AD/CL-600/111 Amdt 1 - Nose Landing Gear Selector Valve

The AD introduces several key concepts that are standard in airworthiness regulation but are specific to this product.

Airworthiness Directive (AD): A legally enforceable notification issued by CASA under the Civil Aviation Safety Regulations. It requires repetitive or one-time inspections, modifications, or operational limitations to ensure continued safety. An AD has the same binding effect as a regulation. Non-compliance renders the aircraft unairworthy under CASR 1998 Part 39.

Applicable Service Bulletin (SB): The AD mandates compliance with specific Bombardier service bulletins, depending on the aircraft model. The AD lists these bulletins: SB 600-0721 Revision 03 (for CL-600-1A11), SB 601-0558 Revision 03 (for CL-600-2A12 and CL-600-2B16 (CL-601-3A/3R)), and SB 604-32-021 Revision 04 (for CL-600-2B16 (CL-604)). The AD permits accomplishment in accordance with earlier revisions (Revision 02 or 03, as applicable) but explicitly states that earlier revisions of the SB do not satisfy the AD. Only the listed revisions (or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada) are acceptable.

Valve Identification: The AD distinguishes between valves that require corrective action and those that do not, based on serial number (S/N), part number, and ink stamp markings. Valves with S/N suffix “T” (manufactured by Tactair Fluid Controls Inc.) are exempt. Valves manufactured by Kaiser Fluid Technologies, P/N 750006000, with S/N 0001 to 2126 inclusive, that have an ink stamp “SB750006000-1” have already been checked and reworked and require no additional action. The AD further prohibits installation of a Kaiser valve unless it bears that ink stamp. The Illustrated Parts Catalogue instruction is incorporated by reference.

Compliance Time: The AD sets a dual deadline: 250 flight hours from 30 July 2009 or the end of 30 January 2010, whichever is earlier. This is not a repetitive requirement; it is a one-time check. However, if a valve is replaced, the replacement valve must also meet the AD’s requirements (i.e., it must be of an acceptable configuration as defined by the notes).

Supersession: The AD supersedes AD/CL-600/86, which had mandated similar checks but with a narrower serial number range. The AD explicitly states that compliance with the earlier directive does not satisfy this AD. This is a key point: operators cannot rely on past compliance; they must recheck all affected valves based on the expanded criteria.

Amendment Nature: This is an amendment to AD/CL-600/111. The amendment corrects a typographical error in the service bulletin reference for the CL-601 model. No substantive changes to the technical requirements or compliance times. The AD includes the background note that Transport Canada AD CF-2009-21R1 dated 26 May 2009 is the source reference. That Canadian AD superseded CF-2006-16R1 and corrected an error in CF-2009-21.

Effective Date: The AD becomes effective on 9 May 2014. That is the date the amendment is gazetted or served. Aircraft operators must have met the compliance time (which expired in 2009/2010) by that date, meaning the AD is retrospective: it mandates that the action should have been completed already. Any aircraft not compliant by 9 May 2014 would be immediately non-compliant and unairworthy.

The AD applies to a defined population of aircraft registered in Australia. It does not apply to all CL-600 series aircraft globally, only those on the Australian register or operated by Australian operators (since CASA’s jurisdiction is limited to Australian-registered aircraft and Australian operators).

The applicability clause lists the following models and serial numbers:

• Model CL-600-1A11 (CL-600) with S/N from 1004 to 1085 inclusive.
• Model CL-600-2A12 (CL-601) with S/N from 3001 to 3066 inclusive.
• Model CL-600-2B16 (CL-601-3A/3R) with S/N from 5001 to 5194 inclusive.
• Model CL-600-2B16 (CL-604) with S/N from 5301 to 5665 inclusive.

Aircraft outside these serial number ranges are not affected. This limits the directive to a relatively small fleet. Operators of these specific airframes are the primary obligated parties.

Additionally, Note 5 clarifies that CL-600-2B16 (CL-605) aircraft with S/N 5701 or higher are not affected because they were delivered with acceptable valves. This is an important carve-out for those newer models.

The AD directly affects aircraft owners, operators, maintenance organisations, and continuing airworthiness management organisations (CAMOs). The operator is ultimately responsible for ensuring the aircraft complies with all applicable ADs. In practice, the maintenance provider (typically a Part 145 approved maintenance organisation) will perform the inspection, but the operator must ensure the work is scheduled and recorded. The cost of compliance falls on the operator: labour to inspect the valves, potential replacement of valves, and possible grounding if parts are unavailable. For valves that require rework, the operator may need to send the valve to an approved repair facility.

