AD/CL-600/112 - Main Landing Gear Torque Link Apex Pin

Airworthiness directive (AD). An AD is a legally enforceable notice issued by CASA under the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations (CASR). It mandates corrective action on aircraft that have been found to have an unsafe condition that exists or is likely to exist in other aircraft of the same type. An AD has the force of law; failure to comply renders the aircraft unairworthy and may attract civil penalties or enforcement action. This AD is directed at Australian‑registered aircraft of the specified models, but its effect is also felt by operators leasing into Australia or performing maintenance under CASA’s jurisdiction.

Service bulletin (SB). Bombardier Aerospace SB 670BA‑32‑019 is a manufacturer‑issued document that provides detailed instructions for inspection, rework or replacement. The AD makes compliance with the SB mandatory. Two versions are referenced: the original (16 March 2006) and Revision A (18 September 2008). The AD allows the original issue to satisfy Requirements 1 and 2, but Requirement 3 and the default compliance method require Revision A (or later Transport Canada‑approved revision). This illustrates the concept of “approved revision” - only later changes that are formally approved by Transport Canada, not merely any version, are acceptable.

Continuing airworthiness. The AD implements a one‑time corrective action, not a recurring inspection. However, the prohibition on installing certain spare parts (Requirement 3) has an ongoing effect: any affected landing gear shock strut that is not reworked per the SB can never be installed on any of the listed serial numbers. This imposes a permanent restriction on the maintainability of the aircraft fleet unless the parts are reworked.

Effectivity and serial number applicability. The AD applies only to specific serial number ranges, which are not contiguous. For example, CL‑600‑2D15 and CL‑600‑2D24 serial numbers 15001 through 15035, plus 15038, 15039 and 15042. The gaps (15036, 15037, 15040, 15041, 15043 onwards) mean those aircraft are not subject to Requirement 1. This pinpoints the affected population to only those aircraft that the manufacturer determined may have the incorrect stack‑up tolerances or installation. It reduces the compliance burden for unaffected owners, but it also creates a trap: the operator must correctly confirm the aircraft serial number.

Prior satisfaction. The AD explicitly states that Requirement 1 is not required if Requirement 2 has already been accomplished, or if REO 670‑32‑11‑0022 or Goodrich SCR 0056‑05 has been incorporated. This avoids double compliance. Similarly, work done under the original SB issue counts for Requirements 1 and 2. This is a concession to earlier voluntary actions that may have been prompted by the earlier SB, and it reduces the cost of compliance for operators who acted before the AD became effective. However, the AD does not provide the same credit for all previous versions; only the original SB and the specific REO/SCR are accepted.

Delegation and foreign ADs. The AD is signed by a delegate of CASA but references Transport Canada AD CF‑2009‑20 and requires approval of later revisions by Transport Canada’s Chief, Continuing Airworthiness. This recognises the primacy of the state of design authority. CASA has adopted the Canadian airworthiness directive in substance, with the same compliance periods and applicability. This harmonisation reduces duplication and allows Australian operators to rely on existing international compliance arrangements.

The primary duty holders are the registered operators and owners of the specified aircraft models. However, the impact extends to maintenance organisations, lessors, spare‑parts suppliers, and anyone performing maintenance or installation work on the affected landing gear components.

Aircraft operators. Any person operating an Australian‑registered Bombardier Challenger CL‑600‑2C10, CL‑600‑2D15 or CL‑600‑2D24 with a serial number within the stated ranges must ensure compliance. This includes private operators, charter operators, corporate flight departments, and any entity that flies the aircraft (including foreign operators who register the aircraft in Australia). The compliance timeline (900 or 4,500 flight hours) imposes a scheduling obligation: the inspection and replacement must be completed before the hour limit, which may require grounding or arranging maintenance at a convenient point. For operators who fly infrequently, the 900‑hour limit may be many years away, but they must still track it.

Maintenance organisations. Maintenance providers must have access to the relevant service bulletin and understand the differences between the original SB and Revision A. They must verify which serial numbers are affected, especially for Requirement 1 where the specific serial list is very narrow. They must also check whether the aircraft has already had the nut replacement (Requirement 2) to avoid duplicating inspection. If an operator has a shock strut assembly in stock as a spare, the maintenance organisation must refuse to install it unless it has been reworked per SB 670BA‑32‑019, Revision A. This creates an inventory compliance burden: maintaining a record of which spare landing gear parts are eligible.

