AD/CL-600/90 - Fuel Line Couplings

The AD is structured around a few discrete concepts and decision points drawn from the source text. These concepts determine the who, what, when and how.

• Applicability. The AD applies to Bombardier Inc. Model CL-600-2B19 aircraft with serial numbers 7003 through 7067, and 7069 through 7981 (Applicability). The serial-number ranges include a single serial-number omission (7068), which the AD does not list as included. The serial-number identification is the primary filter for whether an individual airframe is covered.

• Required action. The mandated mechanical action is replacement of the fuel tube couplings inside the wing and centre fuel tanks with redesigned couplings (Requirement). The replacement must be carried out "according to the Accomplishment Instructions of Bombardier Service Bulletin (SB) 601R-28-054, Revision A, dated 7 August 2006, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada." This couples the mandatory requirement to a manufacturer's service bulletin while reserving regulator approval for subsequent revisions.

• Compliance metric and timing. Compliance is measured in flight hours rather than calendar days. The deadline is within 5000 flight hours after the effective date of the AD (Compliance). The AD’s effective date is 20 December 2007 (Compliance). Operators must therefore track flight hours from that date to monitor when the work becomes mandatory for each affected airframe.

• Safety rationale. The AD is justified by a system safety review performed by Bombardier and lightning testing. The Background explains that certain self-bonded fuel tube couplings were found to have insufficient lightning current capability, and that single-point failures (integration bonding wire failure, excessive axial clearance at reducer ferrules) could impair electrical bonding. The AD links these failure modes to a realistic ignition source inside the fuel tank when subjected to lightning strikes, creating a risk of fuel tank explosion (Background). The service-modification requirement is presented as the corrective action.

• Inter-regulatory linkage. The AD documents reliance on Transport Canada processes: the new fuel tank safety standards were introduced in Chapter 25 of the Transport Canada Airworthiness Manual via NPA 2002-043; the compliance assessment used Transport Canada Policy Letter No. 525-001. The AD also references Transport Canada AD CF-2007-23 (Background; Requirement, Note). It therefore sits in a cross-jurisdictional regulatory context with Transport Canada and Bombardier.

• Delegated regulatory action. The AD is issued under CASA authority, as indicated by the signature of a CASA delegate, but it explicitly defers approval of later SB revisions to the Chief, Continuing Airworthiness, Transport Canada (Requirement). This creates a shared decision space between Australian regulator action and Transport Canada control over admissible SB revisions.

These main concepts determine practical behaviours for operators: check serial number; plan in-tank maintenance; obtain and follow the specified SB; monitor flight hours from the effective date; and, if relying on a later SB revision, ensure it bears approval from the named Transport Canada authority.

The AD’s direct legal target is the operator or owner of an affected Bombardier CL-600-2B19 airframe within the serial-number ranges specified (Applicability). The airworthiness directive imposes an obligation on the holder of the aircraft’s maintenance and airworthiness responsibilities because it prescribes a mandatory physical modification to the aircraft. The AD does not spell out who must pay, but the practical allocation of cost and operational impact will fall to those responsible for airworthiness compliance and for scheduling maintenance on the affected aeroplanes.

Stakeholder groups materially affected include:

• Aircraft owners and operators holding CL-600-2B19 airframes within serial numbers 7003-7067 and 7069-7981 (Applicability). These entities must confirm applicability for each airframe and plan to schedule the required modification within the defined flight-hour window (Compliance).

• Maintenance providers and engineers. The work is specified as replacement of in-tank couplings inside wing and centre fuel tanks (Requirement). This places technical demands on maintenance providers who will carry out the physical removal and installation of the redesigned couplings in accordance with the Bombardier SB’s Accomplishment Instructions.

• Bombardier as the manufacturer. The AD mandates work to be done in accordance with Bombardier SB 601R-28-054 Rev A, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada (Requirement). Bombardier’s SB provides the procedural content for compliance and determines the technical specification of redesigned couplings.

