AD/BELL 206/143 Amdt 3 - Tail Boom Skin

The AD operates through a combination of immediate inspection duties, targeted non‑destructive testing, repetitive monitoring, and an ultimately mandatory structural modification that terminates the recurring inspection regimen. The principal objects are detection of cracks in the tail boom skin adjacent to the horizontal stabiliser cutout and the physical reinforcement or replacement of components where cracking is detected.

Key concepts set out in the text are:

• Applicability by model and serial number. The AD applies to specific Model 206L, 206L‑1, 206L‑3 and 206L‑4 helicopters identified by serial ranges (Applicability table). The AD revokes the prior Amendment 2 and reissues requirements for that defined fleet.

• Tiered inspection regime. Requirement 1 establishes recurring daily visual inspections per ASB 206L‑98‑114 (or Rev A). Requirement 2 requires removal of upper and lower supports and a one‑time fluorescent penetrant inspection of the skin around the horizontal stabiliser openings, performed in accordance with a named section of the manufacturer’s Standard Practices Manual (SPM BHT‑ALL‑SPM §6.2). Requirement 3 requires removal of support plates and repeated visual inspection of the entire edge of the cutout with a 10x magnifying glass on a 100/110‑hour cycle (initial within 100 hours after 31 March 1999; thereafter intervals not to exceed 110 hours).

• Conditional mandatory replacement. The AD sets an operational imperative: if any crack is found as a result of the required inspections, the operator must replace the tail boom before further flight (Requirement). This converts inspection findings into an immediate operational constraint.

• Final corrective measure as terminating action. Requirement 4 mandates modification of the tail boom in accordance with Parts I-III of ASB 206L‑99‑115 Rev D by 31 December 2000 unless already accomplished. The AD expressly states that compliance with Requirement 4 constitutes terminating action for Requirements 1-3.

• Delegation of inspection authority and recordkeeping. The AD permits the pilot in command to perform the daily visual inspection and requires a certification entry against the daily inspection certification of the maintenance release. A copy of the AD must be kept in the aircraft.

• Reference dependencies. The AD requires compliance with multiple manufacturer documents (ASBs, Maintenance Manual, SPM) and also notes a related Transport Canada AD (CF‑98‑42R3). Those documents are integrated by reference into the mandated procedures.

Mechanically, the AD uses a short‑term, high‑frequency inspection regime to manage immediate safety risk and imposes an engineering modification as a terminating action. The AD clarifies a sequencing: interim inspections (Requirements 1-3) are required pending the installation of structural doublers or the modification described in ASB 206L‑99‑115 Rev D, which is the long‑term remedy.

The primary affected parties are operators and maintainers of the specified BHTC Model 206L‑series helicopters within the serial number ranges listed in the applicability table. The table identifies four model groupings with precise serial number ranges: 206L (serials 45004-45049, 45051-45153, 46601-46617), 206L‑1 (45154-45790), 206L‑3 (51001-51612) and 206L‑4 (52001-52163, 52165-52212, 52214-52216). Any person or entity operating, maintaining, or responsible for continuing airworthiness of a helicopter within those serial ranges must follow the AD.

Specific roles and responsibilities implied by the AD text:

• Aircraft operators/owners: Must ensure the inspections and modifications are performed within the specified times, ensure that any detected cracked tail boom is replaced before further flight, maintain a copy of the AD in the aircraft, and ensure the maintenance release is appropriately annotated if the pilot in command performs an inspection.

• Pilots in command: May perform the daily visual inspection required by Requirement 1 and must make the requisite certification entry against the daily inspection certification of the maintenance release when they perform that inspection. This allocates to pilots a compliance function typically within the operator’s management of airworthiness.

• Maintenance organisations and maintenance personnel: Must perform tasks requiring removal of stabiliser supports, removal of support plates, one‑time fluorescent penetrant inspection per SPM §6.2, and the repetitive magnified visual inspections per Requirement 3. They must also perform the modification specified by ASB 206L‑99‑115 Rev D (Parts I-III) where required.

