{"id":"F2006B03250","name":"AD/B747/71 Amdt 1 - Cavity Aft of Wing Centre Section","slug":"ad-b747-71-amdt-1-cavity-aft-of-wing-centre-section","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42674,"registerId":"commonwealth-F2006B03250-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/71 Amdt 1 - Cavity Aft of Wing Centre Section","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 revokes Airworthiness Directive (AD) AD/B747/71 and issues the following 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/B747/71\n\nAmdt 1\n\n  \nCavity Aft of Wing Centre Section 10/2003\n\nApplicability: All Model 747 series aircraft.\n\nRequirement: Action in accordance with the technical requirements of FAA AD 2003-11-01 Amdt 39-13160.\n\nNote: Boeing Alert Service Bulletin 747-51A2057 refers.\n\nCompliance: As specified in the Requirement document, with a revised effective date of 2 October 2003.\n\nThis Amendment becomes effective on 2 October 2003.\n\nBackground: Debris and foreign material may block drainage of the cavity aft of the wing centre section and result in accumulated water leakage onto the lateral flight control cables and/or components and freezing; which could restrict or jam control cable movement and result in loss of controllability of the aircraft.\n\nAmendment 1 is issued in response to a new FAA AD, which adds new repetitive tests and inspections for discrepancies of the drainage system of the canted pressure deck.\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 1 August 2003\n\n![](image.001.png)\n\nThe above AD is notified in the Commonwealth of Australia Gazette on 10 September 2003.\n\n  \n\nPage 1 of 1","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"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Yes. Amendment 1 expands the maintenance scope previously mandated by AD/B747/71 by incorporating FAA AD 2003-11-01 and adding new repetitive tests and inspections of the drainage system of the canted pressure deck (Background; Requirement). Mechanically, the prior AD is revoked and operators must now follow the referenced FAA requirements and associated Boeing alert service bulletin, with a specified effective date of 2 October 2003 (opening paragraph; Note; Compliance). Operators therefore face increased recurring inspection obligations and must budget for associated work and scheduling."},"complexity_factors":["External normative reference: the AD mandates actions “in accordance with the technical requirements of FAA AD 2003-11-01” rather than reproducing requirements (Requirement).","Applicability breadth: applies to “All Model 747 series aircraft,” so obligations affect every operator of that fleet in Australia (Applicability).","Repetitive obligations: Amendment 1 introduces new repetitive tests and inspections, creating recurring maintenance and scheduling burdens (Background).","Cross-reference to manufacturer service information: Boeing Alert Service Bulletin 747-51A2057 is noted, creating an additional source to consult (Note).","Revocation and replacement: the delegate revokes the prior AD and issues this AD under CASR authority, requiring operators to track regulatory history and effective dates (opening paragraph; Compliance).","Fixed compliance timing: revised effective date (2 October 2003) is specified, constraining when operators must have actions completed or scheduled (Compliance).","Operational risk driver identified: the unsafe condition is debris-blocked drainage causing water to reach lateral flight‑control cables and freeze, which ties the inspection scope to specific drainage and canted pressure deck components (Background)."],"plain_english_summary":"This Airworthiness Directive revokes AD/B747/71 and requires all Australian operators of Boeing 747 series aeroplanes to carry out the inspections and corrective actions set out in FAA AD 2003-11-01 for the cavity aft of the wing centre section. It responds to blocked drainage that can cause water to leak onto lateral flight‑control cables and freeze, risking cable restriction or jamming. Amendment 1 adds new repetitive tests and inspections; compliance is effective 2 October 2003."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment stays within the original scope of addressing drainage and flight control cable safety in the wing cavity. It expands the specific maintenance actions required (adding repetitive inspections) but does not broaden the subject matter, affected aircraft types, or regulatory purpose beyond the original safety concern."},"complexity_factors":["Very short document (1 page)","Only 2 substantive operative sections (Applicability and Requirement)","Minimal defined terms (only standard aviation acronyms like AD, FAA, CASA)","Single cross-reference to external FAA document rather than internal legislative references","Simple linear structure with no nested conditions or exceptions","Background section provides clear rationale without legal caveats"],"plain_english_summary":"This mandatory CASA Airworthiness Directive requires operators of all Boeing 747s in Australia to inspect and maintain the cavity behind the wing centre section per FAA AD 2003‑11‑01. It addresses debris-clogged drains that can let water freeze and jam flight‑control cables, risking loss of control. Amendment 1 adds repeated tests and inspections of the drainage on the canted pressure deck; compliance is required from 2 October 2003."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-71-amdt-1-cavity-aft-of-wing-centre-section","history":"/api/acts/ad-b747-71-amdt-1-cavity-aft-of-wing-centre-section/history","analysis":"/api/acts/ad-b747-71-amdt-1-cavity-aft-of-wing-centre-section/analysis","conflicts":"/api/acts/ad-b747-71-amdt-1-cavity-aft-of-wing-centre-section/conflicts","importantCases":"/api/acts/ad-b747-71-amdt-1-cavity-aft-of-wing-centre-section/important-cases","documents":"/api/acts/ad-b747-71-amdt-1-cavity-aft-of-wing-centre-section/documents"}}