AD/B737/198 Amdt 2 - Centre Tank Fuel Pumps

The directive rests on three core concepts: risk mitigation by operational restriction, risk mitigation by hardware inspection and verification, and a conditional terminating action that removes operational restrictions once hardware integrity is verified.

1. Operational restrictions as interim mitigation. For affected aeroplanes (models listed and line numbers 1234 and below), the immediate step is to alter the Aircraft Flight Manual (AFM) Limitations section and to install a cockpit placard (Requirement 1.a-c, Annex A). Annex A spells out the operational procedures and numeric thresholds that reduce the likelihood that fuel vapour in the centre tank will be exposed to an ignition source created by a failed pump motor. Key limits: centre tank pumps must be OFF for takeoff when CWT fuel is less than 5,000 lb (2,300 kg); both pumps must be selected OFF at about 1,000 lb during climb/cruise, or at 3,000 lb during descent/landing; pumps must be switched OFF at first indication of fuel pump low pressure; dispatch requires the CWT fuel quantity indication system operative for CWT mission fuel. These are procedural controls intended to prevent pump operation with vapour pockets present, thereby limiting ignition-source exposure.

2. Part‑level and assembly‑level inspection requirement. Requirement 2 targets both specific pump part numbers and all motor‑impeller assemblies. Two Hydro‑Aire part numbers are singled out (60‑989100‑4 and 60‑755100‑4, equated to Boeing part numbers 60B89004‑14 and 60B92404‑8) such that they may not be installed as replacement parts unless inspected per the Boeing ASB or Crane SB (Requirement 2.a). In addition, any motor‑impeller assembly, regardless of part number, may not be installed in any pump position unless it has been X‑ray inspected since its last end cap/motor‑impeller housing assembly (Requirement 2.b). The inspection objective is explicit in the Background: verify that the stator lead wire bundle is properly routed and has not been positioned such that it can contact the rotor, which had been shown in FAA reports to cause chafing, arcing and pump failures that could become an ignition source in the fuel tank.

3. Optional terminating action by inspection. Requirement 3 allows removal of the AFM revision and the placard when all the pumps in specified tanks on an aeroplane have been inspected using X‑ray in accordance with Boeing ASB 737‑28A1197 or Crane Hydro‑Aire SB Motor‑Impeller‑28‑01 (including Appendix A). Note 1 explicitly frames Requirement 3 as optional terminating action for the fuel usage restrictions in Requirement 1.b and 1.c. The Amendment recognises prior Crane Hydro‑Aire inspections as equivalent where performed before the Amendment’s effective date and accepts inspections done before the original Directive issue date as acceptable for removal of the AFM revision and placard.

Ancillary concepts: cross‑jurisdictional equivalence and AMOCs. The Amendment defers to FAA AMOCs as acceptable means of compliance (Background), and it directly references FAA AD 2002‑19‑52 (Note 2) and the Boeing/Crane service documents as the technical inspection standards. The instrument therefore uses technical materials and prior foreign authority decisions to define compliance actions.

Mechanically discrete elements to track for compliance: aircraft applicability by line number (1234 and below for AFM/placard), the two named Hydro‑Aire part numbers and their Boeing equivalents, the universal prohibition on un‑X‑rayed motor‑impeller assemblies, the X‑ray inspection standard references (Boeing ASB 737‑28A1197; Crane Hydro‑Aire SB Motor‑Impeller‑28‑01 incl. Appendix A), and the AFM/operational thresholds in Annex A (5,000 lb, 3,000 lb, approximately 1,000 lb, CONFIG annunciation 1,600 lb, ZFW allowances).

Directly affected parties

• Operators of Boeing 737-600, -700, -700C, -800 and -900 series aeroplanes, particularly those with line numbers 1234 and below (Requirement 1 and Applicability). These operators must revise AFMs and install cockpit placards within 14 days after the Amendment’s effective date, unless these actions were already accomplished (Requirement 1, Compliance). The AFM limitations constrain flight planning, dispatch decisions and in‑flight fuel management.

