Update of the APU Hours and Cycles in the DMU after APU, ECB or DMU Replacement

TASK 31-36-00-740-004-A
Update of the APU Hours and Cycles in the DMU after APU, ECB or DMU Replacement

NOTE: Before you update the APU hours and cycles, you must energize the ECB (C/B pushed and ground power switched on).

ZONE: 210
FIN: 1TV ** ON A/C NOT FOR ALL

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
210	CKPT,FWD COMPT BHD TO FLT COMPT BULKHEAD

B. Referenced Information

REFERENCE	DESIGNATION
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)

3. Job Set-up
Subtask 31-36-00-860-052-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(2) On the overhead panel, on the APU section of panel 25VU, push the MASTER SW pushbutton switch (the blue-light of the ON legend comes on).

Subtask 31-36-00-865-058-A ** ON A/C NOT FOR ALL

B. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	AIDS/DMU	4TV	K15
121VU	APU/ECB/SPLY	1KD	L41

4. Procedure
Subtask 31-36-00-740-052-I ** ON A/C NOT FOR ALL

A. Enter the APU hours and cycles data into the DMU
(1) You must perform this procedure when:
(a) You install a new Data Management Unit (DMU) on the aircraft.

NOTE: There is an automatic update of the APU Hours and APU Cycles in the DMU, for the installed APU. The replacement of the APU and/or the ECB has no effect on the offsets of the APU Hours and Cycles in the DMU, which remain null.

(2) Do the subsequent steps to update the DMU offsets (OFAHRS and OFCYC) of the APU hours and cycles:

ACTION	RESULT
On the MCDU front panel: Push the MCDU MENU mode key.	On the MCDU display: The MCDU MENU page comes into view.
Push the line key adjacent to the < AIDS indication.	The AIDS page comes into view.
Push the line key adjacent to the < PROGRAMMING indication.	The AIDS DMU PROGRAMMING page comes into view.
Enter the level 1 customer access-code and push the line key adjacent to the * ENTER PASSWORD indication.	The color of the PROGRAMMING MENUS indication changes from cyan into white.
Push the line key adjacent to the < PROGRAMMING MENUS indication.	The AIDS DMU PROGRAMMING page comes into view.
Push the line key adjacent to the STATISTIC < COUNTERS indication.	The AIDS STATISTIC COUNTERS page comes into view.
Set the offset values of the APU hours and cycles to the required value. NOTE: The offset values of the APU hours and cycles are usually set to zero, but in some cases they must be set to 16384.
Push the line key adjacent to the OFFSETS AHRS ACYC 00000 00000 * indications. