AD/AS 355/87 Amdt 1 - Untimely Firing of Squibs

The Directive’s central safety concept is removal of an unintended electrical path that could permit a squib to fire without command, and the temporary operational mitigations needed until the wiring change is embodied. The engineering control is a physical wiring modification: eliminating the ground from the hoist squib circuit (Requirement 4, AS 355 ASB 25.00.85, paragraph 2.B). The operational controls are procedural and informational: squib deactivation (Requirement 1) and mandatory placarding in cockpit and cabin locations to inform flight crew and hoist operators of the change (Requirement 1, referencing paragraph 2.B of AT 25.00.84), together with revised operating procedures set out in paragraph 2.D and 2.B of AT 25.00.84 (Requirements 2 and 3).

Applicability is a core administrative concept: the measures apply only to specific AS 355 variants (E, F, F1, F2, N) and only where the hoist is a Goodrich 76370-XXX series as described, excluding helicopters that have had MOD 073318 embodied (Applicability; Background). That creates a configuration-based compliance trigger: operators must determine hoist model and modification status before concluding whether the Directive applies.

Regulatory flexibility is limited but explicit: the Directive permits the use of later revisions of the Eurocopter service bulletins provided they are approved by EASA (paragraph under Requirement). This links compliance to EASA-approved technical material rather than to a single historic bulletin text.

Temporal staging is another concept embedded in the instrument. Immediate safety steps are required before further hoisting operations (Requirement 1), interim operating instruction compliance follows immediately (Requirement 2), pre-installation requirements apply before fitting any hoist (Requirement 3), and the wiring fix has a 30-day implementation window (Requirement 4) or must be done before installation of an unmodified hoist (Compliance).

Finally, the Directive is framed as an amendment to an earlier Australian Directive (original effective 2 June 2005). The Amendment narrows applicability after MOD 073318 embodiment and makes the wiring modification mandatory on helicopters that remain subject to the AD, while correcting a typographical error in the alert telex number (Background). The Directive cross-references EASA AD 2006-0164 (Note), situating CASA’s measure within the broader EASA/Eurocopter airworthiness process.

The Directive directly affects operators and maintainers of Eurocopter AS 355 E, F, F1, F2 and N helicopters that are fitted with Goodrich electric hoists 76370-XXX as specified (Applicability). Two distinct subsets are in scope: (a) helicopters with Goodrich electric hoists 76370-XXX, all types of motors, that are not modified per MOD 073318 (or not modified per Eurocopter ASB 25.00.85 issued 16 November 2005); and (b) helicopters with Goodrich electric hoists 76370-XXX that are not fitted with the Auxilec motor. The Directive excludes helicopters where MOD 073318 has been embodied, because the Amendment restricts applicability after embodiment (Background). The Directive therefore places an initial identification task on operators: verify helicopter variant, hoist model, presence or absence of the Auxilec motor, and whether MOD 073318 has been embodied.

Aircraft owners and operators bear the immediate compliance obligations: they must arrange for squib deactivation and placarding before the next hoisting operation where the AD applies (Requirement 1; Compliance), implement operating instructions, and schedule the wiring modification within the prescribed window (Requirements 2-4; Compliance). Maintenance organisations and certificated technicians are implicated because Requirement 4 is an electrical wiring modification (AS 355 ASB 25.00.85, paragraph 2.B), and the work will typically require maintenance planning, parts, and an authorised release to service; the Directive cites the Eurocopter ASBs and EASA-approved revisions as the technical basis for works (Requirement paragraph).

Organisations responsible for helicopter operations that conduct hoisting,emergency services, search and rescue providers, utility operators, aerial work contractors,face immediate operational effects because the Directive prohibits hoisting until Requirement 1 is met (Compliance: Requirement 1 before the next hoisting operation) and requires adherence to modified operating instructions before subsequent hoisting or installation (Requirements 2 and 3). Installers of hoists are also affected because Requirement 3 requires compliance with paragraph 2.B of AT 25.00.84 prior to installing a hoist, and Requirement 4 must be completed within 30 days or before installation of an unmodified hoist (Compliance).