• Maintenance, Repair and Overhaul organisations (MROs) and repair stations performing pump replacement or overhaul. Requirement 2 prohibits installation of the specified Hydro‑Aire parts unless inspected as prescribed, and disallows installing any motor‑impeller assembly that has not been X‑ray inspected since its last end cap/motor‑impeller housing assembly. MROs that install such parts must either perform the requisite inspections, subcontract inspections, or decline to install the parts. Independent providers without X‑ray capability may need to coordinate with third‑party inspectors or the OEM/part manufacturer.

• Part suppliers and inventory managers. Sellers of Hydro‑Aire/Boeing pump parts and motor‑impeller assemblies must ensure parts presented for installation have the required inspection history or documentation. Stock rotation, traceability and record‑keeping become compliance levers.

• Pilots and flight crew. Annex A imposes AFM limitations that will change normal pre‑flight checks and decisions (for example, centre tank pumps OFF for takeoff under a specified threshold, monitoring of Fuel Pump Low Pressure lights during defuelling, prohibition on defuelling with passengers onboard). Crew standard operating procedures (SOPs) and training will require updates.

Indirectly affected parties

• Aircraft lessors. For aeroplanes subject to the AFM limitations, lessors and lessees must coordinate to ensure the lessee performs required AFM changes within the 14‑day window and arranges inspections for spare pumps when replacements are required. Lessors that supply spare parts must ensure parts meet inspection requirements.

• Insurers and risk managers. The operational restrictions and the inspection regime affect residual risk profiles. Compliance records and maintenance history will be material to insurance underwriting and claims.

• OEMs and parts manufacturers (Boeing, Crane Hydro‑Aire). The Directive references Boeing ASB 737‑28A1197 and Crane SB Motor‑Impeller‑28‑01; those documents define inspection methodology and allowed remedial actions. The Amendment also recognises Crane Hydro‑Aire inspections done before the effective date as equivalent, concentrating some practical authority with the part manufacturer to certify compliance.

• Regulators and airworthiness authorities. CASA as the issuing authority enforces the AD; FAA and other foreign authorities are implicated through acceptance of FAA‑approved AMOCs and cross‑references to FAA ADs. Operators with multi‑jurisdictional operations must coordinate compliance approaches with different authorities.

Concentration of burden and benefits

• The operational restrictions disproportionately affect older aeroplanes (line numbers 1234 and below). Newer aeroplanes are outside the scope of the AFM limitation, although they remain subject to the installation and inspection prohibitions. Owners of older aircraft bear concentrated costs in operations, inspections and potential downtime.

• The inspection/installation prohibition concentrates commercial advantage with inspection providers and manufacturers able to certify X‑ray inspections. Independent shops without X‑ray capability face either capital expenditure to acquire equipment or reliance on external certified inspectors.

Decision-makers and who pays

• The operator decides on whether to perform inspections, when and where, and whether to remove AFM limitations when inspections are complete. Operators pay for AFM revisions (administrative), placard production/installation (minor), X‑ray inspections and any consequential downtime or spares rework, and the potential operational cost of restricted centre tank fuel usage (fuel uplift, payload planning, flight routing).

• MROs and part suppliers decide whether to hold inspected inventory, invest in inspection capability or outsource inspection. They bear direct inspection costs and record‑keeping burdens, and may reprice services to reflect compliance costs.

Duties imposed by the Amendment

• AFM revision and placard insertion (Requirement 1). For aeroplanes with line number 1234 and below, the operator must remove any previous AFM revision specified by AD/B737/190 Amdt 1 if not already done (Requirement 1.a) and must revise the AFM Limitations section by incorporating the procedures included at Annex A (Requirement 1.b). Operators must also install a placard adjacent to each pilot’s primary flight display (PFD) with one of two permitted wordings (Requirement 1.c). Compliance timing for Requirement 1 is within 14 days after the Amendment’s effective date (Compliance).

• Installation prohibitions for specified parts (Requirement 2.a). Fuel pumps with Hydro‑Aire part numbers 60‑989100‑4 and 60‑755100‑4 (Boeing P/N 60B89004‑14 and 60B92404‑8) may not be installed as replacement parts unless inspected to ensure proper wire bundle routing in the pump since the most recent assembly, in accordance with Boeing ASB 737‑28A1197 dated 23 September 2002 or Crane Hydro‑Aire SB Motor‑Impeller‑28‑01 (including Appendix A) dated 17 September 2002. Requirement 2 is effective as of the Amendment’s effective date.

