AD/DHC-8/103 Amdt 1 - Cockpit Door Hinge Attachment

The directive introduces or relies on several key concepts drawn from aviation regulatory practice and the specific Bombardier modification documentation. Understanding these is essential for compliance.

Airworthiness Directive (AD). This is a mandatory regulatory document issued by CASA under Part 39 of the Civil Aviation Safety Regulations (CASR) that requires an aircraft owner or operator to inspect, modify, or otherwise maintain an aircraft to correct an unsafe condition. ADs are law; failure to comply can lead to the aircraft being unairworthy and enforcement action. This particular AD is numbered DHC-8/103 Amdt 1, meaning it is the 103rd AD for the DHC-8 type and the first amendment to that AD.

Modsum. This is a Bombardier term for a modification summary. A Modsum is a documented set of engineering instructions that describe how to physically alter an aircraft from its original configuration. Here, three Modsums are referenced: 8Q100859, 8Q900267, and 8Q902145 (the latter for the striker plate and latch block rework). Each Modsum corresponds to a specific change and has its own service bulletin. The directive does not reproduce the instructions but requires compliance with the associated Bombardier Service Bulletin and any later Transport Canada approved revision.

Service Bulletin (SB). These are manufacturer-issued documents that provide instructions for optional or mandatory modifications or inspections. When referenced in an AD, the SB becomes mandatory as part of the directive. The AD cites Bombardier SB 8-52-54 (original issue or Revision A) for requirement 1, SB 8-52-58 for requirement 2, and SB 8-52-61 for requirement 3. The phrase “or a later Transport Canada approved revision” allows the manufacturer to issue improvements to the SB without requiring a new AD, provided Transport Canada (the primary certifying authority for this Canadian-designed aircraft) approves the revision. This is important because it delegates some compliance flexibility to the manufacturer’s ongoing development process.

Dash numbers. The directive uses a notation “-( )” in part numbers to denote all dash numbers. For example, the cockpit door installation has part numbers such as 82510074-( ), meaning any suffix (e.g., -1, -2, etc.) is covered. This prevents any ambiguity about which specific variant of the door installation is affected.

Serial number grouping. The AD divides the fleet into two main groups based on serial number. The first group (requirements 1 and for some also note 1) covers most early aircraft. The second group (requirements 2 and 3) covers a later set of serial numbers, including those that appear to have been delivered with a different baseline hinge design. The AD also notes that for the second group, prior incorporation of Modsum 8Q200015 is required before the hinge modification can be done. This means some aircraft may need additional work before the main AD action.

Striker plate and latch block. These are parts of the door latching mechanism. The striker plate is the part mounted on the door frame that the door latch engages. The latch block is the part on the door that engages the striker. The background indicates that the hinge block rotation caused disengagement of the hinge pin, which in turn could stress the door attachment. The additional rework in requirement 3 addresses a separate but related weakness in the striker plate and latch block area. The AD does not state the exact failure mode that led to the striker plate rework, but it is reasonable to infer that Transport Canada’s continued investigation of the hinge issue revealed a need to reinforce the latching system as well.

Transport Canada AD CF-2005-34R1. This is the parent airworthiness directive issued by the Canadian regulator. Note 3 in the AD states that the Transport Canada AD is referred to. The Australian AD is consistent with the Canadian AD, a common practice since the DHC-8 is a Canadian type certificate holder aircraft. The background explicitly states that Amendment 1 is issued in response to a revision of the Transport Canada AD. This shows coordination between regulators but also means Australian operators must track Canadian AD revisions that are incorporated by reference.

Effective date. The directive becomes effective on 20 December 2007. That is the date from which requirement 3’s compliance clock starts. For requirements 1 and 2, the compliance date was already set from 27 October 2005, so the effective date of the amendment does not restart that clock. This is a subtle but important point: the amendment does not give extra time for the hinge modification; it only adds a new task for a subset of aircraft.

Sole signatory. The AD is signed by David Villiers as Delegate of the Civil Aviation Safety Authority on 7 November 2007, with the effective date of 20 December 2007. This indicates the AD was prepared and approved in accordance with CASA’s delegation framework.