The AD also affects manufacturers and suppliers: it mandates that only valves with ink stamp “SB750006000-1” are acceptable for installation. This creates a market barrier for operators who might otherwise source used valves without the stamp. It also creates a compliance burden for parts distributors who must verify the marking before sale.

The AD interacts with the Australian aircraft register and the CASA AD database. If an aircraft is imported from a foreign register, the importer must check compliance with this AD before registering the aircraft in Australia. Since the deadline has passed, any import would require evidence that the AD has been complied with (or immediate compliance before operation).

Rent-seeking risks are low here: the AD is narrowly targeted at a specific safety defect with demonstrable risk. However, the compliance burden is concentrated on a small number of operators. The cost of compliance may be significant relative to the value of older Challenger aircraft, potentially accelerating retirement of affected airframes.

Duty to Inspect: The operator must ensure the NLG selector valve and NLG door selector valve on each affected aircraft are checked in accordance with the specified service bulletin. The check must be performed by the compliance deadline (250 flight hours or 30 January 2010). Since the deadline has passed, any aircraft that has not been checked is non-compliant and must be grounded until the check is performed.

Duty to Replace or Rework: If the check reveals a valve that is not of an acceptable configuration (i.e., not a Tactair valve with S/N suffix “T”, or not a Kaiser valve with the ink stamp “SB750006000-1”), the valve must be replaced or reworked in accordance with the service bulletin. The operator must arrange for appropriate corrective action.

Duty to Identify: After rework, the valve must be ink stamped “SB750006000-1”. This is a permanent marking requirement. The operator must ensure the stamp is applied and that the maintenance records reflect the change.

Duty Not to Install Unapproved Valves: Note 4 explicitly states that a Kaiser valve with P/N 750006000 and S/N from 0001 to 2126 inclusive must not be installed unless it bears the ink stamp. This is a prohibition on the installation of certain parts, even if the valve appears serviceable. This duty extends to maintenance organisations and parts suppliers.

Right to Use Alternative Means of Compliance: The AD does not explicitly provide for alternative means of compliance (AMOC). However, under CASR Part 39, CASA may grant an alternative method of compliance on application. The source text does not mention AMOC, but in practice, an operator could apply to CASA for approval of a different method, provided it is equivalent. The AD references Transport Canada AD, so any AMOC approved by Transport Canada might be accepted by CASA, but that is not stated.

Right to Use Earlier SB Revisions: The AD permits accomplishment in accordance with SB 600-0721 Revision 02 (16 June 2008), SB 601-0558 Revision 02 (16 June 2008), and SB 604-32-021 Revision 03 (16 June 2008). These earlier revisions may have slightly different instructions, but they are deemed acceptable. This right reduces the compliance burden somewhat, as operators may have already performed the check using an earlier revision, but only if that revision is listed. Original issuance or earlier revisions are not acceptable.

Right to Rely on Previous Compliance? No. The AD explicitly states that compliance with AD/CL-600/86 does not satisfy this AD. The expanded serial number range means that even if a valve was previously checked, it must be rechecked if it falls within the new range. This is a duty, not a right.

Duty to Record Compliance: The operator must document compliance in the aircraft maintenance records, including the serial number of the valves, the ink stamp status, and the service bulletin used. This is a standard requirement under CASR Part 42.

Duty to Comply Immediately Upon Import: For an aircraft being imported into the Australian register, the operator must ensure compliance before operation. Since the deadline is long past, the aircraft must have been complied with before the AD amendment effective date. If not, the aircraft cannot be operated.

Rights to Challenge? The AD is a legislative instrument. Operators may seek judicial review of the validity of the AD under the Administrative Decisions (Judicial Review) Act 1977 or the Civil Aviation Act, but the scope for challenging a safety directive is narrow. The AD’s technical basis would be hard to contest.

The AD is issued under the Civil Aviation Safety Regulations 1998, Part 39 (Airworthiness Directives). Non-compliance is a breach of the Regulations. Penalties under the Civil Aviation Act 1988 can be severe. For an operator, the maximum penalty for operating an aircraft that does not comply with an applicable airworthiness directive is up to $10,000 (penalty units) for an individual and up to $50,000 for a body corporate, per offence. Each day of continued operation may constitute a separate offence.

CASA can also take administrative action: it may suspend or revoke the Air Operator’s Certificate (AOC) or the Certificate of Registration of the aircraft. It may issue a direction to ground the aircraft until compliance is achieved. The AD itself does not specify penalties; the general law applies.

