AD/B747/193 Amdt 1 - Fuel Leaks

The AD operates on several key concepts that structure its requirements. The first is “applicability by line number”. The Boeing 747 production line numbers from 1 to 1006 define which aircraft are subject to the directive, and within that range, further sub-ranges (1-628 and 629-1006) trigger different initial actions. This reflects the expectation that earlier and later production aircraft may have different original configurations or service histories, and the AD tailors the starting point of the inspection accordingly. The second concept is “engine type” as a branching factor. For aircraft in the later line-number range (629-1006), the initial valve part number inspection applies only if powered by General Electric or Rolls Royce engines; Pratt and Whitney-powered aircraft in that range are treated separately under paragraph 5, which also captures earlier aircraft where a valve may have been replaced. The third concept is the “fuel shutoff spar valve” itself. This is the component whose part number drives the AD’s central decision tree. The AD identifies four specific part numbers, distinguishing the “good” part (S343T003-40 / ITT 125334D-1) from three “bad” parts (60B92406-161, 60B92406-81, 60B92406-201) and also contemplates the possibility that an unknown or non-listed part might be fitted. The fourth concept is the “one-time general visual inspection” to detect fuel leaks. The AD provides a formal definition of “general visual inspection” in Note 1: it is a visual examination under normally available lighting conditions (daylight, hangar lighting, flashlight, or droplight) that may require removal or opening of access panels or doors, and possibly stands, ladders, or platforms. This is a relatively low-fidelity inspection intended to catch obvious leaks, not a more intrusive technique like dye penetrant or high-pressure testing. The fifth concept is the “maintenance record positive demonstration” that inboard engines have never been located in the outboard position. This record-based determination allows the operator to limit the leak inspection to outboard engines only, reducing the labour and downtime required. If records are insufficient, the AD defaults to inspecting all four engines. The sixth concept is the conditional “before further flight” compliance. Many steps must be completed before the next flight after a triggering inspection, which imposes immediate operational disruption and cost if a non-compliant valve is found or a leak is discovered. This creates a powerful incentive for operators to conduct the initial inspections proactively within the 18-month window, rather than deferring them, because a last-minute discovery could ground the aircraft. The seventh concept is the “service bulletin” as the method of compliance. The AD references three versions of Boeing Service Bulletin 747-28A2199 (original dated 1 August 1996, Revision 1 dated 1 October 1998, and Revision 2 dated 8 July 1999) and also the applicable section of Chapter 71 of the Boeing 747 Airplane Maintenance Manual. The AD does not reproduce the technical details of the replacement or modification procedures; it defers to those documents, which themselves contain engineering instructions. The eighth concept is the “effective date” distinction. The original AD became effective on 28 January 1999, and the amendment becomes effective on 30 November 2000. Some compliance periods are measured from the earlier date (e.g., “within 18 months of 28 January 1999”), while others are measured from the later “effective date of this amended Directive”. This bifurcation means that operators of aircraft newly added by the amendment (or those with Pratt and Whitney engines previously not covered) get a fresh 18-month clock starting 30 November 2000, whereas aircraft already covered by the original AD must comply with the original timeline but are not adversely affected by the amendment if they are already in compliance. Finally, the concept of “no further action required” appears repeatedly. Once an operator has determined that the correct valve part number is installed, or that the maintenance records show no valve replacement on an early aircraft, the AD releases the operator from further obligations under that particular requirement. This creates a clear, binary compliance path for many aircraft, but falling outside that binary path triggers a cascade of mandatory steps.

