{"id":"F2006B03197","name":"AD/B747/304 - Wing Rear Spar Upper Chord and Splice Fitting Structure","slug":"ad-b747-304-wing-rear-spar-upper-chord-and-splice-fitting-structure","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42569,"registerId":"commonwealth-F2006B03197-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/304 - Wing Rear Spar Upper Chord and Splice Fitting Structure","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \n\nAIRWORTHINESS 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\nBoeing 747 Series Aeroplanes\n\nAD/B747/304 Wing Rear Spar Upper Chord and Splice Fitting\n\nStructure\n\n  \n4/2004\n\nApplicability: All Model 747-100, \\-100B, \\-100B SUD, \\-200B, \\-200F, \\-200C, \\-300, 747SR, and\n\n747SP series aircraft.\n\nRequirement: Action in accordance with the technical requirements of FAA AD 2004-03-09 Amdt 39-13453.\n\nNote: Boeing Alert Service Bulletin 747-57A2314 Revision 1 refers.\n\nCompliance: As specified in the Requirement document, with a revised effective date of 15 April 2004.\n\nThis Airworthiness Directive becomes effective on 15 April 2004.\n\nBackground: The manufacturer received reports of forty-three cracks found on eleven aircraft since 1989. This Directive requires repetitive inspections for discrepancies of the structure near and common to the upper chord and splice fittings of the rear spar of the wing.\n\nAn optional modification is provided which terminates the repetitive inspection requirement. Unless detected and corrected, cracking could result in loss of structural integrity of the aircraft and fuel leakage into the wheel well cavity.\n\n![Signature of David Villiers, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 5 March 2004\n\n![](image.001.png)\n\nThe above AD is notified in the Commonwealth of Australia Gazette on 24 March 2004.\n\n  \n\nPage 1 of 1","sortOrder":0}],"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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive addressing a specific structural defect in specific aircraft models. It has not expanded beyond its original purpose of ensuring wing structural integrity."},"complexity_factors":["Very short document (1 page)","No defined terms section — relies entirely on external technical documents (FAA AD 2004-03-09 and Boeing Service Bulletin)","Simple structure: Applicability → Requirement → Compliance → Background","Single, clear requirement: 'do what the FAA says'","No conditional logic or nested exceptions — the only 'option' is clearly labeled as an optional modification","Cross-references to external technical documents rather than internal legislative provisions"],"plain_english_summary":"This safety order requires operators of early-model Boeing 747s (including 747‑100/200/300, SR and SP series) to inspect the wing rear spar upper chord and splice fitting for cracks, using the procedures in FAA AD 2004‑03‑09; an optional modification can eliminate repetitive inspections. It matters because detected cracks have caused structural risk and fuel leaks into wheel wells (43 cracks on 11 aircraft since 1989), and aircraft must comply to remain airworthy."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This AD stays within the original safety-focused purpose: detect and correct cracking in the rear spar upper chord/splice fitting area and provide an optional terminating modification. It does not broaden the scope beyond that structural problem or add unrelated regulatory obligations. The AD aligns Australian requirements with the referenced FAA AD and the Boeing service bulletin; the revised effective date is administrative and does not alter the substantive scope."},"complexity_factors":["Cross-reference to external documents (FAA AD 2004-03-09 and Boeing Alert Service Bulletin 747-57A2314 Revision 1) rather than embedding inspection protocols—requires operators to obtain and reconcile multiple documents","Repetitive inspections requirement (ongoing compliance burden) with an optional terminating modification (choice/conditional pathway)","Applicability covers multiple 747 variants (several model subtypes), so operators must check applicability against their fleet","Safety-critical structural area (rear spar upper chord and splice fittings) requiring technical inspection methods (likely NDT) and potentially specialist repairs","Effective date revision (compliance timing matters) — implementers must note the revised effective date of 15 April 2004","Short, single-page AD with few internal definitions — low textual complexity but operational complexity due to technical subject matter and external references"],"plain_english_summary":"**What this instrument does (mechanically):**\n\n- Requires repetitive inspections of the wing rear spar upper chord and the splice fitting area on a list of Boeing 747 models. The inspections and any corrective actions must be carried out in accordance with the technical instructions of FAA Airworthiness Directive 2004-03-09 (see \"Requirement\").