AD/APU/21 - RE220 Fuel Nozzles

The instrument is an Airworthiness Directive targeted at a specific APU model and specific component part numbers. The core technical elements in the AD are discrete and identifiable by part number. The main concepts are:

• Applicability by APU model and P/N: The AD applies to Honeywell RE220 (RJ) APUs with P/N WE3800770-2. The text specifies that these APUs are "installed in but not limited to Bombardier model CL-600-2C10 aeroplanes" (Applicability section, Note 1). That phrasing indicates that the AD attaches to an APU P/N irrespective of airframe, but the text explicitly notes a primary installation example.

• Component replacement: The central mandated engineering change is the replacement of fuel nozzles. The AD identifies the replaced part as P/N WE3830486-2 and the new-design replacement as P/N WE3830513-1. The AD directs operators to Honeywell Alert Service Bulletin (ASB) RE220-49-A7714 dated 4 November 2002 for information on the replacement procedure (Requirement item 1).

• Re-identification: The AD requires administrative and physical re-identification of the unit on the APU identification plate, by changing the P/N from WE3800770-2 to WE3800770-3 (removing the "-2" and vibropeening or hand stamping a "-3") and by vibropeening or hand stamping the letter "C" after the serial number to indicate conversion, and vibropeening/hand stamping "Change Number 3" on the identification plate adjacent to the MOD RECORD (Requirement item 2). These steps alter the unit's identity as it appears on its identification plate.

• Operational verification: The AD requires starting the APU and performing a visual fuel leak check after one minute of operation (Requirement item 3). This is a simple post-modification verification to detect immediate leaks.

• Prohibition on reverting: The AD imposes a continuing obligation not to install the old nozzle P/N WE3830486-2 into any APU that has been re-identified as P/N WE3800770-3 (Requirement item 4). The prohibition is effective from the AD's effective date.

• Compliance timing and scope: The AD specifies that items 1, 2, and 3 must be done within 30 days after the AD's effective date, unless previously accomplished. Item 4 is required from the effective date forward (Compliance section). The AD becomes effective on 2 August 2007.

• Cross-reference to FAA action and manufacturer service information: The AD notes FAA AD 2003-15-07 and Honeywell ASB RE220-49-A7714. These are treated as sources of procedural information and external regulatory alignment but are cited within the AD text rather than reproduced.

The AD combines hardware change, administrative record alteration, and an operational check into a single compliance package. The re-identification requirement links the physical change to a permanent change of the APU's reported identity, preventing simple reversion by field installation of old nozzles. The AD is both prescriptive on physical work (specific P/Ns and stamping methods) and prescriptive on timing (30 days), and therefore shifts responsibilities onto operators, maintenance organisations and component suppliers to carry out the specified tasks within the set window.

The AD affects owners, operators, and maintenance organisations responsible for aircraft or APUs that contain Honeywell RE220 (RJ) APUs with part number WE3800770-2. The Applicability section states that these APUs are installed in, but not limited to, Bombardier model CL-600-2C10 aeroplanes, which means that any operator or maintenance provider with the specified APU P/N, on any airframe, must treat the AD as applicable.

Specific affected parties include:

• Aircraft operators whose fleets include the specified APU P/N WE3800770-2. Those operators must plan and expend resources to replace the nozzles and re-identify the APUs within the 30-day window after the AD's effective date unless the work has been completed previously.

• Maintenance organisations or approved repair stations that perform the physical replacement, stamping/vibropeening for re-identification, and the post-replacement APU run and visual fuel-leak inspection. The AD specifies methods for marking the identification plate (vibropeen or hand stamping) and labelling positions (e.g. adjacent to the MOD RECORD), so maintainers performing the work must have the capability and authority to perform those markings and comply with the ASB guidance.

• Honeywell International Inc., and parts suppliers, to the extent they must supply new-design fuel nozzles P/N WE3830513-1 and potentially withdrawal or counselling regarding the continued use of the older nozzles P/N WE3830486-2. The AD directs operators to Honeywell's ASB for replacement information.