The AD directly affects any entity that holds an Australian certificate of registration for a Boeing 747 series aeroplane with a line number between 1 and 1006 inclusive, certificated in any category. In practice, this includes commercial airlines, cargo operators, aircraft leasing companies, and private owners or operators of such aircraft that operate under Australian regulatory oversight. The AD also indirectly affects maintenance organisations that perform the inspections, replacements, and modifications required. Because the AD is issued by CASA under CAR 1998, it applies to aircraft on the Australian register regardless of where the aircraft is physically located or where the work is performed. Operators of foreign-registered 747s that operate into Australia are not directly bound by this AD unless CASA has a bilateral agreement requiring equivalent compliance; however, the AD refers to the FAA’s own airworthiness directives (98-21-29 and 2000-14-06), which cover the same unsafe condition for US-registered aircraft, so the practical effect is global for aircraft that operate in multiple jurisdictions. The AD distinguishes between aircraft by line number and engine type, so the burden is not uniform. Operators of earlier aircraft (line numbers 1-628) face a relatively lighter initial requirement: a records inspection. If records show no valve replacement, they have no further obligation under this AD. Their compliance cost is essentially the labour to review maintenance documents. However, if the records are missing, incomplete, or show a replacement, they are thrust into the full inspection and possible replacement/modification regime, which could be significantly more expensive. Operators of later aircraft (line numbers 629-1006) with General Electric or Rolls Royce engines start with a physical inspection of the valve part number. This requires hangar access, technical documentation, and likely the services of a licensed aircraft maintenance engineer. Those with Pratt and Whitney engines in that line range are only caught by paragraph 5 if the valve has been replaced (or records are unclear), which creates an asymmetry: a Pratt-powered 747 from line 629-1006 that has never had an outboard fuel shutoff spar valve replaced may be entirely unaffected by the AD, whereas a GE-powered one of identical age is automatically subject to the valve part number inspection. This differential treatment likely reflects the engineering judgment that the unsafe condition (failure due to high fuel pressure) is more likely in certain valve part numbers that were more commonly installed on GE and Rolls Royce installations, but the AD does not explain the rationale. The AD also affects lessors and financiers who hold security interests in affected aircraft, because non-compliance with an airworthiness directive can ground the aircraft, affect its value, and render it ineligible for operation. The 18-month compliance windows provide some lead time, but the “before further flight” triggers create a risk of sudden grounding if the required actions are not completed before the next flight after a triggering inspection. This interacts with fleet scheduling, spare parts availability, and maintenance capacity. The AD references Boeing service bulletins that may require procurement of replacement valves (the S343T003-40 part) or modification kits. Suppliers may face increased demand, and operators could face lead times that extend beyond the “before further flight” requirement, forcing aircraft out of service until parts arrive. The AD does not require repetitive or recurring actions; it is a one-time campaign. This limits the ongoing compliance burden but concentrates costs and disruption into a defined period.

The fundamental duty imposed by the AD is on the operator of an affected aircraft to complete the specified inspections and, where applicable, corrective actions within the stated compliance times, and to ensure the aircraft is not flown unless those steps have been completed where the AD requires “before further flight” compliance. This duty exists even if the operator doubts the safety rationale, because the AD is legally binding under the CAR 1998. The operator must also ensure that any work performed is done in accordance with the referenced Boeing service bulletins (or the AMM leak check procedures), using approved data and appropriately qualified personnel, as required by the broader maintenance regulations. A key duty arises around maintenance records. For aircraft in the earlier line number range (1-628), the operator must inspect the maintenance history of the aircraft to determine whether either outboard fuel shutoff spar valve has ever been replaced. This duty is not trivial: the records must be searched, and the AD requires that the record inspection be performed in accordance with Boeing Service Bulletin 747-28A2199, Revision 2. The operator must form a judgment about whether the records “positively demonstrate” that the valves have never been replaced. If the records are ambiguous, incomplete, or missing, the operator is treated as if a replacement may have occurred and must proceed to the more onerous physical inspection. This creates a de facto duty to maintain comprehensive and clear maintenance records going forward, because incomplete records increase future compliance costs. Similarly, for any aircraft where the operator wishes to limit the leak inspection to outboard engines only (paragraphs 3 and 7), the operator must rely on maintenance records that “positively demonstrate that the inboard engines have never been located in the outboard position”. That is a high evidentiary standard. If records are not clear, the duty expands to inspecting all four engines. The AD also imposes a duty to use the correct service bulletin revision. The operator may use the original Boeing Alert Service Bulletin dated 1 August 1996, Revision 1 dated 1 October 1998, or Revision 2 dated 8 July 1999 for the part number inspection. However, the leak inspection and the replacement/modification procedures must be done in accordance with Revision 2 (the most recent version cited). The operator does not have a right to use an earlier revision for those steps, even if the earlier revision is technically similar. The AD gives the operator a limited set of options. If a non-compliant valve is found, the operator may either replace it with a new valve (presumably of the compliant part number) or modify the valve body assembly in accordance with the service bulletin. The AD does not specify which option is preferred, so the operator can choose based on cost, availability, and engineering judgment, consistent with the approved data. The AD also provides an alternative means of compliance for the leak inspection: Note 2 states that accomplishment of certain AMM test procedures is acceptable. This avoids duplication for operators who already perform those checks as part of routine maintenance. Operators also have the right to request an alternative means of compliance from CASA under the general provisions of the CAR 1998, though the AD does not explicitly mention this. The AD creates no private right of action; it is a public law instrument enforceable only by CASA. However, compliance may be relevant in civil litigation concerning aircraft accidents or contractual disputes.