• Transport Canada. The AD explicitly references Transport Canada’s Airworthiness Manual, Policy Letter No. 525-001 and a related Transport Canada AD (Background; Requirement, Note). The Chief, Continuing Airworthiness, Transport Canada has delegated approval authority for later SB revisions, which creates a role for Transport Canada in determining whether subsequent SB revisions are an acceptable method for compliance.

• Civil Aviation Safety Authority (CASA). The AD is signed by a CASA delegate and is an Australian airworthiness directive; CASA is the issuing authority for enforcement within Australia (signature block). The AD’s effective date is set by that instrument and it is part of CASA’s continuing-airworthiness regime.

• Insurers and financiers. While the source does not mention them, mandatory in-tank modifications that address a lightning-risk hazard alter the airframe’s compliance status and therefore have implications for an aircraft’s insurability and for financiers who rely on regulatory compliance for asset management. This is an implied consequence of any mandatory AD.

• Regulators and auditors. Auditors, certifying staff and continuing-airworthiness managers must record compliance with the AD (the AD sets the required action and compliance time). The AD also creates an interface between national regulators because it references Transport Canada documents and approval authorities (Background; Requirement).

Entities outside those directly listed remain affected indirectly. For example, operators who must schedule aircraft out of service for the modification will face opportunity costs, which affect their commercial operations and potentially charters and contracts. Those commercial consequences stem directly from the AD’s requirement to perform in-tank work within the specified flight-hour window.

The AD sets a discrete, mechanical duty, establishes the authorised method of compliance, and creates limited regulator discretion over acceptance of later revisions.

Key duties

• Duty to replace couplings. Operators of affected aircraft must replace the fuel tube couplings inside the wing and centre fuel tanks with redesigned couplings (Requirement). The AD specifies the location and scope of the physical modification; the duty is not optional where the aircraft falls under the AD’s applicability.

• Duty to use the specified technical standard. The replacement must be carried out "according to the Accomplishment Instructions of Bombardier Service Bulletin (SB) 601R-28-054, Revision A, dated 7 August 2006" (Requirement). That anchors the technical method to the manufacturer’s instructions.

• Conditional duty to obtain approval for later revisions. If an operator wishes to rely on a later revision of the Bombardier service bulletin, that later revision must be "approved by the Chief, Continuing Airworthiness, Transport Canada" (Requirement). This places a procedural duty on operators or maintenance organisations to ensure any non-Rev A SB is accompanied by the named regulator’s approval.

• Duty to meet the compliance deadline. Replacement must be completed "within 5000 flight hours after the effective date of this AD" (Compliance). The effective date is stated as 20 December 2007. The AD therefore imposes a flight-hour measured compliance window.

Rights and decision points

• Right to comply with later approved SB revisions. The AD allows the use of later revisions of the service bulletin, provided those revisions are approved by the Chief, Continuing Airworthiness, Transport Canada (Requirement). That creates an avenue for technical evolution to be used as a compliance method, subject to regulator approval.

• Right to reference Transport Canada documentation in the safety rationale. The AD explicitly uses Transport Canada’s NPA and Policy Letter No. 525-001 in its background assessment (Background). That is not a procedural right for operators, but it shows which regulatory standards and policies guided the AD’s risk assessment.

• Implied right to maintain airworthiness records. While the AD text does not contain a record-keeping clause, compliance with an AD creates an obligation under continuing-airworthiness regimes to document modifications. The AD’s linkage to Bombardier SB instructions implies that maintenance records demonstrating conformity to the SB will be necessary to show compliance with the AD at audit or inspection.

Delegations and discretion

• Regulator discretion over SB revisions. The Chief, Continuing Airworthiness, Transport Canada has the approval authority for later SB revisions (Requirement). That is a specified delegation and creates an explicit decision point outside the issuing authority’s immediate control.

What the AD does not specify

• The AD does not specify who must pay for the work; it also does not include procedural enforcement details or sanctions in the text provided. The AD prescribes the required physical action and the acceptable technical method, but it leaves cost allocation and enforcement mechanisms to the broader regulatory and contractual frameworks outside the document.

