737-600/700/800/900 Fault Isolation Manual 故障隔离手册 |
805.
Align Fault - Fault Isolation |
A. Description 描述 |
(1)
This task is for this maintenance message: |
(a)
34-21004 ALIGN FAULT |
(2)
The maintenance message is identical for the left and right ADIRS. The left ADIRS maintenance message is shown on the ADIRS L BITE page on the CDU. The right ADIRS maintenance message is shown on the ADIRS R BITE page on the CDU. |
(3)
The ADIRU keeps a record of its last position. You must enter the present position data during the alignment mode. The ADIRU will not go into NAV mode if present position has not been entered by the end of the alignment period. The ADIRU will continue to prompt for a present position and the ALIGN FAULT will not clear. |
(4)
This message shows when you enter position data that is more than 1 degree different than the recorded latitude or 1 degree different than the recorded longitude. This message will also show when the ADIRU’s post alignment computed latitude is different than the manually entered latitude. |
(5)
This condition causes the ALIGN light on the MSU to flash, the status code 04 to show on the ISDU and ENTER IRS POSITION message to show on the CDU. |
B.
Possible Cause |
(1)
The entered present position is more than ±1 degree different than the present position stored in memory. |
NOTE:
This can occur when an ADIRU is replaced (if the ADIRU was turned off at a different location) or the airplane is moved after the ADIRU powered down. It can also occur if ADIRU power is removed before the ADIRU had time to complete a full power down sequence when it stores the last known valid position. |
NOTE:
If this condition occurs, the ALIGN light on the Mode Select Unit (MSU) will flash. Confirm the location of the airplane and enter the present position again to align the ADIRU. |
NOTE:
You might need to enter the data three times. |
(2)
The entered latitude fails the ADIRU’s post alignment performance test. |
NOTE:
If this condition occurs, the ALIGN light on the MSU will flash and the ADIRU will again request a manual entry of position. If the same position that was entered initially is entered again, the ADIRU will fail the post alignment performance test and fault itself. Make sure that the position entered initially was accurate before entering it again. If it was not accurate then enter the accurate position. If the new position entry passes the ADIRU’s post alignment comparison test, the ADIRU will complete the alignment and be ready for NAV mode. |
(3)
ADIRU-1, (2) M1749, (M1752). |
C.
Circuit Breakers |
(1)
These are the primary circuit breakers related to the fault: |
CAPT Electrical System Panel, P18-1 |
|
CAPT Electrical System Panel, P18-2 |
|
F/O Electrical System Panel, P6-1 |
|
D.
Related Data |
(1) WDM 34-61-14 |
(2) WDM 34-21-12. |
E.
Initial Evaluation |
(1)
Confirm the airplane’s position. Use the CDU or the ISDU to enter the correct present position again. The ADIRU must have two identical and valid positions for the alignment. It can be: |
(a)
The ADIRU’s stored position plus an identical manually entered position, or |
(b)
Two identical positions entered sequentially. |
(c)
Do the applicable ADIRS BITE procedure (34-21 TASK 801). |
1)
If the maintenance message does not show on the CDU and the status code does not show on the ISDU, then you corrected the problem. |
2)
If the maintenance message shows on the CDU and the status code shows on the ISDU, then do the Fault Isolation Procedure below. |
F.
Fault Isolation Procedure |
(1)
Do these steps from the CDU to enter the present position (34-21 TASK SUPPORT Figure 301): |
NOTE:
The present position can also be entered from the ISDU. |
(a)
Set the mode select switches on the Inertial Reference System (IRS) MSU to the OFF position. |
1)
Make sure that the ALIGN lights are off. |
NOTE:
It can take up to 30 seconds for the ALIGN lights to turn off. |
(b)
Set the mode select switches on the IRS MSU to the NAV position. |
(c)
Make sure that the ON DC lights on the IRS MSU come ON for a short time. |
(d)
Make sure that the ALIGN lights on the IRS MSU come ON. |
NOTE:
It is acceptable for the ALIGN lights to come ON before or after the ON DC lights. |
(e)
Do these steps to enter the latitude and longitude from a CDU: |
NOTE:
CDU data lines that permit a selection are identified with a caret ( or >). The CDU has 12 line-select-keys (LSK). Six keys are on each side of the display. LSK 1L thru 6L are on the left side, and LSK 1R thru 6R are on the right side. |
1)
Push the INIT REF key on the CDU. |
2)
Push the LSK 6L adjacent to the < INDEX prompt on the CDU. |
a)
Make sure that the CDU shows the INIT/REF INDEX 1/1 page. |
3)
Push the LSK 2L adjacent to the < POS prompt on the CDU. |
a)
Make sure that the CDU shows the POS INIT 1/3 page. |
4)
Put the latitude and longitude data in the scratch pad line of the CDU. |
NOTE:
Do not put a space between the latitude and longitude. The format of the latitude and longitude data is as follows: |
Latitude and longitude: XDDMM.MYDDDMM.M |
|
5)
Push the LSK 4R adjacent to the SET IRS POS > prompt on the CDU. |
a)
Make sure that the CDU shows the latitude and longitude below the SET IRS POS line. |
6)
Do the Repair Confirmation at the end of this task. |
(2)
Confirm the airplane’s position. Use the CDU or ISDU to enter the present position again. |
(a)
Do the Repair Confirmation at the end of this task. |
(3)
If the above steps are followed correctly and the alignment is still not able to be completed, then replace the applicable ADIRU. These are the tasks: |
(a)
Do the Repair Confirmation at the end of this task. |
G.
Repair Confirmation |
(1)
Do the applicable ADIRU BITE procedure (34-21 TASK 801). |
(a)
If the maintenance message does not show on the CDU and the status code does not show on the ISDU, then you corrected the problem. |
(b)
If the maintenance message shows on the CDU and the status code shows on the ISDU then continue the Fault Isolation Procedure at the subsequent step. |