• Parts inventory managers and logistics personnel who must manage the stock of nozzles and ensure that, from the effective date, the older nozzles are not installed in re-identified APUs (Requirement item 4). That prohibition may affect existing inventories of the older nozzles.

• Regulatory and certifying authorities with oversight over maintenance, since the AD is issued by the Civil Aviation Safety Authority (CASA) and became effective on 2 August 2007; the AD is signed by the Delegate of CASA. The AD also cites FAA AD 2003-15-07, indicating cross-jurisdictional regulatory relevance.

• Aircraft lessors, buyers, and sell-side maintenance planners who must account for this AD when transferring aircraft or APUs, because the plate re-identification changes how the unit is logged and identified physically on the APU plate.

Those not affected are units that already had these steps completed prior to the effective date , the Compliance section states the 30-day requirement applies unless the work was previously accomplished. The AD does not provide an exhaustive list of airframes beyond the CL-600-2C10; the phrase "but not limited to" implies evaluation of applicability should focus on the APU P/N rather than airframe model alone. The AD does not list exemptions or alternative methods of compliance within the text provided.

The AD places affirmative duties on operators and maintenance organisations associated with affected APUs. The principal duties are explicit and mechanically specified in the AD's Requirement and Compliance sections. The AD does not articulate rights in the way primary legislation might; it prescribes required actions and a prohibition. The key duties and the manner of performance are:

• Duty to replace fuel nozzles (Requirement item 1): Operators must replace nozzles P/N WE3830486-2 with nozzles P/N WE3830513-1. The AD refers to Honeywell ASB RE220-49-A7714 dated 4 November 2002 for information on fuel nozzle replacement. The duty to replace is mandatory within the compliance window.

• Duty to re-identify the APU identification plate (Requirement item 2): Operators or maintainers must change the P/N on the identification plate from WE3800770-2 to WE3800770-3 by removing the "-2" and vibropeening or hand stamping a "-3". They must vibropeen or hand stamp the letter "C" after the serial number to show conversion. They must vibropeen or hand stamp "Change Number 3" on the identification plate adjacent to the MOD RECORD. Those marking methods are specified by the AD and must be followed.

• Duty to perform a functional check for leaks (Requirement item 3): After the replacement and re-identification, the APU must be started and a visual fuel leak check must be performed after one minute of operation. The AD requires this as part of the replacement package completed within the 30-day compliance window.

• Duty to observe a prohibition on installing old nozzles into re-identified APUs (Requirement item 4): From the effective date, operators must not install nozzles P/N WE3830486-2 into any APU P/N WE3800770-3. This is a continuing restriction on the composition of re-identified APUs.

• Duty to comply with timing (Compliance section): Actions 1, 2 and 3 must be done within 30 days after the effective date of the AD, unless previously accomplished. Action 4 is effective from the AD's effective date.

The AD implicitly confers the right to rely on the Honeywell ASB for technical guidance on the replacement process, as the AD directs operators to that ASB for replacement information. The AD also implicitly confers a right to perform the specified methods of re-identification by vibropeening or hand stamping, as those methods are listed. The AD does not state alternative methods for compliance, nor does it state processes for requesting an alternative means of compliance within the text provided. The AD does not specify record-keeping obligations apart from the physical plate re-identification and the requirement that "Change Number 3" appear adjacent to the MOD RECORD on the identification plate.

Who decides and enforces these duties is reflected in the AD being issued by the Civil Aviation Safety Authority and signed by the Delegate, David Punshon. The AD sets the duties and timing; the AD itself is the instrument of prescription. The AD does not, within the provided text, describe administrative appeal or variance mechanisms.

