RED OEB RED OEB RED OEB RED OEB RED OEB RED OEB RED OEB
Issued by STL
File in FCOM Vol 3
OEB N°: 74/4 DEC 08
Associated with QRH OEB PROC N°: 74/4
- This OEB covers a significant operational issue. Non-compliance with this OEB should have a significant impact on the safe operations of the aircraft. The Operators shall distribute its content to all flight crews without delay. An extract of this OEB is provided for insertion in the QRH.
- It is strongly recommended that all Operators accelerate the incorporation of all corrective Service Bulletins as soon as they are available.
SUBJECT:
IR FAILURE OR ATT FLAG ON PFD
APPLICABLE TO:
All A330 aircraft fitted with NORTHROP GRUMMAN - LITTON ADIRU
CANCELLED BY:
TBD
R
REASON FOR ISSUE 4:
RRRR
The previous OEB revision requested to de-energize the affected ADIRU if the IR and/or ADR OFF lights did not illuminate. The OEB procedure is now revised in order to recommend that the IR mode rotary selector be set to OFF in all cases in order to address all identified failure cases.
Page 1 of 5
Operations Engineering Bulletins are issued by Airbus as the need arises to quickly transmit technical and procedural information. They are distributed to all FCOM holders and to others who need advice of changes to operational information.
Information in this bulletin is recommended by Airbus but may not be approved by Airworthiness Authorities.
If the procedures contained in this OEB differ from the procedures in the AFM, the AFM remains the reference.
OEB N° Page 2 of 5
74/4
REASON FOR ISSUE:
This OEB is issued in order to provide a procedure enabling to mitigate the probability of occurrence of a sudden nose down order.
EXPLANATION:
An A330 aircraft experienced a sudden nose down order during cruise. This order was preceded by an automatic autopilot disconnection and triggering of the NAV IR 1 FAULT ECAM caution.
Investigations highlighted that at the moment of the event the ADR 1 was providing erroneous and temporary wrong parameters in a random manner. This abnormal behavior of the ADR 1 led to several consequences such as unjustified stall and over speed warnings, loss of attitude information on the Primary Flight Display, several ECAM warnings.
Among the abnormal parameters, the provided Angle of Attack value was such that the flight control computers commanded nose down movement.
The aim of the following procedure is to isolate both the IR and ADR when an IR is detected faulty in order to prevent the ADR from providing erroneous data to other aircraft systems.
TO BE CONTINUED ON NEXT PAGE
PROCEDURE:
RRRR
OEB N° Page 3 of 5
74/4
RRRR
If all ADIRU operative before failure:
If one IR is self detected faulty or if the ATT red flag is displayed on the Captain or First Officer PFD, the affected IR and the corresponding ADR must be disconnected.
NAV IR 1(2)(3) FAULT, or ATT flag displayed on CAPT (F/O) PFD
-IR (affected) pb
..
OFF
The affected IR is the one self-detected faulty or supplying the PFD displaying the ATT red Flag.
The OFF light may not illuminate
-ADR (corresponding) pb
..
...
OFF
ADR 1 corresponds to IR 1.
ADR 2 corresponds to IR 2.
ADR 3 corresponds to IR 3.
The OFF light may not illuminate
-IR (affected) MODE rotary selector
.. OFF
The IR mode rotary selector is set to OFF in order to de-energize the ADIRU. The OFF lights of the IR and ADR pushbutton will go off.
Setting the IR mode rotary selector to OFF is an irreversible action. Therefore, both PF and PNF must clearly identify the corresponding selector before setting it to OFF.
If IR 1(2) affected:
In order to prevent possible failure of ADIRU 3, the flight crew must switch the AIR DATA and the ATT HDG in the following order:
-AIR DATA SWTG
........
..
... CAPT (F/O) ON 3
-ATT HDG SWTG ..
.......
.. CAPT (F/O) ON 3
TO BE CONTINUED ON NEXT PAGE
CAUTION
RRRRR RRRR
If one ADIRU already disconnected before failure:
In case of dispatch with one ADIRU under MMEL or one ADIRU already disconnected in flight, and an IR failure occurs, either detected by an IR 1+2 (1+3)(2+3) FAULT or with ATT red flag displayed on CAPT or F/O PFD, the affected IR and the corresponding ADR must be disconnected.
NAV IR 1+2(1+3)(2+3) FAULT, or ATT flag displayed on CAPT (F/O) PFD
-IR (affected) pb
..
.
...
OFF
The affected IR is the one self-detected faulty or supplying the PFD displaying the ATT red Flag.
The OFF light may not illuminate
-ADR (corresponding) pb
...
.. OFF
ADR 1 corresponds to IR 1.
ADR 2 corresponds to IR 2.
ADR 3 corresponds to IR 3.
The OFF light may not illuminate
-IR (affected) MODE rotary selector
.. OFF
The IR mode rotary selector is set to OFF in order to de-energize the ADIRU. The OFF lights of the IR and ADR pushbutton will go off.
Setting the IR mode rotary selector to OFF is an irreversible action. Therefore, both PF and PNF must clearly identify the corresponding selector before setting it to OFF.
CAUTION
If IR 1+2 affected:
In order to prevent possible failure of ADIRU 3, the flight crew must switch the AIR DATA and the ATT HDG in the following order:
-AIR DATA SWTG ..........
.CAPT ON 3
-ATT HDG SWTG .......
...
..
CAPT ON 3
Note: First officer can recover IR information, by using the EFIS DMC selector (copy of the opposite side).
SPD BRK
.
.. DO NOT USE
IF CG AFT 32%:
-T TANK MODE
.
.. FWD
F/CTL ALTN LAW (PROT LOST)
MAX SPEED
..
..
. 330/.82
OEB N° Page 4 of 5
74/4
OEB N° Page 5 of 5
74/4
OEB REMINDER:
On aircraft that have the OEB reminder function, the procedures of NAV IR 1(2)(3) and NAV IR 1+2(1+3)(2+3) FAULT ECAM cautions may be flagged.
The refer to QRH PROC line will then be displayed instead of the procedure itself.
To flag those procedures, the following codes should be entered in the FWC OEB database.
Code WARN STS
NAV IR 1 FAULT YES NO
34/10/050/061
NAV IR 2 FAULT YES NO
34/10/060/063
NAV IR 3 FAULT YES NO
34/10/070/065
NAV IR 1+2 FAULT YES NO
34/10/020/055
NAV IR 1+3 FAULT YES NO
34/10/030/057
NAV IR 2+3 FAULT YES NO
34/10/040/059
CORRECTIVE ACTION:
Under investigation
Note: The interchangeability code, given in the Illustrated Part Catalog (IPC), indicates the conditions for interchangeability of equipment. After installation of corrective modification(s)/SB(s), if an Operator reinstalls any equipment affected by this OEB it is the Operator's responsibility to ensure that the recommendations given in this OEB are applied again for the applicable aircraft.