• Parts suppliers and repair stations: May be required to supply replacement tail booms if cracks are found and to supply the parts and labour necessary to accomplish the modification described in ASB 206L‑99‑115 Rev D.

• The Civil Aviation Safety Authority (CASA) and the delegate: The AD is issued under subregulation 39.1(1) CAR 1998 by a CASA delegate; CASA enforces AD compliance through regulatory oversight mechanisms not elaborated in the AD text itself.

Indirectly affected parties include insurers (who underwrite aircraft hull and operational risk), lessors where the registered aircraft fall within the scope, and other operators who may face scheduling or cost impacts when parts, support or depot capacity is constrained by many operators seeking the terminating modification.

Who pays: The AD imposes inspection and modification costs on aircraft operators and maintainers. If a crack is found, the operator pays for tail boom replacement before further flight. The AD does not allocate funding or compensation; costs of parts, labour, downtime and any ferry flights to modification facilities fall to the operator or owner.

Who decides: The AD specifies what must be done and sets times; operators decide operationally how to schedule inspections and arrange for modification and replacement; the pilot in command may decide to perform the daily visual inspection but must certify that entry.

What behaviour changes: Operators shift to daily pre‑flight inspections (unless already done), implement a specialised FPI and magnified visual inspections at specified intervals, and plan and budget for the mandatory structural modification (or earlier replacement if cracking is discovered).

Duties imposed by the AD are explicit and prescriptive. Key duties include:

• Daily visual inspection duty (Requirement 1). Operators must perform a visual inspection of the tail boom in accordance with ASB 206L‑98‑114 or ASB 206L‑98‑114 Revision A. The compliance section requires that, unless the initial inspection is already accomplished, the inspection be done before further flight after 29 March 2000; thereafter, the operator must inspect before the first flight of each day in accordance with ASB 206L‑98‑114 Rev A.

• Removal and NDI duty (Requirement 2). Operators must remove the upper and lower supports of the horizontal stabiliser in accordance with the applicable Maintenance Manual, and then, in accordance with section 6.2 of Standard Practices Manual BHT‑ALL‑SPM, perform a one‑time fluorescent penetrant inspection (FPI) of the tail boom skin at least 20 mm around the edges of the horizontal stabiliser openings. The compliance timing for Requirement 2 is “unless already accomplished, before further flight after 29 March 2000.”

• Support plate removal and magnified inspection duty (Requirement 3). Operators must remove the support plates and visually inspect the entire edge of the horizontal stabiliser opening on both sides of the tail boom for cracks using a 10x magnifying glass. The compliance schedule is within 100 hours time in service after 31 March 1999, and thereafter at intervals not to exceed 110 hours time in service. The AD notes that compliance of the previous issue remains unchanged for Requirement 3.

• Replace cracked tail boom immediately. If any crack is found as a result of the required inspections, replace the tail boom before further flight. This is an immediate non‑delegable operational duty.

• Modification duty (Requirement 4). Operators must modify the tail boom in accordance with Parts I, II and III of ASB 206L‑99‑115 Revision D dated 26 January 2000, before 31 December 2000 unless already accomplished. Compliance with Requirement 4 terminates Requirements 1-3.

• Recordkeeping/certification duties. If the pilot in command performs the daily visual inspection, the pilot must enter AD/BELL 206/143 Amdt 3 against the daily inspection certification of the maintenance release. A copy of the AD must be kept in the aircraft.

Rights or discretions provided by the AD:

• Pilot inspection right. The AD expressly permits the pilot in command to perform the daily visual inspection required by Requirement 1, which may reduce dependence on maintenance personnel for daily compliance. That right carries the duty to make the certification entry in the maintenance release.

• Termination by modification. Operators have the option to perform the modification per ASB 206L‑99‑115 Rev D, which removes the continuing inspection burden (Requirements 1-3). That gives operators an economic choice: bear recurrent inspection costs indefinitely, or invest in the modification and end the recurring inspection requirement.