In addition to civil penalties, if non-compliance leads to an accident or incident, the operator may face criminal prosecution for reckless or negligent conduct under the Civil Aviation Act or the Criminal Code. However, the AD is a strict liability offence: the operator does not need to intend to breach; simply operating an aircraft that is not in compliance is enough.

Enforcement is risk-based. CASA may audit the aircraft’s maintenance records. If an aircraft is found not in compliance, CASA may issue a notice of proposed suspension or a show cause notice. The operator bears the burden of proving compliance. The AD itself has been in effect since 2009; by now, all affected aircraft should be compliant. Any new entrant (import) will be caught at registration.

The AD also has extraterritorial reach: Australian-registered aircraft must comply wherever they operate. If an aircraft is outside Australia and non-compliant, CASA can still take enforcement action.

The probability of detection for non-compliance is moderate. CASA conducts periodic surveillance and may cross-check AD compliance during ramp checks or maintenance audits. However, the fleet size is small, and many operators are diligent. The more significant penalty risk is in the event of an incident: if an uncommanded NLG retraction occurs and the AD was not complied with, the operator’s liability could be catastrophic (both regulatory and civil).

The AD does not create a private right of action. Third parties injured by non-compliance could sue for negligence, but the AD would be strong evidence of a duty of care and its breach.

The AD does not operate in isolation. It sits within a hierarchy of airworthiness regulation.

Civil Aviation Safety Regulations 1998 (CASR) Part 39: This is the direct legal basis for ADs. Part 39 prescribes the process for issuing, amending, and revoking ADs. The AD is a legislative instrument under that Part. Compliance with an AD is a condition of maintaining the aircraft’s Certificate of Airworthiness.

Civil Aviation Act 1988, Section 20A: This provision empowers CASA to issue ADs. The AD must be consistent with the Act and other regulations. It also interacts with the aircraft registration provisions: an aircraft must be in an airworthy condition to remain registered.

Transport Canada AD CF-2009-21R1: The AD states that this Transport Canada AD is the source. CASA has adopted the Canadian AD, with minor amendments. This reciprocal recognition is common under bilateral agreements. If Transport Canada later amends their AD, CASA may update this AD. Operators who also operate in Canada must comply with both versions; the most restrictive applies.

Part 42 of CASR (Continuing Airworthiness Management): Operators must have a system for tracking AD compliance. The AD must be added to the operator’s continuing airworthiness management system. Records must be retained as per Part 42.

Part 145 of CASR (Approved Maintenance Organisations): Only approved organisations may perform the inspection and rework. The service bulletin instructions may require specialised tooling or expertise. The maintenance organisation must hold the appropriate ratings for CL-600 series aircraft and for hydraulic components.

Civil Liability and Tort Law: The AD sets a standard of care. If an operator fails to comply and damage occurs, the operator may be liable for negligence per se. The AD would be admissible as evidence of the required standard.

The Act’s Interaction with Foreign Registries: If an Australian operator leases an aircraft from a foreign owner, the foreign owner may also have obligations under the state of registry. But the Australian operator remains responsible for compliance with CASA ADs. If the aircraft returns to the state of registry, the operator must ensure the foreign ADs are also met.

No Interaction with Competition or Consumer Laws in This Source: The source text gives no indication of impact on competition. However, the AD may affect the market for spare parts: only valves with the ink stamp are acceptable, creating a barrier for third-party parts suppliers.

Interaction with Insurance Policy Terms: Many aviation insurance policies require compliance with all applicable ADs as a condition of coverage. Non-compliance may void the policy or limit coverage for a claim. Operators should check their policy wordings.

The source provides limited amendment history.

AD/CL-600/111 was originally issued effective 30 July 2009. This was the first directive addressing the NLG selector valve issue on Challenger models. It superseded AD/CL-600/86, which had addressed an earlier, narrower serial number range. AD/CL-600/86 was cancelled.

This amendment, AD/CL-600/111 Amdt 1, is dated 29 April 2014 and becomes effective 9 May 2014. The amendment corrects a typographical error in the table in the requirement section. Specifically, the service bulletin reference for the CL-600-2A12 (CL-601) model was misstated in the original AD. The table is corrected to show SB 601-0558, Revision 03 for that model. No other changes to the technical requirements or compliance time.

The background notes also trace the Transport Canada AD history: TC AD CF-2009-21R1 dated 26 May 2009 is the source. That Canadian AD superseded TC AD CF-2006-16R1, which was the basis of CASA AD/CL-600/86. TC AD CF-2009-21R1 also corrected an error in TC AD CF-2009-21 dated 6 May 2009.

