AD/CL-600/67 - Horizontal Stabilizer Trim Actuator

The AD is built around a small set of technical and procedural concepts taken from the aircraft component and maintenance chain. The central hardware concept is the HSTA lower gimbal primary pin and its potential to migrate. The AD requires a "special check" to measure the clearance between the yoke and the lower side of the gimbal pinhead immediately prior to the modification (Requirement 1a). If migration is evident the AD mandates replacement of the HSTA before further flight (Requirement 1b). If migration is not evident, the AD mandates installation of a gimbal pin kit and re-identification of the HSTA, or replacement with an already-modified unit (Requirement 1c). The specified kits and P/Ns are Bombardier P/N 600K0720 and Goodrich P/N 52-210050; the re-identification standard is Goodrich VSB21207-00X-27-05.

The procedural concept set includes reliance on manufacturer service bulletins and an acknowledgement of foreign-state action. Compliance must be "in accordance with the applicable Service Bulletin (SB) listed below, or later Transport Canada approved revisions" (Requirement 1). The applicable SBs are SB 600-0720 for CL-600-1A11 and SB 601-0555 for CL-600-2A12 and CL-600-2B16, both dated 31 January 2005 (Requirement 1). The AD explicitly references Transport Canada AD CF-2005-20 as related (note in Requirement column).

Timing and scope concepts are central to the AD. Compliance is framed two ways: an hours-in-service limit and a calendar deadline, whichever occurs first , "within 600 hours time in service from the effective date of this directive but not later than 30 November 2006" (Compliance 1). For spare and replacement HSTAs the requirement is effective immediately for installation purposes , they must be modified "from the effective date of this Directive, prior to being installed on any aircraft" (Compliance 2).

Record and feedback concepts are included. If an HSTA shows migration and is replaced, the AD requires notification to Bombardier within seven days by completing and forwarding the Feedback form provided with the applicable Service Bulletins (Requirement 1b). The AD sets out specific part numbers and a re-identification procedure, which creates a traceable altered-part status for both installed and spare HSTAs (Requirement 1c; Requirement 2).

Safety justification is stated: two instances of lower gimbal primary pin failure were found during routine maintenance and, while operation was not impaired in those instances, the AD’s analysis recommends installation of additional pin retainer brackets to mitigate migration risk (Background). The AD therefore mixes preventive inspection, modification, part-identification, manufacturer feedback, and alignment with an overseas regulator’s AD to manage an identified hardware migration risk.

The AD specifies applicability by model and serial number ranges. It applies to Bombardier Inc. Models CL-600-1A11 serial numbers 1004 through 1085; CL-600-2A12 serial numbers 3001 through 3066; and CL-600-2B16 serial numbers 5001 through 5194 (Applicability). That identifies a cohort of aircraft types and serial number ranges to which the AD obligations attach. Any operator, owner, or maintenance organisation responsible for those specific aeroplanes must address the AD’s requirements for the HSTA on those identified aeroplanes.

The instrument speaks to parts suppliers and maintenance supply chains through its requirement that replacement and spare HSTAs be modified with the specified gimbal pin kit and re-identified prior to installation (Requirement 2; Compliance 2). That creates an obligation affecting whoever controls inventory of HSTAs or supplies parts to the aircraft owners/operators for these model/serial ranges.

Bombardier and Goodrich are named as stakeholders by part numbers and re-identification procedure. Bombardier is the recipient of required feedback when migration is found during inspection; the directive instructs operators to "notify Bombardier of the failure by completing and forwarding the Feedback form provided with the applicable SBs" within seven days (Requirement 1b). Goodrich is the source of the re-identification procedure (Goodrich VSB21207-00X-27-05) and a supplier P/N is Goodrich P/N 52-210050 (Requirement 1c). Transport Canada is referenced as the regulator whose approved revisions to the SBs are acceptable, and the AD notes Transport Canada AD CF-2005-20 as related (Requirement note).

