{"id":"F2006B01999","name":"AD/A330/2 Amdt 1 - Digital Distance and Radio Magnetic Indicators","slug":"ad-a330-2-amdt-1-digital-distance-and-radio-magnetic-indicators","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41221,"registerId":"commonwealth-F2006B01999-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/A330/2 Amdt 1 - Digital Distance and Radio Magnetic Indicators","content":"![](image.001.png)\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/A330/2 and issues the following AD under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nAirbus Industrie A330 Series Aeroplanes\n\nAD/A330/2\n\nAmdt 1\n\n  \n\nDigital Distance and Radio Magnetic Indicators\n\n  \n11/2003\n\nApplicability: All A330 series aeroplanes, all Manufacturer Serial Numbers after 0253, fitted with a Thales Avionics (formerly Sextant or Sextant Avionique) Digital Distance and Radio Magnetic Indicator (DDRMI) part number (P/N) 63543-253-1 or 63543-253-2.\n\nAll other A330 series aeroplanes fitted with a Thales Avionics DDRMI with P/N 63543-253-1 or 63543-253-2 and having a serial number (S/N) different from the S/N recorded in the Aircraft Inspection Report (AIR) delivered from the production line, or with a Thales Avionics DDRMI that has been repaired after May 1999.\n\nThis Directive is not applicable to aircraft on which Airbus modification 50453 has been embodied during production (DDRMI P/N 63543-253-3 installed) or a DDRMI P/N 63543-253-3 has been incorporated vide Airbus Industrie Service Bulletin A330- 34-3113 Revision 01 dated 15 July 2003.\n\nRequirement: 1. Deactivate the DDRMI in accordance with paragraph 4 of Airbus Industrie All Operator Telex (AOT) A330-34A3109 Revision 01 dated 21 August 2002.\n\n2. Dispatch with an inoperative standby compass (Master Minimum Equipment List \\[MMEL\\] item 34-22-02 a) is limited to a ‘B’ rectification interval.\n\nNote 1: This Airworthiness Directive supersedes the MMEL for the inoperative DDRMI despatch condition (reference 34-57-01). Therefore this Airworthiness Directive may supersede any Minimum Equipment List (MEL) limitation concerning the DDRMI in accordance with AOT A330-34A3109 Revision 01 paragraph 3.5.\n\nNote 2: DGAC AD 2002-459(B) R2 refers.\n\nCompliance: For Requirement 1 \\- Remains unchanged as ‘Within seven days after the effective date of the original issue of this Directive’.\n\nFor Requirement 2 \\- As of the effective date of this Amendment. This Amendment becomes effective on 30 October 2003.\n\nAirbus Industrie A330 Series Aeroplanes\n\nAD/A330/2 Amdt 1 (continued)\n\nBackground: Airbus received reports from two operators advising of DDRMI circuit breakers tripping, followed by loss of VOR and DME sources for navigation and displays. Investigations showed the DDRMI power transformer had short circuited, leading to leakage of 115 VAC to systems connected to the DDRMI ARINC 429 busses.\n\nThe original issue of this Directive required temporary deactivation of the DDRMI to prevent possible loss of essential equipment due to an in-flight failure of the DDRMI.\n\nThis amendment provides relief from the Requirement 2 MEL restriction by identifying a Service Bulletin which provides for the installation of DDRMI P/N 63543-253-3.\n\nThis original issue of this Airworthiness Directive became effective on 30 October 2002.\n\n![](image.002.png)  \n\nJim Coyne\n\nDelegate of the Civil Aviation Safety Authority 18 September 2003\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 8 October 2003.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Yes. The amendment retains the original safety action (temporary deactivation of the affected DDRMI) but modifies the operational scope by identifying a corrective modification (DDRMI P/N 63543-253-3 and Airbus Service Bulletin A330-34-3113 Rev 01) that, if embodied, exempts an aircraft from the stricter MMEL dispatch restriction. It also clarifies applicability with additional serial/repair conditions. In practical terms the amendment narrows the ongoing operational burden for operators who adopt the retrofit, while maintaining the original short-term mitigation for all affected aircraft."},"complexity_factors":["Multiple precise applicability conditions (MSN after 0253; P/N 63543-253-1 or -253-2; repaired after May 1999; S/N mismatches with AIR).","Cross-references to external technical documents (Airbus AOT A330-34A3109 Rev 01; Airbus Service Bulletin A330-34-3113 Rev 01; Airbus mod 50453).","Interaction with MMEL/MEL rules and a supersession note (Note 1) that affects operational dispatch rules.","Two distinct requirements with different compliance timings (one retroactive seven-day action, one immediate operational consequence on amendment date).","Part- and serial-number specific exceptions (P/N 63543-253-3 exemption) increasing conditional logic."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- This is an Airworthiness Directive (AD) that orders specific actions for Airbus A330 aeroplanes that use a particular model of Digital Distance and Radio Magnetic Indicator (DDRMI).\n- It requires operators of affected A330s to deactivate the DDRMI unit (the electronic navigation indicator) immediately as instructed by Airbus, and it imposes a temporary operational restriction on dispatch when the standby compass is inoperative.\n- The amendment also identifies a fix (a later DDRMI part number and a Service Bulletin) that, if embodied, removes the stricter dispatch restriction for affected aircraft.\n\n**Who it affects**\n\n- A330 operators and their maintenance organisations.\n- Specifically: all A330 aeroplanes with Thales Avionics DDRMI P/N 63543-253-1 or 63543-253-2 on manufacturer serial numbers (MSN) after 0253; and other A330s with those DDRMI P/Ns where the unit’s serial number doesn’t match the Aircraft Inspection Report from the production line, or where the DDRMI has been repaired after May 1999.