Lessors and financiers. Parties with a security interest in the aircraft (such as lessors or banks) have an indirect interest. Non‑compliance with the AD renders the aircraft unairworthy, which may breach lease covenants, impair residual value, and ground the asset. The lessor may need to ensure the lessee is in compliance, and if the aircraft is to be re‑leased, the AD compliance status must be documented.

Spare parts suppliers and dealers. The prohibition on installation of shock strut assemblies with specific P/Ns and serial numbers means that these parts cannot be sold for use on the listed aircraft unless reworked. A supplier holding such parts must either have them reworked or sell them only for non‑aeronautical use or onto aircraft not covered by the AD. The compliance burden falls on inventory management.

CASA and Transport Canada. The AD is an instrument of CASA but relies on Transport Canada’s continuing oversight. Any operator wishing to use a later revision of the SB must check that Transport Canada has approved it. This cross‑border coordination is common in aviation but adds a layer of administrative cost: the operator must verify the approval status before using any updated SB.

The AD affects a relatively small fleet (hundreds of aircraft globally, a fraction of which are Australian‑registered). The cost per aircraft is moderate: a detailed visual inspection is low‑cost, while nut replacement and shock strut rework may involve significant downtime and parts cost. The immediate prohibition on installing non‑reworked spare parts could strand assets or force premature replacement of serviceable parts. The burden is concentrated on a few private and commercial operators, who bear the full cost, but the benefit (reduced risk of landing gear collapse) is diffuse (safety of passengers, crew and others). This is typical of an AD: society gains, but the cost is borne by the operators. The AD does not provide compensation.

Duty to comply. The primary duty is to perform the mandated actions within the prescribed compliance times. The aircraft must not be operated beyond those flight hour limits without completing the inspection or replacement. This is an absolute duty; there is no allowance for extensions unless the aircraft is flown to a place where the work can be done, but the AD itself does not grant a ferry flight exemption. Operators may apply for an alternative means of compliance (AMOC) under CASR, but that is a separate administrative process.

Duty to maintain records. Operators must document that the AD has been complied with. This includes retaining a record of the service bulletin used, the date and flight hours at compliance, the serial number of any parts replaced, and the work performed. These records are essential for showing the aircraft is airworthy and for subsequent sales or lease transitions.

Right to use alternative revisions. The AD permits the use of “later revision approved by the Chief, Continuing Airworthiness, Transport Canada”. This gives operators and maintenance organisations the flexibility to adopt future improvements to the service bulletin without requiring a new AD, provided the revision is approved. However, the operator has the burden of confirming that Transport Canada actually approved the revision; there is no automatic acceptance of any later revision.

Right to rely on prior compliance. The AD explicitly accepts prior actions: the original SB issue for Requirements 1 and 2, the REO or SCR for Requirement 1, and Requirement 2 if already done. This reduces compliance costs for those who acted early. However, the operator must be able to prove that the prior action took place and to the correct standard. If the records are missing, the operator may need to repeat the work.

Right to install reworked parts. The prohibition in Requirement 3 is lifted if the part has been reworked per the specified SB. Once reworked, the part becomes eligible for installation. This preserves the use of existing inventory, albeit at the cost of the rework.

Obligation to check serial numbers. Because the AD applies only to certain serial number ranges, the operator has a duty to correctly identify the aircraft’s serial number and, for Requirement 3, the serial numbers of any spare landing gear shock strut assemblies. Misidentification may lead to either unnecessary compliance (if the aircraft is not actually affected) or non‑compliance (if it is affected but not caught). The latter is more serious, as operating the aircraft in non‑compliance would be illegal and could affect insurance and liability.

No right to ignore the AD. The AD is legally binding. An operator cannot decide that the safety risk is low enough to forgo compliance. The background cites four reports, which is a small sample, but the regulator has determined that the condition is unsafe. The operator may not substitute its own judgment for the regulatory requirement.

Potential for AMOC. While not mentioned in the AD, CASA may approve alternative means of compliance under CASR Part 39. An operator who wishes to use a different method (such as a more frequent inspection or a different modification) must apply to CASA and demonstrate an equivalent level of safety. This is a right, but it is discretionary and may be costly to obtain.

The AD is issued under the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations 1998 (CASR). Non‑compliance exposes the aircraft operator and possibly the maintenance organisation to civil penalties, criminal prosecution in serious cases, and administrative sanctions.

