{"id":"F2006B03101","name":"AD/B747/201 Amdt 3 - Centre Fuel Tank Wiring and Components","slug":"ad-b747-201-amdt-3-centre-fuel-tank-wiring-and-components","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42473,"registerId":"commonwealth-F2006B03101-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/201 Amdt 3 - Centre Fuel Tank Wiring and Components","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nOn the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B747/201 Amdt 2 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/B747/201\n\nAmdt 3\n\n  \nCentre Fuel Tank Wiring and Components 13/2004\n\nApplicability: Model 747 aeroplanes having line numbers 1 through 1124 inclusive.\n\nRequirement: 1. For aeroplanes listed in Boeing Service Bulletin (SB) 747-28-2205 Revision 1 dated 16 April 1998 accomplish the following in accordance with either SB 747- 28-2205 Revision 1 dated 16 April 1998 or Revision 2 dated 17 May 1999:\n\n    perform a one-time visual inspection of the centre fuel tank wiring and components to detect discrepancies (damage, disbonding or incorrect installation), and\n\n    b. perform a one-time electrical bonding test of the centre fuel tank components.\n\nNote 1: For the purposes of this Directive, a visual inspection is considered to be a general visual inspection defined as follows:\n\nA visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light and may require removal or opening of access panels or doors. Stands, ladders, or platforms, may be required to gain proximity to the area being checked.\n\n    2. If, during the Requirement 1.a. visual inspection, any discrepancy is detected, either repair the discrepant component or replace it with a new or serviceable component.\n\n    3. If, during the Requirement 1.b. electrical bonding test, any measured resistance exceeds the limits specified in the service bulletin, rework the discrepant component.\n\nNote 2: Actions performed in accordance with SB 747-28-2205, dated 27 June 1997, accomplished prior to the effective date of this Directive or its original issue, are considered acceptable for compliance only with the corresponding applicable actions specified in this Directive. This excludes certain actions that are not described in that bulletin, such as inspection and testing of the body fuel tank components that are described in Revision 1 of SB 747-28-2205. Regardless of which version of the service bulletin is used to detect any discrepancies, the repair and replacement requirements of this Directive apply.\n\n    4. For aeroplanes listed in Boeing Alert Service Bulletin (ASB) 747-28A2208 dated 14 May 1998, accomplish the following in accordance with either ASB 747- 28A2208 dated 14 May 1988 or Revision 1 dated 26 August 1999:\n\n    perform a one-time insulation resistance test of the fuel quantity indicating system (FQIS),\n\n    b. perform a one-time visual inspection of the FQIS wiring and components to detect discrepancies (chafing, damage to the wiring and incorrect configuration of the terminal blocks),\n\n    c. replace FQIS probes (tank units and compensators) with new or serviceable components as detailed in Figure 5 of either ASB 747-28A2208 dated 14 May 1988 or Revision 1 dated 26 August 1999, and\n\n    d. carry out a system adjustment and system operational test.\n\nNote 3: Aeroplanes required to accomplish Requirement 4 of this Directive are exempt from accomplishing steps 1 through 9 in Figure 11 of SB 747-28-2205,\n\nRevision 1, dated 16 April 1998.\n\nNote 4: For aeroplanes on which steps 1 through 9 in Figure 11 of SB 747-28-2205,\n\ndated 27 June 1997, or Revision 1, dated 16 April 1998, were accomplished prior to the effective date of this Directive, steps 1 through 6 in Figure 16 of ASB\n\n747-28A2208, dated 14 May 1998 or Revision 1 dated 26 August 1999, are not required.\n\n    5. If, during the Requirement 4 inspections and/or tests, any discrepancy is detected perform corrective actions in accordance with either ASB 747-28A2208 dated 14 May 1998 or Revision 1 dated 26 August 1999.\n\n    6. For aeroplanes having line positions 1 through 971 inclusive, install a flame arrestor in the inlet line of the electrical motor-operated scavenge pump of the centre fuel tank, in accordance with ASB 747-22A2210 dated 14 May 1998.\n\nNote 5: FAA AD 99-08-02 R1 Amdt 39-11215, AMOC 99-140S-177 dated 17 May\n\n1999 and AMOC 99-140S-282 dated 11 August 1999 refer.\n\nCompliance: 1. Within 24 months after the effective date of the original issue of this Directive.\n\n    2. Before further flight.\n\n    3. Before further flight.\n\n    4. Within 24 months after the effective date of the original issue of this Directive.\n\n    5. Before further flight.\n\n    6. Within 24 months after the effective date of the original issue of this Directive. This Amendment becomes effective on 23 December 2004.\n\nBackground: This Directive is based on Federal Aviation Administration AD 99-08-02, the issue of which was prompted by a design review and testing results obtained in support of an accident investigation. The Directive is intended to remove ignition sources from the centre fuel tank and prevent consequent fire and/or explosion in the fuel tank.\n\nAmendment 1 clarified Requirement 4.c., removing the terms ‘series 3’ and ‘series 4’ and replacing them with a reference to a figure in the Boeing ASB. A definition of ‘visual inspection’ as applicable to this Directive was also included as a note.\n\nThis amendment introduces an alternate method of compliance (AMOC) for Requirements 1, 2 and 3 reflecting a Federal Aviation Administration AMOC.\n\nAmendment 2 introduced an AMOC for Requirements 4 and 5 reflecting a Federal Aviation Administration AMOC.