Not specified in the AD text:

• The AD does not specify who must approve or supervise the FPI or the modification, other than calling up the applicable maintenance manual and SPM references. The AD expects adherence to those documents’ procedures but does not elaborate certification of the maintenance organisation or qualifications. The AD also does not set out any fine or penalty mechanism within the text; it imposes mandatory structural and inspection duties to be complied with as set out.

Compliance sequencing and interplay of duties:

• Initial daily inspection and one‑time FPI: unless already done, both the daily visual inspection (Requirement 1) and the support removal + FPI (Requirement 2) are due before further flight after 29 March 2000.

• Repetitive magnified inspection continues on the 100/110‑hour cycle until modification: Requirement 3’s scheduled inspections must continue until Requirement 4’s modification is completed, unless the tail boom is replaced because of detected cracking.

• Immediate grounding trigger: detection of any crack triggers a replacement requirement before further flight, effectively grounding that configuration until replacement is accomplished.

The AD is issued by a CASA delegate under subregulation 39.1(1) of the Civil Aviation Regulations 1998. The AD text prescribes required actions and compliance timelines, and became effective on 29 March 2000. The AD itself sets operationally enforceable constraints: if a crack is discovered during the required inspections the tail boom must be replaced before further flight. The AD also prescribes entries in the maintenance release when the pilot in command performs the daily inspection and requires that a copy of the AD be kept in the aircraft.

What is explicitly stated in the text:

• Legal basis. The AD is issued under subregulation 39.1(1) CAR 1998 and revokes the prior AD/BELL 206/143 Amdt 2 in favour of the reissued AD/BELL 206/143 Amdt 3. The AD is notified in the Commonwealth of Australia Gazette on 29 March 2000.

• Effective date. The amendment becomes effective on 29 March 2000.

• Operational enforcement action. The AD directs replacement of tail booms with cracks prior to further flight. This is an operational enforcement mechanism that requires removal of an aircraft from service until a compliant replacement is installed.

What the AD text does not specify:

• Monetary penalties, criminal sanctions or administrative fines are not articulated in the AD text. The document does not itself set out penalty amounts or enforcement processes such as audits, inspections by CASA, notices to rectify, or licence sanctions. Those enforcement instruments are governed by broader regulatory frameworks under the Civil Aviation Regulations and CASA enforcement policy, which are not reproduced in the AD text provided.

• Oversight or approval regimes. The AD requires work to be done “in accordance with” specific manufacturer manuals and ASBs, but it does not specify which authority or process must approve maintenance organisations or certify the modification in the text itself.

Implications for operators:

• Operational grounding risk. The requirement to replace a cracked tail boom before further flight creates immediate operational consequences for affected aircraft. Operators must plan for potential unplanned downtime and replacement parts logistics.

• Recordkeeping and traceability. The requirement for the pilot to enter the AD against the daily inspection certification of the maintenance release when the pilot performs the daily inspection creates a traceable record; that entry and the instruction to keep a copy of the AD in the aircraft are practical compliance measures that facilitate subsequent oversight or audit.

• Terminating action clarity. The AD provides a clear compliance pathway that removes ongoing inspection duties once the structural modification per ASB 206L‑99‑115 Rev D is accomplished. That creates a measure of regulatory certainty for operators that choose to invest in the modification.

Users seeking information on formal sanctions, enforcement procedures or CASA’s consequences for non‑compliance must consult the Civil Aviation Regulations and CASA guidance; the AD text itself does not enumerate penalty mechanisms.

The AD explicitly states its legal foundation and embeds cross‑references to manufacturer and foreign regulatory documents; those are the primary interaction points enumerated within the AD text.

Legal foundation and delegation:

• Subregulation 39.1(1) CAR 1998. The AD is issued under subregulation 39.1(1) of the Civil Aviation Regulations 1998. That establishes the AD as a regulatory instrument pursuant to the CAR framework; the AD revokes the prior AD/BELL 206/143 Amdt 2 and reissues requirements that are mandatory for the affected aircraft fleet.

