AD/CL-600/118 - Bulkhead Check Valves

The AD sets out a small set of interlocking technical and procedural concepts. First, applicability is limited in scope: it affects Bombardier CL-600-2B19 aeroplanes, serial numbers 7003 and subsequent (Applicability). Second, the substantive maintenance action is a schedule revision: operators must revise their Transport Canada approved maintenance schedule to incorporate a specific discard task, Task Number 21-51-21-13, for two part-numbered bulkhead check valves, P/N 92E20-3 and 92E20-4 (Requirement).

Third, the source of the discard task is a Temporary Revision to the Maintenance Requirements Manual. The AD refers to TR 1-2-39, dated 12 December 2008, to CSP A-053 Part 1 MRBR Section 2, System and Powerplant Program, as the document that introduced the discard task (Requirement). That makes the maintenance action a formalised element of the MRBR as of that TR. The AD also cross-references Transport Canada AD CF-2009-31 dated 8 July 2009 as a related document (Requirement, note).

Fourth, the AD alters a prior maintenance philosophy for these components. The background explains three reported in-flight losses of cabin pressurisation attributable to failure of a bulkhead check valve in combination with an air supply duct failure. In response, earlier directives (AD/CL-600/80 and Transport Canada AD CF-2003-05R1) had required a 4,000 flight-hour repetitive inspection. The AD states that the inspection task "has since been superseded by a 3,000 flight-hour periodic discard task for these bulkhead check valves" and that this AD mandates the maintenance schedule revision to incorporate that discard task (Background).

Fifth, timing and mandatory character are explicit. The AD has an effective date, 24 September 2009, and a compliance window: within 60 days after the effective date unless previously accomplished (Compliance). The AD is issued and dated 14 August 2009 and bears the signature of a CASA delegate, James Coyne (signature block). The AD text also confirms that it supersedes previous corrective-action instructions (Background), changing the compliance mechanism from inspection to discard.

These concepts interact: a narrow applicability reduces the population of aircraft affected; but the shift from inspection to discard changes the maintenance inputs (parts and replacement frequency) and operational scheduling (flight-hour-triggered maintenance) for the affected valves. The AD anchors the discard task to an established Maintenance Requirements Manual TR, and requires formal revision of the Transport Canada approved maintenance schedule within a short mandatory period.

The AD explicitly affects Bombardier Inc. Model CL-600-2B19 aircraft with serial numbers 7003 and subsequent (Applicability). That is the universe of aircraft to which the mandatory revision applies, as stated in the AD. The persons or entities that bear the operational and compliance obligations are therefore the operators and maintainers of those specific aeroplanes whose maintenance programmes are approved under Transport Canada processes (Requirement: "Revise the Transport Canada approved maintenance schedule...").

Practically, the directive reaches any organisation that holds the Transport Canada approved maintenance schedule for those serial-numbered aircraft. That will include operators and maintenance organisations responsible for the airworthiness of CL-600-2B19 aeroplanes, and, in particular, those that must incorporate the Maintenance Requirements Manual CSP A-053 Part 1 MRBR Section 2 TR 1-2-39 discard task into an already approved schedule. The AD does not on its face expand beyond that set. It does not list other models, nor separate ownership groups, nor list Australian or other registries by name; it identifies the model and serial-number range only.

The AD also affects technical staff who perform maintenance planning and scheduling, because the required action is a maintenance-schedule revision. Maintenance engineers, planners, and record-keeping staff will need to update approved documentation to include Task Number 21-51-21-13 and ensure maintenance cycles for P/N 92E20-3 and 92E20-4 bulkhead check valves follow the discard interval specified in the MRBR TR (Requirement).

Parts suppliers and logistics managers are affected insofar as a discard task imposes demand for replacement parts at a periodic interval. The AD identifies the specific part numbers involved, P/N 92E20-3 and 92E20-4 (Requirement). The AD also changes the trigger for action from a 4,000 flight-hour repetitive inspection to a 3,000 flight-hour periodic discard, per the Background. That shift alters fleet-level maintenance planning, spare parts provisioning, and scheduling of maintenance slots.

Finally, the AD is issued by the Civil Aviation Safety Authority, via a delegate (James Coyne). The delegate is the signatory who publishes the AD (signature block). That means any regulatory or administrative follow-up would be administered through CASA channels or the processes articulated in the AD and related Transport Canada documents; the AD itself does not list other stakeholders beyond operators and maintainers. The AD’s narrow applicability, explicit task identification and linkage to the MRBR limit the measures to a defined subset of aircraft and the organisations responsible for their maintenance.

