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AD/A330/95 Amdt 2 - Air Data Inertial Reference Unit Operational Procedure
Airbus Industrie A330 Series AeroplanesAirbus Industrie A330 Series Aeroplanes
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Airbus Industrie A330 Series Aeroplanes
| AD/A330/95 Amdt 2 | Air Data Inertial Reference Unit Operational Procedure | 3/2009 TX |
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| 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). |
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| Requirement: | Apply the following operational procedure: |
| - 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. | |
| - 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. | |
| 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). | |
| 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. | |
| Note 2: EASA Emergency AD 2009-0012-E refers. |
| Compliance: | Before 19 January 2009. |
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| This Amendment becomes effective on 18 January 2009. | |
| 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. |