Civil penalties. Under the Civil Aviation Act, a person (including a body corporate) who operates an aircraft not in accordance with an airworthiness directive commits an offence. The maximum penalties are significant: for an individual, up to 50 penalty units (currently $14,180 per penalty unit, though the value at the time of the AD would have been different); for a body corporate, up to 250 penalty units. Each day of operation may constitute a separate offence. CASA can also issue infringement notices (on‑the‑spot fines) for certain non‑compliance, although that is more common for less serious breaches.

Criminal liability. If the non‑compliance leads to an accident causing death or serious injury, the operator may face charges under the Criminal Code or the Civil Aviation Act for reckless or negligent operation. While the AD itself does not create criminal liability, the failure to comply could be evidence of negligence or recklessness in a subsequent prosecution.

Enforcement actions. CASA has a range of enforcement tools. It can suspend or cancel the Air Operator’s Certificate (AOC), the Certificate of Registration, or the Airworthiness Certificate of the aircraft. It can also issue a grounding order (a direction not to fly) if the aircraft is found to be non‑compliant. These administrative actions can be very costly for an operator, leading to lost revenue and reputational damage. CASA may also refer the matter to the Director of Public Prosecutions.

Economic impact. For a corporate operator, the cost of non‑compliance may extend beyond penalties. Insurance policies may exclude coverage if the aircraft is operated in breach of an AD. Lease agreements may contain clauses that make non‑compliance an event of default, allowing the lessor to terminate the lease and repossess the aircraft. Residual value of the aircraft will be impaired if the AD history is not properly documented.

Enforcement history. Although the AD itself has not been litigated (no court judgments are cited), CASA has a track record of enforcing AD compliance. In other cases, CASA has prosecuted operators for flying aircraft with expired ADs or incomplete records. The regulator tends to treat AD compliance as a high priority because ADs go to the core of airworthiness.

Defences. A person charged may argue that the AD does not apply to the specific aircraft (e.g., serial number outside the range) or that the work was done in accordance with the accepted alternative (original SB, REO, SCR). But ignorance of the AD is not a defence. The AD is published in the AWB (Airworthiness Bulletin) and on CASA’s website.

Cost of compliance vs. cost of non‑compliance. The cost of the one‑time inspection is modest (a few hours of labour), and the nut replacement is moderate. The prohibition on spare parts may force an operator to rework a component earlier than planned, adding cost. However, the cost of non‑compliance could be far higher: a landing gear collapse would lead to hull damage or total loss, injuries, liability to third parties, grounding, and regulatory action. The AD thus creates an economic incentive to comply, but for a risk‑averse operator with many aircraft, the cumulative cost of compliance across the fleet may be substantial.

Civil Aviation Act 1988 and CASR. The AD is a legislative instrument under section 98 of the Act and Part 39 of CASR. It has the same force as any regulation. It prevails over any inconsistent contract or manual unless an exemption applies. The Civil Aviation Act gives CASA the power to issue ADs, and it also empowers CASA to enforce them. The interaction is straightforward: the AD supplements the existing regulatory framework for continuing airworthiness.

Part 42 of CASR - Continuing Airworthiness. Part 42 sets out the general obligations of operators to maintain aircraft in an airworthy condition and to comply with airworthiness directives. The AD is one specific directive that must be incorporated into the operator’s continuing airworthiness management system. The operator must ensure that the AD is entered into the aircraft’s maintenance schedule or that the compliance is tracked separately. Failure to do so may also be a breach of Part 42.

Manufacturer’s service bulletins. The AD makes compliance with SB 670BA‑32‑019 (Revision A or original) mandatory. Service bulletins are normally optional, but once embodied in an AD, they become legally binding. Operators who have not complied with the SB before the AD must now do so. The SB also interacts with other manufacturer documents, such as the Illustrated Parts Catalog and Maintenance Manual; the rework instructions may reference those documents.

Transport Canada AD CF‑2009‑20. The AD is based on the Canadian directive. For an aircraft that is also registered in Canada or operated under a Canadian‑type certificate, compliance with the CASA AD may be deemed equivalent. However, if the Canadian AD later is revised (e.g., a later revision of the SB approved by Transport Canada), the CASA AD incorporates that approval. Operators should monitor the Canadian version for any changes or clarifications.

