AD/BELL 204/6 Amdt 13 - Main Rotor Mast and Trunnion - Retirement Index Number (RIN) Recount/Inspection

This instrument is Airworthiness Directive AD/BELL 204/6 Amendment 13, dated 16/2013 and signed by Mike Higgins as Delegate of the Civil Aviation Safety Authority on 26 July 2013. The directive applies to Bell Model 204B helicopters that have specified main rotor mast or main rotor trunnion part numbers installed (see Applicability). Mechanically, it requires operators to determine the accumulated Retirement Index Number (RIN) for the main rotor mast and trunnion, to perform an inspection, and to take the actions mandated by the technical requirements of FAA Emergency Airworthiness Directive 2000-15-52, Amendment 39-12042. The AD explicitly accepts Bell Helicopter Textron Alert Service Bulletin 204-00-51, dated 8 April 2000, when that service bulletin has been approved by the United States Federal Aviation Administration as an Alternative Method of Compliance to the FAA AD, as an acceptable method to comply with the equivalent Requirement in this AD (Requirement paragraph).

The AD removes a prior requirement for retiring bolts that connect the drive link to the rotating swashplate at 500 hours time in service (TIS). Instead, Amendment 13 records that the current life limit of 1000 hours TIS as specified in Bell Helicopter Textron Maintenance and Overhaul Manual BHT-204B-M&O-1 is considered adequate (Background paragraph). The Compliance paragraph states that the AD applies from its effective date and that the amendment becomes effective on 2 August 2013. The instrument therefore both prescribes inspection and RIN accounting actions and alters a prior life-limitation requirement for specific bolts, replacing a 500-hour retirement rule with reliance on the 1000-hour figure set out in the manufacturer’s maintenance manual (Background paragraph).

All operative statements in this summary are taken from the AD’s labelled paragraphs: Applicability, Requirement, Compliance, and Background. The AD also records Amendment 12’s earlier focus on a specific life limitation for bolts connecting main rotor swashplate outer ring trunnions to swashplate drive links, which Amendment 13 modifies (Background paragraph).

The AD rests on five core concepts, each stated in the source text.

1. Targeted applicability. The directive is limited to Model 204B helicopters fitted with certain main rotor mast part numbers (204-011-450-001, -007, -105, -113, or -119) or main rotor trunnion part numbers (204-011-105-001 or -103) (Applicability paragraph). The AD therefore targets specific components and airframes rather than the whole Bell 204 line or other Bell models.

2. Retirement Index Number accounting. The AD requires that operators "determine the accumulated Retirement Index Number (RIN)" for the main rotor mast and trunnion (Requirement paragraph). The RIN is the metric the AD uses to track accumulated life and to trigger inspection and replacement actions. The AD does not reformulate the RIN system; it requires recounting and inspection consistent with the FAA AD referenced.

3. Inspection and mandated actions by reference. Instead of setting out inspection steps in full, the AD instructs compliance "in accordance with the technical requirements of FAA Emergency Airworthiness Directive 2000-15-52, Amendment 39-12042" (Requirement paragraph). That means the FAA AD’s technical instructions are the operative technical standard the Australian directive adopts.

4. Acceptance of an FAA-approved AMOC. The AD says Bell Helicopter Textron Alert Service Bulletin 204-00-51, dated 8 April 2000, where approved by the FAA as an Alternative Method of Compliance (AMOC) to FAA AD 2000-15-52, is acceptable for compliance with the equivalent Requirement of this AD (Requirement paragraph). The directive therefore recognises a pathway by which an FAA-approved AMOC supplies compliance equivalence.

5. Adjustment of life-limited hardware practice. The Background paragraph states that Amendment 13 removes a previous requirement to retire bolts connecting the drive link to the rotating swashplate at 500 hours TIS, and records that the current TIS of 1000 hours per the Bell Maintenance and Overhaul Manual BHT-204B-M&O-1 is considered adequate. The AD therefore changes the life limitation for those bolts from an earlier 500-hour retirement to the manufacturer’s 1000-hour limit.

