{"id":"F2006B01997","name":"AD/A330/18 - Forward Fuselage Frame 12A Stiffener","slug":"ad-a330-18-forward-fuselage-frame-12a-stiffener","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41219,"registerId":"commonwealth-F2006B01997-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\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 CASR 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\n![](image.001.png)  \n\nAirbus Industrie A330 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/A330/18 Forward Fuselage Frame 12A St","sectionType":"part","heading":"AD/A330/18 Forward Fuselage Frame 12A Stiffener 8/2003","content":"# AD/A330/18 Forward Fuselage Frame 12A Stiffener 8/2003\n\nApplicability: All Model A330 aircraft, except for aircraft with Airbus Modification 49694 incorporated in production or Airbus Service Bulletin (SB) A330-53-3130 incorporated in-service.\n\nRequirement: 1. Perform a high frequency eddy current inspection of the stiffener fitting, left hand and right hand sides of frame 12A of the forward fuselage, in accordance with SB A330-53-3135.\n\nIf cracks are detected, accomplish the corrective actions described in the flow chart of SB A330-53-3135, which defines the required compliance time according to the length of detected cracks.\n\n2. If no cracks are detected, repeat the Requirement 1 inspection.\n\nNote: DGAC AD 2003-205(B) refers.\n\nCompliance: 1. Before the accumulation of 13,000 flight cycles.\n\n2. At intervals not to exceed 10,000 flight cycles.\n\nThis Airworthiness Directive becomes effective on 7 August 2003.\n\nBackground: During a scheduled inspection, cracks were detected in the frame 12A stiffener upper attachment fitting on the floor beam, left hand and right hand sides of the fuselage.\n\nInvestigation revealed that the cause of cracking was the high level of fatigue of the fitting due to longitudinal forces. The combined effect of cabin pressurisation and bending induced by thermal effects led to a longitudinal force in the floor beam.\n\n![](image.002.jpeg)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 17 June 2003\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 16 July 2003.","sortOrder":1}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD’s scope is confined to forward fuselage frame 12A stiffener fittings on A330 aircraft, excluding aircraft with a specific production modification or prior SB incorporation (Applicability). It mandates inspection and repair actions to address fatigue cracking discovered during inspection (Background). There is no indication in the instrument text that the scope has been broadened or narrowed from its stated purpose."},"complexity_factors":["Technical inspection method required (high‑frequency eddy current) — requires specialist equipment and skills (Requirement).","Corrective actions are defined by an external Airbus Service Bulletin flow chart, creating dependency on manufacturer instructions for compliance timing (Requirement).","Applicability carve-outs (excludes aircraft with Airbus Modification 49694 or SB A330‑53‑3130) require operators to verify configuration before applying the AD (Applicability).","Compliance is measured in flight cycles with specific thresholds (before 13,000 cycles; repeat every 10,000 cycles), creating record‑keeping and tracking burdens for operators (Compliance).","Legal authority and issuance by the CASA delegate under CASR subreg 39.1(1) centralises regulatory decision but delegates technical discretion to the SB (preamble; Requirement).","Detection-dependent work scope and timing: if cracks are found, required actions and timing vary with crack length, complicating planning and costing (Requirement: SB flow chart)."],"plain_english_summary":"This Airworthiness Directive requires operators of most Airbus A330 aircraft to inspect both left and right frame 12A stiffener fittings with a high‑frequency eddy‑current inspection and to repair any cracks following Airbus Service Bulletin A330‑53‑3135 (Requirement).\n\nThe CASA delegate issued the AD under CASR subreg 39.1(1); inspections must occur before 13,000 flight cycles and repeat every 10,000 cycles if no crack is found (Applicability; Compliance). Operators pay for inspections and repairs; corrective timing is set by the SB flow chart."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It addresses a specific structural fatigue issue in Airbus A330 aircraft frame 12A stiffeners, exactly as intended when issued. There is no evidence of scope creep or expansion beyond the original safety purpose."},"complexity_factors":["Single, specific technical requirement with clear conditional branching (crack detected vs. not detected)","Only 2 defined exceptions to applicability (Modification 49694 and SB A330-53-3130)","References to external technical documents (Service Bulletin A330-53-3135) without reproducing their content","Simple compliance timeline (one-time threshold + recurring interval)","Limited cross-referencing (only one reference to French aviation authority DGAC AD 2003-205(B))","Narrow scope affecting only one aircraft model series"],"plain_english_summary":"Australia’s aviation regulator requires operators of Airbus A330s (except aircraft with Modification 49694 or repaired per SB A330‑53‑3130) to inspect the forward fuselage stiffener at frame 12A using high‑frequency eddy‑current testing for fatigue cracks. The first check must occur before 13,000 flight cycles and repeat every 10,000 cycles; detected cracks must be repaired per the service bulletin.\n\nThis prevents structural failure from fatigue cracking and protects flight safety."}},"importantCases":[],"_links":{"self":"/api/acts/ad-a330-18-forward-fuselage-frame-12a-stiffener","history":"/api/acts/ad-a330-18-forward-fuselage-frame-12a-stiffener/history","analysis":"/api/acts/ad-a330-18-forward-fuselage-frame-12a-stiffener/analysis","conflicts":"/api/acts/ad-a330-18-forward-fuselage-frame-12a-stiffener/conflicts","importantCases":"/api/acts/ad-a330-18-forward-fuselage-frame-12a-stiffener/important-cases","documents":"/api/acts/ad-a330-18-forward-fuselage-frame-12a-stiffener/documents"}}