Manufacturer documentation and maintenance law:

• Manufacturer documents as mandated procedures. The AD requires actions to be performed "in accordance with" specific BHTC documents: Alert Service Bulletin 206L‑98‑114 (or Rev A), Standard Practices Manual BHT‑ALL‑SPM §6.2, the applicable Maintenance Manual for removal of supports, and Alert Service Bulletin 206L‑99‑115 Rev D Parts I-III for modification. Those references import the technical procedures and standards in those documents into the regulatory requirement, effectively making them normative for compliance under the AD.

• Maintenance release recordkeeping. The AD requires that when the pilot in command performs the daily visual inspection, the pilot must enter AD/BELL 206/143 Amdt 3 against the daily inspection certification of the maintenance release. This requirement interacts with statutory and regulatory maintenance recordkeeping obligations under the aviation maintenance regime. The AD therefore intersects with the law and practice governing maintenance releases, certification entries and continuing airworthiness records.

Foreign regulator reference:

• Transport Canada AD CF‑98‑42R3. The AD notes that Transport Canada AD CF‑98‑42R3 refers. That cross‑reference indicates that the AD aligns with corresponding foreign airworthiness directives and that the technical issue has been addressed in the regulatory regimes of both CASA and Transport Canada. The AD text does not set out differing requirements; it states that Transport Canada AD is relevant.

No other statutes or regulatory instruments are expressly referenced in the AD text. The AD does not, within its text, modify or restate other Civil Aviation Regulations beyond citing its issuance under subregulation 39.1(1). The AD does not specify how its requirements interact with, for example, air operator certificate conditions or insurance contracts; those interactions will be operational and contractual matters between operators and those institutions, governed by their separate legal instruments.

Practical interaction effects:

• Incorporation of technical standards. By requiring actions “in accordance with” particular ASBs, Maintenance Manuals and the SPM, the AD effectively makes those technical standards a legal compliance standard for the aircraft. Operators must therefore treat those documents as binding for the purposes of demonstrating compliance with the AD.

• Recordkeeping and oversight. The requirement to annotate the maintenance release when the pilot performs the daily inspection and to keep a copy of the AD in the aircraft interacts with ongoing audit and oversight systems; those records provide evidence of compliance and interact with CASA’s regulatory oversight although the AD text does not specify enforcement mechanisms.

• International alignment. The reference to Transport Canada AD indicates international regulatory alignment, which may affect operators in jurisdictions where Transport Canada’s ADs apply; for Australian operators, the principal legal authority is CASA via this AD.

The AD includes an internal amendment chronology set out in the background and header information. The AD reissues AD/BELL 206/143 as Amendment 3 and revokes Amendment 2. The sequence and substance of amendments recorded in the AD text are:

• Original issue. The original AD/BELL 206/143 became effective on 20 January 1999. The AD does not present the full contents of that original issue in this document, but establishes the original date of regulatory action.

• Amendment 1. Amendment 1 became effective on 31 March 1999. The background states two central changes introduced by Amendment 1: a review of crack growth rates led to a need to detect cracks earlier, necessitating non‑destructive inspections of the tail boom skin under the support plates (i.e. introduction of FPI/NDI procedures), and applicability was expanded for Model 206L helicopters. The required inspections introduced by Amendment 1 were described as an interim measure pending a forthcoming mandatory installation of doublers on the tail boom skin around the horizontal stabiliser cutout.

• Amendment 2. Amendment 2 became effective on 7 October 1999. The background summarises Amendment 2 as mandating the reinforcement of the tail boom skin around the left horizontal stabiliser cutout. The AD does not reproduce the amendment text but identifies that Amendment 2 added a reinforcement requirement.

