{"id":"F2006B10490","name":"AD/HS 125/51 Amdt 3 - Nose Landing Gear Drag Stay Bridge Casting","slug":"ad-hs-125-51-amdt-3-nose-landing-gear-drag-stay-bridge-casting","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116243,"registerId":"commonwealth-F2006B10490-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HS 125/51 Amdt 3 - Nose Landing Gear Drag Stay Bridge Casting","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBritish Aerospace BAe 125 Series Aeroplanes\n\nAD/HS 125/51\n\nAmdt 3\n\n  \nNose Landing Gear Drag Stay Bridge Casting 3/95\n\nApplicability: All BAe 125 series aircraft pre mod 253003A and spare P/N 25UN49A and 25UN49AD bridge casting assemblies.\n\nRequirement: 1. Eddy current inspect P/N 25UN49A and 25UN49AD bridge casting assemblies in accordance with BAe SB 32-184 Revision 5.\n\n2. Blend P/N 25UN49A bridge casting assemblies in accordance with BAe Service Bulletin (SB) 32-184 Revision 5.\n\nCompliance: 1. Initially inspect and blend installed components in accordance with Requirements 1 and 2 at the next Service A check after 2000 landings or at the next Service A check after 30 March 1995, whichever occurs later.\n\n    2. Inspect and blend spare components in accordance with Requirements 1 and 2 before installation on an aircraft or before 30 March 1996, whichever occurs first.\n\n    3. Re-inspect installed components in accordance with Requirement 1 at intervals not to exceed 900 hours time in service or 2 years, whichever occurs first.\n\nNote: Components inspected by previous Amendments of this Airworthiness Directive need not be eddy current inspected until the repeat inspection is due.\n\nBackground: Several cases have occurred of cracking of the bridge casting at the radius of the cut out for the drag stay upper arm. This amendment deletes the penetrant inspection and introduces the more effective eddy current inspection method. The initial inspection for spare components is clarified.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is Amendment 3 to an existing Airworthiness Directive. The scope remains tightly focused on the original safety issue (cracking in nose landing gear bridge castings). The amendment makes procedural improvements (switching inspection methods, clarifying spare parts requirements) without expanding the affected aircraft population or introducing new unrelated requirements."},"complexity_factors":["Short, single-purpose directive (approximately 250 words)","Only 2 defined part numbers (P/N 25UN49A and 25UN49AD)","Single cross-reference to external technical document (BAe SB 32-184 Revision 5)","Clear conditional logic with 'whichever occurs first/last' formulations","No nested exceptions or sub-delegations","Technical terminology requires aviation engineering knowledge but is standard for the field"],"plain_english_summary":"This CASA Airworthiness Directive mandates eddy‑current inspection and blending repair of the BAe 125 nose landing‑gear drag‑stay bridge casting to detect and remove cracks that could cause gear failure. It applies to BAe 125 aircraft not modified by mod 253003A and to spare castings (P/N 25UN49A/25UN49AD), requires work per BAe Service Bulletin 32‑184 Rev 5, and sets deadlines and recurring inspection intervals to ensure continued airworthiness."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This amendment modifies the inspection method (deletes penetrant inspection and mandates eddy-current inspection) and clarifies initial inspection timing for spare components (Background; Compliance 1–2). Applicability remains limited to BAe 125 aircraft pre-mod 253003A and specified spare part numbers, so the affected population is unchanged but the required inspection technique and scheduling are altered."},"complexity_factors":["Change of inspection technique from penetrant to eddy-current (Background) increases equipment/skill requirements for maintainers.","Separate obligations for installed components and spare parts with different deadlines (Compliance 1–2) create scheduling complexity.","Recurring re‑inspection interval defined as ‘not to exceed 900 hours TIS or 2 years’ (Compliance 3) requires tracking flight hours/calendar time.","Two distinct maintenance actions required: eddy-current inspection and blending of P/N 25UN49A (Requirement 1–2).","Applicability limited to BAe 125 pre-mod 253003A and specific part numbers (Applicability) requires parts-level identification and inventory checks.","Exemption for components inspected under previous amendments (Note) adds record-keeping and verification burden to determine applicability."],"plain_english_summary":"Requires eddy-current inspection and blending of specific BAe 125 nose-landing-gear bridge castings (P/N 25UN49A, 25UN49AD) to detect and repair cracking. Affects operators, maintainers and parts suppliers for BAe 125 aircraft pre-mod 253003A and owners of spare castings. Initial and repeat inspection timings differ for installed versus spare parts; rechecks are required at intervals not exceeding 900 hours time-in-service or 2 years. The amendment replaces penetrant inspection with eddy-current and clarifies spare-component timing."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-125-51-amdt-3-nose-landing-gear-drag-stay-bridge-casting","history":"/api/acts/ad-hs-125-51-amdt-3-nose-landing-gear-drag-stay-bridge-casting/history","analysis":"/api/acts/ad-hs-125-51-amdt-3-nose-landing-gear-drag-stay-bridge-casting/analysis","conflicts":"/api/acts/ad-hs-125-51-amdt-3-nose-landing-gear-drag-stay-bridge-casting/conflicts","importantCases":"/api/acts/ad-hs-125-51-amdt-3-nose-landing-gear-drag-stay-bridge-casting/important-cases","documents":"/api/acts/ad-hs-125-51-amdt-3-nose-landing-gear-drag-stay-bridge-casting/documents"}}