The AD itself does not prescribe monetary penalties or criminal sanctions. Those are provided by the broader regulatory framework, principally the Civil Aviation Act 1988 and the Civil Aviation Regulations 1998. Operating an aircraft in contravention of an airworthiness directive is an offence under the regulations. For an aircraft registered in Australia, failure to comply with the AD would mean the aircraft is not maintained in an airworthy condition, which can lead to enforcement action including suspension or cancellation of the certificate of registration, suspension or revocation of air operator certificates, and imposition of civil penalties. The maximum penalty for a breach of a maintenance requirement under CAR 1998 can be significant, often measured in penalty units (each penalty unit being $222 as at 2023, but historical rates may apply). For a corporation, fines can reach hundreds of thousands of dollars for serious offences. CASA also has the power to issue enforceable undertakings, infringement notices, and to seek court injunctions to prevent continued operation of a non-compliant aircraft. The AD itself uses language of mandatory compliance: “the AD requires that the action ... be taken”. This indicates that the AD is not advisory; it is a direction from the CASA delegate. The “before further flight” compliance provisions give CASA a strong enforcement lever. If an operator attempts to operate an aircraft without completing a required step, CASA could issue a formal direction to ground the aircraft, or take immediate enforcement action such as suspending the aircraft’s airworthiness certificate. The AD’s reference to FAA airworthiness directives (Note 3) hints at potential international enforcement implications. If the aircraft operates in US airspace, the FAA could take action for non-compliance with its own directives, which mirror this AD. For Australian operators, the practical enforcement risk is the grounding of the aircraft. The economic cost of grounding a 747 for even a short period far exceeds any monetary penalty CASA might impose, creating a powerful compliance incentive. The AD does not specify record-keeping obligations beyond the use of maintenance records for the inspection history. However, under the CAR 1998, operators must keep detailed records of all maintenance actions, including those performed in compliance with an AD. Failure to retain those records could lead to enforcement action for failing to maintain proper documents. Because the AD was issued in 2000, any current enforcement action would be highly unusual unless an aircraft has remained non-compliant since then, or the AD has been superseded by later directives. No enforcement history is provided in the source.

The AD sits within a hierarchy of aviation safety regulation in Australia. It is issued under subregulation 39.1(1) of the Civil Aviation Regulations 1998, which itself derives from the Civil Aviation Act 1988. The AD has the force of law for the specific aircraft it covers. It interacts with other airworthiness directives that apply to the Boeing 747; the AD revokes the previous issue (AD/B747/193 original) but any other ADs covering different unsafe conditions remain in force. The AD references two FAA airworthiness directives: 98-21-29 and 2000-14-06. This is a recognition that the underlying unsafe condition was identified by the US manufacturer and regulator, and CASA’s AD is aligned with the FAA’s requirements. In practice, if an Australian-registered 747 also operates under FAA jurisdiction (which it might not, unless it is dual-registered or operating under a foreign air carrier permit), the operator would need to comply with both sets of requirements. Since the CASA AD is intended to adopt the FAA requirements, compliance with the CASA AD would likely satisfy the FAA requirements, but the operator should verify that the compliance times and service bulletin revisions are accepted by the FAA. Note 2 of the AD states that inspection actions performed in accordance with the Boeing 747 Airplane Maintenance Manual (AMM) Chapter 71 leak check procedures are acceptable for compliance with the AD’s leak inspection requirements. This means the AD does not create a separate stand-alone inspection requirement; it integrates with the existing AMM-based maintenance schedule. If an operator already performs those AMM leak checks as part of a continuous airworthiness program or a scheduled maintenance check, they may not need to perform additional work, provided the AMM procedure meets the AD’s scope. The AD also references Boeing service bulletins, which are manufacturer-issued documents that provide technical instructions. Those service bulletins are normally voluntary unless mandated by an AD, the type certificate data sheet, or a foreign regulatory requirement. By incorporating the service bulletins into the AD, CASA makes them mandatory. The AD does not interact directly with the Civil Aviation Safety Regulations 1998 (CASR), which were being developed and phased in around the year 2000. CASR Part 39 (Airworthiness Directives) now governs the issuance and compliance with ADs, but at the time of this AD, CAR 1998 Part 39 was the operative provision. For aircraft still on the register today, the AD would be enforced under the current CASR framework, but its substantive requirements remain in effect unless superseded. The AD does not address privacy, trade marks, contract law, or employment law. However, it could have indirect interactions: an operator’s contract with a lessee or customer may include a warranty that the aircraft complies with all applicable ADs. A failure to comply could constitute a breach of contract. Similarly, insurance policies for aircraft typically require compliance with ADs as a condition of coverage.

