AD/HU 369/118 - Landing Gear Fairing Support Assembly

This Directive is structured around a handful of concrete airworthiness-control mechanics: applicability, physical inspection requirements, rework instructions via manufacturer service bulletins, mandatory replacement if cracking is found, a terminating modification option, and a specified compliance cadence.

• Applicability: The AD targets specific airframe models , Model 369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HS, 369HM, and 500N , but only where the components listed in the Assembly/Components Affected list of the specified MD Helicopters Service Bulletins are installed. The Directive expressly excludes helicopters fitted with Aerometals strut part numbers 369XH6001-41, -42, -51, or -52 that have been installed in accordance with Supplemental Type Certificate (STC) No. SR00981LA (Applicability). That means applicability depends both on aircraft model and installed component configuration as identified by the manufacturer’s SBs and the STC.

• Inspection mechanics: The AD requires removal of the landing gear fairings to permit a physical inspection of the landing gear fairing support assemblies to determine rivet count and location and to enable any rework instructions from the relevant service bulletin to be performed (Requirement 1). For strut assemblies with a third rivet hole, inspection requires removal of the fairing inspection button plug and a localised crack inspection with bright light and at least 10x magnification (Requirement 2). The method and the magnification threshold are specified in the Directive rather than left entirely to maintenance practice.

• Corrective action and flight prohibition: If a strut assembly is found cracked, the AD requires replacement with a serviceable assembly before further flight (Requirement 1 and Requirement 2). This imposes an immediate operational constraint: where cracking is found, the aircraft must not be flown until the cracked part is replaced.

• Terminating action: Installing a strut assembly that has only two rivet holes is identified as terminating action for the requirements of the Directive (Note 1). That provides a one-time modification path to remove the need for recurring inspections mandated by the AD, subject to availability and installation of the two-rivet-hole strut assembly.

• Compliance cadence: There is an initial deadline (within four months after 30 August 2007) for accomplishing the first inspection and rework where not already done, and ongoing inspections thereafter at intervals not exceeding 100 hours time in service or during each annual inspection, whichever occurs first (Compliance). The Directive therefore imposes a recurring maintenance obligation rather than a single-point check, unless terminating action is taken.

• Cross-reference: The AD explicitly refers to FAA AD 2007-12-23 (Note 2) and relies on the content and accomplishment instructions of the MD Helicopters service bulletins identified in Applicability and Requirement 1. Thus, the Directive integrates manufacturer guidance and an FAA counterpart into its compliance framework.

These concepts shape the regulatory mechanism: the AD mandates hands-on inspections, ties corrective actions to replacement before flight, supplies a defined recurring interval, and offers a retrofit (two-rivet-hole strut) as terminating action. Applicability is conditional on installed components as identified in the referenced SBs and the STC exclusion.

The Directive affects a defined group of aircraft owners, operators, maintainers, and potentially third-party parts suppliers. The text identifies the affected aircraft models and the component-configurations that trigger the AD.

• Owners and operators of helicopters listed by model: The AD applies to Model 369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HS, 369HM, and 500N helicopters, where the components listed in the Assembly/Components Affected list of the MD Helicopters Service Bulletins (SB369H-244, SB369E-094, SB500N-022, SB369D-200, SB369F-078) are installed (Applicability). Operators must check the service bulletins’ affected-parts lists to confirm whether their particular aircraft configuration is covered.

• Maintenance organisations and licensed maintenance personnel: The Directive requires removal of landing gear fairings, close visual inspection with specified illumination and magnification (10x or greater), and execution of rework instructions in accordance with the Accomplishment Instructions of the relevant MD Helicopters Service Bulletin(s) (Requirement 1; Requirement 2). That means mechanics and organisations conducting maintenance must have access to and follow the named service bulletins and have the tools and skills for close inspection.

• Parts suppliers and modification shops: The AD identifies terminating action as installing a strut assembly with only two rivet holes (Note 1). Suppliers of replacement strut assemblies and shops performing modifications will be involved for operators who choose the terminating modification route. The AD also excludes certain strut part numbers installed under STC SR00981LA, so suppliers of those parts and STC-holders are relevant stakeholders (Applicability).