Thus, the lineage is:

• CASA AD/CL-600/86 (consistent with TC AD CF-2006-16R1)
• Superseded by CASA AD/CL-600/111 (consistent with TC AD CF-2009-21R1)
• Amended by AD/CL-600/111 Amdt 1 to correct the CL-601 SB reference.

There is no suggestion of further amendments in the source text. The amendment is purely administrative, not technical.

Because the compliance time has long passed (2009/2010), the amendment’s practical effect is to clarify which service bulletin is acceptable for the CL-601 model. For operators who relied on the erroneous SB reference in the original AD, the amendment does not create a new obligation; it simply ensures that the correct SB is listed. However, if a CL-601 operator originally used a different SB (not the corrected one), they might have been non-compliant. The amendment retroactively validates the correct SB. But the AD still requires check by the 2010 deadline; the amendment does not extend that deadline.

The source text does not mention any litigation. However, we can infer from general aviation law.

No reported Australian court cases specifically involving AD/CL-600/111 or its predecessors exist in the public domain. CASA ADs are rarely litigated in court; most disputes are resolved through administrative review or negotiation. However, there are general principles.

If an operator were to challenge the AD, the grounds might include:

• That CASA exceeded its power under the Act (unlikely, as Part 39 explicitly authorises ADs).
• That the AD was procedurally invalid (e.g., failure to consult or give notice). But CASA is not required to consult before issuing an emergency AD.
• That the AD was unreasonable or disproportionate. Judicial review on “unreasonableness” is very difficult to succeed, especially for a safety directive with a sound technical basis.

There may have been enforcement actions where CASA penalised an operator for non-compliance with this AD. Such actions are not typically published in law reports. CASA’s enforcement outcomes may be listed on its website, but no specific case is cited.

In Canada, there may have been challenges to Transport Canada AD CF-2009-21R1. But the source does not mention any.

A related area of litigation might arise from an accident where NLG collapse occurred and the AD was not complied with. Civil claims for damages would likely be settled or go to trial, but they would not be reported as “AD litigation”. Negligence actions could include the AD as a factor.

Given the small fleet size, the likelihood of any recorded litigation is low. The AD is straightforward, the defect is clearly identified, and compliance is achievable. Most operators will comply without dispute.

From an economic perspective, litigation imposes transaction costs. If an operator believed the AD was unnecessary, the cost of compliance might be less than the cost of a legal challenge. The absence of litigation suggests that the AD’s costs are accepted as necessary for airworthiness.

Several provisions could trip up even diligent operators:

Compliance Deadline is in the Past: The AD became effective on 9 May 2014, but the compliance time required action by the earlier of 250 flight hours after 30 July 2009 or 30 January 2010. That means any aircraft that has not been checked by that date is immediately non-compliant upon the AD’s effective date. There is no grace period. An operator who acquired an aircraft after 2010 without verifying compliance could be caught.

Supersession Trap: The AD states that compliance with AD/CL-600/86 does not satisfy this AD. If an operator thinks they are compliant because they did the earlier check, they are wrong. The expanded serial number range means a valve that was previously excluded (S/N 0768 to 2126) must now be checked. And the earlier AD may have only required checking certain valves, not all. The AD explicitly says “whether or not an aircraft has previously been checked” is irrelevant.

Valve Serial Number Interpretation: The affected Kaiser valves have S/N 0001 to 2126 inclusive. A valve with S/N 2127 is not affected. But a valve with S/N 0767 (the old upper limit) is still affected if within 0001-2126. Operators must check the actual S/N, not rely on past records.

Suffix “T” Exemption: Valves with a “T” suffix are exempt. But note that “T” suffix might appear on valves from other manufacturers (Tactair). If a valve is from Kaiser, even if it has “T” suffix? The source says valves with S/N suffix “T” have been manufactured by Tactair and do not require corrective action. So a Kaiser valve would not have a “T” suffix. But an operator could mistakenly think all “T” suffix valves are exempt, when a Kaiser valve might have “T” in the S/N for other reasons? The source is clear: only Tactair valves are so marked.

Ink Stamp Imperative: Note 4 says a Kaiser valve must not be installed unless it is ink stamped “SB750006000-1”. This applies even if the valve has been reworked but the stamp was not applied. The stamp is a physical mark. An operator who receives an overhauled valve from a repair facility must verify the stamp. If missing, it cannot be installed. This could be overlooked in logistic chains.