Fleet coverage. The applicability paragraph lists DHC-8 Models 102, 103, 106, 201, 202, 301, 311, 314, and 315, with serial numbers 003 through 557. This covers essentially all Dash 8 Series 100, 200, and 300 aircraft delivered up to that serial number range. Later models (Series 400) are not covered. The directive’s scope is limited to aircraft equipped with specific cockpit door part numbers; if a door has been replaced with a non-listed part number, it may not be affected, but the AD applies to any aircraft originally fitted with those parts or subsequently fitted with them.

The primary persons and entities affected by this airworthiness directive are the owners and operators of Bombardier DHC-8 series aeroplanes that fall within the specified applicability. This includes regional airlines, charter operators, freight carriers, government agencies, and private owners who operate any of the listed models (102, 103, 106, 201, 202, 301, 311, 314, 315) with serial numbers 003 through 557, provided the aircraft is equipped with a cockpit door having one of the listed part numbers. Because the DHC-8 is predominantly used in commercial regional passenger service, the directive has the greatest impact on scheduled airlines such as QantasLink (which operates a large fleet of Dash 8 aircraft in Australia), Virgin Australia Regional Airlines, and various smaller commuter airlines. Each of these operators must ensure that every affected aircraft in their fleet is modified within the compliance time.

The directive also affects maintenance organisations. Approved maintenance organisations (AMOs) holding the appropriate ratings for DHC-8 airframe work will be called upon to perform the modifications. The AMO must have access to the Bombardier Service Bulletins and Modsum instructions, which typically require purchase from the manufacturer or from a distributor. The AMO must also ensure that any prior modifications (8/2337, 8/3339, or 8Q200015) are already incorporated before proceeding with the hinge modification, adding complexity to the work package.

Parts suppliers and distributors are also affected indirectly. They may need to source the hinge kit, striker plate, latch block, and associated hardware for the Bombardier service bulletins. Since Bombardier holds the type certificate, the replacement parts must be produced in accordance with the type design or be approved under a parts manufacturer approval (PMA) or equivalent, though the directive does not specify this.

CASA itself is affected in its oversight capacity. The directive creates a regulatory obligation that CASA must enforce. CASA inspectors will need to verify compliance during routine airworthiness reviews or may conduct targeted audits. If an operator fails to comply, CASA may ground the aircraft, issue a direction to comply, or seek civil penalties under the Civil Aviation Act.

The manufacturer, Bombardier (now part of De Havilland Canada after the program sale), is affected because it must continue to support the service bulletins and make them available. The directive references Transport Canada approved revisions, meaning Bombardier must maintain the technical data and submit revisions to Transport Canada for approval.

Insurance companies may also be indirectly affected. Non-compliance with an AD can affect the airworthiness certificate and therefore the validity of hull and liability insurance. If an aircraft not in compliance with AD/DHC-8/103 suffers an incident, the insurer might deny coverage on the ground that the aircraft was not maintained in an airworthy condition.

Importantly, the directive does not exempt any operator based on the aircraft’s usage. Whether the aircraft is used for scheduled passenger service, charter, freight, or private pleasure, the AD applies equally. The cost impact falls disproportionately on smaller operators with fewer aircraft, as the fixed cost of understanding and managing the compliance program per aircraft may be higher. For airlines with large fleets, the modifications can be scheduled during routine maintenance to minimise downtime, but the one-year compliance for requirement 3 may force earlier hangar visits for aircraft that were not due for heavy maintenance at that time.

The directive also affects future purchasers of affected aircraft. A pre-purchase inspection should verify compliance with all applicable ADs, including this one. If not already complied, the buyer must factor the cost of the modification into the purchase decision.

Finally, the Australian public is affected in the sense that safe operation of aircraft is a public good. The AD’s purpose is to prevent an unsafe condition that could lead to a decompression event and possible loss of cabin pressure or door failure. The cost of the modification is internalised by operators and ultimately passed on to passengers through ticket prices, but the benefit of reduced risk of accident is diffuse.

