{"id":"F2006B10114","name":"AD/G164/9 - Parking Brake Control - Modification","slug":"ad-g164-9-parking-brake-control-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55640,"registerId":"commonwealth-F2006B10114-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G164/9 - Parking Brake Control - 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)  Schweizer (Grumman) G-164 (Ag-Cat) Series Aeroplanes\n\n \n\nAD/G164/9 Parking Brake Control - Modification 6/67\n\nApplicability: All models with S/Nos. 301 and subsequent. Document:  Grumman G164 SB No. 39.\n\nCompliance: 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 AD as supplied sets a clear, narrow scope: it applies to all Schweizer (Grumman) G-164 aircraft with serial numbers 301 and later and requires modification per Grumman G164 Service Bulletin No. 39, to be done forthwith. The text contains no indication that this scope has been broadened or narrowed from an earlier iteration; no amendments or different applicability statements are present in the supplied document."},"complexity_factors":["Narrow applicability: applies only to Schweizer (Grumman) G‑164 series with S/Nos. 301 and subsequent (simple to identify affected aircraft).","Single, clearly referenced technical remedy: compliance is achieved by following Grumman G164 Service Bulletin No. 39 (the AD does not itself set detailed technical steps).","Immediate compliance requirement: \"Forthwith\" imposes scheduling pressure but does not add legal complexity.","Lack of procedural detail in the AD text: no timelines, cost allowances, exemptions, or reporting requirements are specified in the supplied text, reducing statutory complexity but shifting technical detail to the referenced service bulletin.","Legal authority is straightforward: issued under the Civil Aviation safety/directive framework (schedule of airworthiness directives) with no multiple cross-references in the supplied text."],"plain_english_summary":"What this instrument does, mechanically:\n\n- It requires a modification to the parking-brake control on Schweizer (Grumman) G-164 (Ag‑Cat) series aeroplanes. The modification must be carried out in accordance with the manufacturer's paperwork referenced (Grumman G164 Service Bulletin No. 39). (See: “Document: Grumman G164 SB No. 39.”)\n- The requirement is mandatory and immediate: compliance is required “Forthwith.” (See: “Compliance: Forthwith.”)\n\nWho it affects:\n\n- Owners and operators of Schweizer (Grumman) G‑164 aeroplanes with serial numbers 301 and subsequent. (See: “Applicability: All models with S/Nos. 301 and subsequent.”)\n- Maintenance organisations, mechanics and parts suppliers who will perform or supply the modification work and materials referenced in the service bulletin.\n\nWhy it matters and how it works in practice:\n\n- The AD (airworthiness directive) converts a specified technical change from the manufacturer’s service bulletin into a mandatory regulatory requirement for the aircraft identified. (See: header referencing Civil Aviation Safety Authority and the schedule of airworthiness directives.)\n- Owners/operators must arrange for the modification to be done to each affected airframe. That creates direct, concentrated costs for those owners/operators (parts, labour, and aircraft downtime) and potential immediate operational effects because the schedule requires compliance forthwith. The AD itself does not state costs or time to perform the work; it instead identifies the technical instructions to be followed (the referenced service bulletin). (See: “Document: Grumman G164 SB No. 39.” and “Compliance: Forthwith.”)\n\nIncentives, trade-offs and implementation risks (source‑grounded):\n\n- Who pays: The aircraft owner/operator pays for compliance (purchase/installation of parts and labour), because the AD imposes a mandatory modification on the specific serial-numbered fleet. (See: “Applicability” and “Compliance”.)\n- Who decides/schedules: The regulatory requirement is set by the Civil Aviation Safety Authority under the schedule of airworthiness directives; operators have limited discretion other than when (immediately, but subject to arranging resources) to schedule the physical work. (See: header and “Compliance: Forthwith.”)\n- Compliance burden: Immediate (forthwith) compliance raises scheduling and operational burdens — aircraft may be grounded or have reduced availability until the work is done. The AD does not quantify downtime or costs; those are determined by the service bulletin’s technical instructions and by market availability of maintenance capacity and parts. (See: “Compliance: Forthwith.” and “Document: Grumman G164 SB No. 39.”)\n- Effects on private markets: Maintenance providers and parts suppliers for this modification will receive demand from affected owners; owners face a concentrated cost. The AD does not impose ongoing reporting or administrative fees in the text supplied; it simply makes the modification mandatory. (See: entire AD text.)\n- Trade-off: The regulatory action substitutes a short-term compliance cost and operational disruption for the intended outcome of the modification specified by the manufacturer’s service bulletin. The AD text itself states the action required but does not supply a stated cost–benefit analysis. (See: whole AD.)\n\nConcrete implementation considerations for an operator reading this AD:\n\n- Locate Grumman G164 Service Bulletin No. 39 and follow its technical instructions to perform the parking-brake control modification. (See: “Document: Grumman G164 SB No. 39.”)\n- Plan for near‑term scheduling of maintenance work because the AD requires compliance forthwith; allow for parts lead times and availability of appropriately certificated maintenance personnel. (See: “Compliance: Forthwith.” and “Applicability: All models with S/Nos. 301 and subsequent.”)\n\nSource citations: all statements above are drawn from the AD text: the title, applicability line, document reference, and compliance instruction (AD/G164/9 Parking Brake Control - Modification; Applicability: All models with S/Nos. 301 and subsequent; Document: Grumman G164 SB No. 39; Compliance: Forthwith)."},"kimi_summary":{"content_quality":"ok","complexity_score":1,"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 mandating a parking brake modification."},"complexity_factors":["Extremely short document (under 100 words of substantive content)","No defined terms section","No cross-references to other legislation beyond a single service bulletin citation","Simple binary applicability test (serial number 301+)","Single, unconditional compliance requirement ('Forthwith')","No exceptions, exemptions, or conditional logic"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA).\n\n**What it does:** It requires owners and operators of certain Schweizer (formerly Grumman) G-164 \"Ag-Cat\" agricultural aircraft to modify the parking brake control system. The modification must be done according to Grumman Service Bulletin No. 39.\n\n**Who it affects:** Anyone who owns or operates a Schweizer/Grumman G-164 series aeroplane with serial number 301 or higher.\n\n**Why it matters:** Parking brake failures on agricultural aircraft can cause serious ground accidents — imagine a loaded crop-duster rolling away on a sloped airstrip. This directive fixes a known safety defect. The word \"Forthwith\" means **do it immediately** — there's no grace period.\n\n**Key takeaway:** If you've got one of these planes, you can't legally fly it until this brake modification is done."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g164-9-parking-brake-control-modification","history":"/api/acts/ad-g164-9-parking-brake-control-modification/history","analysis":"/api/acts/ad-g164-9-parking-brake-control-modification/analysis","conflicts":"/api/acts/ad-g164-9-parking-brake-control-modification/conflicts","importantCases":"/api/acts/ad-g164-9-parking-brake-control-modification/important-cases","documents":"/api/acts/ad-g164-9-parking-brake-control-modification/documents"}}