{"id":"F2009L00109","name":"AD/A330/95 Amdt 2 - Air Data Inertial Reference Unit Operational Procedure","slug":"ad-a330-95-amdt-2-air-data-inertial-reference-unit-operational-procedure","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":76530,"registerId":"commonwealth-F2009L00109-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Airbus Industrie A330 Series Aeroplanes","sectionType":"division","heading":"Airbus Industrie A330 Series Aeroplanes","content":"### Airbus Industrie A330 Series Aeroplanes\n\n| AD/A330/95 Amdt 2 | Air Data Inertial Reference Unit Operational Procedure | 3/2009 TX |\n| ----------------- | ------------------------------------------------------ | --------- |\n\n| Applicability: | A330 aircraft, models -201, -202, -203, -223, -243, -301, -302, -303, -321, -322, -323, -341, -342 and -343, all serial numbers, equipped with Northrop-Grumman (formerly Litton) Air Data Inertial Reference Unit (ADIRU) Part Number (P/N)465020-0303-03ZZ (with ZZ from 09 up to 16 inclusive). |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | Apply the following operational procedure: |\n| | - NAV - IR 1 (2) (3) FAULTTurn off the affected IR.Turn off the corresponding ADR.Set the affected IR mode rotary selector must be set to OFF.Use AIR DATA switching as appropriate.Use ATT HDG switching as appropriate. |\n| | - NAV - IR 1+2 (2+3) (1+3) FAULTNote: Flight controls are in alternate law. Refer to F/CTL – ALTN LAW (chapter 4of the AFM).Turn off the affected IRsTurn off the corresponding ADRs.Set the affected IR mode rotary selector must be set to OFF.Use AIR DATA switching as appropriate.Use ATT HDG switching as appropriate.Do not use speed brakes• If CG above 32%:Manually perform a forward fuel transfer from the trim tank.Note: If trim tank pump is not available, do not perform manual forward fuel transfer while speed is at or below 270 kt or while in climb. |\n| | Note 1: This operational procedure is covered by Temporary Revision (TR) of the Aircraft Flight Manual (AFM) A330 AFM TR 4.02.00/46 Issue 3 (OEB N°74/4). |\n| | Incorporation of the AFM TR or inserting the above operational procedure or a copy of this Directive into the AFM is acceptable to comply with the requirements of this Directive. |\n| | Note 2: EASA Emergency AD 2009-0012-E refers. |\n\n| Compliance: | Before 19 January 2009. |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | This Amendment becomes effective on 18 January 2009. |\n| Background: | An A330 aircraft experienced a sudden nose down order while in cruise. This order was preceded by an automatic autopilot disconnection and triggering of the “NAV IR1 FAULT” Electronic Centralised Aircraft Monitor (ECAM) Caution.Investigations highlighted that at time of the event the Air Data Reference 1 (ADR) part of ADIRU1 was providing erroneous and temporary wrong parameters in a random manner. This abnormal behaviour of the ADR1 led to several consequences such as unjustified stall and over speed warnings, loss of attitude information on Captain Primary Flight Display (PFD) and several ECAM warnings.Among the abnormal parameters, the provided Angle of Attack (AoA) value was such that the flight control computers commanded a sudden nose down aircraft movement, which constitutes an unsafe condition.At this stage of the investigation, the analysis of available data indicates ADIRU 1 abnormal behaviour is likely at the origin of the event.In order to prevent the ADR from providing erroneous data to other aircraft systems, the original issue of this Directive required, in case faulty Inertial Reference (IR) is detected, to isolate both the IR and ADR by accomplishment of the modified AFM operational procedure. |\n| | Since that Directive was issued, it has been reported that the “OFF” light did not illuminate in the cockpit after setting the IR and ADR pushbuttons to OFF. Investigation has determined that the ADIRU was indeed sometimes affected by another failure condition.To prevent such a failure, the operational procedure has been updated to instruct the flight crew to de-energize the ADIRU if the “OFF” light is not illuminated after setting the IR and ADR pushbuttons to OFF. Consequently, this Amendment required accomplishment of the updated AFM operational procedure. |\n| | Since Amendment 1 was issued, a new in service event has been reported highlighting that, in some failure cases, even though the “OFF” light illuminates in the cockpit after setting the IR and ADR pushbuttons to OFF, the IR could keep providing erroneous data to other systems.In order to address all identified failure cases, de-energizing the affected ADIRU must be done by setting the IR mode rotary selector to OFF. Consequently, this Amendment, requires accomplishment of the updated AFM operational procedure. |\n\n| | The original issue of this Directive became effective on 20 November 2008. |\n| --- | -------------------------------------------------------------------------- |\n| | Amendment 1 of this Directive became effective on 22 December 2008. |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n16 January 