\n- Provides an optional modification that, if installed, stops (terminates) the need for those repetitive inspections.\n- Sets the effective date for the action: 15 April 2004.\n\n**Which aircraft are affected:**\n\n- All Boeing 747-100, -100B, -100B SUD, -200B, -200F, -200C, -300, 747SR and 747SP series aircraft (see \"Applicability\").\n\n**Why it matters (background and risk):**\n\n- The manufacturer reported 43 cracks found on 11 aircraft (since 1989) in the structure around the upper chord and splice fittings of the wing rear spar. The AD says these cracks, if not found and fixed, could reduce structural integrity of the aircraft and could cause fuel to leak into the wheel well cavity (see \"Background\").\n\n**How it works in practice (who does what, who pays, and what changes):**\n\n- The regulator (a CASA delegate) issued this Airworthiness Directive under CASR subregulation 39.1(1). Operators (aircraft owners/operators) must carry out the inspections and any repairs as required by the referenced FAA AD. Maintenance organisations will do the inspections/repairs; the aircraft operator is responsible for arranging and paying for them.\n- Operators have a compliance choice: keep performing repetitive inspections as required, or install the optional modification to terminate the inspection requirement. The AD references Boeing Alert Service Bulletin 747-57A2314 Revision 1 (see \"Note\").\n\n**Claimed purpose vs practical trade-offs:**\n\n- The stated purpose is to detect and correct cracking in a critical wing spars area to protect structural integrity and prevent fuel leakage (stated in Background). The concrete mechanisms are repetitive inspections to find cracks early, plus an optional modification that removes the need for those inspections.\n- Costs and incentives: inspections impose recurring maintenance cost (labour, access, NDT equipment, downtime) on operators. The optional modification imposes an up‑front cost but removes recurrent inspection cost and operational disruption; operators will choose based on a cost/benefit calculation. The AD does not set funding or compensation; those economic choices fall to private operators.\n- Implementation requirements and risk: the AD cross-references an FAA AD and a Boeing service bulletin rather than spelling out inspection methods and intervals in full; operators must obtain and follow those external documents. That cross-reference shifts compliance effort to reading and applying the FAA/Boeing documents exactly.\n\n**Allocation of decision and enforcement:**\n\n- CASA (via its delegate) decides the regulatory requirement and enforces compliance. Operators decide whether to perform the terminating modification or continue inspections, subject to satisfying the AD.\n\n**Operational effects to watch for:**\n\n- Increased scheduled maintenance work and associated downtime until either the optional modification is adopted or a long-running inspection program is absorbed into maintenance cycles.\n- If cracks are found, corrective work (repair or modification) may take aircraft out of service temporarily, with direct costs to the operator. The optional modification concentrates costs up-front but reduces future inspection burden.\n\n(References within the AD: see sections headed \"Applicability\", \"Requirement\" (referring to FAA AD 2004-03-09), \"Compliance\" (effective date), and \"Background\".)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-304-wing-rear-spar-upper-chord-and-splice-fitting-structure","history":"/api/acts/ad-b747-304-wing-rear-spar-upper-chord-and-splice-fitting-structure/history","analysis":"/api/acts/ad-b747-304-wing-rear-spar-upper-chord-and-splice-fitting-structure/analysis","conflicts":"/api/acts/ad-b747-304-wing-rear-spar-upper-chord-and-splice-fitting-structure/conflicts","importantCases":"/api/acts/ad-b747-304-wing-rear-spar-upper-chord-and-splice-fitting-structure/important-cases","documents":"/api/acts/ad-b747-304-wing-rear-spar-upper-chord-and-splice-fitting-structure/documents"}}