{"id":"F2006B02735","name":"AD/B727/34 - Stabilizer Hinge Bearings and Bushings - Replacement","slug":"ad-b727-34-stabilizer-hinge-bearings-and-bushings-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42077,"registerId":"commonwealth-F2006B02735-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/34 - Stabilizer Hinge Bearings and Bushings - Replacement","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)  Boeing 727 Series Aeroplanes\n\n \n\nAD/B727/34  Stabilizer Hinge Bearings and Bushings - Replacement\n\n\n9/66\n\n \n\nApplicability: All models. Document: Boeing SB No. 55-29. Compliance: Forthwith.\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":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive, as presented, mandates replacement of stabilizer hinge bearings and bushings for all Boeing 727 models and references Boeing SB No. 55-29 for technical procedures, with immediate effect. There is no indication in the supplied text that the scope has been expanded or narrowed from an earlier or original intent; the instrument states a single, clear mandatory action (Applicability; Document; Compliance)."},"complexity_factors":["Cross-reference to an external technical document (Boeing SB No. 55-29) — technical detail is not contained in the AD itself, so operators must obtain and interpret an external source (Document).","Immediate compliance requirement (“Forthwith”) increases operational complexity for scheduling and sourcing parts at short notice (Compliance).","Broad applicability to all Boeing 727 models creates a wide operational and logistical footprint for compliance (Applicability).","The AD text is concise and omits explanatory material, time windows, allowable alternatives, or enforcement particulars, requiring implementers to seek further procedural guidance (Title; Document; Compliance)."],"plain_english_summary":"This directive mandates immediate replacement of stabilizer hinge bearings and bushings on all Boeing 727 series aircraft, to be carried out in accordance with Boeing Service Bulletin No. 55‑29.  \n\nIt affects aircraft owners/operators and maintenance organisations, who must fund and schedule the work; compliance is mandatory and dependent on access to the Boeing service bulletin and parts, creating potential downtime and revenue impact."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a vintage AD (originally issued 9/66 — September 1966) that has remained focused on its original narrow technical purpose: replacing specific wear-prone components in the Boeing 727 stabilizer hinge mechanism. There is no evidence of scope creep; it has not expanded beyond this specific airworthiness issue."},"complexity_factors":["Extremely short document — only 4 substantive lines of regulatory text","No defined terms section — relies entirely on external Boeing technical document","No conditional logic or exceptions — blanket applicability to all Boeing 727 models","Single cross-reference only (to Boeing SB 55-29)","Simple command structure: applicability + document reference + compliance deadline"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it requires:** Owners and operators of **Boeing 727 series aircraft** must replace the **stabilizer hinge bearings and bushings** — these are mechanical parts that allow the horizontal tail stabilizer (the small wings at the back of the plane) to pivot and control the aircraft's pitch.\n\n**Why it matters:** Worn or faulty bearings/bushings in the stabilizer hinge could cause control problems, potentially leading to loss of aircraft control. This AD mandates immediate action to prevent accidents.\n\n**Who must comply:** Anyone operating a Boeing 727 in Australia — all models are affected.\n\n**When:** **Forthwith** — meaning immediately, without delay. This is the most urgent compliance timeframe.\n\n**How to comply:** Follow the instructions in **Boeing Service Bulletin No. 55-29**, which provides the technical procedures for the replacement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-34-stabilizer-hinge-bearings-and-bushings-replacement","history":"/api/acts/ad-b727-34-stabilizer-hinge-bearings-and-bushings-replacement/history","analysis":"/api/acts/ad-b727-34-stabilizer-hinge-bearings-and-bushings-replacement/analysis","conflicts":"/api/acts/ad-b727-34-stabilizer-hinge-bearings-and-bushings-replacement/conflicts","importantCases":"/api/acts/ad-b727-34-stabilizer-hinge-bearings-and-bushings-replacement/important-cases","documents":"/api/acts/ad-b727-34-stabilizer-hinge-bearings-and-bushings-replacement/documents"}}