{"id":"F2006B03167","name":"AD/B747/270 - Centre Wing/Horizontal Stabilizer Fuel Tank Override/Jettison/Transfer Pumps","slug":"ad-b747-270-centre-wing-horizontal-stabilizer-fuel-tank-override-jettison-transfer-pumps","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42539,"registerId":"commonwealth-F2006B03167-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/270 - Centre Wing/Horizontal Stabilizer Fuel Tank Override/Jettison/Transfer Pumps","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\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 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\n![](image.001.png)\n\nBoeing 747 Series Aeroplanes\n\nAD/B747/270 Centre Wing/Horizontal Stabilizer Fuel\n\nTank Override/Jettison/Transfer Pumps\n\n  \n5/2002\n\nApplicability: All Model 747 series aeroplanes.\n\nRequirement: 1. Amend the limitations Section of the FAA approved Aircraft Flight Manual (AFM) in accordance with paragraph (a) of FAA AD 2001-12-21; or\n\n    2. Establish that the correct thrust washer is fitted to the centre wing fuel tank override/jettison pumps and, if installed, horizontal stabilizer transfer pumps, following the procedures contained in paragraph (b) of FAA AD 2001-12-21. If the correct washer is fitted, this Airworthiness Directive requires no further action.\n\n    3. For those aeroplanes that do not meet the requirements of paragraph (b) of FAA AD 2001-12-21, or if the serial number on the pump data plate of any centre wing fuel tank override/jettison pump or, if fitted, horizontal stabilizer transfer pumps cannot be determined, replace pumps in accordance with the requirement of paragraph (c) of FAA AD 2001-12-21. Compliance with this requirement terminates Requirement 1 of this Airworthiness Directive and if applicable, the amendment to the AFM may be removed from the manual.\n\nNote: FAA AD 2001-12-21 supersedes FAA AD 98-25-52.\n\nCompliance: Requirement 1 or 2: Within 14 days after the effective date of this Airworthiness Directive.\n\nRequirement 3: If applicable, before 26 April 2003.\n\nThis Airworthiness Directive becomes effective on the 16 May 2002.\n\nBoeing 747 Series Aeroplanes\n\nAD/B747/270 (Continued)\n\nBackground: FAA AD 2001-12-21 was prompted by new information received from the fuel pump manufacturer. This new FAA AD supersedes FAA AD 98-25-52 which caused AD/747/194 TX to be raised and an amendment to be made to the Aircraft Flight Manual (AFM) to prevent dry operation of the centre wing fuel tank override/jettison pumps, and for certain aeroplanes, to prohibit operation of the horizontal stabilizer tank transfer pumps in-flight. This Airworthiness Directive requires verification of pumps fitted, and as necessary, the installation of improved fuel pumps, which terminates the requirements of the AFM amendments and cancellation of AD/747/194 TX.\n\n![Signature of Eugene Paul Holzapfel, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 7 April 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 24 April 2002.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This AD shifts the remedy from an operational restriction (amend the AFM to limit pump use) to requiring hardware verification and, where necessary, mandatory replacement of pumps. The original emergency measure (AFM limitation to avoid dry-running) is retained as a short-term option but the AD broadens scope by mandating inspection and hardware replacement as the long-term resolution. That represents a substantive change in approach from procedural/operational mitigation toward compulsory maintenance/parts replacement, and it cancels the earlier AD and allows removal of the AFM amendment once the hardware fix is fitted."},"complexity_factors":["Cross-reference to external FAA AD (FAA AD 2001-12-21) for technical procedures and parts","Three alternative compliance paths with conditional termination (Requirements 1, 2, and 3)","Time-limited compliance windows (14 days for Requirements 1 or 2; separate calendar deadline for Requirement 3)","Interaction with a prior AD/AFM amendment (terminates earlier AFM amendment and cancels previous AD/requirement)","Dependency on physical evidence (pump data plate serial numbers and thrust washer verification) that can be unreadable and triggers a different compliance path"],"plain_english_summary":"**What this directive does (mechanics)\n\n- This is an Airworthiness Directive (AD) that applies to all Boeing 747 series aeroplanes.  It requires operators to take one of three actions aimed at ensuring the centre wing tank override/jettison pumps and, where fitted, the horizontal stabilizer transfer pumps, are fitted with the correct thrust washer or are replaced with an improved pump.\n\n- Operators must either:\n  - Amend the Aircraft Flight Manual (AFM) limitations as described in paragraph (a) of FAA AD 2001-12-21 (Requirement 1); or\n  - Inspect the pumps and establish that the correct thrust washer is fitted, following the procedures in paragraph (b) of FAA AD 2001-12-21, and if the correct washer is fitted no further action is needed (Requirement 2); or\n  - If the inspection cannot show the correct washer is fitted, or the pump serial number cannot be determined, replace the affected pumps with the improved pumps as required by paragraph (c) of FAA AD 2001-12-21 (Requirement 3). Replacing the pumps removes the need for the AFM amendment imposed under Requirement 1.