AD/A320/167 Amdt 1 - Airborne Ground Check Module

The AD rests on a small set of technical and regulatory concepts that drive the required actions.

• Applicability by part number and production modification. The Directive identifies specific AGCM part numbers (P/N 769104, 769105, 769106) and excludes aeroplanes that incorporated a particular production modification combination (AIRBUS modification 27189 without AIRBUS modification 28413 is excluded; the text reads "except those aeroplanes which have incorporated AIRBUS modification 27189 during production without AIRBUS modification 28413") (Applicability). This defines a materially delimited fleet subset required to comply.

• Immediate (operational) mitigations via AOT actions. The first required action is execution of paragraphs 4.1 and 4.2 of AIRBUS AOT 29A1112 Rev 1 or later DGAC‑approved revisions (Requirement 1). The AD ties those AOT actions to maintenance events on the blue hydraulic system: the AOT actions are required following any maintenance action on the blue hydraulic system until the AGCM is modified (Background). The compliance timing differs depending on whether the maintenance occurred before or after the AD’s effective date, creating an operational deadline structure (Compliance).

• Permanent design modification as terminating action. The second required action is modification of the AGCM per AIRBUS Service Bulletin A320‑29‑1111 (or later DGAC‑approved revisions). Incorporation of that modification is defined as terminating action for the Directive, meaning once the modification is in place the prior mitigation actions triggered by blue system maintenance are no longer required (Requirement 2). The AD sets a calendar deadline for this modification (before 31 July 2007) (Compliance).

• Regulatory cross‑references and approval route. The AD accepts later DGAC‑approved revisions of both the AIRBUS AOT and the Service Bulletin, signalling a route for updated technical material to be incorporated into compliance via foreign authority approval (Requirement). The AD also expressly references a DGAC AD and an EASA approval number (DGAC AD F‑2004‑150(b); EASA approval No 2004‑9025 dated 24 August 2004) (Requirement note).

• Safety defect mechanism. The Background identifies the failure mode: air trapped in the RAT can cause RAT pump cavitations that prevent pressurisation of the blue hydraulic system during an in‑flight RAT deployment test; the AGCM modification prevents trapping of air (Background). The AD therefore establishes both short term mitigations and a long term change to the hardware assembly to remove the root cause.

• Timebound compliance and escalation. The Directive distinguishes short interval operational checks (tight windows, including before further flight after maintenance) from a longer term mandatory hardware change (deadline 31 July 2007). The imposing of "before further flight" in certain maintenance circumstances is an operationally immediate constraint on continued aircraft use (Compliance).

Each of these concepts appears explicitly in the source text and determines who must act, what actions they must take, and the timeframes applicable.

The AD identifies who is within the regulatory reach of the instrument and, by implication, who bears the practical costs and execution responsibilities.

• Operators of AIRBUS A320 aeroplanes equipped with Hamilton Sundstrand AGCM P/N 769104, 769105 or 769106. The Applicability clause names these part numbers specifically (Applicability). Operators of those aeroplanes are the primary actors required to implement the AOT actions and the AGCM modification.

• Maintenance organisations and maintenance personnel. The Required actions tie directly to maintenance events on the blue hydraulic system and to execution of tasks identified in an MRB report (MRB Report task 291000‑7). Compliance obligations include completing the AOT actions after certain maintenance actions and modifying the AGCM in conformity with a Service Bulletin, tasks that will be executed by maintenance providers (Requirement; Compliance; Background).

• Aircraft owners and leaseholders. Where an aircraft is operated under a lease, the owner or lessee will, depending on contract, be the party responsible for ensuring compliance with AD requirements. The AD itself, however, does not allocate financial responsibility; operators/deemed maintainers are practically obliged to implement the required actions to keep the aeroplane airworthy.

• Airworthiness authorities and delegated approvers. The AD accepts "later DGAC approved revisions" of the AOT and Service Bulletin and references DGAC and EASA approvals (Requirement). This implication places DGAC (and by reference EASA in the note) in the role of approving revision material that can update compliance methods; CASA (represented by the signature of a delegate) is the issuing authority for the AD in this document (signature line: James Coyne, Delegate of the Civil Aviation Safety Authority) (signature/date).

