AD/CF6/70 Amdt 1 - Low Pressure Turbine Case

Airworthiness Directive. This instrument is issued under the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations 1998 Part 39. An airworthiness directive has the force of law and is not optional. It identifies an unsafe condition that requires immediate or scheduled corrective action. Non-compliance renders the aircraft unairworthy, which has cascading consequences for the operator's legal right to fly, insurance coverage, and lease obligations.

Low-Pressure Turbine (LPT) Case. The LPT case is the structural housing for the low-pressure turbine section of the engine. The AD applies only to specific part numbers identified in Table 1 of the directive. For CF6-80C2 engines, the listed LPT case part numbers include 1336M99G01 through G15 variants, 1647M68G05/08/09/15, 1713M73G01/02/05, and 9367M99G11/17. For CF6-80E1 engines, the applicable part numbers are 1647M68G02/04/07/12/13. If an engine is fitted with an LPT case not listed, the AD does not currently apply to that engine, though operators should still monitor for future mandates.

Skin Doubler Pads and Deflectors. These are the engineering fix. The AD requires the installation of skin doubler pads and deflectors on the LPT case. These are not the same component: the instrument includes a Parts Identification note stating that a deflector pad is a square-shaped plate with no threaded stud on it, while a deflector is a part that carries a threaded stud. This distinction matters because incorrect installation of the wrong part could constitute non-compliance even if the work looks superficially complete. The rework procedure is defined in GE Service Bulletin CF6-80C2 S/B 72-1171 Revision 1 dated 1 February 2006 (or the equivalent E1 bulletin) and Repair Document 935-314-S4 dated 28 January 2008. The alternative is to install a new or previously reworked LPT case that already has these features.

Compliance Trigger. The trigger is the next time the LPT module is completely disassembled to piece-part level. This is a maintenance event, not a calendar date, so a fleet manager whose engines have long intervals between shop visits might delay the modification for several years. However, the eight-year absolute limit from 18 December 2008 (i.e., 18 December 2016) overrides that deferral. That is a hard stop: any engine that had not undergone the modification by that date would be non-compliant regardless of piece-part disassembly schedules. For an engine that had recently undergone a major overhaul before the AD came out, the compliance window could be up to eight years; for an engine overdue for a shop visit, the trigger could be immediate.

Alternative Methods of Compliance. Amendment 1 expressly accepts an FAA-approved AMOC for compliance with the equivalent requirements of this AD. This reduces duplication between Australian and US regulation, which is efficient given that most of these engines operate globally and are type-certificated by the FAA. However, the acceptance is limited to AMOCs covering the "equivalent requirements" of the AD, not any unrelated modification. The AD also says that later revisions of the GE service bulletins, if approved by the FAA as an AMOC to FAA 2008-21-11, are acceptable for compliance. This gives operators flexibility to use updated repair documents without further CASA approval, provided the FAA has already vetted them.

The primary duty holders are operators of aircraft powered by the listed engines. Because the engines are installed on Airbus A300, A310, and A330 series aeroplanes, Boeing 747 and 767 series airplanes, and McDonnell Douglas MD-11 series aeroplanes (per Note 1), the directive reaches a substantial proportion of long-haul and medium-haul fleets operated by Australian carriers, including Qantas, Virgin Australia's international division (historically), freight operators such as Qantas Freight and Tasman Cargo Airlines, and lessors that place these engines into service with Australian operators. The directive also affects any foreign operator if it flies into Australian airspace with engines that are subject to the AD and CASA has jurisdiction, though practical enforcement would normally rest with the operator's home regulator.

The directive also affects maintenance, repair, and overhaul (MRO) organisations that perform engine shop visits on these engine models. Any MRO that conducts piece-part disassembly of the LPT module must include the rework in their scope of work if the engine is subject to the AD. This imposes a compliance burden on the MRO to maintain the correct service bulletins and repair documents, to train mechanics on the distinction between deflector pads and deflectors, and to document the work in a manner that satisfies CASA's airworthiness record requirements. The MRO will also need to hold inventory of the modification parts, including skin doubler pads and deflectors, or arrange for their supply from GE or authorised distributors.

