{"id":"F2006B03509","name":"AD/BAe 146/59 - Elevator Mass Balance Weight","slug":"ad-bae-146-59-elevator-mass-balance-weight","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43067,"registerId":"commonwealth-F2006B03509-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/59 - Elevator Mass 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)  British Aerospace BAe 146 Series Aeroplanes\n\n \n\nAD/BAe 146/59 Elevator Mass Balance Weight 3/96\n\nApplicability: All Series BAe 146 and Avro 146/RJ aircraft.\n\n \n\nRequirement: Action in accordance with British Aerospace, Avro International Division Mandatory Service Bulletin 55-014-01510A.\n\n \n\nCompliance: Before 30 June 1997.\n\n \n\nBackground:  The manufacturer requires a modification which introduces revised mass balance weights to the elevators in order to counteract possible accumulation of water at the trailing edge of the elevators in severe precipitation.\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 with a single specific purpose. There is no indication of scope creep; it addresses one identified safety issue (water accumulation in elevators) for one aircraft type."},"complexity_factors":["Very short document (under 200 words)","No defined terms section — relies on external technical reference (the Service Bulletin)","Single, unambiguous requirement with clear applicability","No nested conditions, exceptions, or cross-references to other legislation","Straightforward compliance deadline with no alternative methods or phased implementation"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:** It requires owners and operators of British Aerospace BAe 146 and Avro 146/RJ series aircraft to install **revised mass balance weights** on the elevators (the movable surfaces on the tail that control the aircraft's pitch). These weights help prevent water from building up at the trailing edge of the elevators during heavy rain or severe precipitation, which could affect flight control.\n\n**Who must act:** Anyone who owns or operates a BAe 146 or Avro 146/RJ aircraft in Australia.\n\n**What they must do:** Follow the specific instructions in **British Aerospace Mandatory Service Bulletin 55-014-01510A** — a technical document from the manufacturer detailing exactly how to make the modification.\n\n**Deadline:** The work had to be completed before **30 June 1997**.\n\n**Why it matters:** Water accumulation in flight controls is a serious safety risk. This directive ensures aircraft remain safe to fly in wet conditions by addressing a design flaw that could compromise elevator effectiveness."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive's scope aligns with the manufacturer's stated purpose: it mandates the installation of revised elevator mass balance weights for all Series BAe 146 and Avro 146/RJ aircraft by a specified date. It does not expand obligations beyond requiring compliance with the manufacturer's Mandatory Service Bulletin, nor does it add additional measures or exemptions beyond the stated modification and compliance deadline. (Applicability, Requirement, Compliance, Background)"},"complexity_factors":["Short, narrowly targeted directive applying to a single aircraft family (Applicability).","Primary obligation is to follow an external technical document (manufacturer Mandatory Service Bulletin), so the AD itself contains no procedural detail (Requirement).","Fixed compliance date creates a clear but time‑limited enforcement point (Compliance).","Technical implementation requires specialised maintenance resources and parts, creating operational scheduling complexity for operators despite the AD's textual simplicity (Requirement, Compliance).","No conditional or phased requirements, no multiple categories of affected parties — limited legal branching reduces legal complexity (Applicability, Requirement)."],"plain_english_summary":"This airworthiness directive requires owners/operators of all BAe 146 and Avro 146/RJ aircraft to modify elevator mass balance weights per the manufacturer's Mandatory Service Bulletin, completed by 30 June 1997. The change aims to reduce risk from water accumulation on elevator trailing edges in heavy precipitation. Compliance costs (parts, labor, downtime) fall to operators and must follow the service bulletin’s technical instructions; alternatives need regulator approval."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-59-elevator-mass-balance-weight","history":"/api/acts/ad-bae-146-59-elevator-mass-balance-weight/history","analysis":"/api/acts/ad-bae-146-59-elevator-mass-balance-weight/analysis","conflicts":"/api/acts/ad-bae-146-59-elevator-mass-balance-weight/conflicts","importantCases":"/api/acts/ad-bae-146-59-elevator-mass-balance-weight/important-cases","documents":"/api/acts/ad-bae-146-59-elevator-mass-balance-weight/documents"}}