\n\n![Signature of James Coyne, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \nAmendment 2 of this Airworthiness Directive became effective on 6 September 2000\\. Amendment 1 of this Airworthiness Directive became effective on 2 December 1999\\. The original issue of this Airworthiness Directive became effective on 17 June 1999.\n\nJames Coyne\n\nDelegate of the Civil Aviation Safety Authority 11 November 2004\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 1 December 2004.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":false,"description":"This amendment remains focused on its original purpose: preventing centre fuel tank explosions in Boeing 747 aircraft. Amendment 3 introduces an additional Alternate Method of Compliance (AMOC) for Requirements 1-3, but this is a procedural flexibility rather than an expansion of scope. The directive maintains the same applicability (Boeing 747 line numbers 1-1124) and the same fundamental safety objective as the original 1999 issue."},"complexity_factors":["Multiple overlapping requirements (Requirements 1-6) with different applicability criteria based on aircraft line numbers and service bulletin applicability","Extensive cross-referencing to external Boeing Service Bulletins (SB 747-28-2205 Revisions 1 and 2, ASB 747-28A2208 original and Revision 1, ASB 747-22A2210) — compliance requires obtaining and interpreting separate manufacturer documents","Nested conditional logic: Requirement 2 and 3 only apply 'if' discrepancies are found in Requirement 1; Requirement 5 only applies 'if' discrepancies found in Requirement 4","Complex exemption and credit rules in Notes 2, 3, and 4 that create exceptions to exceptions — e.g., certain prior work counts for compliance, certain steps are exempt if other steps were done, etc.","Multiple compliance timeframes that vary by requirement (24 months vs 'before further flight')","Reference to foreign regulatory equivalents (FAA AD 99-08-02 and associated AMOCs) for alternative compliance methods","Technical aviation terminology requiring specialised knowledge (e.g., 'electrical bonding test', 'flame arrestor', 'fuel quantity indicating system', 'line numbers')"],"plain_english_summary":"This AD requires operators of Boeing 747s (line numbers 1–1124) to inspect and repair wiring and components in the centre fuel tank to eliminate potential ignition sources.  \n\nIt affects airlines and maintenance organisations and was issued after a design review and accident investigation; the measures (inspections, tests, replacements and added safeguards) aim to prevent fuel‑tank explosions like past catastrophic events."},"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":false,"description":"Amendments and this issue clarified inspection definitions and introduced alternate methods of compliance (AMOCs) and limited procedural exemptions, but they did not expand the population of affected aircraft (still line numbers 1–1124) nor alter the core safety objective to remove ignition sources from the centre fuel tank (Background; Applicability; Requirements)."},"complexity_factors":["Cross‑references to multiple Boeing documents and specific revisions (SB 747‑28‑2205 Rev 1/Rev 2 for Requirement 1; ASB 747‑28A2208 Rev 0/Rev 1 for Requirement 4) increase procedural complexity (Requirements 1 and 4).","Mixed technical actions required: visual inspections (Note 1 definition), electrical bonding tests (Requirement 1.b), insulation resistance tests (Requirement 4.a), component replacement and system operational tests (Requirements 2–5).","Varied compliance deadlines: some actions due 'before further flight' while others are 'within 24 months' of the original effective date (Compliance section).","Conditional applicability and subsets: the AD applies to line numbers 1–1124 overall but the flame arrestor installation is limited to line positions 1–971 (Applicability; Requirement 6), creating different obligations for different aircraft.","Alternate methods of compliance (AMOCs) and acceptability of earlier bulletin actions (Notes 2–4; Background) create multiple acceptable pathways and require approval/coordination with CASA/FAA.","Technical acceptance criteria (e.g. resistance limits) are specified in the service bulletins rather than the AD text, requiring specialised measurement and judgment during testing (Requirement 1.b; Requirement 4).","Interplay with FAA ADs and FAA AMOCs is referenced (Note 5; Background), meaning operators may need to coordinate compliance records against foreign authority approvals.","Several notes create exceptions and exemptions depending on which steps were previously accomplished, adding conditional compliance logic (Notes 2–4)."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 747 aeroplanes (line numbers 1–1124) to carry out specified inspections, electrical tests, repairs or replacements of centre‑fuel‑tank and fuel‑quantity wiring and components, and to install a flame arrestor on certain scavenge pumps. CASA says the mechanical aim is to remove ignition sources from the centre fuel tank to prevent fire or explosion. Aircraft operators and maintenance organisations bear the cost and scheduling burden; the CASA delegate enforces compliance and permits approved alternate methods of 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-b747-201-amdt-3-centre-fuel-tank-wiring-and-components","history":"/api/acts/ad-b747-201-amdt-3-centre-fuel-tank-wiring-and-components/history","analysis":"/api/acts/ad-b747-201-amdt-3-centre-fuel-tank-wiring-and-components/analysis","conflicts":"/api/acts/ad-b747-201-amdt-3-centre-fuel-tank-wiring-and-components/conflicts","importantCases":"/api/acts/ad-b747-201-amdt-3-centre-fuel-tank-wiring-and-components/important-cases","documents":"/api/acts/ad-b747-201-amdt-3-centre-fuel-tank-wiring-and-components/documents"}}