The AD text as provided does not set out specific penalties or enforcement mechanisms within its own wording. It is an instrument labelled "Airworthiness Directive" and the Compliance section prescribes time-limited mandatory actions, and the text states that "This Airworthiness Directive becomes effective on 2 August 2007." The AD therefore functions as a binding directive from the Civil Aviation Safety Authority, issued by a Delegate, and it establishes mandatory technical and administrative obligations for the specified equipment. The AD does not, within the text supplied, contain explicit enforcement penalties, sanctioning schedules, or administrative fine provisions.

From the wording, the enforcement mechanism implied by the AD is that compliance is required by the effective date and within the stated compliance windows. The AD specifies compliance items and dates, which sets clear standards that regulators can verify during oversight, inspections, or airworthiness audits. The AD also imposes a continuing prohibition on the installation of old nozzles into converted APUs from the effective date. The text does not identify a specific sanctions regime (for example, fines, grounding, or certificate suspension) or a process for declaring non-compliance, nor does it reproduce broader statutory enforcement provisions. The AD does refer to an FAA AD as related material, but does not import the FAA's enforcement language.

Absent express text in this AD about penalties, enforcement will proceed under the Civil Aviation Safety Authority's general regulatory powers and the relevant aviation safety legislation or regulations that govern compliance with ADs. The AD itself documents the required actions and the effective date, and it identifies the official issuer and the date of signature (19 June 2007, David Punshon, Delegate of the Civil Aviation Safety Authority). It thus provides the factual basis that regulators and inspectors would use in determining whether a particular operator or maintenance organisation has complied.

For practitioners and compliance teams, the operational implication is that the AD creates a compliance obligation that can be verified by examining the APU identification plate (to confirm re-identification to P/N WE3800770-3 and stamping of "C" and "Change Number 3"), maintenance records, parts installed (to verify new nozzle P/N WE3830513-1), and evidence of the post-modification functional leak check (start/run report). The AD itself does not set out enforcement escalation steps, but the prescriptive content and effective date are clear points of measurement for compliance.

The AD explicitly references external regulatory and manufacturer documents, which positions it within a network of aviation regulatory instruments. The AD cites Honeywell Alert Service Bulletin RE220-49-A7714, dated 4 November 2002, as the source of information on fuel nozzle replacement, and it references FAA AD 2003-15-07 Amdt 39-13250 dated 24 July 2004 as related material. Those references indicate that the AD is intended to be consistent with manufacturer guidance and an earlier FAA airworthiness directive.

The AD is an instrument issued by the Civil Aviation Safety Authority (CASA) and is dated and signed by a CASA Delegate. While the AD text supplied does not recite the enabling statutory provisions or cross-reference specific Civil Aviation Act or regulations sections, the directive functions as an operational requirement for airworthiness that sits alongside other regulatory obligations of air carriers, maintenance organisations, and aircraft owners. The AD creates an obligation to act within specified timeframes, and it constrains allowable maintenance practices (for example, the prohibited reinstallation of older nozzles into re-identified APUs).

Because the AD refers to an FAA AD and a Honeywell ASB, operators are effectively being directed to follow manufacturer procedures and to note prior or parallel overseas regulatory action. The AD does not, in the text provided, harmonise any record-keeping or approval processes beyond the plate re-identification instructions and the reference to the ASB. The AD does not set out procedures for alternative methods of compliance, nor does it discuss interaction with airworthiness certificates, continuing airworthiness obligations, or air operator certificate conditions; those interactions would typically be governed by broader aviation regulations and oversight practice rather than this AD's text.

The AD's prohibition on installing the older nozzle into converted APUs introduces an equipment-specific constraint that interacts with parts management laws and contractual arrangements for maintenance and spares. The AD does not address commercial or contractual remedies for stranded parts or supply disruptions. It does not specify transitional arrangements for parts in the supply chain.

In summary, within the provided text the AD references and relies on manufacturer service instructions (Honeywell ASB) and a prior FAA AD for context, and it asserts mandatory modification, marking and inspection duties that co-exist with the broader regulatory framework governing airworthiness and maintenance. The AD itself does not set out the general enforcement or statutory framework; those mechanisms are external to the text supplied. Practitioners should treat the AD as a mandatory compliance instrument that fits into an operator's overall statutory obligations under Australian aviation safety law and associated regulations.