The instrument does not specify who pays for inspections, replacements, or modifications. The AD uses imperatives , "Accomplish the following" and "Replacement/spare HSTAs shall be modified" , but it does not allocate financial responsibility in the text. The AD is issued by the Civil Aviation Safety Authority, and the signature shows James Coyne as the CASA delegate issuing the instrument on 15 August 2005, with an effective date of 29 September 2005. Therefore the decision to require the specified action was taken by CASA through a delegated officer and is binding for aeroplanes within the stated applicability.

The AD does not identify exemptions, waivers, or an appeal route within its text. It also does not identify any specific maintenance organisations or classes of operator that are excluded. The compliance windows and "prior to installation" requirements create an immediate operational effect on both in-service aircraft and inventories of spare replacement actuators.

The AD imposes discrete duties on those responsible for the affected aeroplanes and HSTAs. The primary duties are:

• Immediate pre-modification inspection: "Immediately prior to proceeding with the Horizontal Stabiliser Trim Actuator (HSTA) modification in paragraph 1.c below, carry out a special check of the HSTA lower gimbal pin for migration by measuring the clearance between the yoke and the lower side of the gimbal pinhead" (Requirement 1a). This creates a step that must be performed at a defined point in the maintenance sequence.

• Replacement where migration is evident: "If gimbal pin migration is evident, replace the HSTA before further flight" (Requirement 1b). This duty has an operational effect; the aircraft may not continue flying with a migrated pin in place because replacement is required before further flight.

• Notification duty to Bombardier: "Within seven (7) days of the inspection, notify Bombardier of the failure by completing and forwarding the Feedback form provided with the applicable SBs" (Requirement 1b). This creates an information-flow requirement tied to the manufacturer’s feedback mechanism.

• Modification or replacement: "If there is no evidence of gimbal pin migration, modify the HSTA by installing the gimbal pin kit (Bombardier P/N 600K0720; Goodrich P/N52-210050) and re-identify the HSTA as per Goodrich VSB21207-00X-27-05; or replace the installed HSTA with a HSTA that has previously been modified with the gimbal pin kit" (Requirement 1c). This preserves two compliance paths: retrofit or exchange with a pre-modified unit.

• Spare/replacement parts duty: "Replacement/spare HSTAs shall be modified with the gimbal pin kit (Bombardier P/N 600K0720; Goodrich P/N 52-210050) and re-identified as per Goodrich VSB 21207-00X-27-05" (Requirement 2). The AD insists on modification and re-identification for spares before fitment.

• Compliance timing: Carry out required action "within 600 hours time in service from the effective date of this directive but not later than 30 November 2006, whichever occurs first" (Compliance 1). For spare/replacement HSTAs, modification must occur "from the effective date of this Directive, prior to being installed on any aircraft" (Compliance 2).

The AD does not state any formal rights for those affected such as an internal review, exemption, or compensation right. The instrument also does not specify alternative means of compliance, beyond allowing "later Transport Canada approved revisions" to the listed Service Bulletins as the standard for executing the required actions (Requirement 1). That is the only explicitly provided route to vary procedural detail: use of the SBs or later Transport Canada approved revisions.

Operators thus have the duty to inspect, replace or modify, re-identify modified parts, and notify Bombardier when migration is found. Maintenance organisations carrying out these duties must follow the listed Service Bulletins, and use the specified part numbers and re-identification process. The AD’s language assigns obligations in terms of actions to be completed, but it does not allocate costs, indemnities, or other contractual rights.

The AD text does not specify penalties, infringement notices, or enforcement procedures in statutory terms. It does not state fines, administrative sanctions, or criminal penalties. The instrument provides mandatory technical and timing requirements but does not include within the text any description of enforcement mechanisms or specific consequences for non-compliance.

What the instrument does specify is the compliance timeline and the operational requirement that, where migration is evident, the HSTA must be replaced "before further flight" (Requirement 1b), which establishes an operational restriction. The directive also sets the effective date as 29 September 2005 and provides a hard compliance timeframe: within 600 hours time in service or by 30 November 2006, whichever is earlier (Compliance 1). These timing features create clear expectations that may be enforced by the Civil Aviation Safety Authority or during regulatory oversight, but the AD’s text does not itself describe enforcement modalities.