• Prohibition on installing any motor‑impeller assembly without X‑ray inspection (Requirement 2.b). Any fuel pump motor‑impeller assembly, irrespective of part number, may not be installed on any aeroplane in any pump position as a replacement unless the assembly has been inspected using X‑ray methods since its most recent assembly of the end cap and motor‑impeller housing, in accordance with the Boeing ASB or Crane SB (Requirement 2.b).

• AFM removal conditional on inspection (Requirement 3). Operators may remove the Requirement 1.b AFM revision and the Requirement 1.c placard when all fuel pumps for the centre wing tank, horizontal stabiliser tank, centre auxiliary tanks and auxiliary tanks 1 and 4 have been X‑ray inspected in accordance with Boeing ASB 737‑28A1197 or Crane Hydro‑Aire SB Motor‑Impeller‑28‑01, including Appendix A. Note 1 characterises Requirement 3 as an optional terminating action for the fuel usage restrictions.

• Dispatch requirement (Annex A). Annex A requires that the CWT fuel quantity indication system must be operative to dispatch with CWT mission fuel, which places a dispatchability duty on operators to ensure that system is serviceable when CWT fuel is intended for use.

Rights, flexibility and recognised equivalence

• Recognition of prior Crane Hydro‑Aire inspections. Inspection of a pump by Crane Hydro‑Aire before the Amendment’s effective date is considered equivalent to an inspection performed in accordance with Crane SB Motor‑Impeller‑28‑01 (Compliance). Similarly, inspections performed in accordance with Boeing ASB or Crane SB before the effective date of the original issue of the Directive are acceptable for removal of the AFM revision and placard. These provisions grant operators and MROs rights to rely on earlier work rather than repeat inspections.

• Acceptance of FAA AMOCs. The Amendment states that Alternative Methods of Compliance for FAA AD 2002‑19‑52 that are approved by the FAA are acceptable as a means of compliance against this AD (Background). This creates cross‑recognition and a compliance pathway where the FAA has already approved an alternate approach.

• Optional nature of terminating action. The AFM revision and placard remain in force until the operator elects to achieve the terminating action (Requirement 3). Operators can therefore choose between continued operational restrictions or undertaking the inspections necessary to remove them.

Operational duties embedded in Annex A

• Numeric thresholds and mandatory crew actions: pumps OFF for takeoff if centre tank fuel < 5,000 lb (2,300 kg); both CWT pumps OFF at approximately 1,000 lb during climb/cruise and at 3,000 lb during descent and landing; monitor fuel pump low pressure lights and position pumps OFF at first indication; prohibition on defuelling with passengers onboard.

Record-keeping and traceability duties implicit in installation prohibitions

• Although the Directive does not prescribe a specific record-keeping format, operators and MROs will need to maintain traceable records demonstrating that any installed pump or motor‑impeller assembly has been inspected per Boeing ASB or Crane SB, or that it carries prior Crane inspection documentation, to justify removal of AFM limitations or to show compliance during oversight.

Who decides

• Operators decide how to sequence inspections, whether to accept prior Crane inspections as evidence, and whether to pursue FAA AMOCs where applicable. MROs and part manufacturers/inspectors decide whether to perform or certify the X‑ray inspections and to issue the documentation required to show compliance.

What the AD states directly about enforcement

• The text of AD/B737/198 Amdt 2 itself does not specify criminal or civil penalties, fines or explicit enforcement mechanisms. It is an airworthiness directive issued under the authority of the Civil Aviation Safety Authority (CASA), signed by a CASA delegate (Mike Higgins). The instrument sets mandatory compliance actions and deadlines (for example, Requirement 1 within 14 days, Requirement 2 effective as of the effective date), which are obligations under the AD.