The AD document provided does not include a history of amendments to AD/APU/21 itself. The text shows the AD identifier "AD/APU/21", the subject "RE220 Fuel Nozzles", and the date designation "8/2007". The document records its effective date as 2 August 2007 and carries a signature block showing David Punshon as Delegate of the Civil Aviation Safety Authority, dated 19 June 2007. Apart from that issuance metadata, the text does not list prior versions, later amendments, revocations, or consolidated amendment notes within the page provided.

The AD does reference related external material which pre-dates the AD: Honeywell Alert Service Bulletin RE220-49-A7714, dated 4 November 2002, is cited as containing information on nozzle replacement (Requirement item 1). The AD also refers to FAA AD 2003-15-07 Amdt 39-13250 dated 24 July 2004 (Note 2). These references indicate that the technical issue prompting the AD had been addressed by manufacturer service guidance and by an earlier FAA AD, but the AD text provided does not explicitly describe how those prior actions were incorporated into or differ from the present AD. The AD's "Background" section states that the amendment is prompted by reports of cracks occurring in the existing APU fuel nozzles leading to fuel leaks, and that the actions specified are intended to prevent APU compartment fires and fuel vapour explosion. The wording "This amendment is prompted by..." implies the AD is an amendment in a regulatory sense, but the document does not display any earlier text of the same AD for comparison or show a tracked change log.

Therefore, based solely on the AD text supplied, the amendment history available is limited to these points: the AD references prior manufacturer and FAA action, it is dated with a signature of 19 June 2007, and it becomes effective on 2 August 2007. No in-document chronological record of previous issuances or later amendments is included. Practitioners seeking a formal chronological record or subsequent changes would need to consult CASA's AD database or published amendment logs, as such material is not contained within the provided text.

The supplied AD text contains no litigation history. There are no references to judicial decisions, administrative appeals, or formal disputes within the document. The AD does cite external regulatory and manufacturer sources (Honeywell ASB RE220-49-A7714, FAA AD 2003-15-07), but these references are regulatory and technical in nature, not judicial.

Accordingly, the document does not record any court challenges, enforcement proceedings, or case law that interpret, vary, or test the AD's provisions. There is no mention of contested compliance, exemption requests, or contested enforcement actions in the text provided. The AD is a technical regulatory instrument setting out required actions and timing; the text itself does not engage with litigation or dispute resolution history.

For practitioners who require litigation context, the absence of litigation history in the AD means that any analysis of how courts or tribunals have treated this AD would require independent research beyond the supplied text. The AD itself contains only the operative requirements, background safety rationale, effective date, and references to the Honeywell ASB and the FAA AD; it does not refer to any legal proceedings or judicial consideration.

This AD contains several technical and administrative details that can create practical pitfalls for operators, maintainers and parts managers if overlooked. The AD's wording is precise; non-observance of small details can result in failure to meet the directive.

• Applicability is by APU P/N, not by airframe list alone. The Applicability section identifies Honeywell RE220 (RJ) APUs P/N WE3800770-2 and notes these are installed in but not limited to Bombardier CL-600-2C10 aeroplanes. Operators that rely solely on airframe model lists may miss affected APUs installed in other aircraft types. The AD’s scope should be assessed against installed APU part numbers, not solely by aircraft type description.

• The replacement requires a specific new nozzle P/N. The AD mandates replacement with nozzles P/N WE3830513-1 and prohibits installation of the older nozzles P/N WE3830486-2 into re-identified APUs. Inventory managers must ensure the correct P/N is procured and tracked. The AD gives no transitional disposition for existing stocks of the older nozzle P/N.