Mechanically the AD merges foreign technical material into an Australian requirement by reference to a specific FAA AD and to a Bell Service Bulletin where the latter has FAA AMOC approval. The AD both prescribes actions (RIN recount, inspection, and action per the FAA AD) and relaxes a prior bolt retirement requirement by adopting the manufacturer’s 1000-hour figure (Requirement and Background paragraphs). These choices determine compliance tasks, inspection intervals, and the set of documents that maintenance organisations must consult.

The source identifies the affected parties narrowly and the roles of decision makers.

• Operators of Bell Model 204B helicopters that have installed main rotor mast part numbers 204-011-450-001, -007, -105, -113, or -119 or main rotor trunnion part numbers 204-011-105-001 or -103 are the primary parties who must act (Applicability paragraph). Those operators pay for the inspections, any measurement or parts replacement, and any aircraft out-of-service time required to comply.

• Maintenance organisations and engineers who perform RIN determinations, inspections, and any mandated corrective actions will carry out the technical work required by the AD. They will need to consult FAA Emergency Airworthiness Directive 2000-15-52, Amendment 39-12042 for the technical inspection criteria and the Bell maintenance manual for life-limits where relevant (Requirement and Background paragraphs).

• Bell Helicopter Textron is implicated indirectly because the AD adopts the Bell maintenance manual life limit and references Bell’s Alert Service Bulletin 204-00-51 as an AMOC, where it has FAA approval (Requirement and Background paragraphs). The manufacturer’s published documents thereby govern acceptable practices under this AD.

• The Civil Aviation Safety Authority, represented by its delegate Mike Higgins who signed the amendment, is the issuing authority and is the body that set the effective date (signed line and Compliance paragraph). The AD text itself is the decision instrument; the delegate’s signature records who issued it.

• International regulatory materials exert influence. The FAA Emergency Airworthiness Directive 2000-15-52 is the technical standard the AD requires; the Bell Alert Service Bulletin is accepted where FAA-approved as an AMOC (Requirement paragraph). That creates an interaction where Australian compliance obligations refer to foreign regulatory determinations and manufacturer service literature.

Who ultimately pays: operators and maintenance providers. Who decides compliance methods: CASA by issuing the AD, and the FAA and Bell through the referenced FAA AD and AMOC approval process which the CASA AD accepts as equivalent. Who changes behaviour: maintenance schedulers must recount and record RIN, perform inspections, and adjust retirement practices for the bolts previously subject to a 500-hour retirement requirement (Background and Requirement paragraphs).

The AD sets three concrete duties for affected operators and maintenance personnel and records an acceptance right for one alternative compliance route.

Duties

1. Determine accumulated RIN. The AD requires that operators determine the accumulated Retirement Index Number for the main rotor mast and trunnion. The AD does not describe a novel RIN methodology; it requires application of whatever RIN accounting the FAA AD prescribes by reference (Requirement paragraph).

2. Inspect and act. The AD requires inspection and subsequent action "in accordance with the technical requirements of FAA Emergency Airworthiness Directive 2000-15-52, Amendment 39-12042." The AD therefore imposes a duty to follow the inspection procedures, thresholds, and corrective actions set out in that FAA AD (Requirement paragraph).

3. Follow the revised bolt retirement practice. Where earlier amendments required bolt retirement at 500 hours TIS for the bolts that connect the drive link to the rotating swashplate, Amendment 13 removes that 500-hour requirement and records that the current 1000-hour TIS limit in Bell’s Maintenance and Overhaul Manual BHT-204B-M&O-1 is considered adequate. Operators therefore must follow the 1000-hour retirement practice set out by the manufacturer rather than the removed 500-hour rule (Background paragraph).

Rights / accepted alternatives

• Use of an FAA-approved AMOC. The AD explicitly states that Bell Helicopter Textron Alert Service Bulletin 204-00-51, dated 8 April 2000, if approved by the FAA as an AMOC to FAA AD 2000-15-52, is acceptable for compliance with the equivalent Requirement of this AD. That gives operators a recognised alternate compliance pathway, provided the AMOC has FAA approval (Requirement paragraph). The AD does not itself create the AMOC; it accepts it if and when the FAA has given its approval.

