{"id":"F2006B09849","name":"AD/F50/23 - Elevator Control Rod Ends","slug":"ad-f50-23-elevator-control-rod-ends","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54913,"registerId":"commonwealth-F2006B09849-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/23 - Elevator Control Rod Ends","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 F50 (F27 Mk 50) Series Aeroplanes\n\n \n\nAD/F50/23 Elevator Control Rod Ends 10/89\n\nApplicability: F27 Mark 050 aircraft with serial numbers 20103 through 20108, 20110 through\n\n20147.\n\n \n\nRequirement: Action in accordance with Fokker SB F50-27-006.\n\n \n\nNote: RLD AD BLA89-56 refers.\n\n \n\nCompliance: At the next scheduled 3000 hours inspection after 5 October 1989 or prior to 31 March 1990, whichever occurs first.\n\n \n\nBackground: Country of origin AD. Present rod ends have a semi-octagonal section, which may catch and retain foreign objects, leading to a potential jamming of elevator controls. Replacement rod ends required by this AD are less liable to jamming.\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":3,"scope_assessment":{"changed":false,"description":"The AD maintains a narrow, specific scope: it targets defined F27 Mark 050 serial numbers and mandates replacement in accordance with the Fokker service bulletin (Applicability; Requirement). The stated mechanical change and the compliance timing are consistent with the instrument’s expressed purpose (Background; Compliance), so there is no indication in the text that the scope departs from the original stated intent."},"complexity_factors":["Narrow applicability limited to specific serial number ranges (Applicability) reduces scope complexity.","Single technical action (replace rod ends) simplifies required tasks (Requirement).","Reliance on an external manufacturer service bulletin for the technical method creates dependency on that document and any parts it specifies (Requirement).","A fixed, relatively short compliance window linked to a scheduled inspection requires coordination of parts and labour within that timeframe (Compliance).","Technical nature of the work may require qualified maintenance personnel and specific parts, introducing operational and supply‑chain considerations (Requirement; Compliance).","Cross‑reference to related foreign AD (Note) adds a minor traceability step for operators tracking origin information (Note; Background)."],"plain_english_summary":"What this instrument changes mechanically\n\n- It requires replacement of the elevator control rod ends on certain Fokker F50 (F27 Mk 50) aircraft. The replacement must be carried out in accordance with Fokker Service Bulletin F50-27-006 (Requirement).\n- The rule applies only to F27 Mark 050 aeroplanes with serial numbers 20103–20108 and 20110–20147 (Applicability).\n- Timing is prescribed: carry out the replacement at the next scheduled 3000‑hour inspection after 5 October 1989 or before 31 March 1990, whichever comes first (Compliance).\n\nStated purpose and the mechanical test of that purpose\n\n- The Background states the present rod ends have a semi‑octagonal section that \"may catch and retain foreign objects, leading to a potential jamming of elevator controls.\" The Background further states the replacement rod ends \"are less liable to jamming.\"\n- The Requirement directs operators to follow the manufacturer’s service bulletin to effect the replacement (Requirement). Mechanically, the AD changes the aircraft by substituting the existing rod ends for the part described in the service bulletin.\n\nWho decides, who pays, and what changes in behaviour\n\n- The Civil Aviation Safety Authority issues the directive under the Commonwealth civil aviation regulations (header). The directive prescribes the action and the compliance window (Requirement; Compliance).\n- Aircraft operators who run the listed serial‑number aeroplanes are the parties required to arrange and pay for the replacement (Applicability; Requirement). They must schedule the work into the specified inspection window (Compliance).\n\nCompliance burden, implementation mechanics and risks\n\n- Compliance is tied to the operator’s next scheduled 3000‑hour inspection (Compliance), so the AD is designed to be completed within an existing maintenance event rather than creating an immediately separate grounding period. That reduces incremental downtime but still requires parts and labour at that inspection.\n- The AD relies on the manufacturer’s service bulletin for the technical procedure (Requirement). That creates a dependence on the bulletin’s instructions and on availability of the replacement rod ends and qualified maintenance resources.\n\nTrade‑offs, incentives and distribution of effects\n\n- Benefits are concentrated to operators of the listed serial numbers: they receive the direct safety benefit asserted by the Background (Background). The costs (parts, labour, scheduling) are concentrated on those same operators because they are required to perform the replacement (Applicability; Requirement).\n- The directive removes the option for affected operators to continue operating with the existing rod ends beyond the compliance date; it therefore restricts equipment choice for those aircraft for safety reasons (Applicability; Compliance).\n- The AD prescribes a specific technical fix (the replacement specified by Fokker SB), which limits substitution to the parts and method set out in that bulletin (Requirement).\n\nOther implementation notes\n\n- The AD cites a related RLD AD (RLD AD BLA89‑56) as a note (Note). The AD is framed as a response to the country‑of‑origin action (Background).\n\nSource citations: Applicability; Requirement; Compliance; Background; Note."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a limited production run of aircraft. It has not expanded beyond its original purpose of mandating a hardware replacement to prevent control jamming."},"complexity_factors":["Very short document (under 200 words)","Only 4 substantive paragraphs (Applicability, Requirement, Compliance, Background)","Single defined reference (Fokker SB F50-27-006) — external technical document, not defined within the AD itself","Simple conditional logic: 'whichever occurs first' is the only conditional element","No cross-references to other legislation or regulations beyond the note about RLD AD BLA89-56 (a reference to the Dutch aviation authority's equivalent directive)","Narrow, specific applicability (limited serial number range)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of specific Fokker F50 aircraft to replace certain elevator control rod ends (mechanical parts that connect the pilot's control inputs to the elevator, which makes the plane pitch up and down).\n\n**Who it affects:**\nOwners and operators of Fokker F50 aircraft with serial numbers 20103-20108 and 20110-20147 — a limited batch of early production aircraft.\n\n**Why it matters:**\nThe existing rod ends have a semi-octagonal shape that can trap debris (foreign objects), potentially jamming the elevator controls. A jammed elevator means the pilot might lose the ability to control the aircraft's pitch — a serious flight safety risk. The replacement parts have a smoother design less likely to catch foreign objects.\n\n**What must be done:**\nOperators must follow Fokker Service Bulletin F50-27-006 (the manufacturer's official repair instructions) and complete the replacement either:\n- At the next scheduled 3,000-hour inspection after 5 October 1989, **or**\n- Before 31 March 1990,\nwhichever comes first.\n\n**Key point:** This is a time-critical safety fix — not optional, and with a hard deadline."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-23-elevator-control-rod-ends","history":"/api/acts/ad-f50-23-elevator-control-rod-ends/history","analysis":"/api/acts/ad-f50-23-elevator-control-rod-ends/analysis","conflicts":"/api/acts/ad-f50-23-elevator-control-rod-ends/conflicts","importantCases":"/api/acts/ad-f50-23-elevator-control-rod-ends/important-cases","documents":"/api/acts/ad-f50-23-elevator-control-rod-ends/documents"}}