• Re-identification is prescriptive in method and placement. The AD requires changing the P/N on the identification plate from WE3800770-2 to WE3800770-3 by removing the "-2" and vibropeening or hand stamping a "-3". It also requires vibropeening or hand stamping the letter "C" after the serial number and vibropeening or hand stamping "Change Number 3" adjacent to the MOD RECORD. These instructions specify both method (vibropeen or hand stamp) and location (adjacent to MOD RECORD) and will require appropriate tooling, access to the identification plate, and procedural care to avoid damage. Some maintenance organisations may not routinely perform vibropeening or hand-stamping on identification plates, and may need to confirm authority and capability to effect these markings.

• The AD requires a one-minute run before a visual fuel leak check. The Requirement item 3 states: "Start the APU and perform a visual fuel leak check after one minute of operation." The check is operationally timed and visual; absence of a recorded run or evidence of the check could expose an operator in oversight checks. Operators must ensure the run and the check are documented in maintenance records consistent with maintenance record-keeping practice.

• Compliance window is short. The AD requires actions 1, 2 and 3 within 30 days after the AD becomes effective (unless they were already done). The AD becomes effective on 2 August 2007. The 30-day window constrains parts ordering, scheduling downtime, and work on aircraft whose operators have tight maintenance schedules. There is no alternative compliance period specified in the text supplied.

• Prohibition on installing the old nozzle into converted APUs is immediate and continuing. Requirement item 4 states that from the effective date of this AD, do not install fuel nozzles P/N WE3830486-2 into any APU P/N WE3800770-3. That means converted APUs must not be returned to operation using the older nozzle. The prohibition will have consequences for swapping parts during APU servicing unless the APU is still P/N WE3800770-2.

• The AD references external documents for procedure. The AD directs operators to Honeywell ASB RE220-49-A7714 for information on fuel nozzle replacement. Operators must obtain and follow that service bulletin. The AD does not reproduce the detail of the replacement steps, leaving reliance on the ASB for technical instruction. If an operator does not have access to the ASB or misinterprets the ASB, compliance could be defective.

• Marking permanence and traceability. The AD requires physical alterations to the APU identification plate. These markings are permanent physical changes and have implications for traceability and maintenance records. If the physical stamping is inconsistent with maintenance records, inspectors may question the authenticity of compliance. The AD requires that the text "Change Number 3" be placed adjacent to the MOD RECORD; that is a positional instruction that interacts with existing plate content.

• The AD does not set out exceptions or alternative methods within the text supplied. If an operator believes another method would achieve the safety outcome, the AD provides no process within its text for applying for an alternative method of compliance. Practitioners should note that seeking an alternative would therefore require engagement with the regulator outside the AD text, but such procedures are not described in the document.

• The AD does not specify record-keeping requirements explicitly. Although the re-identification is physical, the AD does not itself require a specific maintenance entry or form. Maintenance managers should therefore ensure that their normal record-keeping practice captures the replacement, the re-identification marking, part numbers installed, and the post-start leak check, because evidence of compliance will rely on those records.

• The AD’s wording regarding installation limits could strand parts. The explicit prohibition against installing the old nozzle into converted APUs (Requirement item 4) means that older nozzles might become unusable for a subset of APUs, affecting parts value and replacement strategies.

Careful reading and operational planning around these particulars is necessary to avoid inadvertent non-compliance. The AD’s technical prescriptions and procedural markers are narrowly worded; compliance is implementation-sensitive.

The AD specifies discrete mandatory actions, timing, and marking requirements. The following practical, stepwise compliance checklist follows directly from the AD's Requirement and Compliance sections and the referenced Honeywell ASB citation. This checklist is intended to be an operational translation of the AD as it is written and is grounded only in the AD text.

1. Identify affected APUs by part number. Search your fleet and spares inventory for Honeywell RE220 (RJ) APUs with P/N WE3800770-2. Note the AD’s Applicability section, which specifies the affected APU P/N and observes that these APUs are installed in, but not limited to, Bombardier model CL-600-2C10 aeroplanes. Do not rely only on airframe type lists; confirm the installed APU P/N.