Temporal effect

• Compliance must be from the AD’s effective date. The Compliance paragraph states "From the effective date of this directive" and specifies that the amendment becomes effective on 2 August 2013. That fixes when duties must be performed (Compliance paragraph).

What the AD does not itself do

• The AD does not set out inspection steps or retirement procedures in full text; it delegates the technical content to FAA AD 2000-15-52 and to the Bell service manual or the Bell alert service bulletin where an FAA AMOC applies (Requirement and Background paragraphs). The AD therefore imposes duties but relies on external documents for technical content.

The source text specifies compliance timing but does not set out penalties or enforcement mechanisms. The Compliance paragraph states compliance is required "From the effective date of this directive" and that "This Amendment becomes effective on 2 August 2013." The AD text itself contains no wording that defines sanctions, civil penalties, administrative enforcement procedure, or criminal offences for non-compliance. It also does not include provisions about how CASA will monitor or verify compliance.

Because the directive incorporates the FAA AD’s technical requirements and accepts an FAA-approved AMOC as equivalent in specified circumstances, the AD delegates technical prescriptions to those documents. The AD does not identify which body or how compliance records must be held or inspected. The signed line establishes the issuing authority within CASA; it does not expand upon enforcement tools or compliance oversight in the text supplied (signed line and Requirement/Compliance paragraphs).

For practical purposes drawn strictly from the source, affected operators have a clear date by which obligations begin and a clear set of technical standards to follow, but the AD does not describe the enforcement posture, penalty amounts, or specific oversight mechanisms. The absence of enforcement text in the supplied AD means that any civil, administrative, or criminal penalties, audit mechanisms, or directions about record-keeping are not stated in this instrument. Those matters, if relevant, must be found in other instruments or authorities not included in the supplied source.

Operators should therefore treat the AD as a directive that prescribes tasks and a date for compliance, but the source itself does not describe enforcement consequences. The AD’s silence on penalties is a factual feature of the document; it is not a legal interpretation of enforcement authorities that may exist elsewhere. Any reader that requires the particular enforcement regime that applies to aviation safety directives in Australia must consult other CASA instruments or governing statutes outside the text supplied here.

The AD expressly imports and interacts with two external technical instruments and a manufacturer manual; those interactions are stated in the AD.

1. FAA Emergency Airworthiness Directive 2000-15-52, Amendment 39-12042. The AD requires that the RIN recount, inspection, and "action" be conducted "in accordance with the technical requirements" of that FAA AD (Requirement paragraph). The FAA AD is therefore the technical standard the Australian directive applies to affected components and airframes. The AD does not reproduce the FAA AD’s text; it refers to it as the operative technical specification.

2. Bell Helicopter Textron Alert Service Bulletin 204-00-51, dated 8 April 2000. The AD states that this Service Bulletin, when approved by the FAA as an Alternative Method of Compliance (AMOC) to FAA AD 2000-15-52, "is considered acceptable for compliance with the equivalent Requirement of this AD" (Requirement paragraph). Thus, where the FAA has approved that Service Bulletin as an AMOC, compliance with the Service Bulletin satisfies the Australian AD’s equivalent requirement.

3. Bell Helicopter Textron Maintenance and Overhaul Manual BHT-204B-M&O-1. The Background paragraph references that manual’s TIS limitation for the bolts at 1000 hours and records that the 1000-hour TIS is considered adequate in place of a previously mandated 500-hour retirement (Background paragraph). The AD therefore aligns Australian requirements with the manufacturer’s maintenance manual on that point.

4. Previous Amendment 12. The Background paragraph records that Amendment 12 became effective on 10 August 2000 and that it had required a specific life limitation for bolts connecting main rotor swashplate outer ring trunnions to swashplate drive links. Amendment 13 modifies that earlier approach by removing the 500-hour retirement requirement and referring to the manufacturer’s 1000-hour limit (Background paragraph).

Mechanically, the AD uses cross-reference to foreign regulatory material and manufacturer literature to set out required technical work. The AD accepts an FAA-approved AMOC as satisfying the AD’s requirement, subject to FAA approval of the AMOC. The AD does not itself set out a process to recognise AMOCs other than to state that an FAA-approved AMOC is acceptable. The AD does not purport to harmonise or displace other Australian statutory instruments; it simply directs compliance using the referenced materials as the technical standard.