The source document is itself an amendment: AD/B747/193 Amdt 1. It revokes the original issue of AD/B747/193, which became effective on 28 January 1999. The amendment is dated 24 October 2000 (the date Eugene Paul Holzapfel, CASA delegate, signed it) and was notified in the Commonwealth of Australia Gazette on 1 November 2000. It becomes effective on 30 November 2000. The background section of the amendment states that Amendment 1 was issued to “include additional aeroplanes to the AD applicability, the requirements and compliance periods for the additional aeroplanes and to reference FAA airworthiness directive 2000-14-06 amendment 39-11815.” This indicates that the original AD covered a narrower set of aircraft (likely only those with line numbers 629 through 1006 and with GE or Rolls Royce engines) and did not reference the later FAA directive. The amendment adds line numbers 1 through 628, adds requirements and compliance periods for those aircraft (paragraphs 4 and 5), and adds the Pratt and Whitney engine branch for the later line number range. It also adds the cross-reference to FAA AD 2000-14-06. The original AD’s compliance date for the existing aircraft was “within 18 months of 28 January 1999” (which would expire at the end of July 2000). The amendment does not extend that timeline; paragraph 1 compliance remains “within 18 months of 28 January 1999 (unchanged)”. However, for the newly added aircraft (line 1-628), the compliance period is “within 18 months of the effective date of this amended Directive” - i.e., 18 months from 30 November 2000. This bifurcation means that operators of the earlier aircraft get a fresh compliance clock, while operators of later-series aircraft that were already covered by the original AD are not granted additional time. The amendment also adds paragraph 4(b) and 5(c) with “before further flight” compliance triggers for certain actions. The original AD likely contained similar provisions for its own requirement steps. The amendment also introduces paragraph 5(c)(i) and (ii) offering replacement or modification as options for unknown valve part numbers. The original AD may have only required replacement. No subsequent amendment history is provided in the source, so we cannot say whether this AD was later superseded, rescinded, or incorporated into subsequent bulletins. The AD remains in force until revoked or superseded by a later CASA instrument.

The source document contains no reference to any litigation concerning AD/B747/193 or this amendment. There is no mention of court cases, administrative appeals, or tribunal decisions. Whether any litigation occurred is unknown from the source. Given that airworthiness directives are technical regulatory instruments that rarely attract direct judicial challenge, it is plausible that no litigation eventuated. The AD was issued by a CASA delegate under delegated authority, and any challenge would typically be brought in the Administrative Appeals Tribunal (AAT) or the Federal Court on grounds of jurisdictional error, failure to consider relevant matters, or unreasonableness. The safety case for the AD appears straightforward: reports of fuel component failures due to high fuel pressure could lead to engine fires. The AD is modelled on corresponding FAA directives, which reduces the likelihood of challenge on technical grounds. Operators may have disagreed with the cost or scope of the AD, but the practical incentive is to comply rather than litigate, because the cost of grounding an aircraft while a challenge is pending is prohibitive. The AD includes a mechanism for alternative means of compliance, which gives a pathway for operators to propose different solutions without resorting to litigation. No litigation history is therefore available from the source, and no inference should be drawn that litigation did or did not occur. It is simply not mentioned.

