{"id":"F2006B10493","name":"AD/HS 125/54 - Fuselage Front Pressure Bulkhead - Inspection","slug":"ad-hs-125-54-fuselage-front-pressure-bulkhead-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116249,"registerId":"commonwealth-F2006B10493-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HS 125/54 - Fuselage Front Pressure Bulkhead - 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 125/54 Fuselage Front Pressure Bulkhead - Inspection 10/80\n\nApplicability: All HS/DH/BH 125 models up to and including Series 400. Document:  British Aerospace 125 SB No. 53-52.\n\nCompliance: As per requirement document except that stated flights shall be pressurised flights.\n\n \n\nBackground:  Cracking in the corner bend radii of both control pressings on one aircraft was discovered on an overseas aeroplane after 6700 flights.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific airworthiness concern on a specific aircraft type. It has not expanded beyond its original purpose of mandating inspection for fatigue cracking in a particular structural component."},"complexity_factors":["Extremely short document (approximately 150 words of substantive content)","Only one defined applicability criterion (aircraft model series)","Single cross-reference to external technical document (Service Bulletin 53-52)","One conditional modification to the external requirement (pressurised flights only)","No nested exceptions, no interpretative provisions, no penalty clauses","Standardised AD format with predictable structure (Applicability, Document, Compliance, Background)"],"plain_english_summary":"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:**\n- Requires owners and operators of certain British Aerospace BAe 125 series aeroplanes (specifically HS/DH/BH 125 models up to Series 400) to inspect the **fuselage front pressure bulkhead** — a critical structural component that seals the front of the pressurised cabin.\n\n**Why it matters:**\n- Cracks were discovered in this area on an overseas aircraft after 6,700 flights. If left unchecked, such cracking could lead to **catastrophic failure of the pressure vessel** (the sealed cabin that keeps passengers safe at high altitude), potentially causing rapid decompression or loss of structural integrity.\n\n**Who must comply:**\n- Anyone operating the affected aircraft models in Australia.\n\n**What they must do:**\n- Follow the inspection procedures outlined in **British Aerospace Service Bulletin No. 53-52**.\n- The Australian requirement adds one specific condition: any \"stated flights\" mentioned in the original bulletin must be **pressurised flights** (flights where the cabin is pressurised, not empty ferry flights at low altitude).\n\n**In short:** If you fly one of these specific business jets in Australia, you must check a particular part of the fuselage for cracks, following the manufacturer's instructions, with a slight Australian twist on when those checks apply."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD text, as provided, sets an inspection requirement for specified BAe 125 models and directs operators to follow the manufacturer's Service Bulletin, with one explicit modification (count only pressurised flights). There is no indication in the provided text that the scope of affected aircraft or the inspection mandate was altered from the stated content in the directive itself. The AD's operative scope is limited to the named model series and to the inspection procedures contained in the referenced Service Bulletin, modified only by the pressurised-flight counting instruction (see \"Applicability\", \"Document\" and \"Compliance\")."},"complexity_factors":["Short directive text but depends on an external technical document (British Aerospace 125 SB No. 53-52) for inspection procedures and intervals (\"Document\").","Modification to the external document's metric (stated flights must be pressurised flights) requires operators to interpret and apply the SB differently (\"Compliance\").","Applicability covers multiple model variants (HS/DH/BH 125 up to and including Series 400), requiring operators to confirm model fit and parts/configuration differences (\"Applicability\").","The AD does not state inspection intervals, acceptance criteria, or corrective actions directly, creating reliance on the SB and regulator guidance (implicit complexity from cross-reference).","Technical inspection subject-matter (fuselage front pressure bulkhead cracking in control pressing corners) is specialised and requires qualified maintenance personnel for execution and interpretation (\"Background\")."],"plain_english_summary":"This AD mandates inspections of the fuselage front pressure bulkhead on HS/DH/BH 125 aeroplanes up to Series 400, adopting BAe 125 Service Bulletin No. 53‑52 procedures but requiring flight counts to be measured in pressurised flights. It follows discovery of cracking after 6,700 flights.\n\nIt affects aircraft owners/operators and maintenance organisations, creating inspection, repair and downtime costs while delegating technical detail to the manufacturer’s service bulletin."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-125-54-fuselage-front-pressure-bulkhead-inspection","history":"/api/acts/ad-hs-125-54-fuselage-front-pressure-bulkhead-inspection/history","analysis":"/api/acts/ad-hs-125-54-fuselage-front-pressure-bulkhead-inspection/analysis","conflicts":"/api/acts/ad-hs-125-54-fuselage-front-pressure-bulkhead-inspection/conflicts","importantCases":"/api/acts/ad-hs-125-54-fuselage-front-pressure-bulkhead-inspection/important-cases","documents":"/api/acts/ad-hs-125-54-fuselage-front-pressure-bulkhead-inspection/documents"}}