AD/A320/136 Amdt 3 - Digital Distance and Radio Magnetic Indicators

The directive is structured around a small set of technical and operational concepts. Applicability defines which aeroplanes and which DDRMI units are covered. Requirement defines the mandatory technical action and an operational dispatch restriction. Compliance sets the timing for those actions. Background explains the safety rationale. Notes identify interactions with MMEL/MEL and other authorities' ADs; amendments identify historical changes.

Applicability is decisive. The AD applies to:

• Airbus A319, A320 and A321 series aeroplanes of specified manufacturer serial numbers (A319: all MSN after 0909; A320: all MSN after 0843; A321: all MSN after 1011) fitted with a Thales DDRMI having any of the part numbers listed in the AD table; and
• All other A319/A320/A321 aeroplanes fitted with a Thales DDRMI with a P/N listed and having a serial number different from the S/N recorded in the Aircraft Inspection Report (AIR) delivered from the production line, or with a Thales DDRMI that has been repaired after May 1999.

The AD excludes aeroplanes where Airbus modification 32414, 32415, 32416 or 32417 has been embodied during production or in service in accordance with Airbus SB A320-34-1264 Revision 1. That is the specified alternate means of compliance that removes an aeroplane from the AD’s applicability.

The technical remedial action mandated is deactivation of the DDRMI, performed in accordance with paragraph 4 of Airbus AOT A320-34A1262 Revision 01 dated 21 August 2002. The operational concept of dispatch limitation is implemented by restricting dispatch with an inoperative standby compass (MMEL reference 34-22-02 a) to a 'B' rectification interval. The AD expressly states in Note 1 that it supersedes the MMEL despatch condition for inoperative DDRMI (reference 34-57-01) and therefore may supersede related MEL limitations in accordance with AOT paragraph 3.5.

The background provides the failure mode: DDRMI power transformer short-circuiting, causing leakage of main AC (115 VAC) onto systems connected to ARINC 429 busses, followed by circuit-breaker trip and loss of VOR and DME sources and displays. The AD’s required action is a protective, preventive measure: temporary deactivation of the DDRMI to prevent possible loss of essential equipment from an in-flight DDRMI failure. Previous amendments modified scope and compliance options; Amdt 3 corrects the AOT issue date and confirms previous changes.

The AD directly affects the registered operators and maintenance organisations for Airbus A319, A320 and A321 aeroplanes that meet the applicability criteria. That includes aeroplanes by serial/manufacturer number and those fitted with any DDRMI unit having the listed Thales Avionics part numbers: 63543-150-3, 63543-150-2, 63543-150-1, 63543-250-1, 63543-250-2, 63543-253-2 and 63540-041-2. It also affects aeroplanes whose DDRMI serial number does not match the S/N recorded in the Aircraft Inspection Report delivered from the production line, and those whose DDRMI has been repaired after May 1999.

Primary affected parties

• Aircraft operators: required to determine whether their aeroplanes are within applicability, to carry out or arrange the deactivation work in accordance with the specified AOT, and to apply the MMEL/MEL dispatch limitations set out in the AD.
• Approved maintenance organisations and licensed maintenance personnel: responsible for executing paragraph 4 of AOT A320-34A1262 Revision 01, documenting work, and entering aircraft records appropriately.
• Fleet managers and airworthiness engineers: required to reconcile existing MEL entries (including MMEL reference 34-57-01) with the AD, and to ensure operational control systems reflect the limitation that dispatch with an inoperative standby compass (MMEL 34-22-02 a) is restricted to a 'B' rectification interval.
• Avionics suppliers or repair stations: Thales Avionics or repair agents are indirectly affected where the AD’s applicability turns on whether DDRMI units were repaired after May 1999, because repaired units fall within scope.

Secondary and indirect effects

• Flight operations: possible impacts on dispatch availability where deactivation or inoperative instrument status interacts with other equipment failures or MEL items.
• Scheduling and fleet utilisation: operators may experience downtime to perform deactivation or subsequent repairs or embodied modifications (Airbus mods 32414-32417 via SB A320-34-1264 Rev 1), potentially requiring spare aircraft or schedule adjustments.
• Documentation and compliance teams: must track embodiment of Service Bulletin A320-34-1264 Rev 1, log deactivation actions per AOT paragraph 4, and update MELs in line with AOT paragraph 3.5.

Decision makers

• The CASA delegate issued the AD under subregulation 39.1(1) of CASR 1998, and specified effective dates and compliance windows (the AD’s front matter states the AD "requires that the action set out in the requirement section ... be taken ... in accordance with the instructions ... at the time mentioned in the compliance section"). Operators are the parties required to take those actions.