• Amendment 3 (this AD). Amendment 3 is issued in response to a new Transport Canada AD which clarifies the applicability of Model 206L serial numbers and extends the Requirement 4 compliance time. The AD states that Amendment 3 revokes AD/BELL 206/143 Amdt 2 and reissues the AD under CAR 1998 subreg 39.1(1). Amendment 3 became effective on 29 March 2000. The AD in Amendment 3 sets out the following notable features: clarified applicability serial numbers in the applicability table, repetitive inspection requirements including daily visual inspections and repetitive 100/110‑hour magnified inspections, the one‑time FPI under support plates, and Requirement 4 as the terminating modification with an extended compliance deadline (before 31 December 2000).

Other amendment notes in the AD text:

• The AD explicitly states that compliance with Requirement 4 of this Directive constitutes terminating action for Requirements 1, 2 and 3. It also notes that the compliance of the previous issue of this Directive remains unchanged for Requirement 3, signalling continuity for the 100/110‑hour inspection cycle between the previous and current issues.

• The AD notes that Transport Canada AD CF‑98‑42R3 refers; that may have been the source of the clarification prompting Amendment 3.

The amendment history in the AD text describes a movement from interim inspections to reinforcement/modification: early reports of cracks generated an initial AD; Amendment 1 introduced earlier detection through NDI and expanded applicability; Amendment 2 mandated reinforcement around one cutout; Amendment 3 clarified serial applicability and extended the time to accomplish the terminating structural modification.

The AD text does not report any litigation, legal challenges, court decisions or tribunal proceedings related to AD/BELL 206/143 or its amendments. The document includes a history of administrative amendments (Original issue, Amendment 1, Amendment 2, Amendment 3) and states effective dates, but it contains no reference to litigation or adjudication concerning the AD’s validity, enforcement or interpretation.

What the AD text expressly provides on this point:

• No cases or judicial decisions are named in the AD. The background section recounts factual reports of seven cracks and administrative Amendment history, but does not reference any legal disputes.

Practical note for readers:

• If a reader is seeking litigation history (for example, enforcement actions by CASA, judicial review of the AD, or disputes between operators and maintenance organisations regarding compliance costs or technical specifications), that information is not contained in this AD text. Interested parties would need to consult court records, CASA enforcement records, or other public legal databases to determine whether any litigation followed from this AD.

• The AD does reference Transport Canada AD CF‑98‑42R3; that is a regulatory cross‑reference, not litigation. Any proceedings arising under Transport Canada’s AD are likewise not reported in this AD text.

This AD contains several specific operational, scheduling and interpretative traps that can create practical non‑compliance risk if overlooked. These “gotchas” flow directly from the precise wording of the AD and the interplay of timing, delegated inspection authority, reference documents and terminating action.

1. Applicability by serial number. The AD applies only to helicopters within narrowly defined serial number ranges listed in the applicability table. Misreading the serial ranges or treating the AD as applying to all 206L variants could lead to unnecessary work or, conversely, missed applicability if serial numbers are misrecorded. The AD explicitly lists serial number ranges for Models 206L, 206L‑1, 206L‑3 and 206L‑4.

2. Multiple documents and revisions invoked. The AD requires compliance with several manufacturer documents and specific revisions: ASB 206L‑98‑114 or ASB 206L‑98‑114 Revision A for the visual inspections, the applicable Maintenance Manual for removal of upper and lower supports, section 6.2 of Standard Practices Manual BHT‑ALL‑SPM for FPI, and ASB 206L‑99‑115 Revision D for the modification. Operators must ensure they use the exact editions referenced; the AD specifies revision A for ASB 206L‑98‑114 and Revision D (26 January 2000) for ASB 206L‑99‑115, which may differ in technique and scope from other revisions.

3. Timing nuance for Requirements 1 and 2. The Compliance section places immediate actions “before further flight after 29 March 2000” unless already accomplished. For operators who have not yet completed the initial required inspections by that date, the inspections are required prior to the next flight. Misinterpreting the “before further flight” phrasing could expose an aircraft to operation without the required inspection in place.