Enforcement in regulatory practice (grounded in the nature of ADs, not extra‑textual claims)

• Airworthiness directives are instruments used by airworthiness authorities to mandate corrective action for identified safety issues. While this AD does not recite penalties, failure to comply with an AD commonly exposes an operator to regulatory enforcement actions by CASA, which in practice can include grounding the aircraft, issuance of mandatory rectification notices, or administrative sanctions under applicable aviation safety statutes and regulations. The AD itself does not detail such sanctions; any enforcement outcome will depend on CASA’s broader enforcement framework and statutory authorities, which are not reproduced in the AD text.

Compliance monitoring and evidence

• The AD requires specific technical inspections and AFM/placard actions. Practical enforcement will rely on operators’ maintenance records, logbook entries, and inspection certificates demonstrating compliance with Boeing ASB 737‑28A1197 or Crane Hydro‑Aire SB Motor‑Impeller‑28‑01. The Amendment explicitly accepts certain prior Crane inspections as equivalent (Compliance), which reduces the need for repeat inspection and provides a clear evidentiary basis for compliance where such documentation exists.

Risks of non‑compliance

• The Background describes a safety risk: fuel pump failures resulting from chafing of the stator lead wire bundle creating arcing that could become an ignition source in the fuel tank. The link between non‑compliance (for example, operating pumps when vapour pockets are present or installing uninspected pumps) and a safety hazard is stated in the AD. Regulators, insurers and operators will treat failure to comply as increasing operational and liability risk. The AD’s prescriptive measures reduce that risk when implemented.

Cross‑jurisdictional aspects affecting enforcement

• The Amendment accepts FAA‑approved AMOCs as acceptable means of compliance (Background). For operators subject to multiple authorities, CASA’s acceptance of FAA AMOCs implies that an FAA‑approved alternate method, if applicable and documented, may be used as evidence to CASA that the operator has complied with the AD’s intent. The AD also references FAA AD 2002‑19‑52 (Note 2), indicating coordination with FAA actions.

Limitations in the text regarding enforcement detail

• Because the AD does not prescribe enforcement penalties, parties seeking the exact suite of enforcement tools available to CASA must consult the enabling aviation safety legislation and CASA regulatory policy. This AD should be treated as a mandatory operational and maintenance requirement; the specific enforcement mechanism, including any penalty, will be the product of CASA’s statutory powers and enforcement policy, none of which are set out in the AD text.

Referenced regulatory instruments and standards

• The Amendment explicitly cross‑references and depends upon certain technical documents and other ADs. It refers to Boeing Alert Service Bulletin 737‑28A1197 dated 23 September 2002 and Crane Hydro‑Aire Service Bulletin Motor‑Impeller‑28‑01 (including Appendix A) dated 17 September 2002 as the inspection and verification standards (Requirement 2 and Requirement 3). It also references FAA AD 2002‑19‑52 (Note 2) and accepts FAA‑approved Alternative Methods of Compliance for that FAA AD as acceptable for compliance with this AD (Background). These cross‑references make the Amendment operationally dependent on external technical and regulatory materials.

Interaction with prior CASA ADs

• The Amendment’s text states that the original issue of this Directive superseded AD/B737/190 Amdt 1, which was cancelled (Background). Operators must consider the chain of directives when establishing the current legal obligations applicable to an aeroplane. The Amendment narrows the AFM fuel usage restrictions to aeroplanes before line number 1234 while retaining the installation/inspection prohibition for replacement pumps (Background).

Administrative law and delegation

• The AD is signed by a CASA delegate (Mike Higgins) on 5 September 2011. The instrument is exercised under CASA’s delegated authorisation; the delegation aspects imply that the AD is made under CASA’s enabling legislation and powers. The AD itself does not reproduce the enabling statutory provisions; those would be found in the Civil Aviation Act and associated regulations.

Maintenance regulation and continuing airworthiness regime

• The AD interacts with the continuing airworthiness framework applicable to Australian operators. The AFM revisions and dispatch requirements in Annex A affect operational rules for dispatch and airworthiness determinations. Maintenance organisations must follow the AD’s installation and inspection prohibitions as part of their approval conditions and audit obligations. The AD’s requirement that the CWT fuel quantity indication system be operative to dispatch with CWT mission fuel links directly to regulatory dispatch conditions and the aircraft’s MEL (Minimum Equipment List) and CDL (Configuration Deviation List) procedures.

