{"id":"F2011L01847","name":"AD/B737/202 Amdt 2 - Centre Fuel Tank Limitations","slug":"ad-b737-202-amdt-2-centre-fuel-tank-limitations","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":87147,"registerId":"commonwealth-F2011L01847-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 737 Series Aeroplanes","sectionType":"division","heading":"Boeing 737 Series Aeroplanes","content":"### Boeing 737 Series Aeroplanes\n\n| AD/B737/202 Amdt 2 | Centre Fuel Tank Limitations | 18/2011 |\n| ------------------ | ---------------------------- | ------- |\n\n| Applicability: | Model 737-600, -700, -700C, -800, and -900 series aeroplanes with line numbers prior to 1494. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. If not previously accomplished in accordance with AD/B737/202 original issue or AD/B737/202 Amdt 1: |\n| | Revise the Limitations Section of the Aircraft Flight Manual (AFM) to include the following (this may be accomplished by inserting a copy of this Directive into the AFM): |\n| | CERTIFICATE LIMITATIONSThe centre tank fuel pumps must be OFF for takeoff if centre tank fuel is less than 5,000 pounds (2,300 kilograms) with the aeroplane readied for initial taxi.Both centre tank fuel pump switches must be selected OFF when centre tank fuel quantity reaches approximately 1,000 pounds (450-500 kilograms) during climb and cruise or 3,000 pounds (1,400 kilograms) during descent and landing. The fuel pumps must be positioned OFF at the first indication of fuel pump low pressure.The centre tank fuel quantity indication system must be operative to dispatch with centre tank mission fuel. |\n| | NoteThe CONFIG indicator will annunciate when centre tank fuel exceeds 1,600 pounds (726 kilograms) and the centre tank fuel pump switches are OFF. Do not accomplish the CONFIG non-normal procedure prior to or during takeoff with less than 5,000 pounds (2,300 kilograms) of centre tank fuel or during descent and landing with less than 3,000 pounds (1,400 kilograms) of centre tank fuel. |\n\n| | NoteIn a low fuel situation, both centre tank pumps may be selected ON and all centre tank fuel may be used. |\n| --- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | If the main tanks are not full, the zero fuel gross weight of the aeroplane plus the weight of centre tank fuel may exceed the maximum zero fuel gross weight by up to 5,000 pounds (2,300 kilograms) for takeoff, climb and cruise and up to 3,000 pounds (1,400 kilograms) for descent and landing, provided that the effects of balance (CG) have been considered.If a centre tank fuel pump fails with fuel in the centre tank, accomplish the FUEL PUMP LOW PRESSURE non-normal procedure.When defueling centre or main wing tanks, the Fuel Pump Low Pressure indication lights must be monitored and the fuel pumps positioned to OFF at the first indication of fuel pump low pressure. Defueling with passengers on board is prohibited. |\n| | The limitations contained in this Directive supersede any conflicting basic Aircraft Flight Manual limitations. |\n| | Accomplishment of Requirement 2 of AD/B737/198 or Requirement 1.b. of AD/B737/198 Amdt 1 is acceptable for compliance with the requirements of this Directive. This Directive does not require that those actions be repeated unless the terminating actions specified in Requirement 6 of AD/B737/198 or Requirement 3 of AD/B737/198 Amdt 1 have been accomplished. |\n| | Accomplishment of the terminating actions specified in Requirement 6 of AD/B737/198 or Requirement 3 of AD/B737/198 Amdt 1, does not allow removal of the AFM revisions required by this Directive. |\n| | 2. For mixed fleet operations (i.e. operators with aircraft with line number 1494 and subsequent together with aircraft with line number below 1494) install a placard on the flight deck of aircraft that do not have automatic fuel pump shut-off system installed to alert the crew that the Requirement 1 procedures must be followed on that aircraft stating either: |\n| | “AD/B737/202 fuel usage restrictions required” or“AD 2002-24-51 fuel usage restrictions required”. |\n| | For aircraft that have a placard required by AD/B737/198 or AD/B737/198Amdt 1, that placard can be used to fulfil this requirement for mixed fleet operations. |\n\n| | Note: FAA Emergency AD 2002-24-51 and FAA AMOC Letter 140S-04-105 dated28 May 2004 refer. |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | Date remains unchanged to that detailed in Amendment 1 of this Directive.Despite the new AD/B737/202 Amdt 2, an exclusion or an alternate method of compliance that was in force before the coming into effect of AD/B737/202 Amdt 2 continues to be in force. |\n| | This Amendment becomes effective on 30 September 2011. |\n| Background: | The United States Federal Aviation Administration has received reports indicating that two fuel tank pumps from different Model 747 series aeroplanes showed evidence of extreme localized overheating of parts in the priming and vapour pump section of the fuel pump. The priming and vapour pump section of the pump is open to the fuel tank via the pump inlet line and the vapour vent of the pump. The cause of this overheating is believed to be friction between the pump parts; however, the specific cause of the friction is unknown at this time. |\n| | The fuel pumps installed on Model 737-600, -700, -700C, -800, and -900; Model 747; and Model 757 series aeroplanes are all potentially affected since the pumps are almost identical in design. |\n| | Overheating of the parts in the priming and vapour pump section of the fuel pump provides an ignition source in the fuel tank during dry running of the pump, which could result in fire/explosion of the fuel tank. |\n| | The original issue of this Directive required revision of the AFM to require the flight crew to maintain certain minimum fuel levels in the centre fuel tanks. These procedures specify crew monitoring of fuel levels and shutoff of centre fuel tank pumps at specified levels that ensure the pump inlet remains covered during pump operation. Covering the pump inlet prevents fuel vapours from coming into contact with potentially overheated parts in the priming and vapour pump section of the fuel pump, together with the likelihood of preventing the overheating condition