DOC AIRBUS | TSM A320FFQIS - Attitude Data From the ADIRUs is Possibly Incorrect
TASK 28-42-00-810-848-A
FQIS - Attitude Data From the ADIRUs is Possibly Incorrect
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Fault Confirmation
Subtask 28-42-00-710-097-B ** ON A/C NOT FOR ALL
Subtask 28-42-00-810-097-A
[Rev.8 from Aug 2018]
2026.04.04 04:29:07 UTC
FQIS - Attitude Data From the ADIRUs is Possibly Incorrect
WARNING:
OBEY THE FUEL SAFETY PROCEDURES.
WARNING:
WHEN YOU DO WORK ON THE FUEL SYSTEM WIRING, YOU MUST USE TEST EQUIPMENT THAT IS APPROVED (REFER TO INTERNATIONAL OR NATIONAL SPECIFICATIONS FOR INTRINSICALLY SAFE TEST EQUIPMENT: EN50020, UL913 OR EQUIVALENT). TEST EQUIPMENT THAT IS NOT APPROVED CAN CAUSE FIRE OR AN EXPLOSION.
1. Possible Causes2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | ARINC READER |
| REFERENCE | DESIGNATION |
|---|---|
| AMM 34-12-34-000-001 | Removal of the ADIRU |
| AMM 34-12-34-400-001 | Installation of the ADIRU |
Subtask 28-42-00-710-097-B ** ON A/C NOT FOR ALL
A. Test
FQIC Attitude Information
The primary source of attitude data, the effective pitch and roll, is the ADIRS. The data is ARINC coded and identified as good or bad.
The effective pitch and roll is calculated from the ADIRU data when the longitudinal,lateral and normal accelerations are considered good.
If the two ADIRUs have all three accelerations identified as good, ADIRU-1 will be choosen. If the above conditions are not met, effective pitch and roll is calculated from points of intersection on the fuel probes with the fuel surface, within each tank. Four probe pairs are used to determine effective pitch and roll and the result averaged to provide effective pitch and roll for the aircraft.
(1) Connect an ARINC READER to the TEST CONNECTOR 198VC on the Panel Plate Relay - 188VU128, and located on the right side of the Aft Electronics Rack 80VU.
(2) Set the ARINC Reader to read the labels that follow:
Subtask 28-42-00-710-097-C ** ON A/C NOT FOR ALL FQIC Attitude Information
The primary source of attitude data, the effective pitch and roll, is the ADIRS. The data is ARINC coded and identified as good or bad.
The effective pitch and roll is calculated from the ADIRU data when the longitudinal,lateral and normal accelerations are considered good.
If the two ADIRUs have all three accelerations identified as good, ADIRU-1 will be choosen. If the above conditions are not met, effective pitch and roll is calculated from points of intersection on the fuel probes with the fuel surface, within each tank. Four probe pairs are used to determine effective pitch and roll and the result averaged to provide effective pitch and roll for the aircraft.
NOTE: On the GROUND, if effective pitch and roll cannot be calculated from the data supplied by the ADIRS or the fuel probes, the default attitudes are:
- the effective pitch angle is set to -0.2 degrees
- the effective roll angle is set to 0.0 degrees.
NOTE: In FLIGHT, if effective pitch and roll cannot be calculated from the data supplied by the ADIRS or the fuel probes, the default attitudes are set to those of the normal cruise conditions:
To make this procedure easy it has been assumed that the FQI system, probes, FQIC, are fully serviceable. - the effective pitch angle is set to +2.5 degrees
- the effective roll angle is set to 0.0 degrees.
(1) Connect an ARINC READER to the TEST CONNECTOR 198VC on the Panel Plate Relay - 188VU128, and located on the right side of the Aft Electronics Rack 80VU.
(2) Set the ARINC Reader to read the labels that follow:
- LABEL 331 Longitudinal Acceleration
- LABEL 332 Lateral Acceleration
- LABEL 333 Normal Acceleration.
A. Test
FQIC Attitude Information
The primary source of attitude data, the effective pitch and roll, is the ADIRS.
The FQIC Channel 1 receives accelerations from the ADIRU-1, and the Channel 2 from the ADIRU-2.
The data is ARINC coded and identified as good or bad.
The effective pitch and roll is calculated from the ADIRU data when the longitudinal,lateral, and normal accelerations are considered good.