Operators and maintainers should treat the AD as creating a non-negotiable engineering duty for affected airframes, with some procedural flexibility if a later SB revision has been formally accepted by the named Transport Canada official.

The text of the AD as supplied does not set out specific penalties, fines, or criminal sanctions for non-compliance. The AD becomes effective on a stated date (20 December 2007) and is signed by a delegate of the Civil Aviation Safety Authority, indicating it is an enforceable airworthiness directive within the issuing authority’s regulatory framework (Compliance; signature block). Beyond the effective date and the prescriptive requirements, the supplied instrument does not detail the enforcement mechanisms, processes for inspection, certification requirements post-modification, or the sanctions that may follow non-compliance.

From the document itself, the enforcement posture is conveyed by the mandatory language of the Requirement and the explicit compliance timeframe (Requirement; Compliance), which together identify a binding operational obligation for affected aircraft. However the specific means by which the regulator will monitor, inspect, or sanction non-compliance are not stated in the provided AD text. The AD does indicate cross-reference to Transport Canada documents and a related Transport Canada AD (Background; Requirement, Note), but it does not describe cross-jurisdictional enforcement arrangements or the practical mechanics of regulatory oversight.

Practically, ADs are instruments that change an aircraft’s authorised configuration and, in many regulatory systems, failure to comply will affect an operator’s legal ability to operate the aircraft and to maintain a valid certificate of airworthiness. The supplied AD does not, however, state those consequences directly. The absence of explicit enforcement detail in the AD text means that interested parties must consult the broader regulatory framework under which CASA and relevant civil aviation law operate to determine:

• How CASA will verify compliance (inspections, audits, continuing airworthiness records review).
• Whether and how non-compliance affects an aircraft’s certificate of airworthiness.
• What administrative or criminal penalties, if any, are applied under the broader aviation regulatory statute or regulations for failing to comply with an AD.

The AD’s signature by a CASA delegate (signature block) establishes it as an official CASA instrument and therefore as part of the regulatory obligations on operators, but the supplied document does not articulate the enforcement regime or penalty schedule. Those matters fall to related regulatory instruments and administrative procedures that are not reproduced in this text.

The AD explicitly situates itself in a cross-jurisdictional regulatory network and in a manufacturer-driven corrective-action regime. The Background section states that Bombardier conducted a system safety review against new fuel tank safety standards introduced in Chapter 25 of the Transport Canada Airworthiness Manual via NPA 2002-043 (Background). It also records that the identified non-compliances were assessed using Transport Canada Policy Letter No. 525-001 to determine whether mandatory corrective action was required (Background). Thus the AD is not operating in isolation; it is the Australian regulator’s instrument that draws technical standards, compliance assessment methodology, and a related AD from Transport Canada.

Specific interactions and decision nodes set out in the AD text:

• Reference to Transport Canada standards. The safety standard trigger is Chapter 25 of the Transport Canada Airworthiness Manual as introduced by NPA 2002-043 (Background). Compliance with the AD therefore aligns Australia’s corrective action with Transport Canada’s newer fuel tank safety benchmarks, rather than adopting a bespoke Australian-only technical standard.

• Use of Transport Canada policy for assessment. The AD relied on Transport Canada Policy Letter No. 525-001 to determine whether the identified non-compliances warranted mandatory action (Background). That shows the Australian AD incorporates Transport Canada policy in its risk-assessment methodology.

• Acceptance of Bombardier SB revisions by Transport Canada. The AD allows later revisions to the Bombardier SB to be used for compliance only if approved by the Chief, Continuing Airworthiness, Transport Canada (Requirement). That creates an interaction where an Australian AD defers to a Canadian authority’s approval of subsequent technical revisions for the specific compliance method.

• Cross-reference to Transport Canada AD CF-2007-23. The AD explicitly notes Transport Canada AD CF-2007-23 dated 18 October 2007 as a related document or point of reference (Requirement, Note). This indicates that operators and maintainers should be aware of the parallel Transport Canada regulatory action.