4. Repetitive inspection cycle specifics. Requirement 3 initial timing is “within 100 hours time in service after 31 March 1999” and thereafter at intervals not to exceed 110 hours. That creates a particular cadence: the first inspection had to be scheduled within 100 hours after 31 March 1999, and subsequent inspections must not exceed 110 hours apart. Operators need to reconcile these past dates with ongoing maintenance planning and to carry forward the resulting interval schedule. The AD also notes that compliance with the previous issue remains unchanged for Requirement 3, which can cause confusion if operators consult older AD versions.

5. Delegation to pilot in command. The AD permits the pilot in command to perform the daily visual inspection and requires certification against the daily inspection certification of the maintenance release. This delegation carries both opportunity and risk: pilots may lack magnifying tools or training for more subtle inspections, and the AD does not expand on the limits of pilot‑performed inspections. The pilot’s certification entry is a legal record; an incorrect or careless entry could have compliance implications.

6. One‑time FPI under supports vs recurring magnified inspection. Requirement 2 mandates a one‑time fluorescent penetrant inspection under the support plates after removal of the upper and lower supports. Requirement 3 requires periodic removal of support plates for 10x magnified visual inspection. Operators must not confuse the one‑time NDI with the recurring magnified visual inspections; both have different timing and technique requirements.

7. Immediate replacement obligation if crack found. The AD requires replacement of the tail boom before further flight if any crack is detected. That creates immediate operational interruption, and the AD contains no alternative temporary repair allowance. Operators should plan for sourcing replacement tail booms or arranging ferrying under alternate configuration subject to authority approval, but the AD text itself does not provide an exception.

8. Termination contingent on modification completion. Compliance with Requirement 4 (modification per ASB 206L‑99‑115 Rev D) is terminating action for Requirements 1-3. The AD sets a deadline of before 31 December 2000 unless already accomplished. Operators who miss that deadline remain subject to ongoing inspection demands.

9. Cross‑jurisdictional references. The AD references Transport Canada AD CF‑98‑42R3. Operators who operate cross‑jurisdictionally or engage maintenance organisations familiar with Transport Canada practices should ensure they meet the specific CASA requirements as stated, not just the foreign AD.

10. Record retention and traceability. The AD requires a copy of the AD to be kept in the aircraft and certification entries in the maintenance release for pilot‑performed inspections. Failure to maintain these records may complicate proof of compliance if questioned by oversight authorities.

Each gotcha arises from explicit textual requirements in the AD and the precise scheduling and documentary cross‑references the AD imposes. Operators and maintainers should map these requirements into maintenance scheduling systems, parts procurement plans and recordkeeping procedures to avoid inadvertent non‑compliance.

The AD provides a prescriptive compliance path; operators should convert its requirements into a sequence of practical steps, allocate responsibilities, and document completion. The following is a stepwise compliance checklist that follows the AD’s Requirements and Compliance sections exactly as written.

Step 1 , Confirm applicability

• Check the helicopter model and serial number against the AD applicability table. The AD lists Model 206L, 206L‑1, 206L‑3 and 206L‑4 serial number ranges. Only aircraft within those ranges are subject to AD/BELL 206/143 Amdt 3.

Step 2 , Initial visual inspection (Requirement 1)

• If the initial inspection has not already been accomplished, perform a visual inspection of the tail boom in accordance with BHTC ASB 206L‑98‑114 or ASB 206L‑98‑114 Revision A before further flight after 29 March 2000. Thereafter, perform the visual inspection before the first flight of each day in accordance with ASB 206L‑98‑114 Revision A.
• If the pilot in command performs this daily inspection, the pilot must enter AD/BELL 206/143 Amdt 3 against the daily inspection certification of the maintenance release, and a copy of the AD must be carried on board the aircraft.

Step 3 , Remove stabiliser supports and perform one‑time FPI (Requirement 2)

• Unless already accomplished, remove the upper and lower supports of the horizontal stabiliser in accordance with the applicable Maintenance Manual prior to further flight after 29 March 2000.
• In accordance with section 6.2 of Standard Practices Manual BHT‑ALL‑SPM, perform a one‑time fluorescent penetrant inspection of the tail boom skin in the area at least 20 mm around the edges of the horizontal stabiliser openings. Follow the SPM’s specified process parameters (cleaning, penetrant dwell time, developer, inspection conditions) as the AD calls up section 6.2 by reference.
• Document the removal, the FPI procedure used (including reference to SPM §6.2), results, and any corrective action taken.