Key duty: revise the Transport Canada approved maintenance schedule to include Task Number 21-51-21-13, a discard task for bulkhead check valves P/N 92E20-3 and 92E20-4 (Requirement). The AD is prescriptive about the content of the revision: it must incorporate the discard task introduced by Temporary Revision TR 1-2-39 dated 12 December 2008 to the Maintenance Requirements Manual CSP A-053 Part 1 MRBR Section 2 (Requirement).

Timing duty: complete the revision within 60 days after the AD’s effective date, unless the action has already been completed (Compliance). The AD’s effective date is stated as 24 September 2009 (Compliance). The "unless previously accomplished" qualification gives operators who have already incorporated the discard task into their Transport Canada approved maintenance schedule a defensible position against having to take further action within the 60-day window.

Specificity duty: the AD identifies exact part numbers (P/N 92E20-3 and 92E20-4) and the Task Number (21-51-21-13) to be included in the maintenance schedule (Requirement). It anchors the required task to the Temporary Revision TR 1-2-39 to CSP A-053 Part 1 MRBR Section 2, which provides the procedural and technical content of the discard task (Requirement). The AD therefore requires not a generic check but a particular discard task as documented in the MRBR TR.

Supersession duty: the AD states it supersedes the instructions detailed in Corrective Actions, Part A, of Transport Canada AD CF-2003-05R1, which were previously mandated by AD/CL-600/80 (Background). That creates a duty to follow the discard task in place of the prior 4,000 flight-hour repetitive inspection regime that had previously been mandated.

Rights and discretion: the AD text contains no specific carve-outs, exemptions, or alternative methods of compliance (AMOCs) within the printed text. It does contain the usual conditional phrase "unless previously accomplished" for timing. The AD is issued and signed by a CASA delegate, James Coyne (signature block), which identifies the issuing authority within the document. The AD does not otherwise specify appeal rights, approval routes for alternative measures, or administrative review mechanisms in its text.

Record and documentary implications: while the AD expressly mandates a maintenance-schedule revision, it does not detail record-keeping procedures or documentation beyond the requirement to revise the approved schedule. The AD references the Maintenance Requirements Manual TR as the source for the discard task, which signals that operators must reference TR 1-2-39 to determine the technical content of the task.

In sum, the concrete duties are narrow: revise the Transport Canada approved maintenance schedule to include Task 21-51-21-13 for P/N 92E20-3 and 92E20-4 within 60 days of the effective date, and treat that task as superseding the previous inspection-based corrective actions mandated in earlier ADs.

The AD text does not specify monetary penalties, administrative sanctions, or an enforcement procedure within its body. The directive’s text sets out mandatory technical obligations , a maintenance-schedule revision to incorporate Task Number 21-51-21-13 for P/N 92E20-3 and P/N 92E20-4 , and specifies timing (within 60 days of the effective date of 24 September 2009) (Requirement, Compliance). It is signed by James Coyne, Delegate of the Civil Aviation Safety Authority (signature block), which identifies the issuing authority but the AD itself contains no express penalty provisions or enforcement steps.

Because the document is an Airworthiness Directive, it communicates mandatory regulatory action; however, the AD does not record or explain how non-compliance will be enforced, what administrative proceedings may follow, or what fines or suspensions would attach for failure to revise an approved maintenance schedule. The AD also does not identify a single enforcing office, process for notifications of compliance, or a prescribed format for certifying that the Transport Canada approved maintenance schedule has been revised.

The AD makes cross-references to other Airworthiness Directives and to the Maintenance Requirements Manual TR as the technical basis for the mandated task (Background, Requirement). It also notes Transport Canada AD CF-2009-31, dated 8 July 2009, as a related reference (Requirement: Note). It does not, however, state whether enforcement would occur via Transport Canada processes, Civil Aviation Safety Authority administrative channels, or under some bilateral arrangement between CASA and Transport Canada. The presence of the CASA delegate’s signature indicates the AD was issued under CASA authority or delegated power, but the AD text does not set out the legal basis or enforcement mechanisms.

Practically, the AD’s mandatory language and the presence of an effective date and compliance window mean operators are put on notice of the change and the expectation of action. The AD does not state whether operators must notify CASA, retain documentary evidence, or file a compliance statement; the text is limited to mandating the schedule revision itself. For details on enforcement avenues, penalties or administrative procedures, users must consult the enabling legislation, CASA procedures, or Transport Canada material outside this AD, because those matters are not addressed in the AD’s text.