Several aspects of the AD could catch out an unwary operator or maintenance provider. First, the compliance timeline for the initial valve part number inspection on earlier aircraft (line 1-628) is measured from “the effective date of this amended Directive” (30 November 2000), but for aircraft in the later range (629-1006 with GE or Rolls Royce), the compliance for requirement 1 is “within 18 months of 28 January 1999 (unchanged)”. An operator of an aircraft in the later range who mistakenly believes the 18-month clock restarts with the amendment would be non-compliant. The original deadline would have already passed by the time the amendment was gazetted (November 2000). Any late compliance after 28 July 2000 would have been a breach of the original AD. Second, the “positive demonstration” standard for maintenance records is a high bar. Paragraphs 3, 4(b), and 7 require records that “positively demonstrate” that inboard engines have never been in outboard positions or that valves have never been replaced. If records are lost, incomplete, ambiguous, or not in a form that satisfies the operator’s engineering department, the fallback is to treat the condition as unknown and proceed with the more extensive inspection. This can add significant labour and parts costs for aircraft with poor record-keeping. Third, the leak inspection scope expands to all four engines unless records positively demonstrate the inboard engines have never been in outboard positions. An operator who assumes that a four-engine inspection is the default may try to save time by checking records, but if those records are not up to the “positive” standard, they still must inspect all four engines. Conversely, an operator who does not check records at all and proceeds with an outboard-only inspection could be non-compliant if the records would have shown the engines had never been swapped. The safe approach is to do the record search first. Fourth, Note 2 provides that accomplishment of AMM Chapter 71 leak checks is “acceptable for compliance” with paragraphs 2 and 3. However, this is only acceptable if the AMM procedure actually covers the same inspection area and scope as the AD requires. The AMM leak checks are ground tests (idle leak check or fuel and oil leak check). An operator might rely on a recent AMM check without realising that the AD requires a one-time general visual inspection of components between the fuel shutoff spar valve and the engine fuel shutoff valve, which is broader than a simple leak check at idle. The AD does not provide a definition of the scope of the AMM test, so operators must confirm that the AMM test covers all the components the AD intends. Fifth, the AD states that “accomplishment of the actions specified in AMM 71-00-00/501, Test No. 2” for Rolls Royce and “Test No. 3” for GE engines is acceptable. These are engine-specific procedures. If an aircraft has been re-engined or has engines swapped, the operator must ensure the correct test is applied for the actual engine model installed. Sixth, the AD requires that for aeroplanes with line numbers 1 through 628, the maintenance record inspection be performed “in accordance with Boeing Service Bulletin 747-28A2199, Revision 2, dated July 8, 1999.” This service bulletin presumably sets out a method for reviewing records. An operator who does not obtain and follow that specific bulletin may not be able to demonstrate compliance. Microsoft Word note: the service bulletin may be proprietary and may need to be purchased from Boeing. The cost of acquiring the bulletin is a hidden compliance cost. Seventh, the AD does not explicitly require the operator to mark the aircraft maintenance log or affix a placard after compliance. However, under CAR 1998 and CASR, a maintenance release is required after any maintenance. The AD should be recorded in the aircraft’s permanent maintenance records, and the operator must be able to produce evidence of compliance on request from CASA or an authorised person. Eighth, the AD applies to aeroplanes “certificated in any category”. This includes experimental, restricted, and special purpose categories. Operators of such aircraft often have different maintenance obligations, but the AD does not carve them out. An owner of a vintage 747 used for firefighting or flight testing is caught. Ninth, the AD references “FAA airworthiness directives AD 98-21-29 amendment 39-10837 and 2000-14-06 amendment 39-11815”. These FAA ADs may have different compliance times, different service bulletin requirements, or different aircraft applicability. An operator who holds a US airworthiness certificate (or operates under a bilateral agreement) must ensure compliance with both sets of rules. If the FAA AD requires compliance before the CASA AD, the operator must meet the earlier date. Tenth, the AD does not address what happens if the required service bulletin parts or modification kits are not available within the 18-month compliance window. The operator could request an alternative means of compliance from CASA, but there is no automatic extension. The cost of grounding or deferral falls on the operator.

