AD/CFE 738/4 - Stage 2 High Pressure Turbine Aft Cooling Plate

The AD operationalises three interlocking concepts: targeted applicability, prescriptive technical standards by reference, and a compliance timing rule linked to maintenance opportunity and component life.

Targeted applicability. The AD is limited to engines of a single model and a finite list of serial numbers: CFE Model CFE738-1-1B engines, P/N 3050000-5, with gas generator modules P/N 6091T09G01 and SNs 800421-800430. The AD explicitly notes these engines are installed on, but not limited to, Dassault-Breguet Falcon 2000 series aeroplanes. This establishes that the AD binds owners/operators of those engines wherever fitted, not only on a single aircraft type.

Prescriptive technical standard by reference. The substantive inspection, repair and removal criteria are not contained in full text in the AD. Instead the AD requires compliance "in accordance with" CFE Alert Service Bulletin No. CFE738-A72-8031, Revision 4, dated 27 March 2002: paragraph 2.B.(1) for the inspection and repair/removal acceptance limits, and paragraph 2.B.(2) for removal of raised metal from the rotor disk post aft mating surface. The AD therefore makes the ASB the operative technical standard for workmanship, dimensional acceptance (for example the 0.003 inch indentation repair limit), and accepted remedial actions. Operators must obtain and follow the referenced ASB to determine exact acceptance limits and repair procedures.

Compliance timing rule. The AD ties action to maintenance access and component life: "at the next shop visit where the HPT assembly is sufficiently disassembled to afford access" or "not later than 4,500 part cycles-since-new", whichever occurs earlier. This creates a dual trigger,an access-based, opportunistic trigger and an absolute life-based deadline. The practical effect is that the AD may be complied with during an already-planned HPT overhaul or other shop visit, but must be done by the 4,500 part cycle limit regardless. The AD's Background states the safety objective: prevention of stage 2 HPT aft cooling plate failure that could cause uncontained engine failure and aeroplane damage.

Cross-reference to other instruments. The AD specifically references FAA AD 99-27-16R1 Amdt 39-12791 as a related document. It also references a particular revision of a manufacturer ASB. The AD therefore operates in a technical network of service information and foreign authority directives; those documents provide the detailed inspection criteria and repair techniques that the AD mandates.

The immediate legal addressees are the owners, operators, maintainers and certificated maintenance organisations responsible for the listed CFE738-1-1B engines (P/N 3050000-5) with gas generator modules P/N 6091T09G01 and serial numbers 800421 through 800430. The Applicability table in the AD specifies those engines explicitly. Because the AD applies to the engine assemblies by part number and serial number, the obligation travels with the engine regardless of the airframe on which it is installed; the AD itself notes that those engines are installed on, but not limited to, Dassault-Breguet Falcon 2000 series aeroplanes. Therefore operators of Falcon 2000 aircraft equipped with these engine serial numbers are affected, as are any other operators that have taken possession of engines with those SNs.

Maintenance organisations and repair stations are affected because the AD requires inspections and, where necessary, repairs and removals in accordance with the CFE ASB (Revision 4). The compliance trigger "at the next shop visit where the HPT assembly is sufficiently disassembled to afford access to the stage 2 HPT aft cooling plate" assigns an action to the organisation that performs the shop visit or the HPT disassembly. Those organisations must schedule the required inspection into their shop workscopes when the HPT assembly is exposed.

Lessors and aircraft/engine asset managers are indirectly affected because the AD imposes a mandatory maintenance action tied to specific engines; they must ensure lessees/operators comply within the defined window to preserve airworthiness and the engine’s continued use. Maintenance planning, inventory and logistics functions are affected because the AD may require the procurement of spare or serviceable aft cooling plates and possibly additional labour if removal-and-replacement is required by the ASB's acceptance limits.

Regulatory compliance teams and continuing airworthiness managers must update maintenance tracking systems to reflect the AD's dual trigger,next shop visit with HPT access or 4,500 part cycles-since-new,and to record completion in the appropriate logbooks and returns. The AD does not name or allocate financial responsibility explicitly. The operator or the party responsible for scheduled maintenance and continuing airworthiness will therefore be the party that pays for the inspection, repairs, removal and replacement, and any consequential downtime, subject to contractual allocation between lessor and operator or under warranty arrangements, none of which are set out in this AD.