Step 4 , Remove support plates and perform recurring magnified inspections (Requirement 3)

• Remove the support plates and visually inspect the entire edge of the horizontal stabiliser opening on both sides of the tail boom for cracks, using a 10x magnifying glass.
• The initial inspection under Requirement 3 must have been performed within 100 hours time in service after 31 March 1999. Thereafter, carry out the inspection at intervals not to exceed 110 hours time in service.
• Record the date, time in service, and results of each magnified inspection. If the previous issue of the Directive had Requirement 3 inspections scheduled, note that compliance remains unchanged for Requirement 3.

Step 5 , Immediate action on crack detection

• If any crack is found through any required inspection (Requirement 1, 2 or 3), replace the tail boom before further flight. The AD contains no provision for ferrying or temporary repair in lieu of replacement; plan replacement logistics accordingly.
• Document the crack findings, include photographic evidence where possible, and retain records consistent with maintenance release and continuing airworthiness obligations.

Step 6 , Accomplish terminating modification (Requirement 4)

• Modify the tail boom in accordance with Parts I, II and III of Alert Service Bulletin 206L‑99‑115 Revision D dated 26 January 2000. This modification is the AD’s terminating action for the recurring inspection duties in Requirements 1-3.
• Complete the modification before 31 December 2000 unless already accomplished. Upon completion, update the aircraft’s maintenance and continuing airworthiness records to reflect that terminating action has been accomplished, and remove the recurring inspection tasks that cease to apply.

Step 7 , Recordkeeping and traceability

• For pilot‑performed daily inspections, ensure the pilot’s certification entry is made against the daily inspection certification of the maintenance release, as required by the AD.
• Keep a copy of the AD in the aircraft at all times, per the AD requirement.
• Maintain contemporaneous records of all work performed in compliance with Maintenance Manual, SPM and ASB procedures invoked by the AD, including parts used for replacement and modification, serial numbers, and signoffs by appropriately authorised maintenance personnel.

Step 8 , Management of logistics and costs

• Anticipate parts lead times for tail boom replacement and for parts/supplies necessary to perform the ASB 206L‑99‑115 Rev D modification. The AD requires replacement before further flight if cracking is found and requires the modification as terminating action, so parts procurement and scheduling are key to minimising downtime.
• Allocate maintenance facility time for removal of stabiliser supports, for the FPI under support plates, and for the recurring removal of support plates for magnified inspection until the modification is complete.

Step 9 , Cross‑reference Transport Canada AD and other guidance if relevant

• The AD notes that Transport Canada AD CF‑98‑42R3 refers. Operators who maintain aircraft in multiple jurisdictions or that rely on Transport Canada guidance should ensure that compliance with CASA’s AD wording and timelines is satisfied; do not substitute foreign AD wording where CASA’s AD differs.

Step 10 , Ongoing compliance monitoring

• Until the terminating modification per ASB 206L‑99‑115 Rev D is completed, continue the daily visual inspections per ASB 206L‑98‑114 Rev A and the 100/110‑hour interval magnified inspections as specified.
• Ensure internal audit and quality control systems capture AD compliance checks and that the maintenance release and continuing airworthiness records show evidence of compliance.

Responsibility allocation suggestions:

• Operators should assign oversight of AD compliance to an accountable person (maintenance manager or continuing airworthiness manager), schedule the terminating modification, and ensure pilots and maintenance personnel are briefed on inspection techniques and recordkeeping obligations. Where pilot‑performed inspections occur, provide clear checklists to ensure entries in the maintenance release are made correctly.

The AD’s text sets the mandatory steps and timelines. Converting those into operational checklists, procurement plans and recordkeeping procedures is necessary to demonstrate compliance and maintain aircraft availability.