2009","sortOrder":0},{"sectionNumber":"AD/A330/95 Amdt 2","sectionType":"part","heading":"AD/A330/95 Amdt 2","content":"## AD/A330/95 Amdt 2","sortOrder":1},{"sectionNumber":"Air Data Inertial Reference Unit Operati","sectionType":"part","heading":"Air Data Inertial Reference Unit Operational Procedure","content":"## Air Data Inertial Reference Unit Operational Procedure","sortOrder":2},{"sectionNumber":"3/2009 TX","sectionType":"part","heading":"3/2009 TX","content":"## 3/2009 TX","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This remains a targeted safety directive addressing a specific hardware fault in specific ADIRU units. While Amendment 2 expands the shutdown procedure (adding the rotary selector requirement after discovering pushbutton-only shutdown was insufficient), this is a refinement of the original safety fix rather than scope creep. The directive has not expanded to cover unrelated systems or aircraft types."},"complexity_factors":["Multiple nested failure scenarios (single IR fault vs dual IR fault) with different procedural responses","Cross-references to external documents: Aircraft Flight Manual (AFM) Temporary Revision 4.02.00/46 Issue 3, EASA Emergency AD 2009-0012-E, and AFM Chapter 4","Technical aviation jargon throughout (ECAM, ADIRU, P/N, PFD, AoA, F/CTL ALTN LAW, CG, kt)","Conditional logic: different procedures based on whether CG is above 32%, whether trim tank pump is available, speed below 270 kt, or climb phase","Equipment-specific applicability: narrow part number range (P/N 465020-0303-03ZZ with ZZ 09-16) creates precise but complex targeting","Amendment history references (original issue, Amendment 1, Amendment 2) explaining evolution of the fix without being necessary to current compliance","Dual compliance pathways: either incorporate the AFM revision OR insert the procedure directly OR insert a copy of the Directive"],"plain_english_summary":"This AD orders operators of certain Airbus A330-200/-300 aircraft fitted with specific Northrop‑Grumman ADIRU units to update flight manuals with mandatory emergency procedures. It addresses a dangerous ADIRU fault that has caused an uncommanded nose‑down dive by giving crews a checklist to isolate and shut down a failed unit and use backup instruments.\n\nIt applies to affected aircraft operating in Australia and required compliance by 19 January 2009."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The amendments refine and broaden the operational steps to cover additional failure modes of the same equipment but do not change the Directive's original safety objective. The original intent was to isolate an ADIRU/ADR when faulty to stop erroneous data reaching other systems; subsequent amendments add further methods (de‑energise when OFF light fails to illuminate; set IR mode rotary selector to OFF in particular failure cases) to ensure isolation in more scenarios. This is a refinement of scope to address identified failure cases rather than a significant expansion beyond the original purpose."},"complexity_factors":["Covering multiple A330 variants (about 15 model suffixes) and all serial numbers fitted with a narrowly defined ADIRU P/N range (465020-0303-03ZZ where ZZ = 09–16).","Procedure has distinct branches depending on fault type: single IR fault versus multiple IR faults (conditional logic).","Several interdependent actions required: switching off IR(s), switching off ADR(s), setting IR mode rotary selector to OFF (de‑energise), using AIR DATA and ATT/HDG switching as appropriate.","Additional conditional operational constraints for multi‑IR faults: flight controls change to alternate law; prohibition on speed brakes; fuel transfer required only if CG > 32% and with pump/airspeed/climb exceptions (nested conditions).","Integration requirement with AFM Temporary Revision (administrative step) and cross‑reference to EASA Emergency AD.","Multiple amendment history steps (original directive, Amendment 1, Amendment 2) that modify the procedure to cover additional failure modes (off light not illuminating; de‑energisation required even if off light does illuminate).","Safety‑critical human factors: reliance on crew recognition and manual switching increases implementation complexity despite short written procedure."],"plain_english_summary":"**What this directive does (in plain English)**\n\n- This is an operational safety instruction for Airbus A330 aeroplanes fitted with a specific make and part-numbered Air Data Inertial Reference Unit (ADIRU) (Northrop‑Grumman / formerly Litton P/N 465020-0303-03ZZ, where ZZ is 09–16).\n\n- It requires flight crews to follow a specific checklist-type procedure if one or more Inertial References (IRs) or the Air Data References (ADRs) associated with them behave abnormally. The steps are aimed at isolating (turning off or de‑energising) the affected ADIRU so it stops sending erroneous air data and attitude information to other aircraft systems.\n\n**Who it affects**\n\n- Airlines and operators that fly the listed A330 variants with the specified ADIRU units.