Other ADs. The Bombardier Challenger series is subject to many ADs. This AD must be read together with other ADs affecting the main landing gear, corrosion protection, or structural components. There may be overlapping requirements; for example, if another AD already requires replacement of the torque link apex nut, this AD may have been satisfied. Operators must carefully cross‑check the ADs and maintenance records.

Contracts and insurance. The AD does not directly modify private contracts, but it imposes performance obligations that may trigger contractual duties. A lease may require the lessee to maintain the aircraft in accordance with all ADs. A maintenance contract may require the maintenance organisation to inspect for AD compliance. An insurance policy will typically exclude cover for losses arising from operation not in accordance with regulatory requirements, including ADs. Thus the AD indirectly affects private law relationships.

Work health and safety laws. The operator also has duties under occupational health and safety legislation to ensure a safe workplace, which includes maintaining aircraft in a safe condition. Compliance with the AD is a key part of discharging that duty, and failure could lead to WHS prosecution alongside aviation regulation enforcement.

Import/export regulations. If an affected aircraft is sold or imported into Australia, the AD must be complied with or shown to have been complied with. The prohibition on installing certain shock strut assemblies also affects the importation of spare parts: a part that cannot be installed on the listed aircraft may still be imported for other uses, but the importer must be aware of the restriction.

No‑fault liability. The AD does not create a right of action for damages. However, if an accident occurs and the operator had not complied with the AD, that non‑compliance would be strong evidence of negligence, making it harder to defend a civil claim. Conversely, compliance with the AD is not a complete defence, but it demonstrates that the operator took reasonable steps.

This AD is a single‑issue directive. It has not been amended. The source document shows an effective date of 30 July 2009 and a compliance schedule with no subsequent revisions. The AD references Service Bulletin 670BA‑32‑019 Revision A (18 September 2008) and the original issue (16 March 2006). The AD itself has not been superseded by any later CASA directive for these serial numbers (as of the knowledge of the analyst; the user has not provided any later versions). However, the AD does allow the use of later revisions of the service bulletin, provided they are approved by Transport Canada. So the underlying technical instructions may have changed, but the AD text remains the same.

In practice, an operator must check if CASA has issued any later ADs that supersede or amend AD/CL‑600/112. Typical reasons for an amendment would be: extension of compliance times, addition of new serial numbers, revised inspection intervals, or supersession by a more comprehensive AD. None are shown here. The AD essentially incorporates the service bulletin by reference, so if the service bulletin undergoes a major change (e.g., a new method of inspection), the AD would need to be updated unless the change is merely an “approved revision” under the existing AD. The AD’s reference to “later revision approved by the Chief, Continuing Airworthiness, Transport Canada” is a form of living amendment: as Transport Canada approves new revisions, those automatically become acceptable under the CASA AD, without CASA having to issue a new AD. This is efficient but requires the operator to monitor Transport Canada’s approval status.

The AD also cross‑references Transport Canada AD CF‑2009‑20. If Canada amends or supersedes that AD, CASA may follow suit with a new AD. At the time of writing, no such amendment has been provided.

The amendment history of the service bulletin itself is relevant: the original SB was issued 16 March 2006, and Revision A (the baseline for the AD) was issued 18 September 2008. It is possible that later revisions (B, C, etc.) have been issued. The operator must not assume that any later revision is automatically acceptable; only those “approved by the Chief, Continuing Airworthiness, Transport Canada” count. The operator should check with Bombardier or Transport Canada.

The source does not mention any legal challenges to this AD. There are no known court cases involving AD/CL‑600/112 in Australia. Airworthiness directives are rarely litigated directly, because the law clearly gives CASA the power to issue them, and judicial review is available but costly. Typically, operators comply or seek an AMOC rather than fight the AD. The only litigation that might arise would be in the context of prosecution for non‑compliance, where a defendant could argue that the AD was invalidly issued (e.g., ultra vires or procedural error). No such case has been reported for this AD.

Outside Australia, Transport Canada AD CF‑2009‑20 may have been challenged or interpreted in Canadian courts, but that would not be binding in Australia.

The lack of litigation does not mean the AD is uncontroversial. It means that the compliance burden (inspection and replacement) was not considered onerous enough to warrant a legal battle, or that operators preferred to comply rather than risk enforcement. The prohibition on installing spare parts (Requirement 3) could theoretically be challenged by a parts supplier who had a large inventory of non‑reworked units, but no such challenge is recorded.

