)","No defined terms section — all language is plain technical aviation terminology","Single cross-reference to external document (Beechcraft SI No. 1147 R1) rather than internal legislative complexity","No conditional logic, exceptions, or nested provisions","Linear structure: applicability → requirement → compliance → background","Amendment makes only one simple change (serial number range extension)"],"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) that requires aircraft owners to fix a specific mechanical problem.\n\n**What it does:**\n- **Targets:** Beechcraft 76 \"Duchess\" twin-engine aircraft with serial numbers ME-1 through ME-415\n- **The problem:** The engine mount assembly (the metal frame that holds the engine to the wing) can develop cracks in its lower tubes. If these cracks aren't caught, the engine could detach in flight — catastrophic failure.\n- **The fix:** Owners must follow Beechcraft Service Instruction No. 1147 Revision 1, which details inspection and repair procedures\n- **What's new in Amendment 1:** The serial number range was expanded to cover more aircraft than the original directive\n\n**Who it affects:** Anyone who owns, operates, or maintains a Beechcraft 76 Duchess with the affected serial numbers — private pilots, flying schools, charter operators, and maintenance engineers.\n\n**Why it matters:** Engine mount cracks are a serious airworthiness issue. This directive is legally enforceable — you cannot fly the aircraft until compliance is achieved. Ignoring it risks certificate suspension and, more importantly, potential loss of life."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-76-9-amdt-1-engine-mount-assembly","history":"/api/acts/ad-beech-76-9-amdt-1-engine-mount-assembly/history","analysis":"/api/acts/ad-beech-76-9-amdt-1-engine-mount-assembly/analysis","conflicts":"/api/acts/ad-beech-76-9-amdt-1-engine-mount-assembly/conflicts","importantCases":"/api/acts/ad-beech-76-9-amdt-1-engine-mount-assembly/important-cases","documents":"/api/acts/ad-beech-76-9-amdt-1-engine-mount-assembly/documents"}}