Duties

• Inspect the stage 2 HPT aft cooling plate surface D for nicks, dents and scratches in accordance with CFE ASB No. CFE738-A72-8031, Revision 4, paragraph 2.B.(1). The AD text: "Inspect the stage 2 HPT aft cooling plate for nicks, dents, and scratches on surface D in accordance with the requirements of CFE Alert Service Bulletin (ASB) No. CFE738-A72-8031, Revision 4, dated 27 March 2002, paragraph 2.B.(1)."

• Repair aft cooling plates that have indentation 0.003 inch deep or less in accordance with the same ASB paragraph. The AD requires repair for those parts with indentation at or below the stated limit: "Repair those stage 2 HPT aft cooling plates with indentation 0.003 inch deep or less in accordance with ASB No. ... paragraph 2.B.(1)."

• Remove from service before further flight any aft cooling plate that has nicks, dents and/or scratches that exceed the acceptance limits in the ASB paragraph 2.B.(1) and replace with serviceable parts. The AD mandates removal: "Remove from service before further flight those stage 2 HPT aft cooling plates that have nicks, dents, and/or scratches that exceed the acceptance limits in accordance with ASB No. ... paragraph 2.B.(1), and replace with serviceable parts."

• Inspect the stage 2 HPT rotor disk post aft mating surface for raised metal and remove raised metal if present, in accordance with ASB No. CFE738-A72-8031, Revision 4, paragraph 2.B.(2). The AD states: "Inspect the stage 2 HPT rotor disk post aft mating surface for raised metal, and remove raised metal if present in accordance with ASB No. ... paragraph 2.B.(2)."

• Complete these actions at the next appropriate shop visit where the HPT assembly is sufficiently disassembled to afford access to the stage 2 HPT aft cooling plate, but not later than 4,500 part cycles-since-new. The Compliance text sets this timing floor.

Rights and procedural points implicit in the AD

• The AD’s technical criteria and acceptance limits are set by reference to a CFE Alert Service Bulletin (Revision 4, dated 27 March 2002). The right to know the exact inspection, repair, removal and measurement procedures therefore depends on access to that ASB. The AD does not reproduce the full technical detail; it requires compliance with the ASB paragraphs cited.

• The AD does not specify alternative methods of compliance (AMOCs) or provide an explicit approval route for deviations in the text. The AD therefore delegates the technical standard-setting to the ASB and leaves the AD text silent on any formal administrative process for alternate compliance. Any party seeking an alternate method would need to consult CASA’s general processes for AD AMOCs outside the AD text, but the AD itself does not describe that mechanism.

• The AD mandates "remove from service before further flight" for parts exceeding acceptance limits. That phrase indicates that continued operation in flight after detection of an unacceptably damaged plate is not permitted; the AD gives no exception or relief for temporary continued operation.

• While the AD specifies the engines by serial number and part number, it does not specify who within an operator must carry out the inspection. Standard regulatory practice is that certificated maintenance organisations or appropriately certified personnel perform such inspections; the AD assumes operators will use qualified maintenance providers but does not state certification requirements in the text.

In sum, the duties are concrete and prescriptive: inspect, repair if within a micrometric indentation limit, remove and replace if beyond acceptance limits, and inspect and remove raised metal on the mating surface. The AD assigns timing and references the ASB for technical details. The AD does not set out administrative appeal or alternate compliance procedures within its text.

The AD text itself does not specify civil, administrative or criminal penalties, nor does it lay out an enforcement process within the document. The AD becomes "effective on 16 March 2006" and is issued by a CASA Delegate. The text contains a compliance imperative,inspect and, where necessary, repair or remove and replace the stage 2 HPT aft cooling plate in accordance with the referenced ASB and within the prescribed timing,but it does not, within its four corners, state the sanctions for non-compliance.

Because the AD is a regulatory instrument issued by CASA, enforcement and penalties for non-compliance would ordinarily derive from the broader statutory and regulatory framework governing civil aviation in Australia rather than from this AD text. The AD itself, however, provides no particulars about enforcement procedure, penalty levels, or administrative remedies. Consequently, the AD should be read together with the governing aviation statutes, regulations and CASA enforcement policy if a reader seeks the specific sanctioning regime that applies to failures to comply. None of those instruments are reproduced or summarised in this AD.