Because the text provided contains no domestic statutory cross-references or explicit statements about how the AD modifies or interacts with Australian legislation beyond its immediate requirements, one must read the AD as an instrument that operates by adopting specified external technical standards (FAA AD, Bell Service Bulletin, Bell M&O manual) and by superseding a prior AD requirement (Amendment 12) for the bolt retirement practice. Any broader legal interactions, such as how the AD ties into Australian aviation safety enforcement regimes or record-keeping obligations, are not specified within this source.

The AD itself states a compact amendment history within its Background paragraph.

• Amendment 13. The instrument presented is Amendment 13 of AD/BELL 204/6, issued in 2013 and becoming effective on 2 August 2013 (Compliance paragraph and heading). Amendment 13 removes the prior requirement for retiring bolts connecting the drive link to the rotating swashplate at 500 hours TIS. It records that the current TIS of 1000 hours in the Bell Maintenance and Overhaul Manual BHT-204B-M&O-1 is considered adequate. Amendment 13 also references FAA AD 2000-15-52, Amendment 39-12042, for inspection of the main rotor mast and trunnion, and notes acceptability of an FAA-approved AMOC embodied in Bell Alert Service Bulletin 204-00-51 for compliance with the equivalent Requirement of this AD (Background and Requirement paragraphs).

• Amendment 12. The Background paragraph records that Amendment 12 of this AD became effective on 10 August 2000. Amendment 12 had been issued to require a specific life limitation for bolts connecting main rotor swashplate outer ring trunnions to swashplate drive links. Amendment 13 alters that position by removing the 500-hour retirement requirement imposed earlier and aligning the life limit with the manufacturer’s 1000-hour figure (Background paragraph).

The AD document does not provide earlier amendments or the genesis of AD/BELL 204/6 beyond those two amendments; it records only that Amendment 12 existed and its effective date, and that Amendment 13 supersedes the 500-hour retirement rule imposed by Amendment 12. The document further records its own signature and date by a CASA delegate, Mike Higgins, on 26 July 2013, which situates Amendment 13’s issuance prior to its effective date, 2 August 2013 (signed line and Compliance paragraph).

The AD does not supply the texts of Amendment 12 or earlier ADs. It also does not list a version history of the FAA AD or the Bell Service Bulletin beyond stating the FAA AD’s number and amendment and the Service Bulletin’s date. Any deeper amendment lineage or the content of earlier amendments must be obtained from the separate amendment texts, which are not included in the supplied source.

The supplied AD contains no litigation history, case references, or mentions of disputes. The document includes no cases, judicial decisions, administrative reviews, or enforcement actions arising from the AD or from earlier amendments. The AD’s Background paragraph recounts the administrative change effected by Amendment 13 and the effective date of Amendment 12, but it contains no reference to litigation, appeals, or legal challenges.

Because the source text is silent on litigation, there is no basis in the supplied material to describe any court or tribunal decisions, or to cite dispute resolution proceedings. The AD also does not reference any determinations by the FAA beyond the technical FAA AD number and the FAA’s role in approving an AMOC for the Bell Service Bulletin. It does not refer to any litigation concerning the AMOC, the FAA AD, or the manufacturer.

For readers seeking litigation decisions, enforcement history, or judicial interpretation relevant to AD/BELL 204/6 or its amendments, the supplied document does not provide material. Any litigation history would need to be sought from external legal databases, court records, or CASA public records not included in the supplied AD text.

The AD’s text contains a number of concrete features that may create implementation pitfalls if read only superficially.

1. Narrow applicability by part number. The Applicability paragraph lists specific main rotor mast and trunnion part numbers. Operators of other Bell 204 variants, or Model 204B helicopters fitted with different part numbers, may be excluded. Practically, maintenance records must be checked to confirm the exact part numbers installed, because simple reference to "Model 204B" is insufficient. The AD applies only where one of the enumerated part numbers is installed (Applicability paragraph).