• Manufacturer service bulletin as the technical instrument. The AD requires work be completed according to Bombardier SB 601R-28-054 Rev A dated 7 August 2006 (Requirement). Service bulletins are manufacturer-originated documents; the AD therefore bridges between regulatory obligation and manufacturer technical direction, a common mechanism for enforcing standardised repair instructions across jurisdictions.

Implications for legal and regulatory interfaces

• Harmonisation rather than divergence. The AD shows regulatory harmonisation with Transport Canada in both the standards it references and the approval path it recognises for SB revisions. This reduces the risk of operators facing divergent mandatory practices between Australia and Canada for the same aircraft type, but it also means that the Australian AD effectively imports aspects of Transport Canada’s regulatory judgement.

• Delegated approval creates a single point of international technical control. By making the Chief, Continuing Airworthiness, Transport Canada the approver of later SB revisions acceptable for compliance, the AD grants a form of cross-border technical gatekeeping to a single foreign regulator for that aircraft type.

• Manufacturer-regulator interaction. The AD’s reliance on a Bombardier service bulletin for the required technical method places Bombardier in a central role for implementing the AD. Operators must follow the Bombardier SB and cannot substitute a different technical method unless it is framed in a later SB revision approved by the named Transport Canada official.

• Absent enforcement detail in the AD. The AD does not describe enforcement steps or penalties within the text provided. Enforcement and legal consequences must therefore be sought in the broader statutory framework that empowers CASA to issue and enforce ADs. The AD accordingly interacts with broader civil aviation law and administrative enforcement mechanisms not reproduced in the instrument.

In short, the AD operates as a jurisdictional node that enforces compliance with a manufacturer-prescribed modification, while explicitly aligning its assessment and later-revision approvals with Transport Canada standards and decisions.

The supplied AD text contains a limited but concrete amendment history and related chronology.

• Issuance and signature. The AD is dated with a signature block attributed to David Punshon, Delegate of the Civil Aviation Safety Authority, and is marked with a signature date of 25 October 2007 (signature block). That records the date of the instrument’s signing.

• Effective date. The AD states that it becomes effective on 20 December 2007 (Compliance; effective date line). The interval between the signature date and the effective date is about eight weeks according to the text.

• Relation to Transport Canada AD. The AD contains a note that Transport Canada AD CF-2007-23 dated 18 October 2007 is referred to (Requirement, Note). The placement and dating of the Transport Canada AD suggest contemporaneous regulatory actions across jurisdictions in October 2007.

• Service bulletin revision reference. The technical method of compliance is tied to Bombardier Service Bulletin (SB) 601R-28-054, Revision A, dated 7 August 2006 (Requirement). The AD permits the use of later revisions of the SB, but only if those later revisions are approved by the Chief, Continuing Airworthiness, Transport Canada (Requirement). That approval condition is a standing amendment provision: it allows the technical standard to move forward if an authorised later revision is formally accepted.

Absent changes

• No further amendments, supersessions or revocations are contained in the supplied document. The AD text does not include subsequent amendments, corrections, or a revocation clause in the material provided. There is no record in the supplied text of follow-on amendments to the AD itself.

• No retroactive changes disclosed. The AD does not indicate any retroactive amendments to the compliance window or scope in the provided material.

What the supplied text does not provide

• The AD does not supply a history of prior related ADs other than the Transport Canada AD reference, and it does not show subsequent amendments or revisions to the Australian AD itself. If an operator requires the complete regulatory timeline beyond the signature and effective dates provided, they must consult CASA’s published AD records or the regulatory archive for any later instruments that amend or supersede AD/CL-600/90.

In short, the supplied text records a discrete issuance on 25 October 2007 with an effective date of 20 December 2007, anchors the technical method to a Bombardier SB dated 7 August 2006, and allows approval of later SB revisions by the named Transport Canada official. No further amendment events are recorded in the supplied document.