The central duty imposed by this directive is on the owner or operator of an affected DHC-8 aircraft to ensure the aircraft is modified in accordance with the requirements and within the specified compliance times. This is a non-delegable responsibility in the sense that even if the owner contracts with an AMO to perform the work, the owner remains legally responsible for airworthiness compliance under the Civil Aviation Act and the Civil Aviation Safety Regulations. The duties can be broken down as follows:

Duty to modify the hinge attachment. For aircraft in the first serial number group (003 through 451, with exclusions), the owner must accomplish the modification described in requirement 1. This is not optional: the aircraft may not be operated after the compliance date unless the modification is done. The modification must be in full accordance with Bombardier Service Bulletin 8-52-54 (original or Revision A, or later Transport Canada approved revision). If the aircraft is in the specified sub-range (003 through 407, 409 through 412, 414 through 433), the owner must first ensure that Modifications 8/2337 and 8/3339 are already installed. That imposes a duty to check the aircraft’s modification status and, if those two prior mods are missing, to install them before attempting the hinge work.

Duty to modify using the alternative Modsum. For the second serial number group (452, 464, 490, 506, 508 through 557), the owner must comply with requirement 2 using Modsum 8Q900267 per SB 8-52-58. Again, prior modification (Modsum 8Q200015) must be in place first. This duty is independent of requirement 1; the two groups are exclusive.

Duty to rework the striker plate and replace the latch block. This is the new duty introduced in Amendment 1, applying only to the second serial number group. The owner must either have already accomplished requirement 2 as of 20 December 2007 and then within 12 months accomplish requirement 3a, or if requirement 2 is not yet done, the striker plate rework and latch block replacement must be done concurrently with the hinge modification. This duty means that even if the hinge modification was already done in accordance with requirement 2 before the effective date, the aircraft still needs an additional modification within one year. Owners who completed requirement 2 after the effective date must do both at the same time, potentially increasing the complexity and cost of the maintenance event.

Duty to comply with compliance times. The compliance times are absolute: requirements 1 and 2 must be met by 27 October 2007 (within 24 months after 27 October 2005). This date has already passed at the effective date of the amendment. Therefore, any aircraft not modified by that date is immediately in breach of the AD as of 20 December 2007. For requirement 3, the compliance time is 12 months after 20 December 2007, i.e., 20 December 2008. The AD explicitly states that the compliance time for requirements 1 and 2 remains unchanged by this issue of the directive. This prevents any misconception that the amendment grants an extension.

Duty to use approved revisions. The duty to comply includes the obligation to use the latest Transport Canada approved revision of the service bulletin, not necessarily the original issue. If Bombardier issues a revision that Transport Canada approves, the owner must follow that revision. This imposes a duty to monitor for updates to the referenced documentation.

Rights. The directive does not explicitly grant rights, but some rights can be inferred. The right to use later Transport Canada approved revisions is a flexibility that can reduce the compliance burden if the manufacturer improves the modification procedure or provides less arduous methods. The owner also has the right to apply to CASA for an alternative means of compliance (AMOC) under Part 39 of CASR, though the directive does not mention this. Generally, under CASR, an operator can propose an AMOC that provides an equivalent level of safety; CASA may approve it as an alternative to the strict requirements of the AD. The right to obtain and use the referenced service bulletins and Modsum instructions is also a practical right, though it comes at a cost.

No right to defer. Importantly, the aircraft owner has no right to defer compliance beyond the specified dates without CASA’s explicit approval. Any extension would require a formal exemption or an AMOC.

The directive itself does not prescribe specific penalties; enforcement is governed by the broader Civil Aviation Act 1988 and the Civil Aviation Safety Regulations (CASR). However, the Airworthiness Directive is a legislative instrument, and failure to comply with it renders the aircraft unairworthy. Operating an aircraft that does not conform to its approved type design or is not in a condition for safe operation (including compliance with all applicable ADs) is an offence.