2. RIN recount requirement. The AD requires operators to "determine the accumulated Retirement Index Number (RIN)" for the mast and trunnion. The AD does not set out the method for RIN calculation in the text supplied; instead, it requires application of the FAA AD's technical requirements. Operators must therefore make sure they know the FAA AD’s RIN methodology or have technical guidance available. Failure to align RIN accounting methods with the FAA AD could lead to inconsistent determinations (Requirement paragraph).

3. Reliance on external documents for technical content. The AD delegates technical inspections and actions to the FAA AD and to the Bell Alert Service Bulletin where an FAA AMOC exists. The AD does not reproduce inspection criteria, thresholds, or action lists. Users must therefore obtain FAA AD 2000-15-52, Amendment 39-12042 and, if claiming equivalence via an AMOC, the FAA-approved AMOC version of Bell Alert Service Bulletin 204-00-51. Not having those documents to hand could impede compliance (Requirement paragraph).

4. AMOC acceptance is conditional. The AD accepts Bell Alert Service Bulletin 204-00-51 "approved by the United States Federal Aviation Administration (FAA) as an Alternative Method of Compliance" as acceptable for compliance. The AD does not itself approve the Service Bulletin as an AMOC; it adopts the FAA’s AMOC if and when FAA approval exists. Operators must confirm FAA AMOC approval status before assuming compliance via that bulletin is accepted (Requirement paragraph).

5. Change to life-limit practice may cause record conflicts. Amendment 13 removes the prior specific 500-hour retirement requirement for certain bolts and states that the 1000-hour TIS limit in the Bell maintenance manual is considered adequate. Maintenance records, logbook entries, and organisational procedures that were updated to reflect the 500-hour rule under Amendment 12 will need revision to avoid internal inconsistency. Operators must ensure documented procedures reflect the 1000-hour practice to prevent conflicting maintenance directives (Background paragraph).

The AD’s Requirement and Compliance paragraphs and its Background paragraph supply a compact compliance checklist. Below are stepwise actions, strictly grounded in the AD’s text.

1. Confirm applicability. Check whether the helicopter is a Model 204B and whether it has one of the specified main rotor mast part numbers (204-011-450-001, -007, -105, -113, or -119) or main rotor trunnion part numbers (204-011-105-001 or -103) installed (Applicability paragraph). If not, the AD’s text does not apply.

2. Determine the accumulated RIN. For the main rotor mast and trunnion, determine the accumulated Retirement Index Number. The AD requires this RIN recount, but delegates the technical method to FAA Emergency Airworthiness Directive 2000-15-52, Amendment 39-12042. Obtain and apply the FAA AD’s RIN accounting methodology when performing the recount (Requirement paragraph).

3. Perform inspections and actions specified in the FAA AD. The AD instructs that the recount, inspection, and subsequent actions be performed "in accordance with the technical requirements of FAA Emergency Airworthiness Directive 2000-15-52, Amendment 39-12042" (Requirement paragraph). Obtain FAA AD 2000-15-52, Amendment 39-12042 and carry out the inspection steps, acceptance criteria, and corrective actions it mandates.

4. Where available, confirm AMOC acceptance before using it. If planning to comply via Bell Helicopter Textron Alert Service Bulletin 204-00-51 (dated 8 April 2000), confirm that it has been approved by the FAA as an AMOC to FAA AD 2000-15-52. The AD states that the Bulletin "is considered acceptable for compliance with the equivalent Requirement of this AD" only where it has FAA AMOC approval. Do not assume AMOC status without confirmation (Requirement paragraph).

5. Apply the revised bolt retirement practice. Recognise that Amendment 13 removes the previous requirement to retire bolts connecting the drive link to the rotating swashplate at 500 hours TIS. Instead, follow the current 1000-hour TIS life limit set out in Bell Helicopter Textron Maintenance and Overhaul Manual BHT-204B-M&O-1 where relevant. Ensure maintenance programmes, inspection intervals, and parts retirement policies reflect the 1000-hour limit rather than 500 hours (Background paragraph).

6. Schedule compliance actions from the effective date. The Compliance paragraph states the AD applies "from the effective date of this directive" and that the Amendment becomes effective on 2 August 2013. Plan and document recounts, inspections, and any required corrective work in accordance with that timing (Compliance paragraph).