Contractual and commercial interactions

• Lessors, lessees and maintenance contractors must factor the AD into lease schedules, maintenance planning and spare parts provisioning. Compliance may trigger contractually specified responsibilities for airworthiness actions (for example, where a lease assigns heavy maintenance or modifications to the lessee). The AD’s requirement that certain parts be X‑ray inspected before installation places a practical obligation on parts suppliers and repair stations to provide evidence of compliance, which may be enforced contractually.

International reciprocity and AMOCs

• By accepting FAA AMOCs for FAA AD 2002‑19‑52 as acceptable for this AD, CASA effectively recognises FAA‑approved alternate technical solutions, reducing duplication for operators that already comply with FAA alternative methods. That cross‑recognition streamlines compliance for internationally operated fleets but also requires operators to obtain FAA AMOC documentation and be able to present it to CASA.

Records and evidentiary interaction with safety regulation

• The AD presupposes that operators will retain evidence of inspections to demonstrate compliance. Those records will interact with audit and enforcement regimes under aviation safety law. The AD’s acceptance of prior Crane Hydro‑Aire inspections as equivalent indicates that documented vendor inspections have continuing legal effect for CASA compliance purposes.

Gaps and areas requiring other legal sources

• The AD does not itself set penalties or enforcement procedures; legal practitioners will need to refer to CASA’s statutory powers, civil aviation criminal provisions, and administrative enforcement policies if seeking the full legal consequences of non‑compliance. Similarly, obligations to report defects or occurrences and insurance consequences derive from other instruments and are not repeated in the AD.

Chronology provided within the instrument

• Original Directive: the AD’s original issue became effective on 3 October 2002 (Background). The original AD superseded AD/B737/190 Amdt 1, which was cancelled (Background).

• Amendment 1: Amendment 1 of this Directive became effective on 23 June 2005 (Background). The original Directive required an AFM amendment and placard installation as interim operational mitigations, while providing optional terminating actions.

• Amendment 2: The present document is Amendment 2 to AD/B737/198, and it became effective on 30 September 2011 (Compliance section: "This Amendment becomes effective on 30 September 2011"; signature block dated 5 September 2011). Amendment 2 restricts the applicability of the AFM fuel usage restrictions to aeroplanes before line number 1234 while retaining the inspection requirements for replacement pumps; it also allows alternative placard wording for cross‑reference to FAA AD 2011‑18‑03 and accepts FAA AMOCs for FAA AD 2002‑19‑52 as acceptable compliance measures (Amendment text in Background).

Key changes introduced by the amendments

• From the original Directive to Amendment 2: The original Directive required AFM limitations and placards for the fleet to mitigate the fuel pump failure risk. Amendment 2 narrows the operational restriction to earlier line numbers (1234 and below), thereby reducing the set of aircraft requiring AFM limitations while maintaining a strict prohibition on installing uninspected replacement pumps across all applicable models (Requirement 2).

• Acceptance of prior inspections and equivalence: The Amendment formalises that inspections performed by Crane Hydro‑Aire before the Amendment’s effective date are equivalent to the required Crane SB inspections and that inspections performed before the original issue of the Directive in accordance with Boeing ASB or Crane SB are acceptable to permit removal of the AFM revision and placard (Compliance). This reduces rework where appropriate prior work has already been done.

• Placard wording flexibility: Amendment 2 allows alternate placard wording to cross‑reference FAA AD 2011‑18‑03, which details alternative terminating actions for the requirements of this AD (Amendment text: "Amendment 2 allows alternate wording for the placard... to allow easier cross referencing to FAA AD 2011‑18‑03").

Documents referenced across the amendment history

• AD/B737/190 Amdt 1 was superseded and cancelled by the original AD (Background).

• Boeing Alert Service Bulletin 737‑28A1197 (23 September 2002) and Crane Hydro‑Aire Service Bulletin Motor‑Impeller‑28‑01 (including Appendix A) (17 September 2002) are the service documents referenced repeatedly across the AD and its amendments for the inspection standard.

• FAA AD 2002‑19‑52 is cited as a related FAA action (Note 2). FAA AD 2011‑18‑03 is mentioned as an FAA AD that provides alternative terminating actions to which the Amendment’s placard wording can be cross‑referenced.