• Excluded subset , production‑modified aeroplanes. The Applicability clause excludes aeroplanes that were produced with AIRBUS modification 27189 if they also did not have AIRBUS modification 28413; reading of the exact clause is necessary to determine which production configurations are excluded from the AD (Applicability). Operators of aeroplanes outside the Applicability scope are not required by this AD to undertake the AOT actions or AGCM modification described here.

Who pays and who decides. The source does not specify funding or cost recovery mechanisms; the text makes operators/maintenance organisations the parties who must execute the actions (Requirement; Compliance). Decisions about later revisions of the technical documents are within DGAC (and EASA by reference) and the Documented Airbus Service Bulletins and AOTs, subject to the AD's acceptance of DGAC‑approved revisions (Requirement).

The AD imposes concrete duties and creates one explicit terminating right.

Duties

• Execute AOT actions. Operators must carry out the actions set out at paragraphs 4.1 and 4.2 of AIRBUS AOT 29A1112 Revision 1, or later DGAC‑approved revisions (Requirement 1). The AD connects these actions to maintenance on the blue hydraulic system: they are required after any maintenance action on that system until the AGCM is modified (Background).

• Scheduled timing for AOT actions. Where the blue hydraulic system maintenance was completed since application of the MRB “one star” maintenance task 291000‑7, but the specific AOT actions have not been done, the AD requires those AOT actions to be completed within three days or 20 flight hours after 14 April 2005 (Compliance). For aeroplanes that have any maintenance on the blue hydraulic system after the AD’s effective date, the AOT actions must be completed before further flight (Compliance).

• Modify AGCM per Service Bulletin. Operators must modify the AGCM in accordance with AIRBUS Service Bulletin A320‑29‑1111 or later DGAC‑approved revisions (Requirement 2). The modification is required before 31 July 2007 (Compliance).

• Termination of interim obligations. Incorporation of the AGCM modification specified in Requirement 2 provides terminating action for the Directive. That is, once the modification is in place, the continued requirement to carry out the AOT procedures after blue system maintenance ceases (Requirement 2).

Rights and flexibility

• Right to use later DGAC‑approved revisions. The Directive explicitly permits compliance using later DGAC‑approved revisions of both AIRBUS AOT 29A1112 and AIRBUS Service Bulletin A320‑29‑1111 (Requirement). This provides operators the right to use updated technical instructions once DGAC has approved them, rather than being strictly limited to the Revision 1 documents named in the AD.

• No change to requirement through amendment. The AD’s Amdt 1 is stated to correct only a typographical error in the background and to leave requirements and compliance periods unchanged (Background). That preserves the original duties and deadlines while clarifying an explanatory statement.

Operational consequences of duties

• Immediate operational constraint: "before further flight." The AD places an operational constraint requiring that where maintenance to the blue hydraulic system is carried out after the AD’s effective date, the AOT procedures must be completed before the aircraft is returned to service (Compliance). That creates an immediate operational duty for maintenance providers and operators.

• Calendar compliance pressure for modification: operators must plan for an engineering action (modification of the AGCM per Service Bulletin) with a fixed calendar deadline (before 31 July 2007) (Compliance). The AD declares that the modification is terminating action, creating an incentive to complete the modification to remove the recurrent need for the AOT procedure following blue system maintenance (Requirement 2).

What the AD does not state as duties

• It does not set out specific penalties, enforcement procedures, or sanctions in the published text. The AD prescribes mandatory actions and deadlines, but the text does not itself enumerate civil or criminal penalties or enforcement steps (the document does contain an authority signature) (entire text).

• It does not allocate costs or funding for modifications, nor does it prescribe who pays when aircraft are leased; those practical allocations remain to be handled between operators, owners, lessors, and maintenance organisations.

Citations: see Applicability; Requirement (1 and 2); Compliance; Background.