The AD places procedural duties on operators to use the listed Service Bulletins "or later Transport Canada approved revisions" (Requirement 1). Compliance with SBs and ADs is the normal basis on which aviation regulators judge airworthiness; however, this document does not set out how CASA will monitor, audit, or prosecute non-compliance. The instrument also does not define any documentation/record-keeping standards beyond the instruction to "re-identify the HSTA as per Goodrich VSB21207-00X-27-05", which implies a traceable change of status for modified units, and the requirement to forward Bombardier a completed Feedback form when migration is found (Requirement 1b). Those traceability measures create an evidentiary trail that regulators can require in enforcement interactions, but the AD itself does not spell out investigatory or penalty procedures.

In short, this AD mandates technical and timing obligations, specifies part numbers and SBs, and creates action-specific operational constraints, but it contains no express penalty clause or step-by-step enforcement mechanism within its text.

The AD explicitly interacts with another regulator and with manufacturer-issued service documents. It instructs that the required actions be "in accordance with the applicable Service Bulletin (SB) listed below, or later Transport Canada approved revisions" (Requirement 1). That makes Transport Canada’s approval of later SB revisions an accepted compliance path, thereby recognising an overseas regulator’s continuing authority to refine the technical procedures without requiring immediate amendment of this AD.

The AD also references "Transport Canada AD CF-2005-20" in the note attached to Requirement, indicating that the same technical problem has been addressed by a foreign state regulator and that operators and maintainers should be aware of that foreign AD. This cross-reference may affect the content of the SBs and the technical instructions acceptable for compliance.

The AD requires re-identification "as per Goodrich VSB21207-00X-27-05" and specifies Bombardier and Goodrich part numbers for the gimbal pin kit. That embeds manufacturer instructions and part-management procedures into the compliance regime and therefore interacts functionally with the standards for parts traceability and maintenance recordkeeping that aviation regulators enforce. Though this AD does not cite particular aviation regulations by number, it is an instrument of the Civil Aviation Safety Authority and therefore functions within the broader statutory and regulatory framework governing airworthiness in Australia.

The text does not reference other domestic statutes, subordinate regulations, certification standards, or judicial remedies. It does not discuss export controls, customs, or commercial contract law. The notable cross-jurisdictional link is the acceptance of Transport Canada approved SB revisions and the express reference to Transport Canada’s AD CF-2005-20. The AD therefore incorporates, as permissible compliance methods, technical updates approved by the Canadian authority and mandates use of manufacturer SBs for the physical work and part re-identification.

The text of the directive itself contains dates and a limited documentary trail but no subsequent amendments or revisions. The AD is dated 10/2005, lists Service Bulletins dated 31 January 2005, and provides an effective date of 29 September 2005. The signature block shows James Coyne, Delegate of the Civil Aviation Safety Authority, with the date 15 August 2005. The document also contains internal repetition of the AD identifier and heading but does not present any later amendments or replacement ADs within the text provided.

The AD allows for compliance using "later Transport Canada approved revisions" to the listed Service Bulletins, which is the only mechanism within the document for authorised change to the technical method of compliance without a formal amendment to the AD text. That suggests that operators may follow updated SBs if those updates have the requisite Transport Canada approval; however, the instrument as provided contains no record of Transport Canada revisions or of any acceptance history.

There is a single cross-reference to Transport Canada AD CF-2005-20, but no indication in this text that the AD itself has been amended to reflect any developments arising from that foreign AD. No re-issuance dates, corrigenda, or superseding instruments appear in the supplied text.

If a reader requires a complete legislative or administrative amendment history beyond what this document shows, that is not contained in the AD text. The AD as presented shows an initial issue sequence (SBs dated 31 January 2005, delegate signature 15 August 2005, effective date 29 September 2005, compliance deadlines to 30 November 2006), and it accepts the prospect of later Transport Canada-approved SB revisions as authorised alternatives for the technical work.

