{"id":"F2006B09566","name":"AD/ENST 28/11 - Fuel Tank Vent - Modification","slug":"ad-enst-28-11-fuel-tank-vent-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54229,"registerId":"commonwealth-F2006B09566-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/ENST 28/11 - Fuel Tank Vent - 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)  Enstrom F-28 Series Helicopters\n\n \n\nAD/ENST 28/11 Fuel Tank Vent - Modification 1/76\n\nApplicability: Model F-28A with S/Nos. 03 to 339. Document:  Enstrom Service Note No. 0028.\n\nCompliance: Within 100 hours time in service after 27 February 1976.\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\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1425},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow scope as a targeted safety modification for a specific aircraft type. There is no evidence of expansion beyond the original fuel tank vent modification requirement."},"complexity_factors":["Single, specific compliance requirement (one modification only)","Narrow applicability (one helicopter model with defined serial number range)","No defined terms or interpretation section","Simple deadline structure (100 hours time-in-service from fixed date)","Relies on external technical document (Service Note) for actual procedure details"],"plain_english_summary":"This **Airworthiness Directive** (a mandatory safety order from the Civil Aviation Safety Authority) requires owners and operators of specific Enstrom F-28A helicopters to modify the fuel tank vent system to prevent dangerous fuel leaks or pressure imbalances.\n\n**Who it affects:**\n- Owners and operators of Enstrom F-28A helicopters with serial numbers 03 to 339\n\n**What you must do:**\n- Modify the fuel tank vent system following the manufacturer's instructions in **Enstrom Service Note No. 0028**\n- Complete the work within **100 hours of flight time** after 27 February 1976\n\n**Why it matters:**\nFaulty fuel tank ventilation can cause fuel starvation, leaks, or dangerous pressure build-ups during flight. This directive mandates a specific engineering fix to keep these helicopters airworthy and safe."}},"importantCases":[],"_links":{"self":"/api/acts/ad-enst-28-11-fuel-tank-vent-modification","history":"/api/acts/ad-enst-28-11-fuel-tank-vent-modification/history","analysis":"/api/acts/ad-enst-28-11-fuel-tank-vent-modification/analysis","conflicts":"/api/acts/ad-enst-28-11-fuel-tank-vent-modification/conflicts","importantCases":"/api/acts/ad-enst-28-11-fuel-tank-vent-modification/important-cases","documents":"/api/acts/ad-enst-28-11-fuel-tank-vent-modification/documents"}}