AD/B767/249 - Auxiliary Fuel Tanks

An airworthiness directive (AD) is a direct legislative instrument issued under regulation 37 of the Civil Aviation Regulations 1988. It operates as a mandatory modification or inspection requirement that overrides any permissive approvals, including supplemental type certificates. Non‑compliance with an AD renders the aircraft not airworthy as a matter of law, regardless of its actual physical condition.

The auxiliary fuel tank at issue is an aftermarket modification approved under STC ST00840NY by Pats Aircraft, LLC. The STC would have been a separate approval from the original type certificate, allowing installation of additional fuel capacity in the cargo compartment or other areas of the Boeing 767‑200. The AD targets only the specific STC number; it does not affect all auxiliary tanks on the 767‑200, only those bearing that particular STC.

The concept of “ignition sources inside fuel tanks” refers to a known failure mode on transport‑category aeroplanes: electrical arcs from fuel quantity indication systems (FQIS), fuel pumps, wiring, or static discharge can ignite flammable fuel vapours inside a partially empty tank. This was the mechanism that caused the 1996 TWA Flight 800 Boeing 747 explosion and subsequent regulatory action worldwide. The AD’s background states that the manufacturer identified an unsafe condition but did not provide corrective action, so CASA is forcing deactivation as the only available remedy.

Deactivation under the AD does not equal removal. The operator may leave the tank structure, valves, pumps, and wiring in place provided they are disconnected, secured, and rendered inert. However, the deactivation must be permanent: the tank must be drained and vapour‑cleared, all electrical and plumbing interfaces must be capped and stowed, circuit breakers pulled and collared, and the AFM must be amended to remove all references to the auxiliary tank. The tank may not be reactivated without a new approval.

The Appendix A criteria are not legally binding as requirements; they are stated as matters the deactivation procedure “should” address. But because the procedure must be approved by CASA, any omission from the list risks rejection or delay. In practice, the appendix is a safe harbour: operators who follow it are likely to receive approval quickly; those who deviate must persuade CASA that alternative measures are equivalent.

The AD creates a reporting burden separate from the deactivation. The usage frequency data (total flights per year, and flights using the auxiliary tank) allows CASA to understand how many aeroplanes were actively using the tank and for what proportion of flights. This data may be used for monitoring compliance or for future rulemaking, but the AD itself does not disclose its purpose beyond collection.

The primary subjects are operators of Boeing 767‑200 series aeroplanes that have the PATS Aircraft, LLC auxiliary fuel tank installed under STC ST00840NY. This is a narrowly defined fleet segment: the 767‑200 is the original, shorter variant of the 767 family, typically used in medium‑range operations. Operators who fitted the PATS auxiliary tank would have done so to extend range for transoceanic or long‑haul routes. The typical operator might be a cargo carrier, a charter airline, or a lessor leasing to such operators. Passenger airlines using the 767‑200 (many had retired or upgraded to the 767‑300 by 2009) might also be affected.

The direct compliance burden falls on the Australian‑registered operator, because the AD is issued by CASA under Australian law. However, because the AD references FAA AD 2008‑22‑01, it is likely that the same requirement applies in the United States and possibly elsewhere. Operators who hold a CASA‑issued air operator’s certificate (AOC) for a Boeing 767‑200 will need to ensure compliance with this AD as part of their continuing airworthiness management obligations under regulation 42 of the Civil Aviation Regulations and Part 42 of the Civil Aviation Safety Regulations.

Maintenance organisations performing work under the operator’s maintenance control system will be engaged to design and execute the deactivation procedure. They must submit the proposal to CASA and await approval before proceeding. This creates a scheduling risk: if CASA is slow to approve, the operator may run out of time before the December 2009 deadline.

Parties indirectly affected include lessors and financiers. The deactivation permanently reduces the aircraft’s utility: a 767‑200 without auxiliary fuel tanks has shorter range and lower residual value. Lease agreements that contemplated auxiliary tank operation may need amendment. Insurance policies that cover fuel system risks may be impacted, and the AD may trigger notification clauses.