The Directive references EASA AD 2006-0164 and permits later EASA-approved revisions of the Eurocopter service bulletins to be used for compliance (Note; Requirement paragraph). That means manufacturers, regulatory compliance personnel, and repair organisations must track EASA approvals; they may rely on updated ASB content where EASA has approved revisions. CASA, through its delegate (James Coyne signed the Directive), is the issuing authority and therefore responsible for publishing the instrument and setting its effective date (14 June 2006 signature, effective 28 June 2006).

Duties specified in the Directive are concrete and sequential. They are set out as four Requirements:

• Requirement 1 (operational/placarding): "If not previously accomplished, deactivate the squib and affix placards in the cockpit and in the cabin near the hoist operator in accordance with paragraph 2.B. of Eurocopter Alert Telex (AT) 25.00.84" (Requirement, referencing AT 25.00.84). Compliance timing: before the next hoisting operation (Compliance).

• Requirement 2 (procedural): "If not previously accomplished, comply with the operating instructions specified in paragraph 2.D. of AT 25.00.84." Timing: immediately following Requirement 1 (Requirement; Compliance).

• Requirement 3 (pre-installation procedural): "Comply with the operating instructions specified in paragraph 2.B. of AT 25.00.84." Timing: prior to installing a hoist (Requirement; Compliance).

• Requirement 4 (modification): "Modify the hoist electrical wiring by eliminating the ground from the hoist squib as specified in paragraph 2.B. of AS355 ASB 25.00.85." Timing: within 30 days after the effective date or before installation of an unmodified hoist on a helicopter (Requirement; Compliance).

Rights and limited flexibilities are also expressed in the Directive text. Operators may use later revisions of the Eurocopter service bulletins for compliance provided those revisions are approved by EASA (Requirement paragraph). This creates an explicit right to rely on updated technical instructions if they carry EASA approval. The Amendment also restricts applicability after embodiment of MOD 073318; by implication, an operator who has embodied MOD 073318 may fall outside the Directive’s scope (Background), which functions as an exemption pathway conditioned on that modification.

The Directive does not set out appeal, variance, or alternative method of compliance procedures within its text; however the facility to use later EASA-approved ASB revisions effectively recognises EASA as the technical arbiter for later technical solutions (Requirement paragraph). The note "EASA AD 2006-0164 refers" signals cross-jurisdictional technical coordination and suggests operators can consult EASA documentation for related compliance pathways (Note). The Directive also identifies specific documentation (AT 25.00.84 dated 25 May 2005, ASB 25.00.84 issued 16 November 2005, ASB 25.00.85 issued 16 November 2005) as the normative sources for placarding, operating instructions and the wiring modification.

Operationally, the Directive de facto creates a sequence of mandatory actions that affect rights to perform hoisting operations: until Requirement 1 is done, the operator must not perform hoisting (Compliance). Before installing a hoist, the operator must comply with paragraph 2.B of AT 25.00.84 (Requirement 3). For helicopters still subject to the AD, the wiring change must be done within 30 days or before installing an unmodified hoist; this imposes scheduling and maintenance obligations on operators, and conditions the right to operate hoists that retain the previous wiring configuration.

The Directive text itself does not specify criminal penalties, pecuniary fines, or exact enforcement procedures; it sets mandatory technical and operational requirements and effective dates (Requirements; Compliance). The instrument is issued by the Civil Aviation Safety Authority (CASA) and signed by its Delegate, which indicates that compliance is a regulatory obligation under CASA’s airworthiness oversight regime (James Coyne signature, 14 June 2006; effective date 28 June 2006). The Directive thus functions as a binding airworthiness direction that operators and maintainers must follow.

Because the Directive does not list enforcement mechanisms within the document, the text does not detail the administrative process for CASA inspections, notices of non-compliance, or sanctioning responses; the absence of explicit penalty provisions in the Directive means readers must rely on the broader regulatory framework under which CASA operates for enforcement modalities. The Directive does, however, establish clear compliance times and concrete actions (e.g. deactivate squib before next hoisting operation; wire modification within 30 days or before installation of an unmodified hoist), creating objective checkpoints that inspectors or auditors can verify against the aircraft’s configuration and maintenance records (Requirements; Compliance).

Enforcement in practice will revolve around verifying that the actions mandated by the Directive have been implemented in accordance with the referenced Eurocopter Alert Telex and ASBs or later EASA-approved revisions (Requirement paragraph). The Directive allows use of later EASA-approved ASB revisions for compliance, which affects how an inspector will assess whether the technical steps were correctly performed (Requirement paragraph). The Directive’s effective date and the specific deadlines create temporal markers that could be used by CASA during oversight activities to identify non-compliance (14 June 2006; effective 28 June 2006; Compliance windows).