The supplied AD text includes no litigation history, judicial decisions, or tribunal actions. The instrument names no court cases, administrative appeals, or precedential legal determinations, and it does not record any challenges to the AD itself. The Background and Requirement sections describe the technical basis for the AD and reference Transport Canada documents and a Bombardier service bulletin, but nowhere in the supplied material is there any mention of litigation, appeals, or legal precedent arising from this directive.

Consequently, based on the provided text only, there is no record of litigation related to AD/CL-600/90. Any disputes, enforcement proceedings, or judicial review actions involving this AD would not be revealed by this document alone. Parties seeking the litigation history for this AD should consult court databases, administrative review records, or CASA enforcement archives outside the content of this text. The supplied AD itself does not contain such material.

The AD contains several details that can trap an unwary operator or maintainer if not read carefully. The following items are drawn strictly from the supplied AD text and its implications.

• Serial-number coverage has a gap. The Applicability lists serial numbers 7003 through 7067, and 7069 through 7981 (Applicability). Serial number 7068 is not included. Operators must check individual airframe serial numbers exactly, rather than rely on a broad model-year or fleet assumption. Misreading the ranges could lead to unnecessary work or inadvertent omission.

• Compliance measured in flight hours from the effective date. The compliance requirement is "within 5000 flight hours after the effective date of this AD" (Compliance). The effective date is stated as 20 December 2007. Operators must ensure flight-hour tracking commences from the effective date, not from signature date, service bulletin date, or discovery date. Failure to calculate correctly could result in a missed compliance window.

• The mandated work is inside wing and centre fuel tanks. The Requirement specifies replacement "inside the wing and centre fuel tanks." In-tank work is typically more complex than external tasks. Although the AD does not list the detailed maintenance procedures, the Accomplishment Instructions of the Bombardier SB will govern tank entry, safety precautions, and any special tooling or certification required. Operators should anticipate that the physical access and safe working procedures for fuel tanks will influence scheduling and cost.

• Service bulletin revision approval is a regulator-decided condition. The AD permits later SB revisions to be used only if approved by the Chief, Continuing Airworthiness, Transport Canada (Requirement). That means an operator cannot unilaterally decide to use a newer SB revision unless it bears the specified approval. Using an unapproved revision could fail to meet the AD’s terms.

• Cross-referenced Transport Canada AD. The AD refers to Transport Canada AD CF-2007-23 dated 18 October 2007 (Requirement, Note). The content of that Transport Canada AD is not reproduced here. Operators should be aware that parallel or related Transport Canada material may contain additional technical or procedural detail relevant to compliance.

• Timing between signature and effective date. The AD was signed on 25 October 2007 and becomes effective on 20 December 2007 (signature block; Compliance). This lead time could affect planning windows, but operators must base their flight-hour compliance calculations on the effective date. Confusing the signing date with the effective date is a potential compliance mistake.

• No penalties or enforcement detail in the text. The AD does not specify enforcement mechanisms or penalties (Penalties and enforcement). Operators who assume that the AD is voluntary or that non-compliance will carry only administrative consequences may be mistaken; the broader regulatory framework (not reproduced) will contain enforcement provisions. The AD itself does not clarify those consequences.

• Reliance on Bombardier SB for technical details. The AD requires work "according to the Accomplishment Instructions" of the Bombardier SB (Requirement). The AD does not include the Accomplishment Instructions in-line. Operators must ensure they obtain and follow the Bombardier SB precisely and retain the necessary records to show compliance.

• Potential logistics and availability issues. The AD requires the replacement of specific couplings. The document does not address part supply, lead times, or availability of redesigned couplings. Operators should be mindful that parts procurement constraints could complicate meeting the flight-hour compliance window imposed by the AD.

• Aircraft operational impact. Replacement of in-tank couplings inherently requires removing the aircraft from service for maintenance, but the AD does not detail expected aircraft downtime. Operators should not assume minimal impact and must plan for scheduling and revenue effects.

Each of these "gotchas" follows directly from reading the AD’s Applicability, Requirement, and Compliance text, and from the AD’s invocation of Bombardier SB instructions and Transport Canada approval authority.