The AD also affects the STC holder, PATS Aircraft, LLC. The AD effectively nullifies the certificate for Australian operations, because the tanks must be deactivated. If the STC holder later provides a corrective action that CASA accepts (e.g., an improved design or inspection regime), the AD might be superseded. But as of the AD’s effective date, no such corrective action exists.

The broader aviation industry sees a precedent: CASA is willing to mandate deactivation of an existing approved modification where the manufacturer fails to address a discovered unsafe condition, without waiting for a fix from the original STC holder. This imposes costs on operators who invested in the modification in good faith, who now lose that investment and must absorb deactivation costs.

The AD imposes a clear duty on the operator: comply with Requirement 1 (report) and Requirement 2 (deactivation) within the specified timeframes. The operator cannot avoid the AD by selling the aircraft or ceasing operations. If the aircraft remains on the Australian register, the duty persists. If the aircraft is exported, the AD may no longer apply, but the operator at the time of non‑compliance remains liable.

Operator’s rights include the right to propose a deactivation procedure to CASA and obtain approval. The operator is not forced to follow Appendix A slavishly; it may deviate if it can persuade CASA that the alternative is equivalent. The AD does not limit the number of submissions, so an operator whose first proposal is rejected can revise and resubmit, subject to the drop‑dead date of 16 December 2009.

The operator also has the right to include additional steps in its proposal that it deems necessary (Appendix A paragraph 11). This allows the operator to tailor the procedure to its specific configuration, which may differ from the generic expectation.

Another right is the ability to amend the AFM by inserting a copy of the AD into the manual. This is a simpler approach than publishing a full revision. The AD itself becomes the AFM supplement. However, the AD states that the AFM Supplement for the STC is not in effect, and operating procedures for the auxiliary tank must be removed. The operator must ensure that flight crews no longer have access to the STC supplement.

The operator has a duty to ensure that after deactivation, the aeroplane is returned to service only after leak checks and pressure checks, including verification that the original fuel quantity indication system and fuel distribution systems have not been adversely affected. This imposes engineering oversight: a failed leak check could result in further downtime and cost.

The operator must also revise the instructions for continued airworthiness (ICA) as required. This may involve updating maintenance schedules, removing inspection tasks related to the auxiliary tank, and ensuring that no residual out‑of‑date instructions remain in the maintenance data.

There is no explicit right to seek an extension, exemption, or alternative means of compliance under this AD. The Civil Aviation Act 1988 and Civil Aviation Regulations do provide for exemptions under certain circumstances, but the AD does not mention them. An operator who cannot meet the deadline would need to apply separately under regulation 11 of the Civil Aviation Regulations or similar provision.

Non‑compliance with an airworthiness directive is a serious breach of civil aviation law because an AD directly affects the legal airworthiness of the aircraft. Under section 20B of the Civil Aviation Act 1988, it is an offence to operate an aircraft that is not airworthy. Operating a Boeing 767‑200 after 16 December 2009 without deactivating the auxiliary tanks would almost certainly render the aircraft not airworthy, exposing the operator to prosecution.

The maximum penalty for an individual operating an unairworthy aircraft is 50 penalty units (at the time, $5,500) and for a body corporate, 250 penalty units ($27,500). More commonly, CASA would take administrative enforcement action: suspending the air operator’s certificate, revoking the certificate of registration, or issuing a direction to ground the aircraft. The practical penalty is the loss of revenue from grounded aircraft plus the cost of remedial action.

CASA also has civil penalty powers under Part 15 of the Civil Aviation Amendment Act 2003 (as then in force), allowing it to seek civil penalties of up to $1 million for a body corporate for certain contraventions. However, the AD itself is not a provision carrying a specific penalty; the penalty attaches to the underlying offence of operating an unairworthy aircraft.