The AD explicitly cross-references and supersedes prior Airworthiness Directives and Transport Canada material. The Background explains that earlier measures were taken in response to in-flight pressurisation events; specifically, AD/CL-600/80 and Transport Canada AD CF-2003-05R1 had mandated a 4,000 flight-hour repetitive inspection for the same bulkhead check valves (Background). The AD states that the 4,000 flight-hour inspection "has since been superseded by a 3,000 flight-hour periodic discard task for these bulkhead check valves" and that AD/CL-600/118 "mandates revision of the approved maintenance schedule to incorporate the discard task" and "supersedes the instructions detailed in Corrective Actions, Part A, of Transport Canada AD CF-2003-05R1" (Background).

The AD also references Temporary Revision TR 1-2-39 dated 12 December 2008 to Maintenance Requirements Manual CSP A-053 Part 1 MRBR Section 2 as the source of the discard task (Requirement). That situates the new task within the MRBR, which is a standard industry-maintenance reference. The AD further notes Transport Canada AD CF-2009-31 dated 8 July 2009 as a reference (Requirement, Note). Therefore, the AD functions as a connecting instrument between CASA’s directive and Transport Canada’s MRBR and AD material.

The practical interaction, as documented in the AD, is a cascade: Transport Canada introduced the discard task via a TR to the MRBR, Transport Canada issued AD CF-2009-31 (noted), and CASA issued AD/CL-600/118 to require operators (under the stated applicability) to revise their Transport Canada approved maintenance schedule accordingly. The AD therefore modifies and displaces elements of earlier directives (CF-2003-05R1 and AD/CL-600/80) in favour of the discard-based approach.

The AD text does not identify or discuss enabling statutes, nor does it set out how this directive harmonises with regulatory frameworks in jurisdictions other than those documents expressly referenced. It does not state whether operators under other national authorities must take parallel action, nor does it explain bilateral recognition or reciprocity mechanisms. The document does not list or cite CASA’s legislative source of power in issuing ADs, nor the mechanisms for appeals or alternative methods of compliance.

In short, the AD interacts with other instruments by superseding prior corrective-action instructions in a named Transport Canada AD and by incorporating a TR to the Maintenance Requirements Manual as the technical basis for the new discard task. The AD cross-references Transport Canada AD CF-2009-31 and supersedes Corrective Actions Part A of Transport Canada AD CF-2003-05R1 as previously mandated by AD/CL-600/80, establishing a clear line of precedence among the referenced instruments within the AD’s text.

The AD text itself provides a concise timeline of related amendments and documents. The discard task that the AD requires was introduced by Temporary Revision 1-2-39 to the Maintenance Requirements Manual CSP A-053 Part 1 MRBR Section 2, and that TR is dated 12 December 2008 (Requirement). Transport Canada AD CF-2009-31, dated 8 July 2009, is explicitly referenced in a note to the Requirement (Requirement: Note). The AD itself is signed 14 August 2009 by James Coyne, Delegate of the Civil Aviation Safety Authority (signature block). The AD declares an effective date of 24 September 2009 (Compliance).

The Background section documents the sequence of prior actions that the AD supersedes. Initially, following reports of three in-flight cabin-pressurisation losses attributable to bulkhead check valve failure plus air supply duct failure, an earlier Australian AD (AD/CL-600/80, which in turn adopted Transport Canada AD CF-2003-05R1) had mandated a 4,000 flight-hour repetitive inspection task for P/N 92E20-3 and 92E20-4 bulkhead check valves (Background). That 4,000 flight-hour inspection regime was subsequently "superseded by a 3,000 flight-hour periodic discard task for these bulkhead check valves" (Background). AD/CL-600/118 therefore mandates revision of the approved maintenance schedule to incorporate the discard task and explicitly states it supersedes the instructions in Corrective Actions, Part A, of Transport Canada AD CF-2003-05R1, as previously mandated by AD/CL-600/80 (Background).

Key points of the amendment history supplied in the AD are therefore: December 2008, TR 1-2-39 introduced the discard task into CSP A-053 Part 1 MRBR Section 2; July 2009, Transport Canada AD CF-2009-31 was issued and is referenced; formerly an inspection regime at 4,000 flight-hours had been the mandated approach under earlier ADs; the AD is signed 14 August 2009 and becomes effective on 24 September 2009 with a 60-day compliance window after the effective date (Requirement, Background, Compliance, signature block).