Under CASR Part 42 (continuing airworthiness), the owner or operator is responsible for ensuring that the aircraft is maintained in an airworthy condition. If an aircraft has not complied with an AD, it is not airworthy. Operating or permitting the operation of such an aircraft can lead to civil penalty proceedings. The Civil Aviation Act section 20A provides for civil penalties of up to 1,000 penalty units for individuals and 5,000 penalty units for bodies corporate for contravening a safety provision. A penalty unit is currently $313 (as of 2023 but indexing applies), so maximum penalties for a body corporate could be in the range of $1.565 million per contravention. However, this directive dates from 2007, and the penalty unit values have changed over time; the point is that the financial penalty can be substantial.

Additionally, CASA may take administrative enforcement action. This includes issuing a direction to the operator to ground the aircraft until compliance is achieved. Under section 20BB of the Civil Aviation Act, CASA can give a written direction in the interests of safety. Failure to comply with such a direction can lead to further penalties. CASA may also suspend or cancel the aircraft’s certificate of airworthiness or the operator’s air operator’s certificate (AOC) if systemic non-compliance is found.

For an individual, such as a pilot-in-command or a chief engineer, there are also potential personal consequences. A pilot who operates an aircraft known to be in non-compliance with an AD may be in breach of the Civil Aviation Act and could face enforcement action including licence suspension.

Practical consequences include that the aircraft’s maintenance release (the certificate of release to service) cannot be signed off unless all applicable ADs are complied with. Insurance may also be voided. If an incident occurs due to the uncorrected condition (hinge block rotation leading to door release), the operator could face litigation from passengers or third parties, and the non-compliance with an AD would severely weaken any defence.

The enforcement history of this specific AD is not detailed in the source, but CASA generally enforces AD compliance through its routine surveillance activities. Because the DHC-8 fleet is well known and the AD was coordinated with Transport Canada, it is likely that compliance has been closely monitored. Given that the compliance times for requirements 1 and 2 have long passed, the current relevance of the directive is that any aircraft still operating without the hinge modification would be in serious breach. The amendment’s addition of requirement 3 would also be enforceable.

The source does not mention any specific penalties applied; we must not invent them. However, the general framework is clear.

This airworthiness directive operates within a layered regulatory framework. At the top is the Civil Aviation Act 1988, which confers on CASA the power to issue airworthiness directives and to enforce them. Under that Act, the Civil Aviation Safety Regulations (CASR) Part 39 specifically deals with airworthiness directives. CASR 39.001 defines an AD as a direction issued by CASA that is applicable to an aircraft, aeronautical product, or part and that requires action to be taken to ensure the safety of the aircraft. Subpart 39.B sets out the process for making ADs. This directive is made under that authority.

The directive interacts directly with Transport Canada Airworthiness Directive CF-2005-34R1. Note 3 references this Canadian AD. The Australian AD appears to be a mirror adoption of the Canadian requirement, consistent with the bilateral airworthiness agreement between Australia and Canada or under the reciprocal acceptance principles. The reference means that the detailed technical basis for the modification is the Canadian AD, and the Australian AD incorporates that by reference. If Transport Canada later amends CF-2005-34 again, that amendment is not automatically part of the Australian AD unless CASA issues a further amendment. However, the AD does allow use of later Transport Canada approved revisions of the service bulletins, which is a form of dynamic referencing.

The directive also interacts with the aircraft’s type certificate. The DHC-8 is manufactured under a Canadian type certificate. The modifications required by the AD become part of the type design once installed. That means the aircraft’s approved maintenance schedule and instructions for continued airworthiness must account for the new configuration. The aircraft’s weight and balance manual, flight manual, and other data may need to be updated if the modification changes any parameters.

There is interaction with the maintenance regulations under CASR Part 42 and Part 145. The AMO performing the work must hold an appropriate Part 145 approval for the airframe class. The work must be recorded in the aircraft’s maintenance records in accordance with CASR Part 42 Subpart 42.F. The maintenance release must state that the AD has been complied with. This directive becomes part of the aircraft’s continuing airworthiness records.