• Regulatory delegates and aviation authorities: The Directive is issued by CASA and signed by a delegate (David Villiers). It cross-references FAA AD 2007-12-23 (Note 2) and relies on manufacturer service bulletins. As such, regulators, their airworthiness inspectors, and delegates are implicated in oversight and verification of compliance.

• Affected flight operations and fleet planning: Any operator who must replace cracked struts before further flight will face operational disruption until replacement parts are available and installed (Requirement 1 and Requirement 2). Recurring inspections at intervals not to exceed 100 hours time in service or at each annual inspection will affect maintenance scheduling and potentially aircraft utilisation (Compliance).

• Entities explicitly excluded: Helicopters fitted with Aerometals strut part numbers 369XH6001-41, -42, -51, or -52, installed in accordance with STC No. SR00981LA, are excluded from the AD’s applicability (Applicability). Those owners/operators are not covered by the Directive for those specific configurations.

The Directive’s reach therefore depends on model and component fitment, maintenance capability to perform specified inspections and rework in accordance with manufacturer SBs, availability of replacement struts or terminating strut assemblies, and interaction with annual inspection cycles.

The Directive sets out mandatory duties for operators and maintenance personnel and identifies a terminating option. The source text frames duties primarily as inspection, rework and replacement obligations, and sets a clear compliance timetable.

Duties

• Remove landing gear fairings and inspect support assemblies: Requirement 1 directs the removal of all landing gear fairings and inspection of each landing gear fairing support assembly to determine the number and location of rivets attaching the support assembly to the strut assembly, and to accomplish rework instructions as provided in the Accomplishment Instructions of the applicable MD Helicopters Service Bulletin(s).

• Replace cracked struts before further flight: Both Requirement 1 and Requirement 2 state that if any strut assembly is found cracked, the cracked assembly must be replaced with a serviceable strut assembly before further flight. This places an absolute flight prohibition while a cracked assembly remains installed.

• For struts with a third rivet hole, perform a detailed inspection: Requirement 2 requires removal of the fairing inspection button plug and cleaning and inspection of the area in and around the rivet hole for cracks using a bright light and a 10x or higher magnifying glass. The AD specifies the inspection aid (10x magnification) and general illumination level (bright light), rather than leaving this entirely to general maintenance standards.

• Follow manufacturer service bulletin instructions: Rework is to be accomplished in accordance with the Accomplishment Instructions of the designated MD Helicopters Service Bulletins (Requirement 1). The AD therefore incorporates those service bulletin instructions as required steps.

• Adhere to the compliance schedule: Initial action must be taken within four months after 30 August 2007 unless already accomplished, and recurring inspections must occur at intervals not to exceed 100 hours time in service or during each annual inspection, whichever comes first (Compliance).

Rights / Options

• Terminating action via installation: Note 1 provides an option: installing a strut assembly that has only two rivet holes is terminating action for the requirements of this Directive. Operators may elect to remove the ongoing inspection burden by implementing that modification, assuming availability of the two-rivet-hole strut assembly and appropriate authorisation to install it.

• Applicability exclusions: Operators with Aerometals strut part numbers 369XH6001-41, -42, -51, or -52 installed in accordance with STC SR00981LA are excluded from the AD (Applicability). That exclusion effectively removes the duties in the AD for those specific configurations.

• Reference to FAA AD and service bulletins: The Directive explicitly notes FAA AD 2007-12-23 and relies on MD Helicopters Service Bulletins for accomplishment instructions (Note 2 and Requirement 1). Operators can consult those documents for procedural details and the scope of affected components.

Operational consequences implicit in duties

• The requirement to replace cracked assemblies before further flight creates an operational duty to ground an aircraft with a cracked strut until a serviceable assembly is installed. The compliance cadence imposes recurring maintenance time and resource requirements. The terminating action provides a one-time decision point that trades modification cost and downtime against ongoing inspection labour and potential risk exposure.

The text does not state any rights to compensation, timelines for provision of spare parts, or specific tolerances beyond the inspection aids specified. The Directive binds operators to the inspection and replacement requirements and to the service-bulletin-based rework procedures.

The AD text itself does not specify criminal penalties, civil sanctions, or administrative enforcement procedures. The document records that the directive becomes effective on 30 August 2007 and is signed by a CASA delegate (David Villiers), indicating CASA’s formal regulatory action, but it does not set out the enforcement mechanisms or penalty regime within the text provided.