The AD text does not provide any subsequent amendment or revocation history beyond stating that it supersedes prior corrective-action instructions. No further amendments to the AD itself, nor any later revision dates, are provided in the supplied document.

The supplied AD contains no information about litigation, judicial review, or disputes arising from AD/CL-600/118. The document does not reference any court decisions, administrative appeals, enforcement proceedings, or adjudications related to this directive. It does not identify any contested interpretations of the required discard task, nor does it provide records of compliance disputes or prosecutions.

Because the text contains no litigation history, there is no source-grounded material in this document on precedential rulings, case law, or outcomes that affected the AD’s scope, interpretation or enforceability. The AD does reference earlier Airworthiness Directives and Transport Canada documents (for example, Transport Canada AD CF-2003-05R1 and Transport Canada AD CF-2009-31, and AD/CL-600/80), but no adjudicative outcomes associated with those instruments are included in this document.

For practitioners seeking to know whether AD/CL-600/118 has been the subject of litigation, administrative review, or dispute over technical content or enforcement, this AD provides no record. Any such history would need to be located outside the AD text, in court records, administrative decision databases, or in contemporaneous regulatory correspondence; none of those materials are contained in the supplied document.

The absence of litigation material in the AD means the AD should be treated as a source of technical and administrative prescription only. If a user requires information on whether compliance obligations arising from the AD have been the subject of contested legal proceedings, they must consult external legal or regulatory databases, agency records, or court filings, because the AD itself does not supply that information.

Several practical pitfalls are apparent from the text and deserve attention for compliance planning. First, limited applicability. The AD applies only to Bombardier CL-600-2B19, Serial Numbers 7003 and subsequent (Applicability). Aircraft with serial numbers below 7003 are not covered by this AD text. Operators or maintenance organisations must not assume blanket applicability across all CL-600 variants or serial ranges; the AD’s wording confines the directive to a specifically enumerated subset.

Second, change of maintenance philosophy. The AD explicitly replaces an earlier 4,000 flight-hour repetitive inspection approach with a 3,000 flight-hour periodic discard task (Background). That is a change from inspection to discard, and it may be easy for organisations to misread the AD as merely modifying inspection frequency rather than introducing mandatory discard. The AD states the discard task "has since been superseded by a 3,000 flight-hour periodic discard task" and mandates incorporation of the discard task (Background, Requirement). Make sure planners include discard/replacement logic, not an inspection checklist.

Third, precise task identification. The AD requires incorporation of Task Number 21-51-21-13 specifically for P/N 92E20-3 and 92E20-4 (Requirement). Using an incorrect task number, or omitting the specified part numbers, may result in non-compliance even if similar maintenance activity is carried out. The AD ties compliance to the MRBR TR that introduced that task; operators should reference TR 1-2-39 dated 12 December 2008 for the exact task instructions.

Fourth, the TR and the MRBR are the technical source. The discard task is introduced in Temporary Revision 1-2-39 to Maintenance Requirements Manual CSP A-053 Part 1 MRBR Section 2 (Requirement). Failure to obtain or apply the correct MRBR TR wording could lead to an incorrect implementation of the discard procedure. Some operators might not have an up-to-date MRBR or may have different versions; the AD’s reference to TR 1-2-39 is the authoritative insertion point for the task.

Fifth, supersession of earlier ADs. The AD states it supersedes the instructions in Corrective Actions Part A of Transport Canada AD CF-2003-05R1 that had been mandated by AD/CL-600/80 (Background). Operators that believe they have complied with AD/CL-600/80 through inspections should verify that compliance corresponds to the new discard requirement. Compliance with the earlier inspection-only regime may not satisfy the current AD’s discard obligation.

Sixth, timing window. The compliance window is tight: "Within 60 days after the effective date of this AD unless previously accomplished" and the effective date is 24 September 2009 (Compliance). Operators who have not previously incorporated the TR discard task must implement the maintenance-schedule revision in that 60-day window. Late scheduling or assuming a grace period beyond 60 days would not satisfy the AD’s plain timing requirement.

Seventh, documentation of Transport Canada approval. The AD requires revision of the "Transport Canada approved maintenance schedule" (Requirement). For organisations that hold approvals under other national authorities, or for aircraft operating under different jurisdictional approvals, ensuring the Transport Canada approved schedule is updated is a distinct requirement. Misunderstanding which maintenance approval must be revised could create compliance gaps.

Eighth, vague enforcement language. The AD does not set out enforcement procedures, reporting requirements, or evidence-of-compliance mechanisms in its text (Penalties and enforcement). Therefore, a common pitfall is failing to generate and retain sufficiently clear documentary evidence that the approved maintenance schedule was revised and the discard task implemented, since the AD does not stipulate the form of evidence required.