If the aircraft is operated by an airline holding an AOC under CASR Part 119, the operator must have an approved continuing airworthiness management exposition (CAME) that includes procedures for managing AD compliance. The operator must ensure that this AD is added to the AD compliance list and that the maintenance organisation is tasked with the work.

The directive does not explicitly address state or territory laws, but property law and contract law will apply to the relationship between the owner and the AMO. The cost of the modification may also have tax implications as a capital improvement or as a maintenance expense, but this is beyond the scope of the AD.

Finally, there is interaction with international law through the Convention on International Civil Aviation (Chicago Convention). Australia has an obligation to maintain aircraft registered in Australia in an airworthy condition consistent with ICAO standards. The AD is part of meeting that obligation.

This instrument is identified as AD/DHC-8/103 Amdt 1. The “Amdt 1” designation indicates that it is the first amendment to the original AD that was issued under the same number. The original AD/DHC-8/103 is not reproduced in the source, but its existence can be inferred from the compliance dates and references. The original AD likely issued on or around 27 October 2005, because requirement 1 and 2 compliance is measured from that date (“Within 24 months after 27 October 2005”). That suggests the original AD became effective on 27 October 2005.

The specific changes introduced in Amendment 1 are set out in the background:

• The amendment adds a new requirement 3, applicable to the second serial number group (452, 464, 490, 506, and 508 through 557). This requires rework of the cockpit door striker plate and replacement of the latch block by incorporating Modsum 8Q902145 in accordance with Bombardier Service Bulletin 8-52-61 (original issue dated 20 October 2006, or later Transport Canada approved revision).
• The amendment also clarifies the Modsums required prior to incorporation of Requirement 2. It adds Note 2 stating that installation of Modsum 8Q200015 is required before Modsum 8Q900267. This clarification may have been absent or ambiguous in the original AD.
• The amendment updates the related Transport Canada AD reference; the background states that Transport Canada AD CF-2005-34R1 is now referred to, which is a revision of the earlier CF-2005-34.

There is no indication of any earlier amendments before this one. The AD is signed by David Villiers as Delegate of CASA on 7 November 2007, and it becomes effective on 20 December 2007. That is the date from which requirement 3 compliance is calculated.

The original AD’s compliance for requirements 1 and 2 was within 24 months after 27 October 2005, meaning that by the time of Amendment 1, the original compliance period had already ended (27 October 2007). Therefore, for any aircraft still not modified as of 20 December 2007, the original AD was already in breach. Amendment 1 does not extend that deadline.

The AD number “13/2007” appears in the header. This is likely CASA’s internal serial number for the year 2007, indicating it was the 13th AD issued that year.

The amendment history is important for operators who may have relied on the original AD wording and might have missed the new requirement 3 if they did not track amendments. This amendment should have been distributed to all registered owners of affected aircraft, but with over 550 serial numbers covered, it is possible some owners were unaware.

No further amendments to this AD are reflected in the source. Since this is a 2007 instrument, it is possible that later amendments were issued, but we cannot comment on what is not in the source.

The source text for AD/DHC-8/103 Amdt 1 does not mention any litigation. There is no record of any court or tribunal decisions relating to this specific airworthiness directive. The background section describes the engineering findings that led to the AD but includes no litigation context.

It is possible that no litigation has occurred because most operators complied with the directive within the required timeframes. Airworthiness directives are typically complied with without challenge, given the mandatory nature and the serious consequences of non-compliance. An operator might be more likely to seek an alternative means of compliance or an exemption rather than mount a legal challenge to the directive itself.

If there were litigation, it would likely arise in the context of an enforcement action. For example, if CASA took action against an operator for operating an aircraft that had not complied with requirements 1, 2, or 3, the operator might defend on the ground that the directive was invalid or that an alternative means of compliance had been approved. However, the source gives no indication of such a case.

Another possible litigation avenue is in tort law. If an aircraft experienced a door failure traceable to the hinge block rotation condition, and that aircraft had not complied with the AD, the operator or the manufacturer might be sued for negligence. But again, the source does not mention any such case.