The source document prescribes mandatory actions and dates, but it does not set out explicit penalty provisions, enforcement mechanisms, or sanctions within the text. The AD:

• Declares mandatory actions and deadlines. Requirement 1 and Requirement 2 impose specific actions (AOT checks and AGCM modification) and fixed compliance times (e.g., within 3 days or 20 flight hours after 14 April 2005 for certain cases; before further flight in other cases; modification before 31 July 2007) (Requirement; Compliance).

• Identifies the issuing authority. The document is signed by "James Coyne, Delegate of the Civil Aviation Safety Authority" and dated 24 June 2005 (signature/date). That signature indicates that the AD was issued under the administrative processes of the Civil Aviation Safety Authority, but the AD text itself does not reproduce a statutory enforcement clause.

• Cross‑references foreign authority approvals. The AD refers to DGAC‑approved revisions and to DGAC AD F‑2004‑150(b) with an EASA approval number (EASA approval No 2004‑9025 dated 24 August 2004) (Requirement note). Those cross‑references suggest reliance on internationally produced technical approval pathways, but the AD does not specify how non‑compliance interacts with DGAC/EASA enforcement regimes.

Practical enforcement implications to be inferred from the text

• The AD establishes airworthiness requirements that an operator must implement to return or keep an aeroplane in a specified condition. While the AD text does not list fines or sanctions, mandatory ADs are typically instruments that affect an aircraft's approved airworthiness status; non‑compliance would therefore have immediate operational effects (for example inability to lawfully operate the aeroplane until airworthiness is restored). The AD itself does not state this consequence in the text; this is an operational inference from the existence of the AD and the "before further flight" instruction in some cases (Compliance).

• The AD gives no procedural guidance on how CASA will monitor compliance, audit records, or impose corrective action beyond the stated requirements and the signature of the CASA delegate. The document contains no explicit timeline for reporting compliance to the authority or for documenting work performed.

• The AD offers terminating action via the AGCM modification. Once the modification per Service Bulletin A320‑29‑1111 is embodied, the Directive's interim AOT requirements tied to blue hydraulic maintenance cease (Requirement 2). That provides a compliance pathway to remove recurring procedural obligations.

For regulator, operator, and maintenance provider planning, the absence of explicit penalty language in the AD means that any enforcement actions, notices, or sanctions would be derived from the broader legal framework under which ADs are issued, and are not specified in this document. The AD text itself must therefore be read alongside the issuing authority's statutory instruments and enforcement policies to determine the formal consequences of non‑compliance.

The AD expressly cross‑references foreign authority approvals and related Airbus documents, creating specific interactions with other regulatory material and technical publications.

• DGAC and EASA approvals. The AD allows the use of "later DGAC approved revisions" of AIRBUS AOT 29A1112 and AIRBUS Service Bulletin A320‑29‑1111 for compliance (Requirement). It also explicitly references DGAC AD F‑2004‑150(b) and notes an EASA approval number (No 2004‑9025 dated 24 August 2004) (Requirement note). Those references indicate that the AD contemplates acceptance of documentation, approvals and revisions issued by other aviation authorities, and that compliance may be achieved by following such approved revisions.

• Relationship to Airbus technical publications. The AD requires compliance actions to be taken in accordance with specific Airbus technical publications: AIRBUS AOT 29A1112 Rev 1 (paragraphs 4.1 and 4.2) for interim actions, and AIRBUS Service Bulletin A320‑29‑1111 for the AGCM modification (Requirement). The AD therefore interacts with the body of manufacturer technical material, making those documents functionally part of the compliance standard for the regulated population.

• Interaction with maintenance tasks and MRB reports. The Compliance paragraph refers to completion of a maintenance action on the blue hydraulic system since application of the MRB "one star" maintenance task "Operational check of RAT manual deployment and functional check of RAT using ground test unit followed by check of filter indicator" (MRB Report task 291000‑7) (Compliance). That ties the AD’s requirements into the Maintenance Review Board (MRB) regimen and the maintenance planning records used in continued airworthiness.

• No explicit interplay with statutory penalty provisions in the AD text. The AD itself does not include provisions describing how non‑compliance will be treated under national law; it therefore needs to be read alongside the Civil Aviation Safety Authority's governing statutes, regulations, and enforcement policies to determine legal consequences for non‑compliance. The AD does, however, include the signature of the CASA delegate, consistent with it being an instrument issued within CASA’s regulatory framework (signature/date).