What the document does state and imply

• Mandatory nature: The document is framed and titled as an Airworthiness Directive and sets mandatory requirements and compliance timelines (Requirement 1, Requirement 2, Compliance). The requirement to replace cracked strut assemblies "before further flight" indicates an operational prohibition against flying with known cracking; the AD’s effective date also establishes a binding regulatory instrument from that date.

• Responsible authority: The Directive is issued by CASA and signed by a Delegate, David Villiers, dated 17 July 2007. This identifies the issuing regulator and the official authorising the Directive.

• Absence of explicit penalties in text: The AD contains no express penalties, fines, suspension provisions or enforcement procedures in the provided text. It also contains no statements on how CASA will monitor compliance or what administrative steps will be taken in the event of non-compliance.

Interpretive and practical enforcement considerations (grounded in the text)

• Operational enforcement consequence implied by the Directive: The requirement that cracked strut assemblies be replaced "before further flight" creates an immediate operational compliance constraint: an aircraft found with a cracked strut must be taken out of service until the required replacement is completed. The source text makes that requirement explicit (Requirement 1 and Requirement 2).

• Recurrence and oversight: The AD imposes recurring inspection intervals ("not to exceed 100 hours time in service or during each annual inspection, whichever occurs first") which implies ongoing compliance obligations that CASA or its delegates could audit. The Directive does not describe auditing mechanisms or penalties, but recurring obligations create a record-keeping and maintenance-tracking function that is typically subject to regulator oversight.

• Cross-reference to FAA AD: The AD refers to FAA AD 2007-12-23 (Note 2). That cross-reference suggests harmonisation with FAA actions; however, the Directive itself remains the enforceable CASA instrument for the Australian-registered helicopters it covers.

In sum, the Directive establishes enforceable technical requirements and deadlines but does not include within the text provided any express statement of penalties or enforcement procedures. The document identifies the issuing authority and the operational consequences (no flight with cracked struts) but leaves enforcement mechanisms and sanctioning power unstated in the body of the AD as provided.

The Directive explicitly cross-references and incorporates external materials and approvals, thereby interacting with other regulatory and manufacturer documents.

• Incorporation of manufacturer service bulletins: The AD requires accomplishing rework instructions "in accordance with the Accomplishment Instructions of MD Helicopters Service Bulletin SB369H-244, SB369E-094, SB500N-022, SB369D-200, and SB369F-078, as applicable" (Requirement 1). Those service bulletins are external manufacturer documents. The Directive therefore integrates manufacturer technical instructions into the regulatory obligation, making the SBs part of the compliance pathway.

• Reference to FAA AD: Note 2 explicitly states "FAA AD 2007-12-23 Amdt 39-15101 refers." That indicates the CASA AD was issued in the context of or in response to an FAA airworthiness directive covering a related or identical unsafe condition. The reference suggests alignment with international airworthiness action, though the AD remains an Australian regulatory instrument for aircraft under CASA jurisdiction.

• Interaction with STC approvals: The Applicability clause excludes helicopters that have Aerometals strut part numbers (369XH6001-41, -42, -51, or -52) installed in accordance with Supplemental Type Certificate No. SR00981LA. That demonstrates interaction with STC approvals: aircraft modified under a specific STC and fitted with the specified parts are outside the AD’s scope. The STC and its approval conditions therefore affect whether this AD applies to a particular aircraft.

• Relationship with periodic maintenance requirements: The AD sets inspection intervals "not to exceed 100 hours time in service or during each annual inspection, whichever occurs first" (Compliance). Although the AD does not quote other maintenance law or regulations, this recurring cadence interacts operationally with the statutory or regulatory regime that governs annual inspections and maintenance record-keeping for Australian-registered aircraft. Operators will need to incorporate the AD’s inspection frequency into existing maintenance programmes and record-keeping systems.

• Interaction with flightworthiness and continuing airworthiness obligations: The requirement to replace cracked struts before further flight creates a direct interface with airworthiness determinations at the aircraft level. While the AD does not restate the general legal obligation to maintain airworthiness certificates, it prescribes a specific action that affects whether an aircraft may lawfully be operated.