Given the absence of any litigation reference in the source, we cannot state that there has been any litigation. The deep dive must note that no litigation history is provided in the source.

Several features of this airworthiness directive could catch out an unwary operator or maintenance provider.

Retrospective compliance date for requirements 1 and 2. The effective date of Amendment 1 is 20 December 2007, but the compliance date for requirements 1 and 2 remains 24 months after 27 October 2005, which was 27 October 2007. This means as soon as the amendment is made, any aircraft that has not yet complied with requirement 1 or 2 is already overdue. An operator who focused only on the amendment’s effective date might incorrectly assume that the hinge modification compliance clock restarts. It does not. The amendment explicitly states “The compliance time for Requirements 1 and 2 remains unchanged by this issue of the Directive.”

Dependency on prior modifications. Requirement 1 has a note that installation of Modifications 8/2337 and 8/3339 is required for a large subset of serial numbers (003 through 407, 409-412, 414-433) before the hinge modification. If an aircraft in that serial range has not had those two prior mods installed, the hinge mod cannot proceed until they are done. This could be an unexpected cost and time delay. The AMO must check the aircraft’s modification status carefully.

Requirement 2 has its own prior mod. For the second serial number group, Modsum 8Q200015 must be installed before Modsum 8Q900267. This prior mod is not the same as the two mods in note 1. The operator must ensure this prerequisite is met.

Concurrency trap for requirement 3. Requirement 3 is divided into 3.a and 3.b. For aircraft that have already accomplished requirement 2 as of the effective date, they have 12 months to do the striker plate rework and latch block replacement separately. For aircraft that have not yet done requirement 2, the striker plate work must be done concurrently with the hinge modification. This means that if an operator had scheduled the hinge modification for early 2008 (within the 12-month compliance window for requirement 3 but after the effective date), they would have to also perform the striker plate work at the same time. If they had already done the hinge mod in 2005-2007, they get a separate 12-month window for the extra work. The concurrency requirement could disrupt maintenance planning.

The note about “-( ) denotes all dash numbers” could be overlooked. If a door installation part number ends with a dash and a blank in the AD list, it covers every dash number variant. An operator might think that only a specific dash number is affected, but the AD catches all.

Applicability depends on cockpit door part number. The AD applies only to aircraft equipped with the listed cockpit door part numbers. If an aircraft has a door with a part number not listed, even if it is otherwise within the serial range, it may not be affected. However, verifying that the installed door is not one of the listed numbers requires physical inspection and parts record review. The AD does not provide an exemption for aircraft that have had the door replaced with a non-listed part.

Reference to later Transport Canada approved revisions. The AD permits use of later approved revisions to the service bulletins. This is positive flexibility, but it also means the operator must actively monitor for those revisions. If an operator uses an outdated version of the SB, they might not be in compliance if a newer approved revision changes the procedure. The AD does not specify how to obtain these revisions; the operator must rely on the manufacturer’s distribution.

The directive is silent on acceptable alternative parts. It does not say whether parts from alternative sources (e.g., PMA parts) may be used. In practice, such parts would need to be approved and would require an AMOC.

Requirement 3.a includes the phrase “unless already accomplished”. That means if the striker plate rework and latch block replacement was done before the effective date, no further action is required. But the operator must have documented evidence that it was done, and that it was done in accordance with the specified SB or equivalent. Simply having the work recorded under a different part number may not satisfy CASA.

No alternates or extensions mentioned. The AD does not mention any grace period or waiver process. Operators cannot assume they can get an extension after the compliance date passes without a formal AMOC application.

To comply with AD/DHC-8/103 Amdt 1, the operator or owner of an affected DHC-8 aircraft must take the following steps.