The AD does cross-reference FAA AD 99-27-16R1 Amdt 39-12791, but that document is referenced only as related material and is not itself a source of Australian enforcement of this AD. The AD’s Background describes the safety rationale,prevention of stage 2 HPT aft cooling plate failure and avoidance of uncontained engine failure and aeroplane damage,so non-compliance could also have practical safety consequences and commercial liability implications in the event of an incident, but the AD text does not articulate those legal consequences or liabilities. Parties requiring detail about enforcement and penalties must therefore consult CASA’s enforcement guidance and the applicable statutory provisions outside this AD.

The AD makes explicit cross-references to non-CASA documents and thereby situates itself within a network of technical and foreign regulatory materials. The AD requires compliance with CFE Alert Service Bulletin No. CFE738-A72-8031, Revision 4, dated 27 March 2002; it also notes that "FAA AD 99-27-16R1 Amdt 39-12791 refers." The AD therefore imports, by reference, the technical standards and acceptance criteria of the manufacturer’s ASB and acknowledges a related FAA airworthiness directive.

Beyond those explicit references, the AD does not refer to any other Australian statutes, regulations, or administrative processes within the text. It does not, for example, reproduce or cite the enabling statutory provision under which CASA issues ADs, nor does it define administrative avenues for alternate methods of compliance or appeals. Therefore, the AD must be read in conjunction with the broader Australian airworthiness regulatory framework to understand legal standing, enforcement, record-keeping obligations and the relationship to other continuing airworthiness obligations. The AD itself establishes a mandatory maintenance action; interfacing obligations such as maintenance release, logbook entries, certificate of release to service and continuing airworthiness management are not set out in the AD but would typically be governed by other aviation regulations and standard practices.

The AD’s reference to specific part numbers and serial numbers creates an intersection with contractual arrangements (for example, maintenance agreements, warranty terms, lease arrangements) because owners, operators, lessors and maintenance providers may have contractual duties to carry out work or to share costs. The AD does not specify how those commercial allocations should be made.

In summary, the AD interacts directly with the manufacturer ASB and is informed by a related FAA AD. It does not itself set out interactions with other Australian statutory or regulatory provisions; those interactions are implicit and require reference to the wider aviation regulatory and contractual context outside the AD text.

The AD itself identifies a small number of dated documents and revision numbers that form its amendment history and technical provenance. The AD is numbered AD/CFE 738/4 and carries a date code "3/2006" in the header. The AD text states it becomes effective on 16 March 2006 and is signed 1 February 2006 by James Coyne, Delegate of the Civil Aviation Safety Authority. Within the AD, the technical instructions are tied to CFE Alert Service Bulletin No. CFE738-A72-8031, Revision 4, dated 27 March 2002. Thus the AD’s operative technical standard is a 2002 ASB Revision 4.

The AD also explicitly references FAA AD 99-27-16R1 Amdt 39-12791 as a related item ("Note 2: FAA AD 99-27-16R1 Amdt 39-12791 refers."). The inclusion of that FAA AD in the note indicates that the FAA previously issued related corrective action under its own regulatory authority; the CASA AD therefore references the FAA material as part of the technical context. No other revisions, supersessions or amendments to AD/CFE 738/4 are recorded in the AD text provided.

The document header repeats the AD identifier and the date code multiple times (for example, "AD/CFE 738/4", "3/2006"), and the signature block includes the effective date and signature authority. The ASB revision referenced (Revision 4, 27 March 2002) is earlier than the AD effective date; the AD therefore adopts an existing manufacturer bulletin as the instructive document for mandatory compliance. There is no record in the AD of subsequent revisions, cancellations or updates; the AD does not state that it supersedes a prior CASA AD for the same subject matter within the AD text supplied.

If a practitioner needs the full chain of amendments or any later changes to the AD after its effective date, the AD text supplied does not contain that information; it only provides the original issuance identification, effective date and the ASB revision in force at issuance. Any later amendments or revocations would need to be checked against CASA's subsequent AD bulletins or a consolidated AD register, since this AD text itself does not contain a post-issuance amendment log.