The Directive therefore operates in a web of regulatory and technical instruments: it makes manufacturer SBs mandatory for affected configurations, aligns with an FAA AD, recognises STC modifications as altering applicability, and imposes inspection intervals that must be fitted into broader maintenance regulatory obligations. The AD text, however, does not itself set out the broader statutory framework for enforcement, certification, or continuing airworthiness beyond the specific inspection and replacement requirements it prescribes.

The Directive text supplied contains limited material on amendment history. The document records the following dated actions and references:

• Issuance and effective dates: The Directive is signed by David Villiers, Delegate of CASA, on 17 July 2007, and it states that "This Airworthiness Directive becomes effective on 30 August 2007" (signature and Effective date). The compliance timeline in the AD refers to "within 4 months after 30 August 2007" for initial action where not already accomplished, establishing the first-action deadline.

• Reference to FAA AD: Note 2 references FAA AD 2007-12-23 (Amdt 39-15101). This indicates that the CASA AD was issued in the context of that FAA AD, but the text does not indicate whether the CASA AD amends or supersedes any prior CASA directive, nor does it record prior versions or later amendments to this CASA AD.

• No further amendment entries in the text: The supplied material contains no record of subsequent amendments, revocations, supersessions, or revisions to AD/HU 369/118. There is no note in the supplied text indicating a later effective date, correction, or change.

• Indirect amendment indicators: The AD does include multiple service bulletin numbers covering different airframe models (SB369H-244, SB369E-094, SB500N-022, SB369D-200, SB369F-078) which suggests that the AD was constructed to encompass multiple related bulletins at the time of issue. It does not, however, indicate any history of those service bulletins’ issuance dates, revisions, or whether later SB revisions change the AD’s requirements.

Practical implications given the supplied text

• Single-issue snapshot: Based solely on the supplied text, AD/HU 369/118 appears as a discrete instrument issued in mid-2007 with a defined effective date and compliance windows. The material does not identify any earlier CASA AD that it amends, nor any later CASA action amending this AD.

• Reliance on related documents for updates: The AD’s cross-reference to FAA AD 2007-12-23 and the incorporation of manufacturer service bulletins mean that any changes to those external documents could have implications for operators, but the supplied CASA AD text does not indicate a formal mechanism for amendment or update stemming from future revisions to the referenced documents.

• Record-keeping: For compliance and audit purposes, operators must track the effective date (30 August 2007), the initial four-month compliance deadline, and the recurring inspection intervals. If any later amendments to the CASA AD exist, they are not recorded in the provided text.

In short, the supplied AD text documents the issuance and effective date and cross-refers to related FAA and service-bulletin material, but it contains no explicit amendment history beyond that initial issuance.

The document supplied contains no litigation history, judicial decisions, or recorded legal challenges. There are no cases, appeals, administrative hearings, or dispute records referenced or summarised in the AD text.

What the provided text shows

• No judicial references: The AD does not cite, refer to, or summarise any court decisions, tribunal determinations, or administrative appeals. The only external documents mentioned are FAA AD 2007-12-23 and the MD Helicopters Service Bulletins listed in the Applicability and Requirement sections.

• No recorded disputes: There is no mention in the supplied text of challenges to the Directive’s substance, procedural course, or regulatory basis. The AD presents itself as a regulatory instrument issued by CASA and signed by the Delegate, with no accompanying commentary on contestation.

Operational significance of the absence of litigation history in the text

• Absence of evidence is not evidence of absence: The fact that the AD document does not record litigation does not prove that no litigation ever occurred, only that none is recorded within this instrument. The AD should be treated as a technical regulatory instrument; any administrative or judicial challenges, if they occurred, would ordinarily be recorded or reported elsewhere, not within the text of the AD itself.

• Compliance and defence considerations: Because the supplied AD contains mandatory technical requirements and a compliance schedule but no litigation history, operators or maintenance organisations who need to demonstrate compliance should rely on the AD text, referenced service bulletins, and maintenance records. The AD itself provides no account of prior enforcement dispute outcomes.

In conclusion, the supplied material contains no litigation history. Any inquiry into legal challenges or enforcement contests would require consultation of external judicial or administrative records, which are not included in the text provided.

The AD contains several technical and procedural details that can be sources of confusion, non-compliance risk, or unintended operational consequences if overlooked. These "gotchas" are grounded in the plain language of the Directive.