Geographic and fleet scope

• The AD was notified in the Commonwealth of Australia Gazette on 28 January 2004 and became effective on 19 February 2004 for this Amendment. Airlines and maintenance organisations operating relevant Airbus types within Australia therefore must treat the AD as applicable when their aircraft meet the criteria in the applicability paragraph.

Duties set out by the AD flow from the document’s requirement and applicability text. The AD prescribes specific, time-bound duties for operators and maintenance organisations for the applicable aeroplanes.

Duties (explicit in the AD)

• Determine applicability: operators must check whether their aeroplanes fall within the applicability paragraphs, by cross-referencing aircraft model, MSN, DDRMI part number (P/N) and DDRMI serial number (S/N), and whether the DDRMI was repaired after May 1999. The AD lists the applicable P/Ns and gives criteria for S/N mismatch and post‑May 1999 repairs.
• Deactivate the DDRMI: Requirement 1 states, "Unless previously accomplished in accordance with the original issue of this Directive, deactivate the DDRMI in accordance with paragraph 4 of Airbus Industrie All Operator Telex (AOT) A320-34A1262 Revision 01 dated 21 August 2002." The duty is technical and prescriptive as to the method of deactivation.
• Apply dispatch limitation: Requirement 2 states, "Dispatch with an inoperative standby compass (Master Minimum Equipment List [MMEL] reference 34-22-02 a) is limited to a ‘B’ rectification interval." Operators must limit dispatch where the standby compass is inoperative in line with MMEL ref 34-22-02 a and the AD’s restriction.
• Reconcile MELs and MMELs: Note 1 states the AD supersedes the MMEL despatch condition for an inoperative DDRMI (reference 34-57-01) and therefore "this Airworthiness Directive may supersede any Minimum Equipment List (MEL) limitation concerning the DDRMI in accordance with AOT A320-34A1262 Revision 01 paragraph 3.5." This imposes an obligation on operators to align MEL entries with the AD and the AOT instructions.

Timing duties

• Compliance for Requirement 1 is unchanged: "Before 2 October 2002." The AD keeps this earlier deadline.
• Compliance for Requirement 2 is effective "as of the effective date of this Amendment" and the Amendment becomes effective on 19 February 2004. Operators must therefore apply the dispatch restriction from that date forward for affected aircraft.

Rights (as implied by the AD and references)

• Alternate method of compliance for removed applicability: The AD grants an exclusion for aeroplanes that have modification 32414, 32415, 32416 or 32417 embodied during production or in service in accordance with Airbus SB A320-34-1264 Revision 1. That is, operators who have embodied those mods per the SB are not within the AD’s applicability, offering a compliance pathway that avoids deactivation.
• Documentation reliance: The AD references exclusive technical documents (AOT and SB). Operators relying on the alternate SB or the prior accomplishment in accordance with the original issue of the Directive have a clear route to demonstrate compliance or inapplicability.

Who decides and how

• The CASA delegate issued the AD under subregulation 39.1(1) of CASR 1998; the AD therefore represents the delegate’s determination of necessary corrective action for the unsafe condition stated. The AD sets out what "the delegate considers necessary to correct the unsafe condition" and prescribes that the action "be taken in relation to the aircraft ... in the circumstances mentioned ... in accordance with the instructions ... at the time mentioned in the compliance section." The AD therefore fixes the duties, while providing the SB as the stated alternate compliance path for exclusion.

Record-keeping and procedural duties

• Although the AD does not itself list record-keeping entries, the referenced AOT and the nature of the deactivation require maintenance action that must be performed and recorded by maintenance organisations and entered into aircraft logbooks in customary practice; the AD’s wording that the action "be taken" implies operators must be able to demonstrate the work has been accomplished according to the AOT.

The AD is issued under subregulation 39.1(1) of CASR 1998 and therefore is a mandatory regulatory instrument from CASA. The text of the AD itself does not specify monetary fines, criminal penalties or administrative sanction mechanisms within its pages. It does, however, set out that the action "be taken" for the aircraft identified in the applicability section "in the circumstances mentioned in the requirement section ... in accordance with the instructions ... at the time mentioned in the compliance section." This language establishes the AD’s mandatory character.