• Terminating action and removal of recurring obligations. The AD defines the AGCM modification as terminating action for the Directive (Requirement 2). This creates a direct interaction between the specific hardware modification (service bulletin embodiment) and the continuing obligation to perform AOT checks after blue hydraulic maintenance. In other words, the status of being "modified" under the Service Bulletin changes applicable continuing operational requirements under this and possibly other related ADs or maintenance programmes.

• No express interaction with air operator certificates, insurance, or contractual regimes. The AD does not mention how compliance interacts with an operator’s air operator’s certificate (AOC), insurance requirements, lease contracts, or other commercial arrangements. Practical intersection with those regimes will depend on the broader statutory and contractual context and is not specified in the AD text.

Where the AD directs acceptance of DGAC approvals and EASA reference numbers, it effectively integrates foreign authority technical approvals into the Australian compliance pathway; operators should therefore consider both the AD text and the relevant DGAC/EASA approved documents when establishing a compliance plan.

The source contains a concise amendment history limited to the issuance and a single amendment.

• Original issue effective date. The AD's original issue became effective on 14 April 2005; this date is referenced in the Compliance paragraph as the date from which the initial compliance windows are measured (Compliance; Background: "The original issue of this Directive became effective 14 April 2005.").

• Amendment 1. The document before you is Amendment 1 to AD/A320/167. The header lists "AD/A320/167 Amdt 1" and the table entries show "Amdt 1" with an effective date for the amendment of 4 August 2005 (top table: "This Amendment becomes effective on 4 August 2005.").

• Purpose of the amendment. The Background states that this amendment is issued to correct a typographical error in the background statement only, with no change to the requirements or compliance periods (Background). Thus the amendment does not alter substantive obligations, deadlines or the applicability matrix; it is described as editorial in intent.

• Dates and signature. The AD Amendment 1 is signed by James Coyne, Delegate of the Civil Aviation Safety Authority, and dated 24 June 2005 (signature/date). The chronology shows signature on 24 June 2005, with the amendment becoming effective on 4 August 2005 and the original issue effective 14 April 2005.

• Referenced foreign approvals with their dates. The Requirement contains a note referencing DGAC AD F‑2004‑150(b) and EASA approval No 2004‑9025 dated 24 August 2004. That provides a contemporaneous foreign approval reference point but is not described in the AD as an amendment to this AD (Requirement note).

No other amendments, revocations, or replacement ADs are mentioned in the provided text. The amendment history is therefore limited to the original AD (effective 14 April 2005) and Amdt 1 (effective 4 August 2005) which the document states corrects only a typographical error in the background.

The AD text does not refer to any legal cases, disputes, challenges, or judicial or administrative proceedings. It contains no citations to litigation, no notices of appeals, and no description of contested interpretations. The document is an administrative safety directive issued by the Civil Aviation Safety Authority delegate and signed by James Coyne on 24 June 2005 (signature/date). The Background and Requirement sections describe factual findings and mandated actions but do not recount any enforcement actions or litigation.

Absent any mention in the source, there is no litigation history recorded in the AD itself. If a practitioner needs information about whether this AD was the subject of subsequent legal proceedings or administrative appeals, that information does not appear in the provided text and would need to be sourced from external records of CASA, DGAC, EASA, or court/tribunal archives. The AD, as presented, contains only technical, applicability, compliance, and amendment material and no account of legal challenges or disputes.

The text contains specific details and framing that create practical pitfalls and compliance risks that an operator, maintainer, or compliance professional should bear in mind. Each "gotcha" here stems directly from the document text.

• Narrow applicability by part number and production modification. The AD applies only to aircraft with AGCM P/N 769104, 769105, or 769106, and excludes certain production configurations (Applicability). Operators must confirm the exact AGCM P/N fitted and the production incorporation status of AIRBUS modifications 27189 and 28413 to determine whether the AD applies. Misreading the exclusion clause could lead to incorrect assessments of applicability.