Lessors and financiers are indirectly affected. An engine subject to an outstanding AD that has not been complied with may have diminished residual value, may be more difficult to place on lease, and may create liability under the lease agreement if the lessee is required to maintain the engine in airworthy condition. A lessor seeking to repossess an engine with unfilled AD compliance faces a practical problem: the engine may be unairworthy until the modification is done. The cost of compliance, which includes the rework labour, replacement parts, and associated downtime, must be borne by the party responsible under the lease. Typically that is the lessee, but if the lessee defaults, the lessor may need to absorb the cost to make the engine marketable.

Insurance underwriters are also affected. Non-compliance with an airworthiness directive is a material fact in any aviation insurance policy. If an engine fails due to LPT case wear-through and the AD was not complied with, the insurer is likely to deny cover, leaving the operator exposed to huge third-party liability claims from an engine separation event. The directive thus effectively compels operators to spend money now to avoid a catastrophe that may never happen, but which would be financially ruinous if it did.

The central duty is to perform the modification on each affected engine before the compliance deadline. The operator must choose between two methods: rework the existing LPT case using the specified GE SB and RD, or install a new LPT case that already incorporates skin doubler pads and deflectors. This choice provides some flexibility. An operator with very young engines might prefer to defer the rework to the next planned shop visit and install a new case only if the old case is beyond repair. An operator facing a fleet-wide near-term shop visit might prefer to rework each case as it comes through, balancing cost against the risk of deferral. The AD does not mandate one approach over the other; it leaves that commercial decision to the operator.

An operator also has the right to use an FAA-approved AMOC. This is a significant right because it allows the operator to depart from the precise rework method prescribed in the GE service bulletins if the FAA has already accepted an alternative. That alternative might be cheaper, less intrusive, or more compatible with other modifications. However, the operator must still comply with the Australian AD: the AMOC must be for the equivalent requirement, and it must have been approved by the FAA under FAA AD 2008-21-11. The operator cannot use any arbitrary method and then claim an AMOC; the alternative must have been vetted by the FAA. This reduces but does not eliminate the regulatory burden, as the operator still needs to identify and document the AMOC and ensure that CASA accepts it (which per the AD it does, provided the AMOC meets the stated conditions).

There is also a right to rely on previous credit. Operators that performed the actions using earlier service documents before the effective date of the amendment (14 February 2011) are considered to have satisfied the compliance requirements. The specific earlier documents are: GE SB No. CF6-80C2 S/B 72-1171 dated 25 May 2005 and RD No. 935-314-S2 dated 4 January 2006 or RD 935-314-S3 dated 10 August 2006; and for E1 engines, GE SB No. CF6-80E1 S/B 72-0303 dated 1 June 2005 and the same RDs. This provision protects operators who acted promptly after the original AD was issued in December 2008 from having to redo the work because the service documents were later revised. It also removes the incentive to delay compliance in the hope that later revisions will be simpler.

The AD does not impose a duty on persons who do not own or operate the aircraft. A parts supplier, for example, has no direct duty under this AD, though it may encounter contractual obligations to supply compliant parts. The duty runs to the aircraft operator, who is legally responsible for ensuring that the aircraft is maintained in an airworthy condition.

Non-compliance with an airworthiness directive is a strict-liability offence under the Civil Aviation Safety Regulations 1998 Part 39. The operator does not need to have caused an incident; simply flying an aircraft that has not been modified in accordance with the AD is a breach. The applicable penalties are found in the Civil Aviation Act 1988 and the regulations. For a corporation, the maximum civil penalty is currently 1,000 penalty units (approximately AUD 313,000 as of 2025 indexation, but the amount at the time of the AD was lower). A court can also impose criminal penalties for wilful breach, including fines and, in theory, imprisonment for an individual, though imprisonment is extremely rare in aviation maintenance cases.

CASA has administrative enforcement tools that are often more impactful than court proceedings. If CASA identifies non-compliance, it can ground the aircraft immediately by issuing a suspension or variation of the airworthiness certificate. That means the aircraft cannot lawfully fly until the AD is complied with. For an airline, grounding a revenue-generating aircraft for even a few days imposes costs far exceeding the fine. CASA can also issue a direction to produce records or to carry out inspections. For persistent non-compliance, CASA can suspend the operator's Air Operator Certificate, which grounds the entire fleet. These powers give CASA enormous practical leverage; most AD compliance is achieved through operator self-certification and CASA surveillance, not litigation.