Operators and maintenance organisations should therefore ensure they: verify serial-number applicability; obtain TR 1-2-39 to CSP A-053 Part 1 MRBR Section 2; incorporate Task 21-51-21-13 specifically for P/N 92E20-3 and 92E20-4; schedule discard at the 3,000 flight-hour periodic interval; complete the Transport Canada approved schedule revision within 60 days of 24 September 2009 unless already done; and retain clear documentation evidencing the schedule revision and task implementation.

The AD prescribes a straightforward compliance action and timeframe. To comply with AD/CL-600/118, an operator or maintenance organisation responsible for Bombardier CL-600-2B19 aircraft, serial numbers 7003 and subsequent (Applicability), must revise the Transport Canada approved maintenance schedule to incorporate Task Number 21-51-21-13, the discard task for bulkhead check valves P/N 92E20-3 and 92E20-4 (Requirement).

Step 1 , Confirm applicability. Confirm the aircraft serial numbers are within the affected range, specifically SN 7003 and subsequent, because the AD is limited to that subset (Applicability).

Step 2 , Obtain the technical source. Retrieve Temporary Revision (TR) 1-2-39 dated 12 December 2008 to Maintenance Requirements Manual CSP A-053 Part 1 MRBR Section 2, System and Powerplant Program. The AD identifies that TR as the document that introduced Task 21-51-21-13 and is therefore the technical source for the discard procedure and parameters (Requirement).

Step 3 , Identify the parts and task. Confirm the exact part numbers P/N 92E20-3 and P/N 92E20-4 and the specific Task Number 21-51-21-13 to be included in the maintenance schedule. The AD mandates incorporation of that task for those part numbers (Requirement).

Step 4 , Revise the Transport Canada approved maintenance schedule. Update the approved maintenance schedule documentation to include Task 21-51-21-13, using the TR content as the technical instruction. The AD requires that the "Transport Canada approved maintenance schedule" be revised, not merely the operator’s internal checklist (Requirement).

Step 5 , Meet the timing requirement. Implement the schedule revision within 60 days after the AD’s effective date, which the AD states is 24 September 2009, unless the revision has already been accomplished (Compliance). That means, under the AD’s text, the action should be completed on or before 23 November 2009 unless already completed.

Step 6 , Address the change from inspection to discard. Make explicit in planning documents that the MRBR Task 21-51-21-13 is a periodic discard task (3,000 flight-hour interval per Background) and not the earlier inspection task (4,000 flight-hour repetitive inspection) that AD/CL-600/80 and Transport Canada AD CF-2003-05R1 had previously mandated (Background). Ensure maintenance cycles, parts provisioning and downtime planning reflect discard at the 3,000 flight-hour periodic interval rather than inspection.

Step 7 , Coordinate approvals. Because the AD requires revision of the Transport Canada approved maintenance schedule, ensure that the revision is submitted through the appropriate Transport Canada approval channel for maintenance programmes. The AD does not specify the approval form, but its requirement is to revise the Transport Canada approved maintenance schedule (Requirement).

Step 8 , Retain documentary evidence. Although the AD does not specify reporting or record formats, operators should retain documentation evidencing the approved schedule revision, copies of TR 1-2-39 used to effect the change, and any maintenance records showing discard/replacement of P/N 92E20-3 and 92E20-4 components per Task 21-51-21-13. The AD’s compliance requirement is timing-based; documentary evidence will demonstrate that the schedule revision was accomplished within the 60-day window (Requirement, Compliance).

Step 9 , Review related ADs and notes. The AD notes Transport Canada AD CF-2009-31 dated 8 July 2009; operators may review that and the earlier AD CF-2003-05R1 and AD/CL-600/80 to ensure there are no other outstanding obligations that interact with the discard task (Requirement, Background).

Step 10 , Operationalise logistics. Plan for spare parts procurement and maintenance slots to meet the discard interval. The AD identifies the specific part numbers and the discard task interval (Background, Requirement), so supply-chain and maintenance planning should align to avoid grounded aircraft due to missing parts at scheduled discard intervals.

Following these steps fulfils the AD’s explicit mandate: revise the Transport Canada approved maintenance schedule to incorporate the discard task (Task 21-51-21-13) for P/N 92E20-3 and 92E20-4 within the prescribed 60-day period beginning on the AD’s effective date of 24 September 2009.