• Tight "before further flight" constraint after maintenance. For aeroplanes that have any maintenance on the blue hydraulic system after the AD’s effective date, the AOT actions must be completed before further flight (Compliance). This wording creates an operational constraint: maintenance cannot be considered complete and the aeroplane returned to service until those AOT tasks are done. Failure to schedule the AOT tasks as part of the maintenance action could ground an aircraft unexpectedly.

• Two alternative compliance timeframes for Requirement 1. The Compliance paragraph provides a two‑tiered timing structure depending on whether the blue hydraulic maintenance was performed prior to the AD’s effective date or after it (Compliance). Operators must apply the correct timing to the relevant aircraft populations. The "within 3 days or 20 flight hours after 14 April 2005" window applies only where a specified maintenance action had already been completed but the AOT actions had not. Misapplication could create late compliance risk.

• Terminating action is conditional on modification per a specific Service Bulletin. The AD defines the AGCM modification per AIRBUS Service Bulletin A320‑29‑1111 (or later DGAC‑approved revisions) as terminating action for the Directive (Requirement 2). To obtain the terminating effect, an operator must ensure the modification is embodied exactly as required and documented, and must confirm that it is in fact the correct Service Bulletin and an approved revision if subsequently revised.

• Dependence on DGAC approvals for later revisions. The AD allows "later DGAC approved revisions" of the AOT and Service Bulletin (Requirement). If an operator seeks to rely on a later revision, it must ensure that the revision is DGAC‑approved; reliance on an unapproved alternate revision would not be authorised by the AD text.

• Discrepancy and correction in background only. The amendment is stated to correct a typographical error in the background with no substantive change to requirements or compliance periods (Background). While this suggests the amendment is editorial, parties relying on the background statement for interpretation should be aware that only the substantive requirements and compliance dates remain authoritative; the corrected background does not alter procedural obligations.

• Reference to MRB report and specific MRB task. The Compliance section references MRB Report task 291000‑7 (Operational check of RAT manual deployment and functional check of RAT using ground test unit followed by check of filter indicator) (Compliance). Operators must verify whether and when that MRB "one star" maintenance task was applied to the aeroplane to determine which compliance timing applies. Record‑keeping gaps on historical maintenance could complicate compliance timing.

• Multiple authorities referenced. The AD references DGAC AD F‑2004‑150(b) and an EASA approval number (Requirement note). Practitioners must be careful to treat these as referenced materials rather than automatically identical to the CASA AD; differences in wording among the referenced ADs or approvals could be consequential.

• Deadlines spanning long calendar period. The AGCM modification deadline is calendar dated ("before 31 July 2007") (Compliance). Operators must plan engineering and resource allocation to meet that date; the AD provides no alternative compliance schedule other than later DGAC‑approved revisions of the Service Bulletin.

• No penalties spelled out in the AD. The AD does not include explicit enforcement or penalty language (entire text). While ADs generally carry regulatory force, operators cannot look to this document alone for the procedural steps CASA might take in response to non‑compliance; that creates uncertainty that must be managed through engagement with CASA and reference to the governing statute and enforcement policy.

Each of these gotchas flows from specific wording in the AD and affects operational, compliance and record‑keeping practices.

Compliance requires a two‑step approach: short‑term operational procedures tied to the blue hydraulic system, and a long‑term hardware modification. The AD names the documents and the timing; compliance practitioners should implement the steps below, ensuring traceability to the specified technical material and regulator approvals.

1. Confirm applicability for each aeroplane

   • Verify AGCM Part Number. Check that the aircraft is fitted with Hamilton Sundstrand AGCM P/N 769104, 769105 or 769106 (Applicability).
   • Verify production modification status. Confirm whether the aeroplane incorporated AIRBUS modification 27189 during production and whether AIRBUS modification 28413 was incorporated; the Applicability clause excludes certain production configurations. Ensure records support inclusion or exclusion under the AD.

2. Identify maintenance history triggers

   • Review maintenance records for blue hydraulic system work. If the aircraft had a maintenance action on the blue hydraulic system since application of MRB Report task 291000‑7, determine whether the AOT actions (AIRBUS AOT 29A1112 Rev 1 paragraphs 4.1 and 4.2) have already been completed (Compliance).
   • Confirm MRB task status. The AD explicitly refers to MRB Report task 291000‑7; ensure the maintenance history identifies whether that MRB task has been applied to the aircraft.

