{"id":"F2006B10338","name":"AD/GY80/7 - Propeller Governor Oil Inlet Union - Replacement","slug":"ad-gy80-7-propeller-governor-oil-inlet-union-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56094,"registerId":"commonwealth-F2006B10338-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/GY80/7 - Propeller Governor Oil Inlet Union - Replacement","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)  Aerospatiale GY 80 (Horizon) Series Aeroplanes\n\n \n\nAD/GY80/7 Propeller Governor Oil Inlet Union - Replacement 6/79\n\nApplicability: All GY80 aircraft fitted with variable pitch Hartzell propeller. Document: Aerospatiale Horizon SB No. 37.\n\nCompliance: Within 100 hours time in service after 31 July 1979.\n\n \n\nBackground:  This Directive is issued as the result of overseas notification of oil loss caused by failure of the crankcase mounted union.\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 document sets a targeted mandatory replacement for a specific component on a defined subset of GY80 aircraft (Applicability; Compliance). There is no indication in the text that the AD’s scope was altered from an earlier intent; it plainly applies to all GY80 aircraft with the variable-pitch Hartzell propeller and requires replacement within the stated 100-hour window (Applicability; Compliance)."},"complexity_factors":["Narrow applicability: applies only to GY80 aircraft fitted with variable-pitch Hartzell propellers (Applicability).","Single, time-limited mandatory action: one replacement required within a fixed 100-hour compliance window (Compliance).","Reliance on external technical document: procedural details are delegated to Aerospatiale Horizon SB No. 37 rather than set out in the AD (Document).","Limited operational detail in the AD: parts, costs, and follow-up inspection intervals are not specified in the AD text (Document; Compliance).","Clear stated cause: Directive issued in response to reported oil loss from crankcase-mounted union failures, which narrows the technical focus (Background)."],"plain_english_summary":"This AD mandates replacement of the propeller governor oil‑inlet union on Aerospatiale GY80 (Horizon) aircraft fitted with variable‑pitch Hartzell propellers, using Aerospatiale Horizon Service Bulletin No. 37, to be completed within 100 hours TIS after 31 July 1979. It affects GY80 owners/operators, who must schedule and pay for the work; the measure aims to prevent oil loss from reported crankcase‑union failures."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused on a specific mechanical defect. It has not expanded beyond its original purpose of addressing the oil inlet union failure risk."},"complexity_factors":["Extremely short document — approximately 150 words total","Only one substantive requirement (replacement of a single component)","No defined terms section — all terminology is standard aviation maintenance language","No cross-references to other legislation beyond the parent Civil Aviation Regulations 1998","Simple conditional logic: single applicability criterion (GY80 aircraft + Hartzell variable pitch propeller)","Single compliance deadline with straightforward calculation (100 hours time in service after fixed date)","No exceptions, exemptions, or alternative compliance methods specified"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it requires:** Owners and operators of **Aerospatiale GY80 (Horizon) series aeroplanes** fitted with **variable pitch Hartzell propellers** must replace the **propeller governor oil inlet union** (a fitting that connects oil lines to the propeller control system) within **100 hours of flying time** after 31 July 1979.\n\n**Why it matters:** The directive was issued after overseas reports of **oil loss caused by failure of the crankcase-mounted union**. If this union fails, it could lead to loss of oil pressure, propeller malfunction, or engine damage — creating serious flight safety risks.\n\n**Who must comply:** Anyone operating the affected aircraft — typically private owners, flying schools, or charter operators using these French-built single-engine aircraft from the 1960s-70s.\n\n**Key deadline:** The replacement had to be completed within 100 flight hours after 31 July 1979 (so this directive is long past its compliance date, but remains on the books as a historical safety requirement)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-gy80-7-propeller-governor-oil-inlet-union-replacement","history":"/api/acts/ad-gy80-7-propeller-governor-oil-inlet-union-replacement/history","analysis":"/api/acts/ad-gy80-7-propeller-governor-oil-inlet-union-replacement/analysis","conflicts":"/api/acts/ad-gy80-7-propeller-governor-oil-inlet-union-replacement/conflicts","importantCases":"/api/acts/ad-gy80-7-propeller-governor-oil-inlet-union-replacement/important-cases","documents":"/api/acts/ad-gy80-7-propeller-governor-oil-inlet-union-replacement/documents"}}