Compliance with AD/B747/193 Amdt 1 requires a systematic, step by step process. The first step is to identify the affected aircraft. The operator must confirm whether their Boeing 747 has a line number between 1 and 1006 inclusive. The line number is typically found on the fuselage data plate or in the aircraft’s delivery records. If the line number is outside this range, no action is required under this AD. If within range, proceed to step two: determine the engine type for the aircraft. If the line number is 1-628, any engine type is covered. If the line number is 629-1006, a distinction is made between General Electric/Rolls Royce engines and Pratt and Whitney engines. Step three: for aircraft in line numbers 629-1006 with GE or RR engines, perform a one-time inspection to identify the part number of the fuel shutoff spar valve for the left and right outboard engines. This must be done in accordance with Boeing Alert Service Bulletin 747-28A2199 (original, Rev 1, or Rev 2). If the valve part number is S343T003-40 (ITT P/N 125334D-1), no further action is needed for that requirement. If not, either replace the valve with a compliant one or modify the valve body assembly per the service bulletin. This replacement or modification must be done before further flight after the inspection. Step four: for the same subset of aircraft, perform a one-time general visual inspection for fuel leaks of the components between the fuel shutoff spar valve and the engine fuel shutoff valve on all four engines. However, if the maintenance records positively demonstrate that the inboard engines have never been in the outboard position, the inspection can be limited to outboard engines only. If a leak is found, replace the part with a serviceable part before further flight. Note: the operator may use the AMM Chapter 71 leak check (Test No. 2 for RR, Test No. 3 for GE) instead of the service bulletin for the leak inspection. Step five: for aircraft in line numbers 1-628 (all engine types), perform a one-time inspection of maintenance records to determine if either outboard fuel shutoff spar valve has ever been replaced. This must follow Boeing Service Bulletin 747-28A2199 Rev 2. If the records show that neither valve has been replaced, no further action is required. If either valve has been replaced, or if the records do not clearly establish that neither has been replaced, proceed to the next step. Step six: for aircraft identified in step five, or for aircraft in line numbers 629-1006 with Pratt and Whitney engines, perform the one-time part number inspection on the outboard fuel shutoff spar valves as described in step three, using the same service bulletins. Depending on the part number found: (a) if it is the correct part (S343T003-40), no further action. (b) if it is one of the three listed “bad” part numbers (60B92406-161, 60B92406-81, 60B92406-201), then either perform a leak inspection (step seven) or a modification/replacement (step eight) as the AD presents alternatives. Actually, the AD says if a “bad” part number is found, accomplish either paragraph 6 or 7 (the leak inspection options). If an unknown part number is found (not among the four listed), the operator must either replace or modify the valve (paragraph 5(c)(i) or (ii)) and also perform the leak inspection (paragraph 6 or 7). Step seven: perform the one-time general visual leak inspection as described in step four, but for all four engines unless records allow outboard-only inspection. Step eight: for valves that require replacement or modification, accomplish that before further flight after the part number inspection. Step nine: document all findings, inspections, replacements, and modifications in the aircraft maintenance records, including references to the service bulletins used, the part numbers found, the inspection date, and the condition of the components. Ensure the entry is signed by a licensed aircraft maintenance engineer. Step ten: review the cross-referenced FAA ADs. If the aircraft holds a US airworthiness certificate, compliance with those FAA directives must also be verified and documented separately. The FAA ADs may require additional or different actions, such as different compliance times or part numbers. For any area of uncertainty (ambiguous records, unavailable parts, or disagreement with the methodology), the operator should contact CASA for an alternative means of compliance or an extension before the deadline. The 18-month windows provide adequate time, but the “before further flight” triggers mean that the initial inspections should be scheduled well ahead of any expected maintenance downtime, to avoid a situation where a non-compliant valve or a leak is discovered and the aircraft cannot fly without immediate rectification. A practical compliance plan would include: (a) gathering all maintenance records for the aircraft; (b) ordering any necessary service bulletins and replacement parts; (c) scheduling the inspections during a routine heavy maintenance check; (d) having the engineering department review the record evidence for valve replacement and engine position history; and (e) training maintenance personnel on the AD requirements, particularly the definition of a general visual inspection and the acceptable alternative AMM tests.