The AD text contains no litigation history. It does not reference any judicial decisions, administrative appeals, or disputes relating to AD/CL-600/67. There are no citations to cases, determinations, or court orders within the supplied material. The directive simply records the technical requirement, the service documents to use, effective and compliance dates, and the background safety rationale.

Because the document does not include any record of legal challenges, injunctions, or enforcement proceedings, the AD provides no information about how courts or tribunals have interpreted or applied its requirements. The only procedural trace is the procedural linkage to Transport Canada AD CF-2005-20 and the manufacturer Service Bulletins. Any litigation that may exist concerning this AD, these SBs, or the underlying component failures is not recorded within the supplied text.

Professionals seeking litigation history or precedent must therefore look beyond this document, because the AD itself does not provide cases, appeals, or enforcement actions referencing its operation.

The AD contains a number of specific procedural and timing details that can create operational pitfalls if overlooked.

• Immediate pre-modification check. The AD requires a "special check" to be carried out "immediately prior to proceeding with the Horizontal Stabiliser Trim Actuator (HSTA) modification" (Requirement 1a). This sequencing means that an inspection conducted substantially earlier than the modification may not satisfy the AD’s instruction. If maintenance teams read the AD as merely requiring a prior inspection without regard to the "immediately prior" timing, they risk non-conformance with the AD’s stated procedure.

• Migration without impairment. The background notes that in both reported failure cases the primary pin "had not migrated to the extent that the operation of the HSTA was impaired." That creates a gotcha in that absence of discernible operational problems does not remove the need to inspect and, absent migration, to modify. Operators cannot rely on a lack of symptomatic failure to defer action.

• Replacement "before further flight." If migration is evident, the AD requires replacement "before further flight" (Requirement 1b). That is an operational constraint that can ground the aircraft until a replacement HSTA is installed. Logistics for obtaining a modified replacement HSTA or performing the retrofit on-site must be considered in maintenance planning.

• Seven-day feedback requirement. When migration is found and an HSTA is replaced, the operator must "Within seven (7) days of the inspection, notify Bombardier of the failure by completing and forwarding the Feedback form provided with the applicable SBs" (Requirement 1b). Operators must therefore have access to the applicable SBs and the Feedback form, and a process to complete and forward the form within the seven-day window.

• Parts and re-identification specifics. The AD prescribes specific part numbers for the gimbal pin kit (Bombardier P/N 600K0720; Goodrich P/N 52-210050) and requires re-identification "as per Goodrich VSB21207-00X-27-05" (Requirement 1c; Requirement 2). Using the wrong kit P/N or failing to re-identify per the indicated Goodrich VSB may result in a non-compliant installation.

• Spare HSTAs requirement. The AD mandates that "Replacement/spare HSTAs shall be modified" and re-identified before being installed, effective from the AD's effective date (Requirement 2; Compliance 2). This means inventory control practices must ensure that no unmodified spare HSTA is fitted after the effective date. The compliance obligation applies to parts in inventory as well as to installed parts.

• Dual compliance timeframe. The AD uses a mixed compliance trigger: a service-hours threshold (600 hours time in service) and a calendar backstop (not later than 30 November 2006), "whichever occurs first" (Compliance 1). Maintenance planners must track both hours-in-service and the calendar date to determine the actual deadline for each airframe.

• Reliance on SBs and Transport Canada approvals. The AD requires work "in accordance with the applicable Service Bulletin ... or later Transport Canada approved revisions" (Requirement 1). If an operator follows a later SB revision, it must confirm that Transport Canada has approved that revision. Blind reliance on an SB revision without confirming Transport Canada approval may not meet the AD’s stated compliance route.

• No penalties stated. Because the AD does not specify penalties or enforcement procedures in its text, operators may mistakenly assume there is flexibility where the regulator intends none. The lack of penalty text does not mean the AD is unenforceable; rather, enforcement mechanisms are external to the printed AD.

• Records and traceability. The AD requires re-identification of modified parts but does not prescribe the exact form of the record-keeping. Operators must therefore ensure their maintenance records capture re-identification per Goodrich VSB standards and the required notification to Bombardier when migration is found, because those records underpin compliance evidence.