The directive itself does not specify penalties; those arise from the parent legislation. The practical deterrent is the loss of airworthiness. An operator that attempts to defer the work beyond the eight-year deadline faces a hard stop: on 18 December 2016, every affected engine that had not been modified became unairworthy. CASA could be expected to audit compliance against the AD. The previous credit provisions mean that operators who did the work using earlier SBs are safe, but operators who did nothing face a scramble to get the work done before the deadline, potentially causing maintenance bottlenecks and higher labour costs as MRO capacity is booked.

An interesting enforcement nuance in this particular AD arises from the AMOC acceptance. If an operator uses an FAA-approved AMOC that CASA has deemed acceptable, but the operator misapplies the AMOC or does not properly document it, CASA could still treat the engine as non-compliant. The burden of proving compliance rests with the operator. An operator that relies on an AMOC must maintain the relevant FAA approval documentation and be able to show that the AMOC was correctly applied to the specific engine.

This AD sits within a web of Australian and international aviation law. Domestically, it is issued under the authority of the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations 1998 Part 39. Part 39 gives CASA the power to issue an airworthiness directive when it finds an unsafe condition. Compliance with the AD is a condition of the aircraft's certificate of airworthiness. If the AD is not complied with, the aircraft is not airworthy, and operating it would also breach regulation 42ZC of the Civil Aviation Safety Regulations (operation of unairworthy aircraft). There is also interaction with the operator's maintenance control manual, which must incorporate AD compliance steps. An operator that fails to incorporate the AD into its maintenance schedule could be in breach of its approved maintenance organisation's exposition or its own maintenance procedures.

Internationally, the AD interacts with the US Federal Aviation Administration's airworthiness directive system. The AD expressly references FAA AD 2008-21-11 Amdt 39-15695 dated 10 October 2008. The US directive is substantively similar: it requires the same modification on the same engines. By accepting FAA-approved AMOCs, CASA aligns its regulatory regime with the FAA's, reducing duplication for operators that are subject to both jurisdictions. This is particularly important for Australian carriers that operate internationally, because they must comply with the FAA directive as a matter of US law when operating into or over the United States. The acceptance of FAA AMOCs avoids a situation where an operator could comply with the US directive using an alternative method but then be non-compliant with the Australian directive because CASA did not approve the same method. This reduces transaction costs and compliance complexity.

The AD also interacts with lease agreements and financing documents. Most aircraft operating leases require the lessee to maintain the aircraft in accordance with all applicable airworthiness directives. A lessee that fails to comply with AD/CF6/70 Amdt 1 is in breach of the lease, giving the lessor the right to terminate and repossess. Similarly, an engine that has an outstanding AD requirement may be considered a maintenance reserve event, triggering a claim against the lessee's maintenance reserves held by the lessor. For financing, a secured lender's interest in the engine may be impaired if the engine's value drops due to non-compliance, potentially triggering a default under the loan agreement.

Product liability law is also relevant, though not directly referenced. If an engine fails due to LPT case wear-through and the AD has not been complied with, the manufacturer (GE) might raise a defence that the operator's failure to comply was the cause of the loss. Conversely, if the modification is performed but the failure still occurs, GE could face liability for a defective design or inadequate modification instructions. The AD does not change the law of tort or contract, but it creates a clear standard of care: a reasonable operator must comply with the AD. Deviation from that standard would be strong evidence of negligence.

The original AD/CF6/70 was issued with an effective date of 18 December 2008. That directive required the same LPT case rework or replacement on the same engine models and with the same compliance time limit (next LPT module disassembly not to exceed eight years). The original AD did not contain an explicit provision accepting FAA-approved AMOCs. Amendment 1, effective 14 February 2011, added that provision. The amendment was signed by David Villiers, a Delegate of the Civil Aviation Safety Authority, on 8 February 2011.

The amendment is brief and surgical. It changes only the parts of the AD that deal with the acceptability of FAA AMOCs and the acceptance of later revisions to the GE service bulletins that are approved by the FAA. It also added the previous credit language to clarify that operators who had already used the earlier service documents (dated 2005 and 2006) are credited. The amendment does not change the applicability, the required actions (rework or replacement), the compliance deadline of eight years, or the parts identification notes. Importantly, the amendment does not extend the compliance deadline; the eight-year clock started on 18 December 2008 and expired on 18 December 2016 regardless of when Amendment 1 was issued.