The Directive also restricts applicability if MOD 073318 has been embodied (Background), which creates an objective criterion for inspectors: verify the embodiment status of MOD 073318 to determine whether the aircraft remains subject to the Directive. The document does not describe dispute resolution, alternative means of compliance, or bespoke exemptions; such mechanisms, if available, would be found outside the text. The Directive’s silence on penalties means any enforcement or sanctioning measures would be applied under CASA’s general statutory powers and procedures rather than under provisions contained in this specific instrument.

The Directive explicitly interacts with Eurocopter technical publications and EASA airworthiness directives. It references Eurocopter Alert Telex (AT) 25.00.84 dated 25 May 2005 and Eurocopter ASBs 25.00.84 and 25.00.85 issued 16 November 2005 as the technical instructions to implement the measures (Requirement; Applicability). The Directive states that later revisions of the above service bulletins approved by the European Aviation Safety Agency (EASA) may be utilised for compliance with the applicable requirements of this Directive (Requirement paragraph). The Directive also notes that "EASA AD 2006-0164 refers" (Note), explicitly linking CASA’s mandate to parallel EASA action.

The Amendment also changes applicability contingent upon the embodiment of MOD 073318 (Background). That creates an interaction between this Directive and airframe or equipment modification records and approvals. Where MOD 073318 has been embodied, the aircraft may be outside the Directive’s scope; therefore maintenance and certification records that show embodiment directly determine the Directive’s applicability for a particular helicopter (Background).

While the Directive does not cite specific Australian statutory provisions or CASA regulations, as an airworthiness directive it sits within CASA’s regulatory scheme for airworthiness and safety oversight. The Directive’s measures must be implemented using Eurocopter technical procedures or later EASA-approved revisions, which places EASA-approved technical material as the normative source for compliance. That means operators and maintainers should ensure that any corrective work aligns with the EASA-approved revisions of the Eurocopter documents referenced in the Directive.

The link to EASA AD 2006-0164 indicates cross-jurisdictional technical harmonisation: CASA’s AD aligns with EASA’s findings and guidance. The Directive therefore functions in concert with EASA documentation; where EASA approves revised ASBs, those can be used for compliance under this Directive (Requirement paragraph). The Amendment’s correction of a typographical error in the alert telex number and the narrowing of applicability after MOD embodiment are internal to CASA’s update, but still point to reliance on Eurocopter/EASA records for technical detail and applicability determination (Background).

Because the Directive is technical and prescriptive about wiring and operating instructions, it also interacts practically with maintenance certification and release-to-service processes: the wiring modification (Requirement 4) must be carried out and verified per the ASB procedure used for compliance. The Directive does not state how logbook entries, form 1 releases, or similar certification steps must be recorded; those compliance mechanics are handled under the broader maintenance and certification regulatory framework rather than within this Directive’s text.

The Directive is an amendment (AD/AS 355/87 Amdt 1) to an earlier Australian airworthiness directive concerning the same safety issue. The document records the following chronology and changes in the Background and header details:

• Original issue: The original Directive addressing untimely squib firing became effective on 2 June 2005. That original issue required inhibition of the squib function, operation of the manual cable cutter and adaptation of operational procedures (Background).

• Amendment (this document): This Amendment was prepared and signed 14 June 2006 by James Coyne, Delegate of the Civil Aviation Safety Authority, and becomes effective on 28 June 2006 (signature and effective date stated at the end of the document). The Amendment retains the substantive requirements of the original Directive but narrows applicability for helicopters where MOD 073318 has been embodied. At the same time, it renders mandatory the wiring modification (eliminating ground from the hoist squib) on those helicopters still within scope (Background).

• Typographical correction: The Amendment also corrects a typographical error in the number of the alert telex referenced in the original Directive (Background). The document clarifies references to Eurocopter Alert Telex (AT) 25.00.84 and ASBs 25.00.84 and 25.00.85, with AT 25.00.84 dated 25 May 2005 and ASBs dated 16 November 2005 (Requirement; Applicability).