The AD document as supplied contains no litigation history, citations to case law, or references to disputes or judicial review concerning its issuance or application. The AD comprises a technical and regulatory directive: applicability, required actions, compliance timing, and a background safety rationale. It does not recount any legal challenges to the AD or related court decisions.

Where dispute or litigation arises in practice,whether over a determination that a part exceeds acceptance limits, contractual responsibility for cost and downtime, alleged non-compliance leading to an incident, or the validity of the AD,such matters would be resolved through the ordinary legal processes available in Australia (administrative review, judicial review or civil proceedings). None of those processes or their outcomes are set out in the AD text. The AD does note a related FAA AD (FAA AD 99-27-16R1 Amdt 39-12791) but does not describe any litigation that may have attended that foreign authority action.

For practitioners seeking precedent or guidance on disputes arising from this AD, the AD itself does not provide precedential material or litigation references. Any legal history concerning enforcement, civil liability, or judicial constructions of similar CASA ADs would need to be sourced from case law databases and CASA records outside the text of this AD.

The AD includes several technical and procedural features that can create practical pitfalls if not carefully handled.

1. Applicability is narrow and serial-number specific. The AD applies only to CFE738-1-1B engines P/N 3050000-5 with gas generator modules P/N 6091T09G01 and serial numbers 800421 through 800430. Because the AD is serial-number specific, operators must maintain accurate engine serial-number tracking. Failure to identify an affected engine (for example, due to incomplete records or engine exchanges) could result in non-compliance. The AD also notes these engines are installed on, but not limited to, Dassault-Breguet Falcon 2000 series aeroplanes; the engine-bound scope means applicability does not depend on airframe type.

2. The technical acceptance limits and repair criteria are not printed in the AD. The AD requires compliance "in accordance with" CFE ASB No. CFE738-A72-8031 Revision 4, paragraph 2.B.(1) and 2.B.(2). Operators therefore must obtain and follow that ASB to know the acceptance limits (for example the specific measurement tolerance that triggers removal versus repair) and correct repair method. If an operator relies only on the AD text without consulting the ASB, they will lack the actual criteria required to assess a plate.

3. The AD prescribes a micrometric repair threshold (indentation 0.003 inch). The text requires repair where indentation is 0.003 inch deep or less and removal where acceptance limits are exceeded. Accurate measurement requires appropriate tooling and measurement procedure as set out in the ASB; imprecise measurement or inconsistent measuring technique can lead to disputes about whether a part is repairable or must be removed.

4. Compliance timing is a dual trigger and may be operationally ambiguous. The AD requires action "at the next shop visit where the HPT assembly is sufficiently disassembled to afford access" but not later than 4,500 part cycles-since-new. Operators must therefore interpret what constitutes a "shop visit" and maintain accurate records of part cycles-since-new for the affected assemblies. Without consistent cycle accounting, determining the latest permissible compliance time could be unclear. The AD does not define "part cycle" within the text provided.

5. The AD mandates "remove from service before further flight" for components that exceed acceptance limits. That phrase provides no operational relief for interim flights; parts deemed unacceptable must be replaced prior to the next flight. This can have immediate operational consequences if the defect is discovered away from base or during in-service checks.

6. The AD does not describe alternate methods of compliance or the administrative procedure for CASA approval of different remedies. If a maintenance organisation wishes to use an alternate repair technique or acceptance criterion, the AD text provides no procedural route; operators will need to consult CASA's wider processes to obtain any approval.

7. Record-keeping and logbook entries. The AD requires actions whose completion must be demonstrable in continuing airworthiness records, but the AD does not itself prescribe the exact form of those records. Practitioners must ensure that inspections, repairs and part replacements are entered in the airworthiness records consistent with other applicable maintenance regulations.

8. Cross-referenced FAA AD. The AD notes FAA AD 99-27-16R1 Amdt 39-12791 refers. Operators should not assume that FAA material substitutes for the ASB material mandated by the AD. They must check both documents to ensure the technical action taken satisfies CASA's requirement by conforming to the referenced ASB paragraphs.

9. Commercial allocation of costs is not addressed. The AD does not specify who pays. Lessors, operators and maintenance providers need to consult their contracts and warranties to allocate costs and downtime. That contractual process may be time-sensitive because the AD’s "remove from service before further flight" requirement can generate urgent operational costs.

