{"id":"F2006B10404","name":"AD/HS 125/125 - APU Power Supplies","slug":"ad-hs-125-125-apu-power-supplies","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116071,"registerId":"commonwealth-F2006B10404-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HS 125/125 - APU Power Supplies","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 125/125 APU Power Supplies 3/92\n\nApplicability: As specified in the requirement document.\n\n \n\nRequirement: Action in accordance with BAe Service Bulletin 49-37-25A253A&B.\n\n \n\nNote: Action is accordance with this SB is classified mandatory by the UK CAA.\n\n \n\nCompliance: Prior to 30 March 1992.\n\n \n\nBackground: The APU power supply connections are relocated to protect against damage from engine debris.\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-limited safety directive focused on a specific mechanical modification. It has not expanded beyond its original purpose of addressing the APU power supply vulnerability."},"complexity_factors":["Extremely short document (under 200 words)","Only 4 substantive sections: Applicability, Requirement, Compliance, Background","Single technical action required (relocate connections per manufacturer bulletin)","No defined terms section — relies entirely on external technical reference (Service Bulletin 49-37-25A253A&B)","No conditional logic, exceptions, or nested provisions","Fixed deadline with no alternative compliance methods stated"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety order — issued by Australia's Civil Aviation Safety Authority (CASA) for a specific type of aircraft.\n\n**Who it affects:** Owners and operators of **British Aerospace BAe 125 Series Aeroplanes** (business jets). The exact serial numbers or models covered are found in a separate technical document referenced here.\n\n**What it requires:** Operators must follow the instructions in **BAe Service Bulletin 49-37-25A253A&B** — a manufacturer-issued repair notice. Specifically, they must **relocate the APU power supply connections**. \n\n*(APU = Auxiliary Power Unit, a small engine at the back of the plane that provides electricity and air conditioning when the main engines are off. The \"power supply connections\" are the electrical hookups for this unit.)*\n\n**Why it matters:** Engine debris could damage these electrical connections. If damaged, the APU might fail or cause electrical problems — potentially serious during ground operations or emergency situations.\n\n**Deadline:** The work had to be completed **before 30 March 1992**.\n\n**Key point:** This directive adopts a British safety mandate (from the UK Civil Aviation Authority) and makes it legally binding in Australia."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text of the AD sets a focused technical requirement: relocate APU power supply connections in accordance with BAe Service Bulletin 49-37-25A253A&B and complete the work before 30 March 1992. There is no indication in the AD that the scope has been expanded or narrowed from its original stated purpose (protecting APU connections from engine debris). The AD relies on the external service bulletin for procedural detail and does not change that procedural scope within the text (Requirement; Background; Compliance)."},"complexity_factors":["Direct, single-action requirement: relocation of APU power supply connections specified (Requirement)","Prescriptive reference to an external BAe Service Bulletin (49-37-25A253A&B) rather than internal procedural detail (Requirement)","Applicability not detailed within the AD text—applies \"as specified in the requirement document\" (Applicability)","Fixed compliance deadline (prior to 30 March 1992) creates scheduling pressure (Compliance)","Cross-jurisdictional note that the UK CAA classifies the SB as mandatory, adding regulatory context but not additional procedural detail (Note)","Instrument is short and leaves costs, authorised providers, and alternative compliance pathways unspecified (silence in text)"],"plain_english_summary":"This AD requires operators of specified BAe 125 aircraft to relocate APU power‑supply connections exactly as set out in BAe Service Bulletin 49‑37‑25A253A&B, to reduce the risk of engine‑debris damage. Compliance is mandatory under CASA and must be completed before 30 March 1992. The directive prescribes the manufacturer procedure by reference, affects operators’ maintenance scheduling, and is silent on costs, alternate methods, or who must pay."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-125-125-apu-power-supplies","history":"/api/acts/ad-hs-125-125-apu-power-supplies/history","analysis":"/api/acts/ad-hs-125-125-apu-power-supplies/analysis","conflicts":"/api/acts/ad-hs-125-125-apu-power-supplies/conflicts","importantCases":"/api/acts/ad-hs-125-125-apu-power-supplies/important-cases","documents":"/api/acts/ad-hs-125-125-apu-power-supplies/documents"}}