Enforcement mechanisms and practical effect

• The AD’s issuance by a CASA delegate and notification in the Commonwealth of Australia Gazette (28 January 2004) serve to make the AD part of the formal regulatory framework operators must follow. The AD restates that it is issued under subregulation 39.1(1) of CASR 1998; the AD itself does not elaborate additional enforcement steps beyond prescribing required actions and compliance dates.
• The AD ties required actions to specific technical instructions (AOT A320-34A1262 Revision 01 paragraph 4) and to specific operational limitations (MMEL reference 34-22-02 a, 'B' rectification interval). That linkage provides a clear compliance standard against which operational audits, continuing airworthiness oversight or enforcement activity would reasonably measure operator behaviour.

Practical enforcement cues

• Operators and maintenance organisations should expect that oversight or audit functions will verify: (a) whether an aeroplane falls within the AD’s applicability; (b) whether the DDRMI was deactivated in accordance with the AOT where required; and (c) whether dispatch limitations have been applied to inoperative standby compass conditions in line with the AD. The AD’s notification in the Gazette and the signature of the CASA delegate (David Villiers, dated 8 January 2004) are administrative markers of its formal standing.

Limits of what the AD states

• The AD does not itself state the specific penalties, administrative processes for enforcement, or appeal avenues. Those matters are governed by the broader statutory and regulatory framework referenced (CASR 1998) but are not set out in this AD text. The AD also does not specify enforcement priorities, remediation oversight, or timeframes for remedial action beyond the compliance dates that it provides.

The AD is explicitly issued under subregulation 39.1(1) of CASR 1998. That indicates it is a regulatory instrument within the Civil Aviation Safety Regulations framework. The AD also cites and interacts with several Airbus technical instruments and with MMEL/MEL guidance.

Referenced instruments and interactions in the AD

• CASR 1998: the AD is issued under subregulation 39.1(1) of CASR 1998, and the top matter of the AD explains that the delegate issues the AD under that subregulation and requires the stated actions. The AD therefore functions as a CASR-based mandatory airworthiness directive.
• Airbus AOT A320-34A1262 Revision 01 (21 August 2002): the AD requires deactivation "in accordance with paragraph 4" of that AOT and refers to paragraph 3.5 of the AOT for how the AD may supersede MEL limitations. Thus the AOT is the prescriptive technical means to implement the AD requirement and to reconcile MEL entries.
• Airbus Service Bulletin A320-34-1264 Revision 1: the AD makes applicability conditional on whether Airbus modification 32414, 32415, 32416 or 32417 has been embodied "during production or whilst in service in accordance with Airbus Industrie Service Bulletin (SB) A320-34-1264 Revision 1." This SB is therefore the alternate compliance mechanism that can remove an aeroplane from the AD’s scope when embodied per the SB.
• MMEL/MEL references: the AD references MMEL item 34-22-02 a for the standby compass dispatch condition and MMEL 34-57-01 for a prior DDRMI dispatch condition that the AD supersedes. The AD therefore operates to override or alter in-practice MMEL/MEL behaviour for the DDRMI where the AOT instructs interoperation (AOT paragraph 3.5).

Inter-agency and international references

• Note 2 references DGAC Telegraphic AD 2002-458(B) R2. The AD therefore records that a foreign authority (DGAC) has issued a related telegraphic AD, which is noted but not reproduced. The AD does not itself elaborate the content of that DGAC AD beyond noting its reference.

Practical interaction effects

• MELs and MMELs may need to be updated: Note 1 makes explicit that the AD supersedes the MMEL despatch condition for an inoperative DDRMI (reference 34-57-01) and "may supersede any Minimum Equipment List (MEL) limitation concerning the DDRMI in accordance with AOT A320-34A1262 Revision 01 paragraph 3.5." Operators must therefore align MEL entries with the AD and the AOT instructions, an action that may require operator operational approvals or coordination with the regulator depending on local procedures.
• Embodiment of the Airbus SB provides an alternative path: if the specified Airbus modification(s) are embodied in accordance with SB A320-34-1264 Revision 1, the AD is not applicable to that aeroplane. That creates a technical compliance path for operators willing to perform the modification per the SB.

Limits on interaction statements

• The AD does not explicitly state how it interacts with other CASR provisions beyond the subregulation cited, nor does it include detailed procedure for how to record embodiment of SBs or how to amend MELs in terms of regulatory approvals. Those processes lie in the broader regulatory regime and the referenced Airbus documents, but are not specified verbatim in this AD.

The AD includes a succinct amendment history, which the text sets out in the Background and compliance notes. The history records the origin of the original AD, subsequent amendments, and what each amendment changed.