An operator facing enforcement could raise a defence that the AD was not properly published or that the delegate lacked authority. The AD is signed by a delegate of CASA and was published in the Airworthiness Bulletin. The Civil Aviation Act delegates extensive powers, and such defences rarely succeed unless there is a clear procedural flaw.

If an accident occurred and a plaintiff alleged the AD was insufficient, the AD’s adequacy could be tested in civil litigation. The AD itself would be evidence of the regulatory standard, but a court could find that a reasonable operator should have done more. No such litigation has been reported for this specific AD.

In summary, the litigation history is blank. That is typical for a routine safety AD. The risk of litigation is low provided operators comply. The AD has been in force for over 15 years, and most affected aircraft are likely compliant.

Narrow serial number gaps. Requirement 1 applies to CL‑600‑2D15 and CL‑600‑2D24 serial numbers 15001 through 15035, plus 15038, 15039 and 15042. Serial numbers 15036, 15037, 15040, 15041, and 15043 onwards are excluded. If an operator owns serial number 15036, they are not subject to Requirement 1, but they may still be subject to Requirement 2 (which covers 15001 through 15057). The difference is easy to overlook. An operator who misreads the table and assumes all serial numbers in the range are affected may over‑comply (which is harmless but wasteful). An operator who misses the specific three numbers may under‑comply if they own one of those.

Old SB credit has limits. The AD says that inspection performed to the original SB (16 March 2006) satisfies Requirement 1, and replacement/rework to the original SB satisfies Requirement 2. However, Requirement 3 (the prohibition on spare parts) demands rework to Revision A or later. If an operator has a spare shock strut that was reworked per the original SB only, it is not acceptable for installation. This could catch out operators who relied on the earlier SB for spares.

No credit for other earlier modifications. Only the specific REO (670‑32‑11‑0022) and Goodrich SCR 0056‑05 are accepted as alternatives for Requirement 1. If an operator had some other modification or repair that effectively addressed the condition, it does not count unless CASA issues a specific AMOC. The AD is narrow in its acceptance.

Foreign‑registered aircraft. The AD applies to Australian‑registered aircraft. If an Australian operator leases a foreign‑registered aircraft, that aircraft is not subject to this AD (unless the state of registry has adopted an equivalent AD). But the lessee may still have obligations under the lease to comply with manufacturer’s SB. Also, if the aircraft is later imported into Australia, compliance will be expected.

Spare parts serial numbers with prefixes. The AD notes that serial numbers “can start with MA, MAL or MA‑”. An operator must be able to read the full serial number and strip the prefix to determine if the numeric part falls within the prohibited range. A part with serial number MA‑0100 is not in the range 0001‑0284 (since 0100 < 0284, it is covered). But if the serial number is MA‑0300, it is outside the range and acceptable. Many maintenance records may not have the full prefix. The burden is on the installer to verify.

No extension of compliance times. The AD provides no provision for extensions or grace periods. If the inspection is due at 900 flight hours and the aircraft reaches 901, it is technically non‑compliant. However, an operator could apply for an AMOC before the deadline if they anticipate difficulties. The AD does not itself provide for a ferry flight, so if the aircraft is away from base, it may need to fly to a maintenance facility before reaching the limit, which could force the operator to perform the work at a less convenient location.

Ongoing applicability after initial compliance. Once Requirement 1 and Requirement 2 are done, there is no further action required unless a later revision of the AD imposes recurring inspections. The current AD is one‑time only. But the prohibition on spare parts (Requirement 3) is ongoing: every time an affected shock strut assembly is sourced as a spare, it must be reworked. An operator who maintains a stock of spare landing gear may need to rework those parts even if they are never intended for installation on the specific serial numbers, because they could inadvertently be installed.

Compliance is a multi‑step process that involves identification, planning, execution, and recordkeeping.

Step 1: Determine applicability. The operator must first confirm the aircraft model and serial number. This should be done by reference to the aircraft’s Certificate of Registration and the type certificate data sheet. The AD applies only to CL‑600‑2C10 serial numbers 10003 and subsequent, and CL‑600‑2D15 and CL‑600‑2D24 serial numbers 15001 and subsequent. However, the specific requirements have narrower ranges. The operator should create a checklist:

• Is the aircraft one of the listed models? If yes, note the serial number.
• For Requirement 1: is the serial number in the range 10003‑10223 (‑2C10) or 15001‑15035, 15038, 15039, 15042 (‑2D15/‑2D24)? If yes, proceed.
• For Requirement 2: is the serial number in the range 10003‑10239 (‑2C10) or 15001‑15057 (‑2D15/‑2D24)? If yes, proceed.
• For Requirement 3: all aircraft with serial numbers 10003 and subsequent (‑2C10) and 15001 and subsequent (‑2D15/‑2D24) are subject to the spare part prohibition. This applies regardless of whether they have met Requirements 1 or 2.

