{"id":"F2006B09758","name":"AD/F28/21 - Passenger Door - Locking Mechanism Modification","slug":"ad-f28-21-passenger-door-locking-mechanism-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54624,"registerId":"commonwealth-F2006B09758-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F28/21 - Passenger Door - Locking Mechanism 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)  Fokker F28 Series Aeroplanes\n\n \n\nAD/F28/21 Passenger Door - Locking Mechanism Modification NK\n\nApplicability: As detailed in the requirement document. Document:  Fokker SB F28/52-43, Part IV. Compliance:              Before 31 October 1974.\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":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive issued for a specific aircraft type and specific technical issue. It has not expanded beyond its original purpose of mandating a door locking modification for Fokker F28 aircraft."},"complexity_factors":["Extremely short document — only a few lines of operative text","No defined terms section — relies entirely on external reference to Fokker Service Bulletin","Single, unambiguous compliance requirement with a clear deadline","No conditional logic, exceptions, or nested provisions","Cross-reference is simple and explicit (one document reference: Fokker SB F28/52-43, Part IV)","Applicability is delegated to the external technical document rather than defined in the instrument itself"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:**\nIt requires owners and operators of **Fokker F28 series aircraft** to modify the passenger door locking mechanism on their planes.\n\n**Who it affects:**\nAnyone who owns, operates, or maintains Fokker F28 aeroplanes in Australia.\n\n**The specific requirement:**\nOperators must follow the instructions in **Fokker Service Bulletin F28/52-43, Part IV** — a technical document published by the aircraft manufacturer detailing exactly what modifications need to be made to the door locking system.\n\n**When it had to be done:**\nThe modification had to be completed **before 31 October 1974**.\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety instructions. They are issued when a potential safety defect is discovered in an aircraft type. In this case, there was evidently a problem with the F28's passenger door locking mechanism that could pose a safety risk — possibly the door opening unexpectedly during flight or failing to seal properly. The directive ensures all affected aircraft were fixed before the deadline to prevent accidents."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The supplied text specifies a requirement to modify the passenger door locking mechanism for Fokker F28 series aeroplanes as detailed in the referenced service bulletin, with a compliance deadline. The instrument as presented does not indicate any change from that original requirement or expand/narrow scope within this text; applicability is delegated to the referenced service bulletin. No textual evidence here shows the scope has been altered from the directive's stated content."},"complexity_factors":["Technical specificity delegated to an external service bulletin (Document: Fokker SB F28/52-43, Part IV) increases operational complexity for implementers.","Applicability is not listed directly in the AD text here (\"As detailed in the requirement document\"), requiring users to consult the external document to determine affected aircraft.","Compliance deadline is fixed (Before 31 October 1974), creating a time-pressure dimension to scheduling and logistics.","Regulatory enforcement is straightforward (a single mandatory action) which reduces legal complexity, but technical and logistical complexity remains for operators and maintenance providers.","Historical context (date in 1974) may complicate parts availability and approved procedures for modern implementers, if relevant."],"plain_english_summary":"This airworthiness directive mandates a modification to the passenger door locking mechanism on specified Fokker F28 aircraft, as detailed in Fokker Service Bulletin F28/52‑43 Part IV. Affected operators must complete the change by 31 October 1974.\n\nIt primarily affects Fokker F28 owners/operators, maintenance organisations that perform the work, and the regulator enforcing compliance; operators bear the cost and scheduling burden."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f28-21-passenger-door-locking-mechanism-modification","history":"/api/acts/ad-f28-21-passenger-door-locking-mechanism-modification/history","analysis":"/api/acts/ad-f28-21-passenger-door-locking-mechanism-modification/analysis","conflicts":"/api/acts/ad-f28-21-passenger-door-locking-mechanism-modification/conflicts","importantCases":"/api/acts/ad-f28-21-passenger-door-locking-mechanism-modification/important-cases","documents":"/api/acts/ad-f28-21-passenger-door-locking-mechanism-modification/documents"}}