{"id":"F2006B07617","name":"AD/Y12/3 - Fuselage Stringer 13 Between Frame 13 and 14","slug":"ad-y12-3-fuselage-stringer-13-between-frame-13-and-14","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":50329,"registerId":"commonwealth-F2006B07617-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nHarbin Y12 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/Y12/3 Fuselage Stringer 13 Between Fr","sectionType":"part","heading":"AD/Y12/3 Fuselage Stringer 13 Between Frame 13 and 14 3/2003","content":"# AD/Y12/3 Fuselage Stringer 13 Between Frame 13 and 14 3/2003\n\nApplicability: Model Y12 II aircraft, serial numbers up to and including 90 and 92. Requirement: Inspect in accordance with Harbin Aircraft Service Bulletin No. Y12-53-0059R1.\n\nNote: China CAAC AD CAD95-Y012-03 refers.\n\nCompliance: Initially, upon accumulating 2,000 flight hours. Thereafter, at intervals not to exceed 1,000 flight hours.\n\nThis Airworthiness Directive becomes effective on 20 March 2003.\n\nBackground: A report was received of cracking on fuselage stringer 13 and the skin between frames 13 and 14, and reinforced areas; on both sides of the fuselage.\n\n![Signature of David Alan Villiers Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 29 January 2003\n\n![](image.001.png)","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive targeting a specific structural defect on specific aircraft models. It has not expanded beyond its original purpose of addressing the reported cracking issue."},"complexity_factors":["Very short document (under 300 words)","Only 3 defined structural terms (stringer, frame, fuselage) — all standard aviation terminology","Single, unambiguous compliance requirement with clear time triggers","No cross-references to other legislation beyond a single note referencing a Chinese aviation directive","No conditional logic or exceptions — applies to all listed serial numbers equally","Single action required (inspect per specified bulletin)"],"plain_english_summary":"This safety order requires owners/operators of Harbin Y-12 II aircraft (serials up to and including 90 and 92) to inspect for cracks at stringer 13 between frames 13 and 14 on both sides of the fuselage and comply with Harbin Service Bulletin Y12-53-0059R1. \n\nFirst inspection at 2,000 flight hours and repeat every 1,000 hours. It responds to discovered fuselage cracking that, if undetected, could cause catastrophic structural failure in flight."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD implements targeted inspections for the stated Harbin Y‑12 II serial numbers and sets explicit compliance intervals to address reported cracking. It follows the service bulletin and CAAC reference and does not expand applicability or requirements beyond those corrective inspection measures."},"complexity_factors":["Narrow technical scope: single structural area (stringer 13 and adjacent skin) reduces breadth of requirements.","Cross‑reference to a manufacturer service bulletin (Harbin Y12‑53‑0059R1) adds technical complexity and reliance on external instructions.","Specific applicability by serial number (up to and including 90 and 92) requires operator fleet tracking.","Fixed compliance timing (initial at 2,000 FH, recurrent every 1,000 FH) imposes straightforward scheduling and recordkeeping.","Safety‑critical nature increases operational consequences if inspections identify cracks.","Reference to China CAAC AD (CAD95‑Y012‑03) introduces international regulatory linkage but no substantive additional actions in the AD text."],"plain_english_summary":"This Airworthiness Directive mandates inspections of fuselage stringer 13 and the adjacent skin between frames 13 and 14 on Harbin Y‑12 II aircraft (serial numbers up to and including 90 and 92) in accordance with Harbin Service Bulletin Y12‑53‑0059R1. Inspections must start at 2,000 flight hours and repeat every 1,000 hours. The AD was issued after reports of cracking; aircraft operators must arrange and pay for the inspections, and CASA enforces compliance."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-y12-3-fuselage-stringer-13-between-frame-13-and-14","history":"/api/acts/ad-y12-3-fuselage-stringer-13-between-frame-13-and-14/history","analysis":"/api/acts/ad-y12-3-fuselage-stringer-13-between-frame-13-and-14/analysis","conflicts":"/api/acts/ad-y12-3-fuselage-stringer-13-between-frame-13-and-14/conflicts","importantCases":"/api/acts/ad-y12-3-fuselage-stringer-13-between-frame-13-and-14/important-cases","documents":"/api/acts/ad-y12-3-fuselage-stringer-13-between-frame-13-and-14/documents"}}