Practical effect of amendment sequencing

• The sequence shows an initial universal operational mitigation (AFM limits and placards), then a later refinement to limit AFM measures to older aeroplanes while relying on an inspection-based remedy as the path to restore normal operations. The Amendment’s wording also indicates regulatory coordination with the FAA and reliance on OEM/provider technical documentation to define the inspection standard.

What the source contains

• The AD text does not report any litigation concerning AD/B737/198 or its amendments. The document references FAA ADs and Boeing/Crane service documents but does not cite any judicial decisions, disputes or legal challenges.

Implications from the absence of litigation in the text

• Because the AD itself contains no litigation history, practitioners must assume that there is no litigation disclosed in this instrument. Where litigation or precedent is material, it would need to be sourced from judicial or administrative records outside the AD text, or from CASA enforcement records, none of which are provided here.

References to other instruments that could be the subject of litigation

• The AD references FAA AD 2002‑19‑52 and FAA AD 2011‑18‑03. Any legal disputes about the technical sufficiency of AMOCs or equivalence determinations by the FAA could, in principle, generate litigation in US courts or administrative proceedings, but no such litigation is referenced in this AD.

How practitioners should treat this gap

• For legal analysis of precedential or contested interpretations (for example, the scope of “inspection” equivalence or the sufficiency of corrective steps), counsel should consult CASA enforcement decisions, administrative rulings, and any court decisions interpreting AD compliance. None of those materials are included in this instrument, and the AD does not purport to summarise them.

Terminology and line number scope

• Applicability by line number is precise: the AFM/placard requirements apply only to aeroplanes "with a line number 1234 and below" (Applicability, Requirement 1). Practitioners should confirm the aeroplane’s production line number against manufacturer records; mis‑identifying the line number could lead to unnecessary operational limits or non‑compliance. The AD does not explain how to determine or verify the line number; that information must be obtained from OEM documentation or the aircraft’s certificate.

AFM thresholds are numeric but unevenly qualified

• Annex A uses precise numeric thresholds for many items (for example 5,000 lb, 3,000 lb, 1,600 lb), but also uses the phrase "approximately 1,000 pounds" for the climb/cruise threshold. The word "approximately" introduces interpretive margin; operators should clarify how to translate cockpit indication tolerances and instrument resolution into the AFM requirements for dispatch and in‑flight decision making.

CONFIG annunciation and non‑normal procedure timing

• Annex A warns that the CONFIG indicator will annunciate when centre tank fuel exceeds 1,600 lb and the centre tank fuel pump switches are OFF, and it instructs: "Do not accomplish the CONFIG non‑normal procedure prior to or during takeoff with less than 5,000 pounds ... or during descent and landing with less than 3,000 pounds ..." This creates a procedural interaction where following a CONFIG non‑normal procedure inappropriately could violate the AFM limitations. Flight crews need specific SOPs and training to avoid this pitfall.

Defuelling with passengers and monitoring low pressure lights

• Annex A prohibits defuelling with passengers on board and requires monitoring Fuel Pump Low Pressure indication lights when defuelling. Operators that routinely defuel with passengers on board (for example in quick turn ground operations) must change procedures and training. The AD does not describe where to record compliance with this defuelling prohibition; operational documentation and SOPs should be updated.

Installation prohibition applied to any motor‑impeller assembly

• Requirement 2.b bars installation of any motor‑impeller assembly as a replacement without X‑ray inspection, regardless of part number. That means a previously unproblematic part number from another supplier still needs X‑ray verification since its last assembly. Maintenance planners must ensure that spare stock is documented as inspected or else unavailable for service installation without inspection.

Inspection method specificity

• The AD specifies X‑ray methods in accordance with Boeing ASB 737‑28A1197 or Crane Hydro‑Aire SB Motor‑Impeller‑28‑01 including Appendix A. Operators that perform an X‑ray inspection using local or proprietary procedures risk non‑acceptance unless those methods are explicitly equivalent or accepted by FAA AMOC. Reliance on local non‑standard inspection techniques risks regulatory objection.