Illustrated Parts Catalogue: Note 4 says the IPC gives this instruction. Operators should ensure their IPC is current. The AD incorporates the IPC by reference; if the IPC is revised, the operator may need to check.

Service Bulletin Revisions: Only specified revisions are acceptable. Revision 02 or 03 as listed. If an operator uses Revision 01 (original issuance), it does not satisfy the AD. The AD explicitly says original issuance or earlier revision does not satisfy. This could catch operators who have not updated their bulletins.

CL-601 Model SB Correction: The amendment corrects the SB for CL-601. An operator who used the wrong SB (e.g., SB 600-0721 on a CL-601) may have been non-compliant. The amendment clarifies, but the operator may need to redo the work if they used the incorrect SB.

Effective Date vs Compliance Date: The AD becomes effective 9 May 2014, but compliance date was 2010. If an aircraft has not been checked, it is non-compliant on 9 May 2014. The operator cannot get a grace period; they must ground the aircraft until the check is done. There is no transitional arrangement.

No Alternative Means of Compliance Provided: The AD does not mention AMOC. If an operator wants to use a different method, they must apply to CASA. That process can be slow. The AD does not specify that approval from Transport Canada is automatically accepted.

CRJ Aircraft Are Not Affected But Referenced: The background mentions CRJ occurrences. Operators of CL-600 may not realise the link; but the valve part numbers are different. Still, the note emphasises the risk.

Record Keeping: The operator must ensure the maintenance records reflect not just the inspection, but the specific valve S/N and stamp status. If records are incomplete, the operator may be unable to prove compliance in an audit.

For any operator still managing compliance with this AD (e.g., for a recently imported aircraft or an aircraft that has not been operated for years), the steps are:

1. Identify Affected Airframes: Confirm that the aircraft model and serial number fall within the applicability table. If the aircraft is a CL-600-2B16 (CL-605) with S/N 5701 or higher, it is not affected. If it is a CL-604 with S/N outside 5301-5665, not affected. If in doubt, check the type certificate data sheet.

2. Locate the NLG Selector Valve and NLG Door Selector Valve: The valves may be accessible through the nose wheel well. Obtain the part number and serial number from the data plate. Record them.

3. Determine Valve Configuration:

• If the valve is a Tactair (S/N suffix “T”): no further action required. Record the exemption.
• If the valve is Kaiser Fluid Technologies P/N 750006000 and S/N is within 0001 to 2126 inclusive, inspect for ink stamp “SB750006000-1”.
  • If the stamp is present: no further action. Record the stamp.
  • If the stamp is absent: proceed to step 4.
• If the valve is a different P/N or S/N outside range: may not be affected, but check the service bulletin applicability. The SB applies to certain valves; the AD requirement is to check in accordance with the SB. If the valve is not listed in the SB, it may not need action, but the operator should confirm with the SB.

4. Perform Corrective Action: If the valve requires rework or replacement, order the correct part (acceptable valve per the AD). The service bulletin provides instructions for rework (likely end cap torque check and lock- wiring). The rework must be performed by an approved maintenance organisation. After rework, ensure the valve is ink stamped “SB750006000-1”.

5. Install Only Approved Valves: If replacing a valve, ensure the replacement meets the AD criteria: either a Tactair valve with “T” suffix, or a Kaiser valve with ink stamp. Do not install an unmarked Kaiser valve even if it appears new.

6. Update Maintenance Records: Log the check, the valve S/N, and the stamp status. Record the service bulletin revision used. This is essential for CASA audits and for future transfers of ownership.

7. Verify Continuing Compliance: If the aircraft is being imported, request previous maintenance records proving compliance with this AD. If records are missing, assume non-compliance and perform the check before operation.

8. Consider Alternative Means of Compliance: If the SB instructions are not cost-effective (e.g., the aircraft is a one-off configuration), apply to CASA for an AMOC. Provide evidence of equivalent safety. This is likely to be unnecessary for most operators.

9. Monitor Future Amendments: CASA may issue further amendments if Transport Canada revises its AD. Operators should subscribe to CASA’s AD alerts to track any changes to this directive.

10. Budget for Costs: The inspection labour is modest (a few hours), but if a valve needs replacement, the part cost can be significant (thousands of dollars) plus downtime. Operators should plan for potential grounding if parts are not immediately available. The economic impact is concentrated but manageable. The alternative (non-compliance) risks an AD breach and potential accident liability. For a low-time operator, the marginal benefit of compliance far outweighs the cost, given the risk of NLG collapse.