{"id":"F2006B09664","name":"AD/F100/7 - Vertical Stabiliser","slug":"ad-f100-7-vertical-stabiliser","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115792,"registerId":"commonwealth-F2006B09664-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F100/7 - Vertical Stabiliser","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nFokker F100 (F28 Mk 100) Series Aeroplanes\n\nAD/F100/7 Vertical Stabiliser 4/99\n\nApplicability: F.28 Mk.0100 aircraft, serial numbers 11244, 11245, 11250 through 11256 and 11268\n\nthrough 11273.\n\nRequirement: Inspect the vertical stabiliser and install three reinforcement doublers in accordance with Fokker Service Bulletin (SB) F100-55-011 dated 1 October 1991.\n\nNote: RLD BLA 91-117 refers.\n\nCompliance: Unless previously accomplished, before accumulating 6,500 flight cycles since new.\n\nThis Airworthiness Directive becomes effective on 22 April 1999.\n\nBackground: Fatigue tests on the F.28 Mk.0100 have revealed cracks in the skin of the vertical stabiliser at rib 5.0 near intermediate spars I and II, and in the underlying structure. This AD requires a modification to prevent cracks and to improve the fatigue life of the vertical stabiliser.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD enforces a modification that aligns with the stated original intent: to prevent cracks and to improve the fatigue life of the vertical stabiliser (Background). Mechanically, it prescribes inspection and installation of reinforcement doublers per the named Fokker Service Bulletin (Requirement) for a defined set of serial-numbered aircraft (Applicability) with a clear flight-cycle compliance point (Compliance). The directive does not, in the text shown, broaden the technical scope beyond that stated purpose or add unrelated obligations."},"complexity_factors":["Narrow applicability limited to a short list of serial numbers (Applicability)","Single, specific technical remedy required (install three reinforcement doublers) referenced to an external Fokker Service Bulletin (Requirement)","Compliance metric tied to a clear flight-cycle threshold (before 6,500 flight cycles) rather than calendar time (Compliance)","No alternative compliance paths, exemptions, or procedural discretion specified in the text provided (Requirement; Compliance)","Dependence on an external technical document (Fokker SB F100-55-011) for procedural detail increases operational, but not legal, complexity (Requirement)"],"plain_english_summary":"Owners/operators of seven specific Fokker F100 (F28 Mk 100) airframes (listed serial numbers) must inspect the vertical stabiliser and install three reinforcement doublers per Fokker Service Bulletin F100-55-011. Work must be done, if not already, before the aircraft reaches 6,500 flight cycles.  \n\nThe directive mandates operator-funded parts, labour and downtime to address fatigue cracks found in the stabiliser skin and underlying structure, aiming to extend fatigue life."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted airworthiness directive addressing a specific fatigue issue identified in testing. It remains tightly scoped to the original safety concern without expansion into broader operational or regulatory matters."},"complexity_factors":["Very short document (under 200 words)","Only 11 specific aircraft affected by serial number","Single, clear mechanical requirement: inspect and install three doublers","One straightforward compliance deadline (6,500 flight cycles)","No nested exceptions, conditional logic, or extensive cross-referencing","References only one external technical document (Fokker Service Bulletin)"],"plain_english_summary":"This is a **safety order for specific Fokker F100 aircraft**.\n\n**What it does:**\n- Requires owners/operators of certain Fokker F100 planes (specific serial numbers listed) to **inspect the tail fin** (vertical stabiliser) and **install three metal reinforcement plates** (doublers) to strengthen it.\n\n**Who it affects:**\n- Only applies to **11 specific aircraft** with serial numbers: 11244, 11245, 11250-11256, and 11268-11273.\n\n**Why it matters:**\n- **Fatigue testing found cracks** in the tail fin skin and underlying structure at a specific location (rib 5.0). Without this fix, the tail fin could develop dangerous cracks from repeated stress during flights.\n- The modification must be done **before the aircraft reaches 6,500 flight cycles** (roughly, one takeoff and landing = one cycle).\n\n**Key deadline:**\n- The order took effect on **22 April 1999**, and compliance was required before hitting the flight cycle limit."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-7-vertical-stabiliser","history":"/api/acts/ad-f100-7-vertical-stabiliser/history","analysis":"/api/acts/ad-f100-7-vertical-stabiliser/analysis","conflicts":"/api/acts/ad-f100-7-vertical-stabiliser/conflicts","importantCases":"/api/acts/ad-f100-7-vertical-stabiliser/important-cases","documents":"/api/acts/ad-f100-7-vertical-stabiliser/documents"}}