\n\n- Timing: Requirements 1 or 2 must be done within 14 days of the AD's effective date (the AD itself sets specific dates; see the \"Compliance\" section). If replacement is required under Requirement 3, that must be done by the date stated for that requirement (the AD gives a calendar deadline — see \"Compliance\").\n\n- Background: The AD follows new information from the pump manufacturer and supersedes earlier FAA and Australian AD action that had imposed AFM limitations to prevent dry-running of the pumps and, for some aeroplanes, to prohibit in-flight use of horizontal stabilizer transfer pumps. This AD moves from operational limits toward verifying and, if needed, replacing pump hardware.\n\nWho this affects\n\n- Primary affected parties: Boeing 747 operators and their maintenance organisations. They must perform the inspections, AFM amendment, or pump replacements and keep records showing compliance.\n\n- Indirectly affected: maintenance suppliers (parts and labour), regulatory compliance staff, and potentially flight operations that rely on affected pumps.\n\nWhy it matters (safety and operational mechanics)\n\n- The directive addresses a potential unsafe condition in fuel pump hardware (incorrect thrust washers) that could cause pump malfunction. Malfunction of override/jettison or stabilizer transfer pumps can affect fuel management and, if uncorrected, create risk in flight operations.\n\nCosts, incentives and trade-offs (practical effects)\n\n- Who pays: The aircraft operator pays for inspections, AFM amendment work, and any pump replacements and associated labour and downtime.\n\n- Incentives: Operators have an incentive to perform the inspection that confirms the correct washer is fitted (Requirement 2) because that avoids the more expensive pump replacement (Requirement 3) and permits removal of AFM restrictions once replacements are done. If serial numbers are unreadable or washers cannot be verified, replacement is mandatory.\n\n- Trade-offs: The AD relaxes operational limitations only when hardware has been verified or replaced. Operators must choose between a short-term operational fix (AFM limitations) or the potentially higher immediate cost and aircraft downtime to replace pumps and remove the limitations permanently.\n\nCompliance burden and implementation risks\n\n- Administrative and maintenance burden: Operators must update the AFM or conduct pump inspections, and where necessary source and install replacement pumps and update maintenance records.\n\n- Supply and logistics risk: Availability of replacement pumps and certified maintenance slots may create delays and additional costs. If pump data plates are unreadable, the AD forces replacement, increasing parts demand.\n\n- Enforcement and discretion: The AD is issued by the CASA delegate under the aviation regulations and relies on cross-referenced FAA AD procedures; operators must follow the specified FAA AD paragraphs for the technical steps.\n\nOther practical notes\n\n- Completing the replacement (Requirement 3) terminates the need for the AFM amendment imposed earlier under Requirement 1 (that is, the hardware fix removes the operational limitation).\n\n- The AD cites and relies on FAA AD 2001-12-21 for the detailed procedures and parts to be used; operators will need that FAA document to carry out the mandated actions.\n\n(Sections cited: Requirement 1–3; Compliance; Background.)"},"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":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific mechanical defect in B747 fuel pumps. It does not expand beyond its safety-critical purpose of ensuring proper thrust washer installation. The instrument actually narrows operational impact by offering a pathway (pump replacement) to terminate earlier, more restrictive flight manual amendments."},"complexity_factors":["Short, single-purpose instrument (approximately 400 words)","Only 3 defined compliance pathways with clear conditional logic (if/then structure)","Single cross-reference to external document (FAA AD 2001-12-21) which itself supersedes prior directives","Limited technical terminology ('thrust washer', 'override/jettison pumps') but context makes meaning clear","No nested exceptions or recursive definitions","Clear compliance dates and termination clauses (Requirement 3 cancels Requirement 1)"],"plain_english_summary":"This AD mandates action for all Boeing 747s to address incorrect thrust washers in centre wing and horizontal stabilizer fuel pumps that could cause pump failure or fire if run dry. Operators must quickly either add a temporary AFM pump restriction, inspect pumps to confirm correct washers, or replace nonconforming/uncertain pumps with improved units; doing so lifts prior flight restrictions. Short compliance windows apply (14 days for restriction/inspection; replacement deadline 26 Apr 2003)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-270-centre-wing-horizontal-stabilizer-fuel-tank-override-jettison-transfer-pumps","history":"/api/acts/ad-b747-270-centre-wing-horizontal-stabilizer-fuel-tank-override-jettison-transfer-pumps/history","analysis":"/api/acts/ad-b747-270-centre-wing-horizontal-stabilizer-fuel-tank-override-jettison-transfer-pumps/analysis","conflicts":"/api/acts/ad-b747-270-centre-wing-horizontal-stabilizer-fuel-tank-override-jettison-transfer-pumps/conflicts","importantCases":"/api/acts/ad-b747-270-centre-wing-horizontal-stabilizer-fuel-tank-override-jettison-transfer-pumps/important-cases","documents":"/api/acts/ad-b747-270-centre-wing-horizontal-stabilizer-fuel-tank-override-jettison-transfer-pumps/documents"}}