{"id":"F2006B07284","name":"AD/TB10/17 - Horizontal Stabilizer Balance Weight","slug":"ad-tb10-17-horizontal-stabilizer-balance-weight","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49236,"registerId":"commonwealth-F2006B07284-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TB10/17 - Horizontal Stabilizer Balance Weight","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)  Aerospatiale (Socata) TB9 and TB10 (Tobago) Series Aeroplanes\n\n \n\nAD/TB10/17 Horizontal Stabilizer Balance Weight 4/91 DM\n\nApplicability: Model TB9 and TB10 series with serial numbers 1 through 1217. Requirement:  Action in accordance with Alert SB 57.\n\nCompliance: Within 25 hours time in service after 13 February 1991.\n\n \n\nBackground:  Directive requires an inspection to determine whether both attaching nuts of the horizontal stabilizer balance weight are within the required safety dimension.\n\nDetachment of balance weight may lead to a dangerous flutter condition.\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 airworthiness issue. It has not expanded beyond its original purpose of mandating an inspection for a specific defect in specific aircraft."},"complexity_factors":["Extremely short document (under 200 words)","Only 4 operative provisions: applicability, requirement, compliance deadline, and background","No defined terms section","No cross-references to other legislation (only references manufacturer service bulletin)","Simple conditional logic: if aircraft is in serial number range, then inspection required","Single compliance deadline with clear trigger (25 hours time in service after fixed date)"],"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) for specific aircraft.\n\n**What it does:** It requires owners or operators of certain Socata TB9 and TB10 Tobago aeroplanes (serial numbers 1 to 1217) to inspect the horizontal stabilizer balance weight within 25 hours of flying time after 13 February 1991.\n\n**Why it matters:** The balance weight is a counterweight on the tail of the aircraft. If its attaching nuts are not properly secured within specific safety measurements, the weight could fall off. This could cause \"flutter\" — a dangerous vibration that can make the aircraft uncontrollable or cause structural failure.\n\n**Who must act:** Anyone operating the affected aircraft models must follow the inspection procedure outlined in \"Alert SB 57\" (an urgent service bulletin from the manufacturer)."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive’s scope is limited and clearly stated: it applies to TB9 and TB10 aeroplanes with serial numbers 1–1217 and mandates an inspection per Alert SB 57 within a fixed short window. There is no indication in the text provided that the scope was altered from the instrument’s stated aim of inspecting horizontal stabilizer balance-weight attaching nuts to verify they meet required dimensions (Applicability; Requirement; Compliance; Background)."},"complexity_factors":["Narrow applicability (specific models and serial numbers 1–1217) reduces scope complexity (Applicability).","Single technical action required (inspection) rather than a multi-step regime simplifies compliance (Requirement).","Short compliance window (25 hours time in service) increases operational urgency and scheduling complexity (Compliance).","Dependence on an external document (Alert SB 57) for technical detail adds a modest layer of complexity and delegation (Requirement).","Safety-critical technical judgement (measuring nuts against a 'required safety dimension') requires qualified maintenance personnel, adding technical complexity despite procedural simplicity (Background)."],"plain_english_summary":"CASA requires owners/operators of Aerospatiale (Socata) TB9 and TB10 aeroplanes (serials 1–1217) to carry out the inspection described in Alert Service Bulletin SB 57 within 25 hours time in service after 13 February 1991. The check verifies the horizontal-stabilizer balance-weight attaching nuts meet required dimensions to prevent detachment and possible flutter.\n\nOwners/operators must pay for the inspection and any corrective work, face short-notice scheduling/downtime, and must follow the manufacturer’s bulletin for measurement and repair criteria."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tb10-17-horizontal-stabilizer-balance-weight","history":"/api/acts/ad-tb10-17-horizontal-stabilizer-balance-weight/history","analysis":"/api/acts/ad-tb10-17-horizontal-stabilizer-balance-weight/analysis","conflicts":"/api/acts/ad-tb10-17-horizontal-stabilizer-balance-weight/conflicts","importantCases":"/api/acts/ad-tb10-17-horizontal-stabilizer-balance-weight/important-cases","documents":"/api/acts/ad-tb10-17-horizontal-stabilizer-balance-weight/documents"}}