• Relationship to EASA: The Amendment notes that later revisions of the referenced service bulletins approved by EASA may be used for compliance and explicitly references EASA AD 2006-0164 as related material (Requirement paragraph; Note). That indicates an alignment between CASA’s amendment and contemporaneous EASA action.

The document does not record any further amendments beyond this Amdt 1. It does not contain a statutory history or citations to enabling legislation within the text; it is presented as an operative CASA airworthiness directive with the stated amendments to scope and mandatory modification. The Amendment’s mechanical effect is to exempt helicopters where MOD 073318 is embodied while imposing a mandatory wiring change on other affected helicopters and to tighten operational requirements via placarding and operating instructions as set out in the Eurocopter AT/ASBs.

The Directive itself does not record any litigation history, legal challenges, or judicial decisions. The text contains no references to court cases, disputes, or precedent. It is an administrative airworthiness instrument; its content is technical and prescriptive rather than adjudicative. The document identifies the technical problem, the corrective actions, the aircraft/hoist configurations to which the actions apply, and timing obligations (Background; Applicability; Requirement; Compliance), and is signed by a CASA delegate (James Coyne) without further legal commentary.

Because the Directive does not provide information about enforcement proceedings, appeals, or dispute resolution mechanisms within its text, it contains no material on litigation brought to test its validity or to dispute an enforcement action. Any such litigation resulting from non-compliance, enforcement notices, or related regulatory action would lie outside this document and is not referenced here.

For practitioners, the absence of litigation history in the Directive means one must look to CASA’s wider administrative and legal records or to court and tribunal databases for any cases that may have arisen concerning this AD. The Directive’s text itself should be treated as the source of the regulatory obligations; the document sets compliance steps and timeframes rather than enforcement processes or legal contestation narratives.

The Directive contains several potential compliance traps and practical risks that arise from its drafting, sequencing and scope. These are drawn directly from the document text and should be monitored practically:

• Configuration-based applicability: The AD applies only to AS 355 E, F, F1, F2 and N helicopters fitted with Goodrich electric hoists 76370-XXX where the hoist is not modified per MOD 073318 (or not modified in accordance with Eurocopter ASB 25.00.85), or where the hoist lacks the Auxilec motor (Applicability). Operators must verify hoist serial/model numbers, motor type, and whether MOD 073318 has been embodied. Misidentifying an aircraft’s configuration can lead to unnecessary work or, conversely, to a non-compliant helicopter continuing to operate.

• Timing sequencing: The Directive sets different times for different actions. Requirement 1 must be done before the next hoisting operation; Requirement 2 must be complied with immediately after Requirement 1; Requirement 3 must be complied with prior to installing a hoist; Requirement 4 must be completed within 30 days of the effective date or before installation of an unmodified hoist (Compliance). Failure to respect those specific time triggers can technically amount to non-compliance even if the eventual modification is completed.

• Pre-installation obligations: Requirement 3 obliges compliance with paragraph 2.B of AT 25.00.84 prior to installing a hoist (Requirement). Installers who fit hoists without confirming compliance with that paragraph may inadvertently violate the AD.

• Interplay with MOD 073318: The Amendment restricts applicability where MOD 073318 has been embodied (Background). Determining whether MOD 073318 truly removes the risk,or whether it has been properly embodied and certified,requires checking maintenance and modification records carefully. Operators should not assume exemption without documentary proof.

• Use of later EASA-approved revisions: The Directive permits later revisions of the Eurocopter service bulletins if they are approved by EASA (Requirement paragraph). However, relying on an unapproved revision or on a revision not yet endorsed by EASA would not meet the Directive’s expressed permission. Practically, operators must confirm EASA approval status before relying on an updated ASB.

• Ambiguity on enforcement mechanics and recordkeeping: The AD does not state how compliance should be recorded in logbooks or maintenance records, nor does it state the enforcement steps CASA will take for non-compliance (Penalties and enforcement). Operators should therefore ensure that their own maintenance records, placard installation records, and evidence of operational instruction compliance are clear and readily available for CASA verification, even though the Directive does not specify the required documentation style.

• Multiple documents referenced: The Directive references Eurocopter AT 25.00.84 and ASBs 25.00.84 and 25.00.85 with dates (Requirement; Applicability). Practitioners must ensure they consult the correct paragraphs cited (e.g. paragraph 2.B and 2.D of AT 25.00.84, paragraph 2.B of ASB 25.00.85) to implement precise placarding, operating instruction, and wiring changes. Misreading the paragraph numbers or using a different or older document risks non-compliance.