In short, the key "gotchas" are: the need to obtain and follow the ASB to apply the AD, accurate serial-number and cycle tracking, precision measurement requirements, mandatory removal-before-flight for exceeded limits, lack of AMOC procedure in the AD text, and the contractual and logistical consequences of unscheduled part replacement.

The AD sets out a concrete sequence of actions and a compliance timing rule. To comply with the AD as written, an operator or maintenance organisation must take the following steps, grounded in the AD text and the referenced ASB:

1. Identify affected engines. Verify whether any engines in the operator’s fleet match CFE Model CFE738-1-1B, P/N 3050000-5, with gas generator module P/N 6091T09G01 and serial numbers 800421 through 800430 as listed in the Applicability table. The AD notes these engines are installed on, but not limited to, Dassault-Breguet Falcon 2000 aircraft. Ensure engine serial-number data is up to date in the continuing airworthiness records.

2. Obtain the referenced ASB. Acquire CFE Alert Service Bulletin No. CFE738-A72-8031, Revision 4, dated 27 March 2002, because the AD requires inspections and remedial actions "in accordance with" paragraph 2.B.(1) (inspection, repair/removal acceptance limits) and paragraph 2.B.(2) (removal of raised metal on rotor disk post aft mating surface). The AD does not reproduce the technical acceptance limits beyond the 0.003 inch indentation mention, so the ASB must be read to implement the inspection correctly.

3. Plan the work at the next appropriate shop visit. Schedule the inspection at the next shop visit where the HPT assembly is sufficiently disassembled to afford access to the stage 2 HPT aft cooling plate. If such a visit will not occur before the engine reaches 4,500 part cycles-since-new, plan to perform the inspection earlier so that the AD is complied with by the absolute deadline of 4,500 part cycles-since-new.

4. Conduct the inspection in strict accordance with ASB paragraph 2.B.(1). Inspect surface D of the stage 2 HPT aft cooling plate for nicks, dents, and scratches following the ASB's measurement procedures and acceptance criteria.

5. Apply the repair or removal decision using the ASB criteria. If indentation is 0.003 inch deep or less, perform the repair prescribed by the ASB paragraph 2.B.(1). If nicks, dents or scratches exceed the ASB acceptance limits, remove the aft cooling plate from service before further flight and replace with serviceable parts as required by the ASB and the AD.

6. Inspect the stage 2 HPT rotor disk post aft mating surface per ASB paragraph 2.B.(2). Where raised metal is present, remove raised metal in accordance with the ASB procedure referenced by paragraph 2.B.(2).

7. Certify the work and record the action. Make the appropriate entries in the engine and aircraft maintenance records or logbooks to reflect compliance with AD/CFE 738/4 and the ASB procedure followed. The AD itself does not specify the exact record format, so follow required maintenance record-keeping provisions under applicable continuing airworthiness regulations and organisational procedures.

8. If replacement parts are required, source "serviceable parts" as the AD requires replacement with such parts. Ensure parts provenance and traceability meet regulatory and organisational standards.

9. If an operator intends to use an alternative procedure or repair technique not contained in the ASB, consult CASA’s processes for approval of alternate methods of compliance. The AD does not provide an AMOC method within its text.

10. Monitor for related directives. The AD references FAA AD 99-27-16R1; operators should monitor any further CASA ADs or ASB revisions that may update technical standards or compliance requirements.

Costs and operational considerations to factor into compliance planning are not enumerated in the AD but are implied by the required tasks: access to the HPT assembly (which may require shop disassembly), measurement and repair tooling per the ASB, potential replacement parts procurement, and aircraft downtime while the engine is removed or the work is performed. The AD requires that these steps be completed by 4,500 part cycles-since-new in any event, so maintenance planners should prioritise scheduling if the engine’s life counters approach that threshold.

Compliance with the AD will be demonstrated by carrying out the inspections and remedial actions exactly as directed by the ASB paragraphs cited, within the timing constraints stated. The AD’s effective date is 16 March 2006; work performed before that date is described in the AD as "unless previously accomplished," meaning already-completed compliance actions in accordance with the ASB before the effective date satisfy the AD’s requirements.