• Applicability depends on both model and specific component lists in the service bulletins: The AD applies to a list of helicopter models only where "any of the components in Assembly/Components Affected list of MD Helicopters Service Bulletin SB369H-244, SB369E-094, SB500N-022, SB369D-200, and SB369F-078, as applicable, [are] installed" (Applicability). Operators must consult the applicable service bulletin’s affected-parts list to determine whether their specific aircraft configuration is captured. Treating the model list as sufficient without checking the SB affected-components list risks misapplying or ignoring the AD.

• STC exclusion must be verified precisely: The AD excludes helicopters fitted with Aerometals strut part numbers 369XH6001-41, -42, -51, or -52 if those were installed in accordance with STC No. SR00981LA (Applicability). Owners should verify not only the part numbers but also that the parts were installed under that specific STC. Misreading the exclusion could cause an operator with such parts but without the STC authorisation to think they are excluded when they are not.

• Inspection technique is specified and non-trivial: For strut assemblies with a third rivet hole, the AD requires removal of the fairing inspection button plug and inspection "using a bright light and a 10x or higher magnifying glass" (Requirement 2). Casual or cursory inspection under lesser magnification or without removing the button plug risks failing to detect small cracks that the AD is designed to uncover.

• Third rivet hole has special implications: The AD identifies strut assemblies that have a third rivet hole as requiring additional inspection steps (Requirement 2). Determining whether a strut has a third rivet hole may require fairing removal and close examination , operators who assume all struts are of a single configuration risk missing the subset requiring intensified scrutiny.

• Replacement before further flight is absolute: The AD mandates replacing any cracked strut assembly "before further flight" (Requirement 1 and Requirement 2). This is an operational hard-stop. Operators who attempt to defer replacement or operate with a known cracked component will be non-compliant with the AD.

• Terminating action is configuration-specific: The Directive states that installing a strut assembly that has only two rivet holes is terminating action for the AD (Note 1). That provides a path to remove ongoing inspection requirements, but it is contingent on availability and authorised installation of that two-rivet-hole strut assembly. The AD does not provide any schedule for availability or an authorised source, so assuming such installations are immediately available may be incorrect.

• Recurring inspection intervals create scheduling impacts: The AD requires repeat inspections at intervals not to exceed 100 hours time in service or during each annual inspection, whichever occurs first (Compliance). That requires maintenance programme adjustments and tracking to ensure inspections occur no later than the prescribed interval. Failing to schedule inspections within these limits will result in non-compliance.

• Reliance on external documents for procedural detail: The AD makes rework subject to the "Accomplishment Instructions" of the specified MD Helicopters Service Bulletins (Requirement 1). Those Accomplishment Instructions are not reproduced in the AD text and must be obtained and followed exactly. Treating the AD as self-contained without consulting the relevant SB could result in incomplete compliance.

• Cross-reference to FAA AD not self-explanatory: Note 2 refers to FAA AD 2007-12-23. Operators may assume the FAA AD contains identical content or additional guidance, but the CASA AD makes only a reference. Operators should not rely solely on that reference without reviewing the full FAA AD and the MD service bulletins for procedural specifics.

• No penalties or enforcement detail in the AD text: The supplied document does not state enforcement procedures or penalties (Penalties and enforcement). Operators should not assume the absence of explicit penalties in the text means leniency; the AD nonetheless creates mandatory technical obligations and operational constraints that will affect flightworthiness determinations.

Being alert to these points when reading and implementing the AD will help operators avoid misunderstandings that could lead to non-compliance, grounding, or unsafe conditions.

Compliance with this AD requires a sequence of discrete steps based on the Directive’s requirements and compliance timelines. The AD itself sets out the mandatory tasks, the inspection methods, the corrective action thresholds, and the recurring inspection interval. Operators and maintenance providers should follow the steps below, grounded in the Directive’s text, and retain records demonstrating compliance.

