{"id":"F2006B10495","name":"AD/HS 125/56 - Aileron, Rudder & Elevator Trim Jack Input Gear Shafts - Inspection","slug":"ad-hs-125-56-aileron-rudder-elevator-trim-jack-input-gear-shafts-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116253,"registerId":"commonwealth-F2006B10495-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HS 125/56 - Aileron, Rudder & Elevator Trim Jack Input Gear Shafts - Inspection","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 125 Series Aeroplanes\n\n \n\nAD/HS 125/56 Aileron, Rudder & Elevator Trim Jack\n\nInput Gear Shafts - Inspection Applicability: All HS/DH/BH125 aircraft all series up to and including series 700. Document:              British Aerospace HS 125 SB No. 27-130, Rev. 1.\n\nCompliance: At next removal of control surfaces.\n\n \n\nBackground: Failure of a trim jack input gear shaft has occurred in service.\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\n8/81\n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical failure mode in a specific aircraft type. It has not expanded beyond its original purpose of mandating inspection of trim jack input gear shafts."},"complexity_factors":["Single, specific mechanical component addressed","No defined terms section — uses standard aviation terminology","Simple conditional trigger: 'at next removal of control surfaces'","No cross-references to other legislation or complex procedural requirements","References only one external technical document (manufacturer's service bulletin)","Extremely short — approximately 100 words of substantive content"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires aircraft owners and operators to inspect or fix specific problems.\n\n**What it does:**\nOrders inspections of **trim jack input gear shafts** on British Aerospace BAe 125 series aircraft. These are mechanical components that help control the ailerons, rudder, and elevator — the surfaces that steer and stabilise the plane.\n\n**Why it matters:**\nOne of these gear shafts failed in actual flight operations. If the shaft breaks, pilots could lose control of the aircraft's trim systems, making the plane difficult or impossible to fly safely.\n\n**Who must comply:**\nAnyone operating **HS/DH/BH 125 aircraft** (all models up to series 700). This includes airlines, charter operators, and private owners.\n\n**When to do it:**\nAt the **next removal of control surfaces** — meaning whenever the wings or tail sections are taken off for maintenance, rather than requiring an immediate special inspection.\n\n**The fix:**\nFollow the procedures in **British Aerospace Service Bulletin 27-130, Revision 1** — a technical document from the manufacturer detailing exactly how to inspect the shafts."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive as presented requires inspection of the specified trim jack input gear shafts for all HS/DH/BH125 aircraft up to series 700 at the next removal of the control surfaces, referencing BAe Service Bulletin 27-130 Rev. 1, with the stated background that a failure occurred in service. There is no information in the provided text indicating a change in scope from the original intent."},"complexity_factors":["Narrow technical scope: single component group (trim jack input gear shafts) across multiple control surfaces.","Simple compliance trigger: inspection required at next removal of control surfaces rather than recurring intervals or condition-based thresholds.","Dependency on an external document (British Aerospace HS 125 SB No. 27-130, Rev. 1) for inspection procedure and corrective action increases procedural dependency.","Applicability across multiple aircraft sub-series (all series up to and including series 700) requires fleet-level tracking.","Operational impact concentrated on maintenance events (control-surface removals), which may be infrequent and thus affect scheduling.","Regulatory issuance under Part 39 creates a mandatory compliance obligation with limited discretion for operators."],"plain_english_summary":"CASA requires operators of British Aerospace HS/DH/BH 125 series (up to series 700) to inspect the aileron, rudder and elevator trim jack input gear shafts at the next removal of the associated control surfaces, per British Aerospace Service Bulletin 27‑130 Rev. 1. \n\nThe measure responds to an in‑service trim jack input gear shaft failure and is implemented and funded by aircraft owners/operators, with compliance tied to existing control‑surface removals."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-125-56-aileron-rudder-elevator-trim-jack-input-gear-shafts-inspection","history":"/api/acts/ad-hs-125-56-aileron-rudder-elevator-trim-jack-input-gear-shafts-inspection/history","analysis":"/api/acts/ad-hs-125-56-aileron-rudder-elevator-trim-jack-input-gear-shafts-inspection/analysis","conflicts":"/api/acts/ad-hs-125-56-aileron-rudder-elevator-trim-jack-input-gear-shafts-inspection/conflicts","importantCases":"/api/acts/ad-hs-125-56-aileron-rudder-elevator-trim-jack-input-gear-shafts-inspection/important-cases","documents":"/api/acts/ad-hs-125-56-aileron-rudder-elevator-trim-jack-input-gear-shafts-inspection/documents"}}