\n- Flight crews of those aircraft: they must learn and apply the changed procedure during flight.\n- Maintenance and operations staff: they must insert the Temporary Revision (TR) into the Aircraft Flight Manual (AFM) or otherwise make the procedure available and ensure compliance.\n\n**The required actions (mechanics of the procedure)**\n\n- For a single IR fault (e.g. \"NAV - IR 1 FAULT\"):\n - Turn off the affected IR and the corresponding ADR.\n - Set the IR mode rotary selector for that IR to OFF (this de‑energises the unit).\n - Use AIR DATA and ATT/HDG switching as appropriate.\n\n- For multiple IR faults (e.g. \"NAV - IR 1+2 FAULT\"):\n - The flight control law changes to \"alternate law\" (different flight control protections); follow the AFM chapter on Alternate Law.\n - Turn off the affected IR(s) and corresponding ADR(s).\n - Set the affected IR mode rotary selector(s) to OFF (to de‑energise the ADIRU(s)).\n - Use AIR DATA and ATT/HDG switching as appropriate.\n - Do not use speed brakes.\n - If the aircraft centre of gravity (CG) is above 32%: perform a manual forward fuel transfer from the trim tank (with procedural limitations: if the trim tank pump is inoperative, do not do a manual forward transfer when speed is ≤ 270 kt or while in climb).\n\n- The directive allows compliance by inserting the AFM Temporary Revision that contains the procedure, or by inserting a copy of the Directive into the AFM.\n\n**Why it matters (stated purpose and practical testing of that claim)**\n\n- Stated purpose: prevent unsafe flight commands caused by an ADIRU/ADR supplying erroneous air data (for example, faulty Angle of Attack values that led flight computers to command a sudden nose‑down). The directive arose after in‑service events where ADR or ADIRU failures produced intermittent, incorrect data with hazardous consequences.\n\n- How the measure achieves that: it isolates (powers down) the affected ADIRU so it cannot continue to feed bad data to flight displays, autopilot, flight control computers and warning systems.\n\n**Trade‑offs, costs and practical impacts**\n\n- Who pays: operators bear the costs — training crews on the new procedure, inserting the AFM temporary revision, and dealing with any operational disruptions when the procedure is used (e.g. degraded navigation/attitude sources, potential diversion or performance impacts).\n\n- Behaviour changes required: flight crews must take additional switching actions during an in‑flight fault, follow fuel management steps when CG is high, and avoid using speed brakes in multiple‑IR fault scenarios.\n\n- Compliance burden: low to moderate administrative burden (AFM update and crew training) and occasional operational burden when the procedure is used (increased pilot workload, potential fuel transfers and handling degraded navigation/attitude information).\n\n- Opportunity costs and substitution: operators facing recurrent ADIRU faults may choose to remove/replace affected units, retrofit newer hardware, or accept more frequent operational disruption; the directive does not mandate replacement, only an immediate operational mitigation.\n\n- Implementation risks: success depends on crews recognising the failure mode and correctly performing the procedure (including setting the IR mode rotary selector to OFF to de‑energise units in failure modes where the cockpit \"OFF\" light may or may not illuminate). If crews fail to isolate the unit, erroneous data can continue to affect other systems.\n\n- Effects on competition and private choice: the requirement applies equally to all operators of affected A330s; it may temporarily increase operating cost/risk for operators who have many aircraft with the affected ADIRU P/Ns, but does not change market rules or entry/exit conditions beyond the technical and operating costs described.\n\n**Cross‑references and notes**\n\n- The procedure is provided as (or via insertion of) an AFM Temporary Revision (A330 AFM TR 4.02.00/46 Issue 3) and references an EASA Emergency AD for the same issue.\n\n**Bottom line**\n\n- This Directive prescribes a cockpit procedure to isolate an identified faulty ADIRU/ADR configuration on certain A330s to stop erroneous air data from driving flight controls and displays. It tightens the earlier procedure by requiring the IR mode rotary selector be set to OFF (to de‑energise the unit) so the fault cannot continue to propagate even in failure cases where cockpit lights are misleading."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-a330-95-amdt-2-air-data-inertial-reference-unit-operational-procedure","history":"/api/acts/ad-a330-95-amdt-2-air-data-inertial-reference-unit-operational-procedure/history","analysis":"/api/acts/ad-a330-95-amdt-2-air-data-inertial-reference-unit-operational-procedure/analysis","conflicts":"/api/acts/ad-a330-95-amdt-2-air-data-inertial-reference-unit-operational-procedure/conflicts","importantCases":"/api/acts/ad-a330-95-amdt-2-air-data-inertial-reference-unit-operational-procedure/important-cases","documents":"/api/acts/ad-a330-95-amdt-2-air-data-inertial-reference-unit-operational-procedure/documents"}}