1. Determine applicability precisely

   • Consult the AD’s Applicability clause: confirm whether the helicopter is one of the listed models (369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HS, 369HM, 500N).
   • Obtain and check the Assembly/Components Affected list in the relevant MD Helicopters Service Bulletin(s) (SB369H-244, SB369E-094, SB500N-022, SB369D-200, SB369F-078) to verify whether the installed landing gear fairing support assembly/components on the specific airframe are included. The AD’s applicability turns on both model and specific parts listed in the SBs.
   • Confirm whether the aircraft has Aerometals strut part numbers 369XH6001-41, -42, -51, or -52 installed under STC No. SR00981LA. If so, the AD excludes that configuration (Applicability).

2. Schedule and perform initial actions within the required timeframe

   • If the actions required by the AD have not already been accomplished, perform the initial inspection and any rework "within 4 months after 30 August 2007" (Compliance). That means the initial deadline is within that four-month window after the AD’s effective date. If already done, retain records evidencing the earlier compliance.

3. Remove fairings and perform the prescribed inspections

   • Remove all landing gear fairings to access the landing gear fairing support assembly (Requirement 1).
   • Inspect each support assembly to determine the number and location of the rivets that attach the support assembly to the strut assembly, following the Accomplishment Instructions of the applicable MD Helicopters Service Bulletin(s) (Requirement 1).
   • Where a strut assembly is found to have a third rivet hole, remove the fairing inspection button plug and clean and inspect the area in and around the rivet hole for cracks using a bright light and a 10x or higher magnifying glass (Requirement 2).

4. Carry out manufacturer rework instructions

   • Where rework is indicated, accomplish rework instructions in accordance with the Accomplishment Instructions of the applicable MD Helicopters Service Bulletin(s) named in the AD (Requirement 1). Obtain the correct bulletin revision applicable to the aircraft configuration and follow the procedures precisely.

5. Replace cracked strut assemblies before further flight

   • If any strut assembly is found cracked during inspection, replace the cracked strut assembly with a serviceable strut assembly before further flight (Requirement 1 and Requirement 2). Do not operate the aircraft with a known cracked strut assembly.

6. Consider terminating action

   • If operational or economic considerations favour a one-time modification, install a strut assembly that has only two rivet holes. Installing such a strut assembly is terminating action for the AD’s requirements (Note 1). Ensure the replacement assembly is authorised for installation and that the installation is performed in accordance with applicable airworthiness approval processes and the manufacturer’s instructions.

7. Implement and document recurring inspections

   • After the initial actions, perform inspections at intervals not to exceed 100 hours time in service or during each annual inspection, whichever occurs first (Compliance). Adjust maintenance scheduling and programs to ensure inspections occur within these maximum intervals.
   • Record inspections, findings, rework, and replacements in maintenance logs and continuing airworthiness records to demonstrate compliance with the AD.

8. Retain and consult referenced documents

   • Maintain copies of the MD Helicopters Service Bulletin(s) referenced in the AD, and any FAA AD 2007-12-23 material referred to by the Directive for technical and procedural details (Note 2). The AD requires rework "in accordance with the Accomplishment Instructions" of the service bulletins, so those documents are necessary to meet the AD’s requirements.

9. Verify parts and approvals where exclusions or modifications are claimed

   • Where claiming the applicability exclusion based on STC SR00981LA and the specified Aerometals part numbers, ensure documentation proves the parts were installed in accordance with that STC.
   • Where installing the two-rivet-hole terminating strut, confirm that the strut assembly and its installation meet applicable airworthiness approvals and that the installation is recorded properly.

10. Coordinate operational impacts

    • Plan for potential aircraft downtime: replacement of cracked strut assemblies before further flight will ground the aircraft until replacement is completed. Anticipate lead times for serviceable strut assemblies or for performing terminating modifications.
    • Incorporate the recurring inspection interval into the operator’s maintenance planning and monitoring systems to avoid missing the "not to exceed" interval.

Record-keeping and audit trail

• Retain records of the initial inspection and any subsequent recurring inspections, including dates, times in service at inspection, inspection method (tools, magnification), findings, any rework performed as per the MD Helicopters Service Bulletin(s), parts installed, identity of maintenance personnel and organisations, and evidence of parts provenance or STC compliance where relevant.

By following these steps, operators and maintenance organisations will have executed the actions that the AD mandates: removal and inspection of fairings and support assemblies, rework per the manufacturer’s Accomplishment Instructions, replacement of cracked strut assemblies before further flight, and recurring inspection at the specified intervals unless terminating action is implemented.