• Operational downtime risk: Because Requirement 1 must be completed before the next hoisting operation, and the wiring modification has a 30-day window, operators that rely heavily on hoist capability should plan for temporary capability restrictions or arrange expedited maintenance to avoid operational gaps.

• Cross-reference to EASA AD 2006-0164: The Directive notes that EASA AD 2006-0164 refers (Note). Practitioners should check that EASA AD for any technical clarifications or expanded applicability. Relying solely on CASA’s AD text without consulting the EASA material that it references could miss useful or necessary detail.

Compliance follows the four Requirements and the stated timing windows. The following checklist maps the Directive’s instructions into practical steps, strictly grounded in the Directive text.

1. Determine applicability

   • Confirm the helicopter model is AS 355 E, F, F1, F2 or N (Applicability).
   • Confirm the hoist model is Goodrich electric hoists 76370-XXX (Applicability).
   • Confirm whether MOD 073318 has been embodied on the helicopter, or whether the hoist has been modified per Eurocopter ASB 25.00.85 (Applicability; Background).
   • Confirm whether the hoist is fitted with the Auxilec motor; if fitted, check applicability language (Applicability).

2. If the Directive applies, implement Requirement 1 immediately

   • Deactivate the hoist squib and affix placards in the cockpit and in the cabin near the hoist operator in accordance with paragraph 2.B of Eurocopter AT 25.00.84 (Requirement 1).
   • Timing: do this before the next hoisting operation (Compliance).

3. After Requirement 1, implement Requirement 2

   • Comply with the operating instructions specified in paragraph 2.D of AT 25.00.84 (Requirement 2).
   • Timing: immediately following Requirement 1 (Compliance).

4. If installing a hoist, implement Requirement 3

   • Prior to installing a hoist, comply with the operating instructions specified in paragraph 2.B of AT 25.00.84 (Requirement 3; Compliance).

5. Schedule and complete the wiring modification (Requirement 4)

   • Modify the hoist electrical wiring by eliminating the ground from the hoist squib as specified in paragraph 2.B of AS355 ASB 25.00.85 (Requirement 4).
   • Timing: complete within 30 days after the Directive’s effective date (28 June 2006) or before installation of an unmodified hoist on a helicopter (Compliance).
   • Ensure the work is performed to the Eurocopter ASB procedures or to a later revision approved by EASA if using a revised ASB (Requirement paragraph).

6. Use of later EASA-approved revisions

   • If relying on later revisions of AT/ASBs, confirm that those revisions are expressly approved by EASA before using them to satisfy the Directive (Requirement paragraph).

7. Recordkeeping and verification

   • Although the Directive does not prescribe specific documentation formats, maintain records that show: (a) determination of applicability, (b) evidence of squib deactivation, placard installation (including locations per paragraph 2.B of AT 25.00.84), (c) evidence of compliance with operating instructions in paragraph 2.D and 2.B of AT 25.00.84, and (d) evidence that the wiring modification per ASB 25.00.85 paragraph 2.B has been completed within the prescribed window. These records will be the logical evidence for CASA inspection or audit, even though the Directive itself does not specify record formats.

8. Cross-reference EASA AD

   • Consult EASA AD 2006-0164 as referenced (Note) for any related technical guidance or clarifying information that may affect implementation. Confirm whether EASA has approved later ASB revisions that you plan to use for compliance.

9. Operational planning

   • Because Requirement 1 must be satisfied before any further hoisting operations, plan hoist-dependent missions around the deactivation and placarding step if work is required. If the wiring modification cannot be completed within operational windows, arrange for alternative operational arrangements while remaining compliant with the AD’s timing constraints.

10. Liaise with maintenance provider/manufacturer

    • For the electrical wiring change (Requirement 4), engage appropriately authorised maintenance personnel to perform the modification in accordance with ASB 25.00.85 paragraph 2.B (Requirement 4). Ensure any release-to-service complies with applicable maintenance certification practices.

The Directive is signed by CASA’s delegate and becomes effective 28 June 2006 (signature and effective date). Use only Eurocopter AT/ASB materials or later EASA-approved revisions as the technical basis for each step (Requirement paragraph).