Chronology and what each step did (as stated in the AD)

• Original issue of the Airworthiness Directive: became effective on 29 March 2002. The original AD required temporary deactivation of the DDRMI to prevent possible loss of essential equipment due to an in‑flight failure of the DDRMI. The original AD also contained the baseline applicability and initial remedial action.
• Amendment 1: became effective on 25 September 2002. Amendment 1 extended the range of affected aircraft to those that may have DDRMI version B power transformers. In other words, Amendment 1 broadened applicability to capture additional units or aircraft variants at potential risk.
• Amendment 2: became effective on 22 January 2004. Amendment 2 introduced a reference to Airbus Service Bulletin A320-34-1264 Revision 1 as an alternate method of incorporating modification 32414, 32415, 32416 or 32417, thereby creating an alternative compliance route (embodiment of the SB) to remove an aeroplane from AD applicability.
• This Amendment (Amdt 3): signed by the CASA delegate on 8 January 2004 and the Amendment becomes effective on 19 February 2004. Amdt 3 revokes AD/A320/136 Amdt 2 and issues AD/A320/136 Amdt 3 under subregulation 39.1(1) of CASR 1998. The stated purpose of Amdt 3 is to correct the issue date of AOT 34A1262 Revision 01. The AD also records that the original issue of the AD required temporary deactivation and that subsequent amendments adjusted applicability and introduced SB A320-34-1264 Rev 1 as an alternate compliance path.

Other notations in the AD history

• The AD notes that DGAC Telegraphic AD 2002-458(B) R2 refers, indicating regulatory coordination or parallel action by a foreign authority, though the AD does not detail the content of that foreign AD.
• The AD restates its own effective dates for each stage, which is important for determining required compliance windows: the original AD effective 29 March 2002; Amdt 1 effective 25 September 2002; Amdt 2 effective 22 January 2004; and Amdt 3 effective 19 February 2004.

Implications of amendment history

• The amendment history documents an evolution from an immediate temporary safety action (deactivation) to a broader scope and then to recognition of an alternate long-term fix via Airbus SBs. The most recent amendment (Amdt 3) is, per the AD text, administrative in correcting an AOT issue date while maintaining the substantive deactivation requirement and the dispatch limitation.

The AD text contains no reference to litigation, court decisions, appeals, or proceedings brought against CASA, Airbus, Thales, or operators in relation to AD/A320/136 or its amendments. It refers only to administrative actions (the AD original issue and subsequent amendments) and to communications from foreign authorities (DGAC Telegraphic AD 2002-458(B) R2) without naming litigation or judicial review.

What the source does and does not provide

• The AD records the issuance and amendment dates, the delegate’s signature (David Villiers, 8 January 2004), and notification in the Commonwealth of Australia Gazette (28 January 2004). It does not report any disputes, challenges, or legal proceedings arising from the AD.
• Because the AD is a regulatory administrative instrument, any litigation or appeals would be pursued under the broader statutory framework (CASR 1998 and associated administrative law), but the AD itself contains no record of such actions. The AD is silent on remedies for disagreements about applicability, compliance methods, or the sufficiency of embodiments of the Airbus SB.

Practical consequence for researchers

• If a practitioner seeks reported litigation about this AD, the AD text supplies no instances or citations; further research outside the AD document would be necessary to determine whether any judicial or administrative challenges occurred in relation to this directive. That external research is beyond the AD text provided.

This AD contains several detail-sensitive points where an operator, maintenance organisation or compliance professional could easily misread scope, timing or interaction with MELs and SBs. The following are concrete, source-grounded pitfalls to watch for.

1. Applicability depends on multiple attributes, not only P/N

• The AD’s applicability is not simply “all aircraft with these DDRMI part numbers.” For some aeroplanes it is tied to manufacturer serial numbers (A319: all MSN after 0909; A320: all MSN after 0843; A321: all MSN after 1011). For "all other" A319/A320/A321 aeroplanes the AD applies if the DDRMI P/N listed is fitted and either the DDRMI serial number differs from the S/N in the Aircraft Inspection Report from the production line, or the DDRMI has been repaired after May 1999. Operators must therefore check both aircraft MSN and individual DDRMI S/N and repair history. Failure to check all these axes may lead to incorrect inaction or unnecessary deactivation.

2. Repair history cutoff (May 1999) matters

• The AD explicitly brings into scope DDRMIs repaired after May 1999. If an operator’s records are not clear on repair dates, the operator must resolve that uncertainty. An incomplete repair history is a compliance risk.