itself. This action was considered interim and further rule making is anticipated. |\n| | This amendment recognises incorporation of an automatic fuel pump shut-off system on line number 1494 and subsequent. The amendment also introduces a requirement for placarding aircraft without the automatic shutoff system in mixed fleet operations. |\n| | Amendment 2 allows alternate wording for the placard detailed in Requirement 2. This is to allow easier cross referencing to FAA AD 2011-18-03 which details the terminating actions for the requirements of this AD.Alternative Methods of Compliance for AD 2002-24-51 that are approved by the FAA are acceptable as a means of compliance against this AD. |\n\n| | The original issue of this Directive became effective on 26 November 2002.Amendment 1 of this Directive became effective on 23 June 2005. |\n| --- | ----------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)\n\nMike Higgins \nDelegate of the Civil Aviation Safety Authority\n\n5 September 2011","sortOrder":0},{"sectionNumber":"AD/B737/202 Amdt 2","sectionType":"part","heading":"AD/B737/202 Amdt 2","content":"## AD/B737/202 Amdt 2","sortOrder":1},{"sectionNumber":"Centre Fuel Tank Limitations","sectionType":"part","heading":"Centre Fuel Tank Limitations","content":"## Centre Fuel Tank Limitations","sortOrder":2},{"sectionNumber":"18/2011","sectionType":"part","heading":"18/2011","content":"## 18/2011","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Amendment 2 modifies scope relative to the original Directive by recognising aircraft with an automatic fuel pump shut‑off (line number 1494 and subsequent) and adding a specific placard requirement for mixed‑fleet operators where the automatic shut‑off is absent (Requirement 2). It also allows alternate placard wording and explicitly accepts FAA‑approved AMOCs. The core AFM fuel‑limit requirements remain, and AFM revisions must be retained even after terminating actions from related ADs."},"complexity_factors":["Applicability cut‑off by line number (pre‑1494 vs ≥1494) creating mixed‑fleet rules","Operational numeric thresholds for pump operation (5,000 lb, ~1,000 lb, 3,000 lb, CONFIG annunciation at 1,600 lb)","Multiple operational constraints (takeoff, climb/cruise, descent/landing, defueling) that crews must follow","Cross‑references to other ADs and terminating actions (AD/B737/198, FAA AD 2002‑24‑51, FAA AMOC Letter) affecting compliance pathways","Exceptions and grandfathering (prior exclusions/AMOCs remain in force) increasing record complexity","Mandatory placarding wording with allowed alternate phrasing and reuse of earlier placards","Prohibition (defueling with passengers) and monitoring obligations (switching off at first low‑pressure indication)","Requirement that AFM revisions remain even after terminating actions creates persistent administrative burden","Acceptance of FAA‑approved alternate methods of compliance introduces dependency on external regulator decisions","Effective date and layered amendment history (original AD, Amdt 1, Amdt 2) requiring operators to track compliance timeline"],"plain_english_summary":"This Directive requires operators of certain Boeing 737-600/-700/-700C/-800/-900 aeroplanes (line numbers before 1494) to revise the Aircraft Flight Manual and crew procedures so centre-tank pumps are OFF at specified fuel quantities, to monitor low‑pressure indications, and to placard mixed‑fleet aircraft that lack an automatic pump shut‑off. The change is intended to reduce the risk of fuel‑tank ignition from pump overheating.\n\nOperators bear the costs of AFM revisions, placards and training; flight crews must follow the new switch and monitoring rules; CASA enforces compliance and accepts FAA‑approved alternate methods of compliance."},"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":4,"scope_assessment":{"changed":true,"description":"The original directive was an interim safety measure requiring manual flight crew procedures to prevent fuel pump overheating. Amendment 2 has expanded scope to address fleet modernisation (recognising factory-installed automatic shut-off systems in newer aircraft) and operational complexity (mixed fleet placarding requirements). It also increasingly harmonises with US FAA regulatory framework, accepting FAA-approved alternative compliance methods. The directive has evolved from a simple 'do this procedure' order to a more nuanced regulatory instrument managing transitional fleet states and international regulatory equivalence."},"complexity_factors":["Multiple cross-references to previous versions of the same directive (AD/B737/202 original, Amendment 1) and related directives (AD/B737/198)","Conditional logic based on aircraft manufacturing line numbers (pre-1494 vs post-1494)","Mixed fleet operational requirements creating dual compliance paths","Specific weight thresholds in both imperial (pounds) and metric (kilograms) units with varying precision (e.g., '450-500 kilograms')","Nested exceptions and alternative compliance methods (AMOCs) recognised from US FAA","Interaction between manual procedures and automatic systems requiring careful parsing of what supersedes what","Terminating actions that don't actually terminate the flight manual revision requirements"],"plain_english_summary":"This CASA Airworthiness Directive orders operators of certain older Boeing 737-600/700/700C/800/900 (line numbers before 1494) to change flight manuals—and, where mixed fleets exist, add cockpit placards—to prevent centre fuel tank pumps running dry. The measures (manual pump-off thresholds) stop pump overheating and potential fuel-tank ignition. Amendment 2 notes newer aircraft have a factory fix and eases citing equivalent FAA compliance options."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-202-amdt-2-centre-fuel-tank-limitations","history":"/api/acts/ad-b737-202-amdt-2-centre-fuel-tank-limitations/history","analysis":"/api/acts/ad-b737-202-amdt-2-centre-fuel-tank-limitations/analysis","conflicts":"/api/acts/ad-b737-202-amdt-2-centre-fuel-tank-limitations/conflicts","importantCases":"/api/acts/ad-b737-202-amdt-2-centre-fuel-tank-limitations/important-cases","documents":"/api/acts/ad-b737-202-amdt-2-centre-fuel-tank-limitations/documents"}}