{"id":"F2006B09572","name":"AD/ENST 28/17 - Wide Chord Tail Rotor Counterweights - Modification","slug":"ad-enst-28-17-wide-chord-tail-rotor-counterweights-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54250,"registerId":"commonwealth-F2006B09572-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/ENST 28/17 - Wide Chord Tail Rotor Counterweights - 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 28/17  Wide Chord Tail Rotor Counterweights - Modification\n\nApplicability: Models F-28C and 280C with S/Nos. as listed in the requirement document. Document:               Enstrom Service Directive Bulletin No. 0042.\n\nCompliance: Within 10 hours time in service after 19 October 1977.\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\n10/77\n","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":757},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This directive maintains its original narrow scope: a specific mandatory modification for specific Enstrom helicopter models regarding tail rotor counterweights. No expansion beyond the original technical safety issue."},"complexity_factors":["Very short single-issue directive (approximately 100 words)","Only two models affected with specific serial number restrictions","Single compliance requirement with clear time limit","Relies on external technical document (Service Directive Bulletin No. 0042) for actual modification details"],"plain_english_summary":"**What this does:**\nThis is a mandatory safety directive (called an \"Airworthiness Directive\") that requires owners of specific Enstrom F-28C and 280C helicopters to modify the wide chord tail rotor counterweights on their aircraft.\n\n**Who it affects:**\nOperators and owners of Enstrom F-28C and 280C helicopters with specific serial numbers listed in Enstrom Service Directive Bulletin No. 0042.\n\n**What must be done:**\nThe aircraft must be modified according to the instructions in Enstrom Service Directive Bulletin No. 0042. This modification must be completed **within 10 hours of flying time** after 19 October 1977.\n\n**Why it matters:**\nAirworthiness Directives are legally enforceable safety orders. Failing to comply means the aircraft cannot be flown legally, as it would be considered unairworthy. This specific directive addresses a safety issue with the tail rotor counterweights that could affect flight safety."}},"importantCases":[],"_links":{"self":"/api/acts/ad-enst-28-17-wide-chord-tail-rotor-counterweights-modification","history":"/api/acts/ad-enst-28-17-wide-chord-tail-rotor-counterweights-modification/history","analysis":"/api/acts/ad-enst-28-17-wide-chord-tail-rotor-counterweights-modification/analysis","conflicts":"/api/acts/ad-enst-28-17-wide-chord-tail-rotor-counterweights-modification/conflicts","importantCases":"/api/acts/ad-enst-28-17-wide-chord-tail-rotor-counterweights-modification/important-cases","documents":"/api/acts/ad-enst-28-17-wide-chord-tail-rotor-counterweights-modification/documents"}}