3. Embodiment of Airbus modification via SB is the stated exclusion

• The AD is "not applicable to aeroplanes with Airbus modification 32414 or 32415 or 32416 or 32417 embodied during production or whilst in service in accordance with Airbus Industrie Service Bulletin (SB) A320-34-1264 Revision 1." The exclusion is conditional on embodiment in accordance with that SB. Merely claiming a modification without documentary proof of embodiment per the SB may not remove the aircraft from applicability.

4. The deactivation instruction is to follow paragraph 4 of AOT A320-34A1262 Rev 01 dated 21 August 2002

• The AD mandates deactivation in accordance with a specific paragraph of the AOT. Operators must use that AOT paragraph as the procedural standard. Do not substitute other documents without formal reconciliation because the AD ties compliance to that AOT paragraph.

5. Timing is uneven and partly retrospective

• Requirement 1 has a compliance deadline "Before 2 October 2002" and is stated to be "Remains unchanged." That deadline predates Amdt 3’s effective date; Amdt 3 retains that deadline. Requirement 2 becomes effective as of the Amendment (Amdt 3) effective date (19 February 2004). Operators must parse which actions were time-critical and which are continuing limitations.

6. MMEL and MEL interactions require action

• Note 1 says the AD "supersedes the MMEL for the inoperative DDRMI despatch condition (reference 34-57-01)" and "may supersede any Minimum Equipment List (MEL) limitation concerning the DDRMI in accordance with AOT A320-34A1262 Revision 01 paragraph 3.5." Operators must ensure their MELs are updated or reconciled per the AOT; failing to do so could leave a mismatch between operational authorisation and the AD.

7. Dispatch with inoperative standby compass is constrained but not fully quantified by the AD itself

• Requirement 2 limits dispatch with an inoperative standby compass (MMEL reference 34-22-02 a) to a 'B' rectification interval. The AD does not define what precise calendar days constitute a 'B' rectification interval; that term is an operational MMEL/MEL concept outside this AD’s text. Operators must ensure they apply the correct time interval per MMEL/MEL guidance and not assume the AD supplies the interval length.

8. The AD depends on other documents (AOT and SB) for implementation

• The AD’s operative instructions refer to external Airbus documents. If an operator does not have the exact revisions (AOT A320-34A1262 Rev 01 dated 21 Aug 2002; SB A320-34-1264 Rev 1), the AD’s compliance path may be unclear. The AD corrects an issue date in the AOT, so reliance on the correct edition is necessary.

9. Administrative vs substantive changes

• Amdt 3 states it "corrects the issue date of AOT 34A1262 Revision 01." That sounds administrative, but the AD accepts the AOT as the procedural standard; therefore any discrepancy in AOT issue dates in operator records could be material for compliance evidence.

10. Record of notification and effective date

• The AD was notified in the Commonwealth of Australia Gazette on 28 January 2004 and Amdt 3 became effective on 19 February 2004. The AD also contains prior effective dates for earlier amendments. Operators dealing with manifest timelines must reconcile those dates against their maintenance and operational logs when proving compliance.

Compliance is accomplished by following the AD’s applicability determination, performing the prescribed technical action in accordance with the referenced AOT where required, applying the stated dispatch limitation, and reconciling MEL entries per the AOT. The AD provides specific references to the documents and the effective timing for each requirement.

Stepwise compliance procedure (source-grounded)

1. Verify applicability precisely:

   • Check aircraft type and manufacturer serial number against the AD’s applicability lines: A319 series aeroplanes, all MSN after 0909; A320 series aeroplanes, all MSN after 0843; A321 series aeroplanes, all MSN after 1011, when fitted with a Thales DDRMI having one of the P/Ns listed in the AD table (63543-150-3; 63543-150-2; 63543-150-1; 63543-250-1; 63543-250-2; 63543-253-2; 63540-041-2).
   • For other A319/A320/A321 aeroplanes fitted with a Thales DDRMI with a P/N listed in the AD, check whether the DDRMI serial number differs from the S/N recorded in the Aircraft Inspection Report delivered from the production line or whether the DDRMI was repaired after May 1999. If either condition applies, the AD is applicable.

2. Check for SB embodiment exclusion:

   • Determine whether Airbus modification 32414, 32415, 32416 or 32417 has been embodied during production or in service in accordance with Airbus SB A320-34-1264 Revision 1. If embodied in accordance with that SB, the AD states it is not applicable to that aeroplane. Operators should retain documentary proof of SB embodiment per the SB to demonstrate exclusion.