The AD prescribes a single corrective pathway and a compliance window. The steps below translate the AD’s text into an operational compliance checklist, strictly on the basis of the supplied document.

1. Confirm applicability for each airframe. Check the aircraft serial number against the ranges specified in the Applicability: serial numbers 7003 through 7067, and 7069 through 7981 are covered (Applicability). Do not assume coverage by model alone. If an airframe is not within these serial numbers, the AD does not apply as written.

2. Establish the compliance deadline in flight hours. The AD requires replacement "within 5000 flight hours after the effective date of this AD" (Compliance). The effective date is 20 December 2007. Compute remaining flight hours by subtracting hours accumulated since that effective date from 5000, to determine when the modification becomes mandatory.

3. Acquire the technical instructions. Obtain Bombardier Service Bulletin 601R-28-054, Revision A dated 7 August 2006, and ensure the relevant Accomplishment Instructions are available for the maintenance organisation performing the work (Requirement). Do not attempt to improvise procedures outside the SB.

4. If relying on a later SB revision, obtain regulator approval. The AD allows later revisions of the Bombardier SB only if approved by the Chief, Continuing Airworthiness, Transport Canada (Requirement). If a later revision exists and you prefer to use it, secure the necessary approval documentation from the named Transport Canada official prior to commencing work.

5. Plan for in-tank fuel-system work. The couplings to be replaced are located "inside the wing and centre fuel tanks" (Requirement). Ensure the maintenance facility, personnel qualifications, tooling, and safety procedures required for fuel-tank entry and in-tank work are in place. Although the AD does not prescribe those procedures verbatim, they will be addressed in the Bombardier SB Accomplishment Instructions and in applicable continuing-airworthiness regulations.

6. Schedule aircraft downtime and parts procurement. Order redesigned couplings and associated parts per the Bombardier SB, allow for possible lead times, and schedule maintenance slots to complete the work prior to the flight-hour deadline. The AD itself does not provide parts lists in-line; use the SB for part numbers and quantities.

7. Execute the modification per the SB Accomplishment Instructions. Perform the replacement of fuel tube couplings inside wing and centre fuel tanks strictly in accordance with the Bombardier SB Accomplishment Instructions, Revision A or an approved later revision (Requirement).

8. Document compliance. Record in the aircraft maintenance log and continuing-airworthiness records that the AD work was completed, including details of the SB revision used, the approval for any later revision (if applicable), part numbers installed, certifying personnel, and the date and aircraft hours at completion. Although the AD does not explicitly set record-keeping steps, continuing-airworthiness practice requires documentation to prove compliance.

9. Retain regulator correspondence. If any deviation or alternative method of compliance is requested, record and retain all regulator approvals. In particular, if a later SB revision was used, retain the approval issued by the Chief, Continuing Airworthiness, Transport Canada (Requirement).

10. Monitor for related ADs or guidance. The AD refers to Transport Canada AD CF-2007-23 dated 18 October 2007 and to Transport Canada policy documents and NPA material (Background; Requirement, Note). Check for any related or subsequent ADs or regulatory guidance from CASA or Transport Canada that might affect maintenance procedures or extend the scope or compliance timing.

Practical notes grounded in the AD text

• Use the Bombardier SB as the procedural guide. The AD’s Requirement ties the permitted method of compliance to the SB’s Accomplishment Instructions and to regulator-approved SB revisions, so the SB is the operative technical manual for compliance.

• Do not rely on the signing date. The AD’s effective date controls the compliance clock (Compliance). Use 20 December 2007 for the start of the 5000 flight-hour window.

• Verify serial number inclusion at the aircraft level. The Applicability defines the population by serial number; maintain a clear record of which aircraft in your fleet fall within the listed ranges.

• Expect to interact with Transport Canada approval processes if you want to use a later SB revision. The AD explicitly routes SB-revision approval to a named Transport Canada official, so plan for the administrative interface and allow lead time for approvals.

Following these steps, which are directly derived from the AD’s Applicability, Requirement and Compliance clauses and their cross-references, will put an operator in a position to demonstrate compliance with the directive as written.