The effective pitch and roll can also be calculated from the points of intersection of the probes with the fuel surface, within each tank. A minimum of three probes are required to calculate these angles. For the wing tanks, only the inner cell probes are used for this purpose. If the ADIRS derived attitudes are available and valid they are always used in preference to attitudes calculated from the data that comes from the probes.
If the ADIRS derived attitudes are not available or are not valid for 10 seconds continuously, the attitudes calculated from the probes are used, provided that they are available and valid.
If the ADIRS and probe height derived attitudes are not available or not valid for 30 seconds continuously, default attitudes are used.
To make this procedure easy it has been assumed that the FQI system, probes, FQIC, are fully serviceable.
(1) Connect an ARINC READER to the TEST CONNECTOR 198VC on the Panel Plate Relay - 188VU128, and located on the right side of the Aft Electronics Rack 80VU.
(2) Set the ARINC Reader to read the labels that follow:
4. Fault IsolationFQIC Attitude Information
The primary source of attitude data, the effective pitch and roll, is the ADIRS.
The FQIC Channel 1 receives accelerations from the ADIRU-1, and the Channel 2 from the ADIRU-2.
The data is ARINC coded and identified as good or bad.
The effective pitch and roll is calculated from the ADIRU data when the longitudinal,lateral, and normal accelerations are considered good.
The effective pitch and roll can also be calculated from the points of intersection of the probes with the fuel surface, within each tank. A minimum of three probes are required to calculate these angles. For the wing tanks, only the inner cell probes are used for this purpose. If the ADIRS derived attitudes are available and valid they are always used in preference to attitudes calculated from the data that comes from the probes.
If the ADIRS derived attitudes are not available or are not valid for 10 seconds continuously, the attitudes calculated from the probes are used, provided that they are available and valid.
If the ADIRS and probe height derived attitudes are not available or not valid for 30 seconds continuously, default attitudes are used.
NOTE: On the GROUND, the default attitudes are:
- the effective pitch angle is set to 0.0 degrees
- the effective roll angle is set to 0.0 degrees.
NOTE: In FLIGHT, the default attitudes are set to those of the nominal cruise conditions:
If a preferred attitude source was not available or not valid and subsequently becomes available for the necessary time (10 seconds for ADIRS data, 30 seconds for probe height data) the preferred source is reselected. - the effective pitch angle is set to +2.0 degrees
- the effective roll angle is set to 0.0 degrees.
To make this procedure easy it has been assumed that the FQI system, probes, FQIC, are fully serviceable.
(1) Connect an ARINC READER to the TEST CONNECTOR 198VC on the Panel Plate Relay - 188VU128, and located on the right side of the Aft Electronics Rack 80VU.
(2) Set the ARINC Reader to read the labels that follow:
- LABEL 331 Longitudinal Acceleration
- LABEL 332 Lateral Acceleration
- LABEL 333 Normal Acceleration.
Subtask 28-42-00-810-097-A
A. Procedure
(1) If the acceleration outputs show any signs of incorrect fluctuations.
(2) Replace the ADIRU-2 [1FP2] AMM 34-12-34-000-001 and AMM 34-12-34-400-001.
(3) Swap the ADIRU-2 with the ADIRU-1 (change positions of ADIRU-1 and ADRIU-2), AMM 34-12-34-000-001 and AMM 34-12-34-400-001.
(5) If the acceleration outputs show any signs of incorrect fluctuations, replace the second ADIRU-2 ADIRU-1 [1FP1] AMM 34-12-34-000-001 and AMM 34-12-34-400-001.
(1) If the acceleration outputs show any signs of incorrect fluctuations.
(2) Replace the ADIRU-2 [1FP2] AMM 34-12-34-000-001 and AMM 34-12-34-400-001.
(3) Swap the ADIRU-2 with the ADIRU-1 (change positions of ADIRU-1 and ADRIU-2), AMM 34-12-34-000-001 and AMM 34-12-34-400-001.
NOTE: Step (3) is necessary because due to aircraft design it is only possible to examine the ADIRU ARINC BUS 2 output when installed in the ADRIU-2 position.
(4) Do the test given in Para. 3.A. (5) If the acceleration outputs show any signs of incorrect fluctuations, replace the second ADIRU-2 ADIRU-1 [1FP1] AMM 34-12-34-000-001 and AMM 34-12-34-400-001.