The AD does not impose a monetary penalty for failing to submit the report by 45 days. However, non‑compliance with the reporting requirement may be a breach of the AD itself, which would be a breach of a direction given under regulation 37 of the Civil Aviation Regulations. That could be prosecuted as a breach of a condition of the AOC or as an offence under regulation 267 of the Civil Aviation Regulations (failing to comply with a direction of CASA). The practical risk is small but not zero.

CASA usually enforces ADs through a combination of surveillance (e.g., checking maintenance records during ramp inspections) and mandatory occurrence reporting. If an operator reports itself for non‑compliance, CASA may issue a warning or require a rectification plan. If an event occurs (e.g., a fuel tank explosion) before deactivation, the operator would face both prosecution and civil liability.

The AD does not mention criminal liability for directors or officers, but the Civil Aviation Act includes imputation provisions for body corporate offences, and directors can be prosecuted under the general criminal law for reckless conduct if the non‑compliance causes harm.

AD/B767/249 is issued under the Civil Aviation Regulations 1988, which sit under the Civil Aviation Act 1988. It takes precedence over any less stringent regulatory approvals. The STC ST00840NY was previously approved, but the AD overrides that approval for continued operation: the tanks must be deactivated. The STC itself is not revoked; it remains valid for installation purposes, but operation is prohibited.

The AD states in Note 2 that “FAA AD 2008‑22‑01 Amdt 39‑15696 dated 9 October 2008 refers.” This suggests that the FAA issued a similar directive for US‑registered aircraft. For an operator who holds both FAA and CASA approvals, compliance with the FAA AD may not satisfy the CASA AD because the deactivation procedure must be approved by CASA. However, if the operator can show that the FAA‑approved procedure meets the Appendix A criteria, CASA may accept it. There is no mutual recognition clause in this AD.

The AD interacts with the continuing airworthiness requirements under Part 42 of the Civil Aviation Safety Regulations 1998 (CASR). The deactivation must not result in additional instructions for continued airworthiness (ICA). This means that after deactivation, the operator cannot be required to perform recurring inspections or maintenance on the deactivated components. The operator must revise ICA already in place for the auxiliary tank, removing those tasks. This ensures that the deactivation does not create a future compliance burden.

The AD also interacts with the aircraft maintenance manual (AMM). The operator must amend the AMM to remove auxiliary tank maintenance procedures. This ensures that maintenance personnel do not inadvertently perform work on a deactivated system. Failure to amend the AMM could lead to confusion and unintended maintenance actions.

The AD interacts with the weight and balance document. If the deactivation changes the empty weight or centre of gravity (e.g., by removing fluid and leaving structure), the operator must revise the weight and balance document and obtain CASA approval. That approval must be obtained before the aircraft returns to service.

The AD does not affect the original Boeing 767‑200 type certificate. The aircraft’s original fuel system is unaffected. The AD only addresses the auxiliary tank installation.

The AD may interact with lease agreements that require the lessee to maintain the aircraft in a condition complying with all applicable ADs. The lessee must deactivate the tank, which may reduce the aircraft’s value and utility. The lessor may have a right to require restoration at the end of the lease, but the AD makes reactivation without new approval impossible, so the lessor would need to accept the deactivated configuration or re‑approve a new STC.

The source text of AD/B767/249 shows no amendments. It appears as a single‑issue AD with effective date 15 January 2009. The AD number “1/2009” indicates it was the first AD issued in 2009 for this airframe series. There is no reference to a previous version of this AD, nor to any superseded directives. The appendix is printed as part of the same instrument rather than as a separate amendment.

Airworthiness directives are living documents; they can be amended by CASA through a subsequent directive (e.g., AD/B767/249 Amdt 1). Typical reasons for amendment include extension of compliance time, addition of new aircraft serial numbers, inclusion of corrective actions developed by the manufacturer, or alternative means of compliance. However, from the source provided, no such amendment history is recorded. The AD appears to have been issued and likely remained in force for the affected fleet with no textual changes, or such changes are not captured in this document.