3. Implement interim AOT actions where required (Requirement 1)

   • Where that prior maintenance occurred and the AOT actions are outstanding, complete paragraphs 4.1 and 4.2 of AIRBUS AOT 29A1112 Rev 1, or a later DGAC‑approved revision, within 3 days or 20 flight hours after 14 April 2005 (Compliance). Practically, given the AD dates, this is a retrospective compliance window; nevertheless, operators should document completion against the AD requirement.
   • For any blue hydraulic system maintenance carried out after the AD’s effective date, complete the AOT paragraphs 4.1 and 4.2 before further flight (Compliance). Ensure these AOT tasks are written into the maintenance task card for the event so that the aircraft is not returned to service until completion is documented.

4. Plan and perform AGCM modification (Requirement 2)

   • Obtain and review AIRBUS Service Bulletin A320‑29‑1111 and any later DGAC‑approved revisions. The AD requires modification in accordance with that Service Bulletin; operators must ensure they have the correct revision and any DGAC approvals if relying on a later revision (Requirement).
   • Schedule the modification to be embodied before 31 July 2007 (Compliance). Even though that deadline is historical, the AD mandates completion by that date; operators must have records showing embodiment by that deadline or documentation showing reliance on any later DGAC‑approved revision if applicable.
   • Confirm that embodiment of the Service Bulletin is performed to standard maintenance practice and recorded in the aircraft technical log and maintenance records to evidence that the modification has been completed and that the terminating action applies (Requirement 2).

5. Record and certify compliance

   • For both the interim AOT actions and the AGCM modification, ensure appropriate signatures, release certificates, and logbook entries are completed consistent with maintenance regulations and the operator’s continuing airworthiness procedures. While the AD does not specify the precise format for certification, traceable documentation tying the work to the AD paragraphs and the relevant AOT or Service Bulletin is required for audit and to demonstrate the modification is terminating action.

6. Use later DGAC‑approved revisions if necessary

   • If relying on later revisions, confirm DGAC approval for the specific revision used. The AD permits use of later DGAC‑approved revisions of the AOT and the Service Bulletin, but compliance is conditioned on DGAC approval (Requirement). Retain evidence of DGAC approval with the maintenance records.

7. Communicate with regulators and stakeholders

   • Notify or liaise with the competent airworthiness authority and, where appropriate, the lessee/owner and insurance carriers to ensure consensus on timing, scheduling and financial responsibility for the modification. The AD does not allocate costs; operators should resolve responsibilities prior to undertaking the work.

8. Quality control and verification

   • Implement quality checks to ensure the AGCM modification prevents air trapping as intended by the Service Bulletin embodiment and that RAT functional checks are satisfactorily completed post‑modification. The Background explains the failure mechanism (air trapped in the RAT leading to pump cavitation) and the intended effect of the modification (prevention of air trapping) (Background); operators should ensure acceptance tests are recorded.

9. Dealing with uncertainties or disputes

   • If there is any uncertainty about whether an aeroplane falls within the Applicability, or about acceptance of a particular Service Bulletin revision, seek confirmation from the Civil Aviation Safety Authority or the DGAC point of contact referenced in the Service Bulletin approvals. The AD accepts DGAC approvals for later revisions (Requirement), therefore formal clarification from the authority will reduce compliance risk.

10. Retain documentary evidence of amendment and dates

• Keep the AD amendment information (Amdt 1 effective 4 August 2005; original effective date 14 April 2005) and the CASA delegate signature on file to document the AD’s provenance and the amendment’s editorial status (Background; Amendment effective date; signature/date).

In sum, compliance is a record‑driven exercise: verify applicability, perform specified AOT and Service Bulletin tasks within the AD’s timing windows, ensure work is certified, and retain DGAC approval documents where later revisions are used. The AD defines the AGCM modification as terminating action; documenting full embodiment of that modification is the most direct way to remove the recurrent obligations tied to blue hydraulic system maintenance.