Compliance with the AD requires a sequence of actions tied to the Service Bulletins and the specified parts, with attention to timing and record-keeping. The AD lists the required SBs and provides compliance windows; follow those elements exactly.

Step 1 , Confirm applicability. Check that your aeroplane model and serial number fall within the AD’s applicability: CL-600-1A11 serial numbers 1004 through 1085; CL-600-2A12 serial numbers 3001 through 3066; CL-600-2B16 serial numbers 5001 through 5194 (Applicability). If your aircraft is not in those ranges, the AD, as written, does not apply.

Step 2 , Use the applicable Service Bulletin. Perform all required work "in accordance with the applicable Service Bulletin (SB) listed below, or later Transport Canada approved revisions" (Requirement 1). The SBs named are: SB 600-0720 dated 31 January 2005 for CL-600-1A11, and SB 601-0555 dated 31 January 2005 for both CL-600-2A12 and CL-600-2B16 (Requirement 1). If you intend to use a later revision of those SBs, confirm Transport Canada approval of that revision before relying on it for AD compliance.

Step 3 , Pre-modification special check. Immediately prior to proceeding with the physical modification, carry out a special check of the HSTA lower gimbal pin for migration by "measuring the clearance between the yoke and the lower side of the gimbal pinhead" (Requirement 1a). Ensure the inspection is performed at the point in time specified by the AD , "immediately prior to" modification , to satisfy the AD’s sequencing.

Step 4 , If migration is evident. If the special check reveals gimbal pin migration, replace the HSTA "before further flight" (Requirement 1b). After replacement, within seven days of the inspection, complete and forward the Feedback form provided with the applicable SBs to Bombardier to notify them of the failure (Requirement 1b). Keep a record of the inspection results, the replacement action, and the submitted Feedback form.

Step 5 , If migration is not evident. If the special check shows no migration, modify the HSTA by installing the gimbal pin kit specified (Bombardier P/N 600K0720; Goodrich P/N 52-210050) and re-identify the HSTA as per Goodrich VSB21207-00X-27-05 (Requirement 1c). Alternatively, you may replace the installed HSTA with one that has already been modified with that same kit and re-identification. Ensure re-identification marks and maintenance records comply with the Goodrich VSB instructions.

Step 6 , Spare and replacement HSTAs. From the effective date of the AD, ensure that no replacement or spare HSTA is installed unless it has been modified with the gimbal pin kit and re-identified according to Goodrich VSB21207-00X-27-05 (Requirement 2; Compliance 2). Update inventory controls and parts procurement practices so that only modified and re-identified HSTAs are fitted after the effective date.

Step 7 , Observe the compliance window. Complete the inspection/modification for in-service installed HSTAs "within 600 hours time in service from the effective date of this directive but not later than 30 November 2006, whichever occurs first" (Compliance 1). Track each airframe’s time in service and the calendar date to determine the applicable deadline for that airframe.

Step 8 , Documentation and records. Record the special check measurement, any replacement, the installation of the gimbal pin kit including the kit part numbers (Bombardier P/N 600K0720; Goodrich P/N 52-210050), and the re-identification per Goodrich VSB21207-00X-27-05. If migration is found and a replacement performed, retain a copy of the Feedback form submitted to Bombardier and any correspondence confirming receipt.

Step 9 , Follow-up and conformity. Ensure that maintenance procedures and quality control steps reflect the SB instructions and any later Transport Canada approved SB revisions. If relying on a later SB revision, maintain proof of Transport Canada approval of that revision as part of the compliance record.

Step 10 , Operational planning. Anticipate that if migration is detected the aircraft cannot fly until the HSTA is replaced. Plan logistics for obtaining modified replacement HSTAs or for performing the retrofit in a timely fashion to manage aircraft availability.

The AD becomes effective on 29 September 2005. For any procedural detail not specified in the AD text, rely on the applicable Service Bulletin and any Transport Canada approved revision of that bulletin, and retain documentary proof of compliance steps, part numbers used, and notifications made.