The amendment history also includes, implicitly, the prior amendments that are not shown in this text but may have occurred if the AD number is AD/CF6/70 and this is Amendment 1. There may have been no amendments before this one, or the original AD might have been amended shortly after issuance for technical corrections. The text provided does not disclose any earlier amendments. The notation "Amdt 1" suggests that the original AD was numbered AD/CF6/70 and this is the first formal amendment. The amendment was published in the CASA "Airworthiness Directives" gazette notice or on the CASA website, as is typical. The PDF image at the bottom of the page (not readable in text) may contain the CASA stamp and reference number.

Because this amendment was issued over a decade ago, the AD is now likely either superseded by a later amendment or has expired (if not superseded, the eight-year deadline has passed). Operators still in possession of these engines should check for later amendments or replacement ADs. The amendment history is a reminder that ADs are living documents; the original 2008 AD was not the final word. An operator relying on the original AD without the AMOC acceptance would have been at risk of non-compliance if they used an FAA AMOC before 14 February 2011. After the amendment, those AMOCs became acceptable, but only prospectively.

There are no reported Australian cases that directly reference AD/CF6/70 Amdt 1 or its original version. This is not surprising. Airworthiness directives are rarely the subject of litigation in Australia. When they are, the dispute typically arises in the context of enforcement proceedings by CASA or in civil litigation between lessors and lessees over maintenance obligations. If an accident occurred involving an engine subject to this AD, the AD would become a crucial piece of evidence in any negligence or product liability claim, but the AD itself would not be the defendant; it would be the standard of care against which the operator's conduct is measured.

In the United States, there have been legal proceedings relating to CF6 engine failures, including engine separations. The FAA AD 2008-21-11 was issued following four events of LPT case wear-through. These events likely involved hull loss or major damage. Any litigation arising from those events would have been settled or tried in US courts. Australian courts might consider US precedent on the reasonableness of the AD as influential but not binding. The lack of Australian litigation does not mean the AD is unimportant; it means that operators complied or settled disputes privately. If an operator had disputed the validity of the AD and refused to comply, CASA could have sought an injunction or penalty order in the Federal Court of Australia. But no such case appears in public records.

The amendment itself is unlikely to be litigated because it expands compliance options by accepting FAA AMOCs. That is unambiguously beneficial for operators. No operator would challenge an amendment that makes compliance easier. The only conceivable litigation would be from an operator who had already performed the rework using an earlier service bulletin and then sought a refund from GE or CASA arguing that the work was now redundant. But the previous credit provision in Amendment 1 protects operators: if they used the earlier SBs, they are credited. So that potential dispute was addressed by the amendment.

From a broader litigation perspective, any lawyer advising a client on compliance with AD/CF6/70 Amdt 1 would need to investigate not only the text of the AD but also the underlying service bulletins and repair documents, which are proprietary and subject to GE's intellectual property. A dispute over whether the rework was performed in accordance with the Accomplishment Instructions could arise if GE later revises the SB and claims that the earlier revision was inadequate. The AD's acceptance of later revisions as AMOCs could provide a defence: if an operator used a later FAA-approved revision, they should be compliant even if the original SB has been superseded. But that depends on the terms of the AMOC approval. Given the lack of case law, this remains a theoretical risk.

The compliance deadline is gone. This AD is now historic. The eight-year period from 18 December 2008 expired on 18 December 2016. Any operator that has not complied by that date is in breach. But the AD may have been superseded by a later directive, or the affected engines may have been retired. Lawyers and compliance professionals reviewing an engine's records should check whether a later AD superseded this one. If not, the engine must have the modification or have been permanently removed from service. This is a critical point for due diligence in aircraft or engine acquisitions.

The trigger is ambiguous. The compliance trigger is "the next time the LPT module is completely disassembled to piece-part level". What constitutes "piece-part level" could be disputed. If a mechanic partially disassembles the module to replace a bearing but does not separate every component, is that enough to trigger the AD? The ordinary meaning suggests full disassembly down to individual parts, not just removal of the module from the engine. Operators and MROs must interpret this consistently. A conservative approach is to treat any shop visit that breaks the LPT module seal as triggering the requirement, though technically the AD says "completely disassembled to piece-part level". If an operator defers the work because they consider a partial disassembly insufficient to trigger the AD, they take the risk that CASA may disagree after an audit.

Parts identification can trip you up. The AD distinguishes between a deflector pad (square plate, no threaded stud) and a deflector (has threaded stud). It is possible for an MRO to install the wrong part if the engineering drawings are not consulted. If the wrong part is installed, the engine does not comply. The AD does not provide a grace period; the error is non-compliance from the moment the engine is returned to service. An operator must ensure that the MRO correctly identifies and installs the right parts. This is a simple but non-trivial error risk.