Evidence of prior inspections accepted, but documentation required

• The AD states that inspection by Crane Hydro‑Aire before the effective date is considered equivalent (Compliance). That relies on evidence from Crane Hydro‑Aire. Operators should ensure they have traceable documentation showing that inspections were performed and meet the specified SB or ASB standards. Absent clear documentation, CASA may not accept the claim that an inspection is equivalent.

Timing constraints and practical scheduling

• Requirement 1 must be accomplished within 14 days after the effective date, a short window for fleet‑wide AFM changes and placard installation. Operators with dispersed fleets or aircraft in foreign maintenance facilities must plan to satisfy this timing or document prior compliance.

Cross‑reference to FAA ADs and AMOCs

• Although the AD accepts FAA AMOCs for the FAA AD as acceptable, the operator must obtain and be able to present the FAA AMOC approval. Simply having implemented an FAA‑proposed alternative without documented FAA approval will not necessarily discharge the CASA AD obligation.

Potential supply chain bottlenecks

• The X‑ray inspection requirement for any replacement motor‑impeller assembly creates potential bottlenecks: independent MROs without X‑ray facilities will need to route parts to qualified inspection providers or the OEM. This could lead to increased lead times for repairs and spare exchange, and to concentration of work at authorised inspection centres.

Optional nature of terminating action may delay relief

• Requirement 3 is an option: operators can either continue operating under AFM restrictions or perform the comprehensive X‑ray inspections to remove the restrictions. The requirement that ALL pumps across multiple tanks be inspected before removing the AFM revision may require significant scheduling and downtime across the aircraft, leading some operators to continue under restrictions as a pragmatic choice, which can have ongoing operational cost impacts.

Step‑by‑step compliance checklist (grounded in the AD text)

1. Determine applicability. For each aeroplane in the fleet, confirm model and production line number. If the aeroplane is Model 737‑600, ‑700, ‑700C, ‑800 or ‑900 and has line number 1234 or below, Requirement 1 AFM revisions and placards apply (Applicability, Requirement 1). Requirement 2 (installation/inspection prohibitions) applies to all listed models regardless of line number (Requirement 2: "For all Model 737‑600, -700 ... -900 series aeroplanes").

2. AFM revision and placard installation (for line number 1234 and below). If not previously done in accordance with the original issue of the Directive, within 14 days after the Amendment’s effective date:

   • Remove the AFM revision required by AD/B737/190 Amdt 1, if applicable (Requirement 1.a).
   • Revise the Limitations section of the Aircraft Flight Manual by incorporating the procedures included at Annex A to this Amendment. This may be accomplished by inserting a copy of Annex A into the AFM (Requirement 1.b; Annex A contains the precise text and numeric thresholds).
   • Install a placard adjacent to each pilot’s primary flight display (PFD) that reads either "AD/B737/198 fuel usage restrictions required" or "AD 2002‑19‑52 fuel usage restrictions required" (Requirement 1.c). The Amendment allows alternate wording to cross‑reference FAA AD 2011‑18‑03 where appropriate.

3. Immediate prohibition on installing certain parts (effective as of Amendment effective date). For any replacement fuel pumps:

   • Do not install Hydro‑Aire part numbers 60‑989100‑4 or 60‑755100‑4 (or Boeing part numbers 60B89004‑14 and 60B92404‑8) unless the pump has been inspected to ensure proper wire bundle routing since the most recent assembly of the end cap and motor‑impeller housing, in accordance with Boeing ASB 737‑28A1197 or Crane Hydro‑Aire SB Motor‑Impeller‑28‑01 including Appendix A (Requirement 2.a). Ensure the inspection certificate or documentation explicitly references the Boeing ASB or Crane SB as the inspection standard.
   • For any motor‑impeller assembly (any part number), do not install it in any pump position as a replacement unless the assembly has been inspected using X‑ray methods since its most recent assembly of the end cap and motor‑impeller housing, in accordance with Boeing ASB 737‑28A1197 or Crane Hydro‑Aire SB Motor‑Impeller‑28‑01 including Appendix A. Maintain the X‑ray inspection records with the part or in the aircraft maintenance records (Requirement 2.b).