The lack of an amendment history may be significant for litigation or compliance verification. An operator looking to show compliance at a later date should consult the current version of the AD on the CASA website or the Australian Government Federal Register of Legislation, as later amendments might exist but are not included in this copy.

Note that the AD incorporates by reference “FAA AD 2008‑22‑01 Amdt 39‑15696 dated 9 October 2008.” That FAA AD may have been amended or superseded later. The CASA AD does not automatically adopt those changes; each AD is independent.

The source text contains no reference to any litigation involving AD/B767/249. That does not mean litigation never occurred, but no case is cited in the AD itself. A search of Australian aviation case law would be required to determine whether any operator challenged the AD on procedural or substantive grounds.

Given that the AD relates to a relatively small number of aircraft and the compliance burden is finite (design and execute a deactivation), it is unlikely that an operator would risk the expense and regulatory exposure of litigation over it. The cost of compliance is probably lower than the cost of a court challenge. Operators who relied on the auxiliary tank for revenue might have sought an exemption rather than go to court.

If litigation did occur, it would likely have been in the Administrative Appeals Tribunal (AAT) or the Federal Court under the Administrative Decisions (Judicial Review) Act 1977, challenging CASA’s satisfaction of the “unsafe condition” test or the reasonableness of the compliance deadline. However, the power to issue ADs under regulation 37 is very broad, and courts typically defer to CASA on technical airworthiness matters.

No evidence in the source or publicly available information suggests any reported case.

The AD’s compliance deadline may be tighter than it appears. The first requirement (report) is due within 45 days of the effective date of 15 January 2009, i.e., by 1 March 2009. That deadline is not generous if the operator must gather usage frequency data from historical records. If the operator’s records are incomplete, they must estimate or explain why data is unavailable. CASA does not specify a format for the report or mention any extension option.

The deactivation procedure must be approved by CASA “as soon as possible to ensure timely review and approval.” This language is optimistic; it places no binding obligation on CASA to approve within a certain time. If CASA is backlogged, the operator may approach December 2009 without approval. The operator must plan to submit its proposal many months before that date to allow for review, questions, and resubmission. A government shutdown or CASA internal delays could cause an operator to miss the deadline through no fault of its own.

Appendix A criteria are labelled “should” not “must,” but in practice they are strongly prescriptive. An operator who omits, say, the requirement to cap pneumatic connections or to leave auxiliary tank vent lines open during decompression may find its procedure rejected. The requirement to leave vent lines open is counterintuitive because an open line could allow fuel vapours to escape during flight, but the AD mandates it to prevent structural deformation. Operators must not cap those lines.

The AD requires that any auxiliary tank component remaining on the aeroplane must be secured and have “no effect on the continued operational safety and airworthiness.” This is a broad, open‑ended requirement. The operator must ensure that disconnected wiring, capped plumbing, and inactive pumps cannot come loose or interfere with other systems. A wire left dangling that chafes against a hydraulic line could cause a fire; the operator bears the risk of such an outcome even after deactivation.

The AD prohibits deactivation from resulting in additional instructions for continued airworthiness. This means the operator cannot add a recurring task like “inspect auxiliary tank drain valves every 100 hours.” But the operator must still verify that the deactivation is permanent; some periodic leak check may be needed. The AD does not say that no inspection is needed at all, only that no additional ICA beyond what exists for the basic aircraft can be introduced. This creates ambiguity: if a leak develops after deactivation, the operator may have to repair it, but there is no scheduled task to find it. The operator must include leak checks in the return‑to‑service procedure.

The AD references “AC 25‑8 Auxiliary Fuel System Installations” as the source for an approved method of capping fuel feed and vent plumbing. Not all operators may have that document. It is not included in the AD. The operator must source it or propose an equivalent method.