\n- Aircraft that already have Airbus production modification 50453 (which installs DDRMI P/N 63543-253-3) or that have incorporated DDRMI P/N 63543-253-3 via Airbus Service Bulletin A330-34-3113 Rev 01 are excluded from this AD.\n\n**Required action and timing**\n\n- Requirement 1: Deactivate the DDRMI in accordance with paragraph 4 of Airbus All Operator Telex (AOT) A330-34A3109 Rev 01. (This was to be done within seven days after the original issue of the AD.)\n- Requirement 2: Dispatching an aircraft with an inoperative standby compass is limited to a ‘B’ rectification interval under the Master Minimum Equipment List (MMEL) item 34-22-02 a). (This limitation took effect as of the amendment’s effective date.)\n- The amendment becomes effective on 30 October 2003.\n\n**Why the AD was issued (background summary)**\n\n- Two operators reported DDRMI circuit-breaker trips followed by loss of VOR and DME navigation sources. Investigations found the DDRMI power transformer had shorted and leaked 115 VAC onto ARINC 429 data buses, risking loss of essential navigation/data displays.\n- The original AD mandated temporary deactivation of the DDRMI to prevent in‑flight failures from affecting other systems.\n- The amendment identifies a later DDRMI part (P/N 63543-253-3) and a corresponding Airbus Service Bulletin as a corrective modification; aircraft with that mod are not subject to the AD’s restrictions.\n\n**Practical effects, incentives and costs**\n\n- Who pays: aircraft operators bear direct costs — maintenance shop time to deactivate or to install the corrected unit, parts costs if they choose to fit DDRMI P/N 63543-253-3, and any disruption to flight schedules while the work is done.\n- Who decides: the CASA delegate issued the AD; operators decide whether to operate under the temporary restriction or to install the modification identified by Airbus to remove the restriction.\n- Behaviour change required: operators must either (a) deactivate the DDRMI as instructed and accept the MMEL dispatch restriction while arranging corrective action, or (b) install the identified corrective DDRMI (P/N 63543-253-3) per the Airbus Service Bulletin to avoid the restriction.\n- Compliance burden and operational trade-offs: deactivation reduces available cockpit instrumentation and may trigger short-term dispatch limits or flight cancellations. Installing the new part reduces operational constraints but imposes one-off retrofit costs and uses maintenance capacity. Availability of parts and approved maintenance slots is an implementation risk and an opportunity cost (aircraft out of service).\n- Effects on private enterprise: the AD enforces a safety standard that creates a near-term maintenance market (parts and labour) for those DDRMI units and imposes operational constraints on airline scheduling. The AD does not change ownership or contractual rights, but it does constrain how operators may use affected aircraft until they comply.\n\n**Interaction with other documents and discretion**\n\n- The AD cross-references Airbus AOT A330-34A3109 Rev 01, Airbus Service Bulletin A330-34-3113 Rev 01, the MMEL, and the Airbus production modification 50453. Compliance requires following those external technical documents.\n- The CASA delegate issued the AD under regulation power provided by CASR 1998 subregulation 39.1(1), which gives the delegate discretion to require measures considered necessary to correct the unsafe condition.\n\n**Key sections cited**: Applicability; Requirement (items 1 and 2); Compliance; Background."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment stays within the original scope of addressing the DDRMI electrical fault. It provides a relief mechanism (installation of upgraded hardware) rather than expanding to new aircraft types or unrelated systems. The original intent was to prevent unsafe electrical conditions; this amendment simply offers an alternative compliance path (replacement vs. deactivation) while maintaining the same safety objective."},"complexity_factors":["Multiple nested applicability conditions combining aircraft serial numbers, part numbers, repair history, and production modifications","Cross-references to external documents: Airbus AOT A330-34A3109, Airbus Service Bulletin A330-34-3113, DGAC AD 2002-459(B) R2, and MMEL item 34-22-02","Two-tier compliance structure with different effective dates for original requirement vs. amendment","Technical aviation terminology requiring domain knowledge (ARINC 429 busses, VOR, DME, MMEL rectification intervals)"],"plain_english_summary":"This CASA Airworthiness Directive orders removal or repair of faulty Thales DDRMI units on affected Airbus A330s after reports that a transformer short can leak 115V into navigation systems and cause loss of VOR/DME. Operators must deactivate the defective unit promptly (7 days under the original AD) to prevent in‑flight nav failures; aircraft already fitted with the upgraded P/N 63543‑253‑3 are exempt.\n\nThis amendment shortens repair timing when a standby compass is unserviceable (B‑interval) unless the upgraded DDRMI is installed, allowing restoration of full navigation functionality once corrected."}},"importantCases":[],"_links":{"self":"/api/acts/ad-a330-2-amdt-1-digital-distance-and-radio-magnetic-indicators","history":"/api/acts/ad-a330-2-amdt-1-digital-distance-and-radio-magnetic-indicators/history","analysis":"/api/acts/ad-a330-2-amdt-1-digital-distance-and-radio-magnetic-indicators/analysis","conflicts":"/api/acts/ad-a330-2-amdt-1-digital-distance-and-radio-magnetic-indicators/conflicts","importantCases":"/api/acts/ad-a330-2-amdt-1-digital-distance-and-radio-magnetic-indicators/important-cases","documents":"/api/acts/ad-a330-2-amdt-1-digital-distance-and-radio-magnetic-indicators/documents"}}