4. Planning and logistics for X‑ray inspections

   • Identify all pumps requiring X‑ray inspection on each aeroplane: centre wing tank, horizontal stabiliser tank, centre auxiliary tanks, and auxiliary fuel tanks 1 and 4 (Requirement 3).
   • Determine whether existing inspections by Crane Hydro‑Aire or prior compliance with Boeing ASB/Crane SB have already been performed and documented. The AD accepts Crane Hydro‑Aire inspections before the effective date as equivalent and accepts inspections performed in accordance with Boeing ASB or Crane SB before the original Directive issue date for removal of the AFM revision and placard (Compliance notes).
   • If inspections are not present, schedule X‑ray inspections in a manner that minimises aircraft downtime. Consider using authorised external inspection providers, OEM inspection services, or investing in local X‑ray capability if a business case exists.

5. Removal of AFM revision and placard (optional terminating action)

   • Once all the pumps listed in step 4 on an aeroplane have been inspected using X‑ray in accordance with Boeing ASB 737‑28A1197 or Crane Hydro‑Aire SB Motor‑Impeller‑28‑01 (including Appendix A), the operator may remove the Requirement 1.b AFM revision and the Requirement 1.c placard (Requirement 3; Note 1).
   • Retain inspection certificates and records to demonstrate that each pump was inspected according to the specified documents, as these will be required if CASA queries the removal of the AFM limitations.

6. Dispatch and flight operations changes per Annex A

   • Update SOPs and crew training to reflect Annex A limitations: centre tank pumps OFF for takeoff if CWT fuel < 5,000 lb; both centre pumps OFF when CWT fuel reaches approximately 1,000 lb during climb and cruise or 3,000 lb during descent and landing; pumps OFF at first indication of fuel pump low pressure; ensure the CWT fuel quantity indication system is operative to dispatch with CWT mission fuel; monitor Fuel Pump Low Pressure lights during defuelling and switch pumps OFF at first indication; do not defuel with passengers on board.
   • Update dispatch documentation to reflect the requirement that the CWT fuel quantity indication system must be operative for dispatch when CWT fuel will be used (Annex A).

7. Record‑keeping and evidence for regulators and auditors

   • Maintain AFM revision records, placard installation evidence (photographs, placard part number and installation log), X‑ray inspection certificates that explicitly reference Boeing ASB 737‑28A1197 or Crane Hydro‑Aire SB Motor‑Impeller‑28‑01 including Appendix A, and any Crane Hydro‑Aire documentation for inspections performed before the effective date that the AD treats as equivalent.
   • If relying on FAA AMOCs, retain FAA approval documentation showing the AMOC is applicable to the specific aircraft/configuration.

8. Coordinate with lessors, insurers and MROs

   • For leased aircraft, ensure lease schedules allocate responsibility and time for AFM revisions, placard installations and X‑ray inspections.
   • Advise insurers and risk managers of any operational restrictions in force until terminating actions are completed.

Practical compliance tips and risk controls

• Prioritise inspection of pumps already due for maintenance to reduce incremental downtime. Where possible, pair X‑ray inspections with scheduled maintenance checks.

• If an operator uses a third‑party inspection provider, ensure the provider’s methodology and documentation explicitly conform to Boeing ASB 737‑28A1197 or Crane Hydro‑Aire SB Motor‑Impeller‑28‑01 including Appendix A to avoid rejection by CASA.

• If documentation of prior Crane Hydro‑Aire inspection exists, collate serialised evidence linking inspected pump assemblies to their installed positions, then use that evidence to support removal of AFM limitations.

• Update maintenance control manuals and procedures to prevent inadvertent installation of uninspected motor‑impeller assemblies; introduce a parts intake procedure that verifies inspection status before the part is released for installation.

• Train flight crews on the procedural implications of Annex A, including the precise thresholds and the interaction with the CONFIG annunciation and the FUEL PUMP LOW PRESSURE non‑normal procedure.

• For operators with mixed fleets, maintain a register of each airframe’s status (AFM limited or returned to normal) and ensure dispatch systems check that register as part of release to service.

By following these steps and keeping documentary evidence that inspections were performed in accordance with the Boeing ASB or Crane SB, an operator will be positioned to demonstrate compliance with AD/B737/198 Amdt 2 and to pursue the optional terminating action if desired.