The AD also requires pulling and collaring circuit breakers used to operate the auxiliary tank. If those circuit breakers also supply other systems common to the tank, the operator must ensure that deactivation does not disable essential equipment. The AD does not provide guidance; only the operator can resolve this.

Finally, the AD does not mention record keeping. The operator should retain all documentation: the approved deactivation procedure, evidence of CASA approval, completed checklists, leak test results, weight and balance revision, AFM amendment records, and maintenance manual amendments. Those records will be needed to demonstrate compliance during audits and to satisfy the conditions of the AOC.

Step 1: Identify applicability. The operator must verify that the aircraft is a Boeing 767‑200 series (not the 767‑300 or other variant) and that the auxiliary fuel tank installed bears STC ST00840NY. Check the aircraft’s modification records. If no such STC is installed, the AD does not apply.

Step 2: Submit the report under Requirement 1. Use the fax number provided in the AD: (02) 6217 1914 (note this is a Sydney number, likely changed since 2009). Alternatively, submit by correspondence to the Manager, Systems and New Technologies, Airworthiness Engineering Group. The report must include the aircraft registration, the STC number, and usage frequency. The usage frequency can be annualised from operator records for the preceding 12 months or a representative period. If data is unavailable, note that in the report. Complete and send within 45 days of 15 January 2009 - i.e., by 1 March 2009.

Step 3: Develop a deactivation procedure. Use Appendix A as a template. Address all 11 criteria. The procedure should include: (a) permanent draining and vapour clearing of the auxiliary tanks; (b) disconnection and stowage of FQIS, fuel pump, and float switch wiring; (c) disconnection and capping of pneumatic connections (if present) at the pneumatic source; (d) disconnection and capping of fuel feed and vent plumbing at the aeroplane OEM tank side, using methods equivalent to AC 25‑8; (e) leaving the auxiliary tank vent lines open and secured; (f) pulling and collaring all circuit breakers for the auxiliary tank; (g) revising weight and balance document (if required) and submitting that to CASA for approval; (h) amending the AFM to remove the STC supplement and insert a copy of this AD, adding a placard in the flight deck that “AUXILIARY FUEL TANK DEACTIVATED”; (i) amending the maintenance manual to remove auxiliary tank procedures; (j) performing leak checks and pressure checks to confirm original fuel systems are unaffected; (k) revising ICA as needed; (l) adding any operator‑specific steps.

Step 4: Submit the proposed procedure to CASA for approval. Address to the Manager, Systems and New Technologies, Airworthiness Engineering Group, with sufficient lead time before the deactivation deadline. Include supporting drawings, schematics, or engineering analyses for any deviation from Appendix A.

Step 5: Obtain CASA approval. Keep the approval letter or email with the aircraft records. Do not begin deactivation until approval is received.

Step 6: Execute deactivation. Coordinate with maintenance. Use an appropriately licensed aircraft maintenance engineer. Follow the approved procedure exactly. Document each step with sign‑offs. Conduct the post‑deactivation checks.

Step 7: Complete the documentation amendments. Update the weight and balance document and obtain CASA approval (if required). Amend the AFM. Insert a copy of the AD. Place the placard. Remove or archive the STC supplement from active manuals. Amend the maintenance manual.

Step 8: Return the aircraft to service. Issue a certificate of release to service (CRS) or equivalent. Ensure that all applicable leak checks and pressure checks are passed and recorded.

Step 9: Mandatory occurrence reporting. If any anomaly is found during deactivation (e.g., cracked fuel lines, corroded wiring), the operator must report it under the mandatory occurrence reporting scheme (regulation 4.01 of CASR Part 4).

Step 10: Maintain records indefinitely. Keep the approved procedure, CASA approval, deactivation records, AFM revisions, and weight and balance revision with the aircraft historical records. They will be needed for future audits, sale inspections, or if the aircraft is re‑registered in another jurisdiction that asks for compliance history.