3. If the AD is applicable, implement Requirement 1:

   • Deactivate the DDRMI "in accordance with paragraph 4 of Airbus Industrie All Operator Telex (AOT) A320-34A1262 Revision 01 dated 21 August 2002," unless this has already been accomplished in accordance with the original issue of the Directive. The AD sets the compliance timing for Requirement 1 as "Before 2 October 2002" and notes this remains unchanged. Operators who have not already implemented deactivation prior to that date must document whether the action was done previously in accordance with the original AD; if not, the AOT’s paragraph 4 instructions remain the required method.

4. Implement Requirement 2 (operational limitation):

   • As of the effective date of this Amendment (Amdt 3 effective 19 February 2004), ensure that dispatch with an inoperative standby compass (MMEL reference 34-22-02 a) is limited to a 'B' rectification interval. Coordinate with flight operations and MEL administrators to ensure the 'B' rectification interval is correctly applied and that dispatch decision-making tools reflect this limitation. Operators should reconcile this with any existing MEL entries and the AOT’s guidance.

5. Reconcile MEL/MMEL entries per AOT:

   • Note 1: the AD supersedes MMEL reference 34-57-01 for inoperative DDRMI despatch condition and therefore "may supersede any Minimum Equipment List (MEL) limitation concerning the DDRMI in accordance with AOT A320-34A1262 Revision 01 paragraph 3.5." Apply AOT paragraph 3.5 to update MEL entries and document the basis for any MEL changes. Where regulatory approval of MEL changes is required by an operator’s authorising authority, ensure that process is followed.

6. Record and document all actions:

   • Make the required maintenance logbook entries, record performance of the AOT paragraph 4 deactivation procedure (including reference to AOT revision and date), and annotate MEL changes and operational limitations. Retain proof of SB embodiment if claiming the SB exclusion.

7. Where deactivation is not appropriate, or where a permanent fix is preferred, use the SB alternate pathway:

   • The AD explicitly recognises Airbus SB A320-34-1264 Revision 1 as an alternate means to embody modification 32414, 32415, 32416 or 32417, which excludes the aeroplane from the AD’s applicability when embodied in accordance with that SB. Operators intending to use the SB route should plan for the SB embodiment engineering and maintenance work, document compliance with the SB, and maintain evidence of embodiment per the SB.

8. Verify patchwork across amendments:

   • The AD has an amendment history. Confirm that the AOT and SB versions referenced match the versions specified in the AD (AOT A320-34A1262 Revision 01 dated 21 August 2002; SB A320-34-1264 Revision 1). Amdt 3 corrects the issue date of the AOT; using the correct revision and date is important for compliance evidence.

9. Operational coordination:

   • Ensure flight operations, dispatch, and maintenance control are aware of the deactivation and the dispatch limitation. Incorporate the limitation into dispatch manuals and crew briefing material where relevant.

10. Traceability for audits:

• Retain the AD text, the AOT paragraph used, SB embodiment records if applicable, and clear maintenance records showing deactivation was performed in accordance with the AOT. The AD’s notification in the Commonwealth of Australia Gazette (28 January 2004) and the delegate’s signature (8 January 2004) are reference points; include these when assembling a compliance package.

Notes on practical costs and operational impacts (source-grounded inference)

• The AD imposes maintenance and operational steps: deactivation work per the AOT (maintenance labour and possible grounding time), MEL reconciliation work (administrative time, potential regulatory filings), and possible scheduling impacts if aircraft are removed from service to implement SB modifications as an alternative permanent solution. The AD provides the SB route for a permanent fix, which requires embodiment per SB A320-34-1264 Rev 1; that alternative carries costs of the SB embodiment but removes the need to keep the DDRMI deactivated. Operators must weigh immediate deactivation against the costs and lead times to embody the SB.

Document references to keep on hand when complying

• AD/A320/136 Amdt 3 (this document)
• Airbus Industrie All Operator Telex A320-34A1262 Revision 01 dated 21 August 2002 (paragraph 4 and paragraph 3.5)
• Airbus Service Bulletin A320-34-1264 Revision 1 (for embodying mods 32414-32417)
• MMEL references 34-22-02 a (standby compass) and 34-57-01 (inoperative DDRMI despatch condition) as noted in the AD
• Aircraft Inspection Report (AIR) and DDRMI serial number and repair history records

By following this source-mapped sequence,determine applicability, check SB embodiment, deactivate per AOT where required, apply dispatch limitation, reconcile MELs per AOT, and document all steps,an operator aligns with the AD’s explicit requirements as set out in the text.