Previous credit only for specific earlier documents. The AD grants credit only for rework performed using GE SB No. CF6-80C2 S/B 72-1171 dated 25 May 2005 and RD 935-314-S2 or S3. If an operator performed the rework using a different earlier SB or a repair designed in-house, that is not credited. The operator would need to redo the work using the accepted documents. Given the costs involved, an operator could be out of pocket for an earlier unsuccessful compliance attempt. This is a trap for operators who did not follow the exact prescribed documents from the beginning.

The AD applies only to engines with specific LPT case P/Ns. An operator may assume that all CF6-80C2 and 80E1 engines are affected, but the AD only applies to those with the listed part numbers. Engines with non-listed LPT case part numbers are not required to comply, even if they are otherwise identical. However, the list of P/Ns is extensive, covering most of the common variants. An operator should physically check the data plate on each engine, not rely on the engine model alone. A mistake could lead to unnecessary expenditure on engines that are not subject to the AD, or failure to act on engines that are.

The AD does not cover all CF6-80C2 variants. Note that variants like CF6-80C2B1F1, B1F2, B6FA, etc., are listed, but there may be other dash numbers in the fleet that are not. The AD is limited to those explicitly named. An operator with a rare or custom variant must confirm its status. If the variant is not listed but has the same issue, CASA may issue a separate AD. But for this AD, the list is exhaustive.

Compliance must be carried out methodically and documented. The following steps assume the operator owns or leases an engine that may be affected. First, establish applicability by cross-referencing the engine model and the LPT case part number against Table 1 in the AD. This should be done from the engine's technical records or physical data plate. If the engine is a CF6-80C2 variant listed in the left column, and the LPT case part number is one of the numbers listed in the right column, then the AD applies. Same for the CF6-80E1 models listed. If the engine is not listed or has a different LPT case P/N, no further action is needed, though the operator should retain evidence of that conclusion.

Second, determine whether the required work has already been performed. Review the engine's maintenance history for any rework of the LPT case that involved installation of skin doubler pads and deflectors. Specifically, check whether the work was done using GE SB CF6-80C2 S/B 72-1171 Revision 1 dated 1 February 2006 and RD 935-314-S4 dated 28 January 2008 (or the E1 equivalent). If the work was done using earlier documents (the 2005 SB and RD 935-314-S2 or S3) before 14 February 2011, the previous credit provision applies, and no further action is needed. If the work was done using a later revision that is FAA-approved as an AMOC, that also satisfies the AD. Documentation of the specific SB and RD used must be retained.

Third, if the work has not been done, plan the LPT module disassembly. The compliance timeline is the next time the LPT module is completely disassembled to piece-part level. Do not defer beyond 18 December 2016 (the eight-year cap). If the engine is approaching that date without a scheduled shop visit, the operator must bring it in for the modification before the deadline. This may involve fleet planning, spare engine provisioning, and coordination with an approved MRO. The cost of an unscheduled shop visit is significant, and the operator should consider whether to rework the existing case or buy a reworked replacement case. The choice depends on the condition of the case, the cost of rework labor versus new parts, and downtime.

Fourth, execute the rework or replacement. For rework, the MRO must follow the Accomplishment Instructions in the appropriate GE SB and RD exactly. The parts must be correctly identified: deflector pads (square, no stud) and deflectors (with stud). After installation, the MRO must perform any required testing, leak checks, or dimensional inspections as specified in the SB. The MRO must also complete a maintenance release and an airworthiness certificate for the engine.

Fifth, document compliance in the engine's maintenance records. This should include a reference to the AD number (AD/CF6/70 Amdt 1), a statement of the action taken (rework or replacement), the SB and RD used, the date of compliance, and the signature of the certifying engineer. If an FAA-approved AMOC was used, attach a copy of the FAA approval letter or alternative method of compliance approval. The records must be kept for the life of the engine and be available for CASA inspection.

Finally, monitor for future amendments or superseding ADs. Because this AD is now old, an operator who recently acquired an engine with these models should confirm whether the work was done and whether a newer AD has replaced or amended AD/CF6/70. CASA's AD register should be checked. If the engine is compliant with the AD but later a new AD imposes additional requirements, that new AD will also need to be complied with. Compliance is a continuous obligation, not a one-off event.