2. Obtain Honeywell ASB RE220-49-A7714 (4 November 2002). The AD directs operators to this Alert Service Bulletin for information on fuel nozzle replacement. Ensure the maintenance team has the ASB in hand and follows its procedural and safety instructions when performing the nozzle replacement.

3. Procure the replacement nozzles. Order and secure the specified new-design fuel nozzles P/N WE3830513-1. Verify part numbers when receiving and prior to installation. Arrange parts logistics to accommodate the AD's compliance timeline.

4. Schedule maintenance within the compliance window. The AD requires that Requirement items 1, 2 and 3 be done within 30 days after the effective date of the AD, unless the work was already done. The AD is effective on 2 August 2007. Plan APU downtime and maintenance slots to accomplish the replacement, marking and run test within that 30-day timeframe.

5. Replace nozzles in accordance with ASB instructions. Follow the Honeywell ASB RE220-49-A7714 instructions for replacing P/N WE3830486-2 nozzles with P/N WE3830513-1. Confirm that each nozzle installed is the new-design P/N WE3830513-1 and record serial numbers and part numbers in maintenance entries.

6. Re-identify the APU identification plate as specified. After replacing the nozzles, change the APU P/N on the identification plate from WE3800770-2 to WE3800770-3 by removing the "-2" and vibropeening or hand stamping a "-3" in its place. Vibropeen or hand stamp the letter "C" after the serial number to show conversion. Vibropeen or hand stamp "Change Number 3" on the identification plate adjacent to the MOD RECORD. Use the specified marking methods (vibropeen or hand stamp) and ensure the marking location is adjacent to the MOD RECORD as the AD requires. Take appropriate precautions to prevent damage to the plate or adjacent markings.

7. Perform the mandated start and visual leak check. Following the nozzle replacement and plate re-identification, start the APU and, after one minute of operation, perform a visual fuel leak check. Ensure the one-minute operational interval is observed and that the visual inspection is completed and documented.

8. Document completion. Record, in the aircraft/APU maintenance log and maintenance records, the replacement of nozzles (identifying old and new P/Ns), the re-identification stamping performed (including photographs of the identification plate if available), and the results of the one-minute run and visual fuel leak check. The AD’s requirements are partly evidenced by the physical plate markings; co-ordinate records to reflect those markings and to support evidence of compliance.

9. Observe the continuing prohibition. From the effective date of the AD, do not install fuel nozzles P/N WE3830486-2 into any APU P/N WE3800770-3. Ensure parts-control procedures and maintenance work orders reflect this prohibition. Adjust parts and spares management to prevent inadvertent installation of older nozzles into converted APUs.

10. Consider inventory disposition and procurement planning. The AD’s prohibition on installing older nozzles into converted APUs may make older nozzles unsuitable for certain units. Evaluate whether older nozzle stock needs to be quarantined, returned to suppliers, used only on non-converted APUs, or otherwise managed to ensure compliance.

11. Coordinate with regulators and documentation. Although the AD text does not set out an approval process for alternative compliance, if an operator believes an alternative procedure is necessary, contact the Civil Aviation Safety Authority to request guidance. Otherwise, ensure that maintenance actions align with the AD and the Honeywell ASB referenced. Retain documentation to demonstrate compliance in the event of regulatory inspection.

12. Verify across fleet and future maintenance. Ensure that procedures for installation of nozzles during routine maintenance and APU servicing reference the prohibition. Train maintenance staff to check the APU identification plate P/N before installing nozzles to avoid contravening the AD.

The AD provides clear, prescriptive steps and a short compliance window. Compliance requires technical work consistent with the Honeywell ASB, specific physical marking actions on the identification plate, a short timed operational check, and ongoing parts-management controls to implement the prohibition. Operators should plan for parts lead times, access to plate-marking tooling, and documentation practices to produce clear evidence of compliance.