1. Determine applicability. Check the aircraft model and serial number against the listing in the applicability paragraph. Also verify the cockpit door part number. If the aircraft is a DHC-8 model 102, 103, 106, 201, 202, 301, 311, 314, or 315, with serial number 003 through 557, and is equipped with one of the listed door part numbers, the AD applies. If the serial number falls in the first group (003-451 except those excluded) or the second group (452, 464, 490, 506, 508-557), different requirements apply. Excluded serial numbers in the first group are 452, 464, 490, 506, and 508-557 (which are in the second group). Also excluded from first group: all serial numbers not listed (453-463, 465-489, 491-505, 507 are included but note 452, 464, 490, 506 are excluded; careful reading of the list "003 through 451, 453 through 463, 465 through 489, 491 through 505, and 507" means those serials are included; 452, 464, 490, 506, 508-557 are the second group).

2. Check modification history. For the first group, check if Modifications 8/2337 and 8/3339 are already installed if the serial number is between 003 and 407, 409-412, or 414-433. If not, those must be installed before proceeding. For the second group, check if Modsum 8Q200015 is installed. If not, that must be installed before the hinge modification.

3. Perform the hinge modification. For the first group: accomplish the two-point hinge modification per Modsum 8Q100859 in accordance with Bombardier SB 8-52-54 (original issue or Revision A, or later Transport Canada approved revision). For the second group: accomplish per Modsum 8Q900267 in accordance with SB 8-52-58. This work must be done by an approved maintenance organisation with the appropriate DHC-8 airframe rating.

4. For the second group only, perform additional striker plate rework and latch block replacement. Determine whether requirement 2 (the hinge mod) was already accomplished as of the effective date of 20 December 2007. If yes, you have 12 months from that date (by 20 December 2008) to accomplish the striker plate rework and latch block replacement per Modsum 8Q902145 in accordance with SB 8-52-61 (original issue or later approved revision). If the hinge mod was not yet done, you must accomplish both the hinge mod and the striker plate work concurrently, whenever you schedule the hinge mod. In that case, the compliance time for the striker plate work is effectively the same as for the hinge mod (though the hinge mod deadline is already past, the concurrency requirement means both must be done at the same time).

5. Documentation. Record the accomplishment of the modifications in the aircraft maintenance records. Include the AD number, the service bulletin numbers and revisions used, the Modsum numbers, the date of accomplishment, and the signature of the certifying maintenance engineer. The maintenance release must reference this AD.

6. If not yet complied with requirements 1 or 2. As of the effective date of 20 December 2007, any aircraft not already modified per requirements 1 or 2 is in breach of the AD and must not be operated. The operator must immediately ground the aircraft and arrange for the modification to be performed. After the modification is completed, the aircraft can return to service. However, the operator should also consider whether an AMOC or exemption is needed for the period of non-compliance; this may be relevant for any enforcement action.

7. Monitor for approved revisions. The AD allows the use of later Transport Canada approved revisions to the service bulletins. Therefore, before performing the work, verify that the version of the SB you intend to use is still current and approved. Bombardier distributes revisions notification through technical newsletters. The AMO should have a system to track these.

8. If you have already complied with requirement 3a before the effective date. Ensure that the records show it was done in accordance with the required SB (8-52-61) or equivalent. If the work was done using a different method, consider applying for an AMOC to have it accepted as compliant.

9. Consider applying for an alternative means of compliance (AMOC). If the prescribed modification is impractical or if an equivalent level of safety can be achieved by other means, the operator may submit a request to CASA under CASR Part 39. An AMOC would need to demonstrate that the alternative provides an equivalent level of safety, and would need to be approved in writing. The AD does not provide an automatic AMOC pathway; this is an extra step.

10. Fleet management. For operators with multiple affected aircraft, a schedule should be created to ensure all aircraft in the second serial number group have the striker plate work completed by 20 December 2008. For those in the first group, the hinge mod should already be done; verify that. For any new aircraft added to the fleet, check AD status.

In summary, compliance requires detailed inspection of the aircraft’s serial number and modification status, procurement of the correct service bulletins and parts, scheduling of maintenance with an appropriate AMO, and meticulous record keeping. The financial and operational burden includes the cost of the modification, potential downtime, and the risk of grounding if not timely. The directive is mandatory, and failure to comply carries significant legal and safety risks.