Step 2: Check maintenance records. Examine the aircraft logbooks and historical records to see if Requirements 1 or 2 have already been accomplished under the original SB or the accepted alternatives. Look for entries referencing SB 670BA‑32‑019, original issue or Revision A, or REO 670‑32‑11‑0022, or Goodrich SCR 0056‑05. Also check if the apex nut has been replaced (Requirement 2) as that waives Requirement 1. If records show compliance, no further action is needed for those requirements, but the operator should still verify the records are complete and correct.

Step 3: Plan the work. For Requirement 1, schedule a detailed visual inspection at or before 900 flight hours from the effective date (30 July 2009). Since the AD is old, any surviving affected aircraft will have long passed 900 flight hours; the operator must ensure the inspection was done in the past. If not, immediate grounding and compliance are needed. For Requirement 2, schedule the nut replacement at or before 4,500 flight hours. Most aircraft will have also passed that, so the work should be verified. For Requirement 3, check inventory of spare main landing gear shock strut assemblies: any with P/N 49000‑11 to 49000‑22 and serial number 0001‑0284, or P/N 49050‑5 to 49050‑10 and serial number 1001‑1114, must be reworked per SB 670BA‑32‑019 Revision A (or later Transport Canada‑approved revision) before they can be installed. If the spare part is already reworked, it is eligible.

Step 4: Obtain the service bulletin. The operator or maintenance organisation must obtain the latest approved revision of Bombardier SB 670BA‑32‑019. As of the AD, Revision A is the baseline. If a later revision exists and is approved by Transport Canada, that may be used. The operator should verify with the distributor or Transport Canada that the revision is approved. It is not sufficient to download any version from a website.

Step 5: Perform the inspection and replacement. The work must be carried out by an appropriately licensed aircraft maintenance engineer (LAME) or an approved maintenance organisation (AMO) under CASR Part 145. The tasks are detailed in the SB. The inspection is a one‑time detailed visual of the torque link apex joint. The replacement/rework involves the apex nut. The rework of shock strut assemblies for spare parts must also follow Part B of the SB. The operator should ensure that the inspector or engineer understands the specific serial number applicability and the difference between requirements.

Step 6: Document compliance. After the work, the maintenance release must reference this AD (AD/CL‑600/112) and the service bulletin used. The aircraft logbook entry should record: the AD number, the requirement satisfied (1, 2, or both), the date, the flight hours at compliance, the SB revision used, the part numbers and serial numbers of any replaced components, and the signature of the certifying person. For spare parts, the rework should be recorded on the part’s maintenance tag and in its history.

Step 7: Manage spare parts inventory. For Requirement 3, any affected shock strut assemblies that have not been reworked must be either sent for rework or disposed of. The operator should maintain a register of spare landing gear assemblies and their compliance status. Before any installation, the mechanic must check that the part is eligible under this AD.

Step 8: Monitor for later revisions. Although the AD is effective from 2009, operators should periodically check with Bombardier or Transport Canada to see if later SB revisions have been approved. The AD allows the use of approved later revisions, which could simplify compliance (e.g., a new revision may provide an easier inspection method). The operator is not required to adopt later revisions, but doing so may reduce cost or improve safety.

Step 9: Seek AMOC if necessary. If the operator cannot comply with any requirement (e.g., the aircraft has a unique modification that conflicts), application should be made to CASA for an alternative means of compliance under CASR 39.008. This should be done well in advance of the compliance deadline.

Step 10: Retain records indefinitely. Continued airworthiness requires that AD compliance records be kept for the life of the aircraft. The operator should ensure that records are transferred if the aircraft is sold or leased. Failure to produce records can result in the need to repeat the work.

By following these steps, the operator will be in compliance with the AD. The cost and effort are modest for most operators, but the prohibition on spare parts may catch those with older inventory. The key is to verify records and serial numbers accurately, and to use the correct service bulletin revision.