{"id":"F2006B04196","name":"AD/BEECH 77/6 - Engine Mount Assembly to Firewall Attach Bolts","slug":"ad-beech-77-6-engine-mount-assembly-to-firewall-attach-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43952,"registerId":"commonwealth-F2006B04196-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 77/6 - Engine Mount Assembly to Firewall Attach Bolts","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 77 (Skipper) Series Aeroplanes\n\n \n\nAD/BEECH 77/6 Engine Mount Assembly to Firewall Attach Bolts 12/80\n\nApplicability: All model 77 with S/Nos. WA-1 to WA-156, WA-158 to WA-161, WA-163 to WA- 171, WA-173, WA-174, WA-177 and WA-178.\n\n \n\nRequirement: Action in accordance with Beechcraft SI No. 1153.\n\n \n\nNote: FAA AD 80-21-10 refers.\n\n \n\nCompliance: Within 25 hours’ time in service after 30 October 1980.\n\n \n\nBackground: The engine mount assembly attachment bolts and barrel nuts may have threads which were damaged at initial factory installations.\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":3,"scope_assessment":{"changed":false,"description":"The instrument’s scope is confined to the listed Beechcraft 77 serial numbers and requires a single remedial action per the manufacturer’s service instruction. The text contains no amendment history or indication that its applicability or requirements were altered from an earlier version, so there is no evidence in this text that the scope has changed from the original intent."},"complexity_factors":["Narrow, specific applicability limited to a set of serial numbers (Applicability) — reduces complexity.","Single, prescriptive requirement to follow a manufacturer service instruction (Requirement) — straightforward but depends on external SI availability.","Short and definite compliance period (25 hours after 30 October 1980) (Compliance) — creates scheduling pressure but not legal ambiguity.","Technical nature of the work (inspect/repair/replace threaded fasteners) requiring certified maintenance capability — adds operational complexity.","Cross-reference to FAA AD (Note) — introduces an external document for context but does not materially complicate the directive.","Lack of the full remedial steps in the AD itself (SI is not reproduced) — requires access to SI No. 1153, which is an extra procedural step for affected parties."],"plain_english_summary":"This airworthiness directive requires owners/operators of specified Beechcraft 77 (Skipper) serial numbers to inspect/repair engine‑mount attachment bolts and barrel nuts—following Beechcraft Service Instruction No. 1153—because threads may have been damaged at factory installation. \n\nThe mandated work must be completed within 25 hours’ time in service after 30 October 1980, is at the owner’s expense, and will require qualified maintenance, parts, and short downtime."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific manufacturing defect in a specific aircraft model. It has not expanded beyond its original purpose of mandating inspection/replacement of potentially defective engine mount bolts."},"complexity_factors":["Very short document (under 200 words)","Only 4 operative provisions: applicability, requirement, note, and compliance","Single cross-reference to external technical document (Beechcraft SI No. 1153)","Single cross-reference to equivalent FAA directive (FAA AD 80-21-10)","No defined terms section","No conditional logic or nested exceptions","Simple temporal compliance requirement (25 hours time in service after fixed date)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific **Beechcraft 77 \"Skipper\" aeroplanes** (particular serial numbers listed).\n\n**What it does:**\n- Requires owners/operators to inspect and fix **engine mount bolts** that attach the engine to the firewall (the protective wall between the engine and cockpit).\n- The bolts and barrel nuts may have **damaged threads** from when they were first installed at the factory.\n\n**Who must act:**\n- Anyone who owns or operates the affected Beechcraft 77 aircraft.\n\n**What they must do:**\n- Follow the instructions in **Beechcraft Service Instruction No. 1153** (a technical document from the manufacturer).\n- Complete the work **within 25 hours of flying time** after 30 October 1980.\n\n**Why it matters:**\nDamaged bolts could fail, potentially causing the engine to detach from the aircraft — a catastrophic safety risk. This directive forces a one-time inspection and correction to prevent accidents."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-77-6-engine-mount-assembly-to-firewall-attach-bolts","history":"/api/acts/ad-beech-77-6-engine-mount-assembly-to-firewall-attach-bolts/history","analysis":"/api/acts/ad-beech-77-6-engine-mount-assembly-to-firewall-attach-bolts/analysis","conflicts":"/api/acts/ad-beech-77-6-engine-mount-assembly-to-firewall-attach-bolts/conflicts","importantCases":"/api/acts/ad-beech-77-6-engine-mount-assembly-to-firewall-attach-bolts/important-cases","documents":"/api/acts/ad-beech-77-6-engine-mount-assembly-to-firewall-attach-bolts/documents"}}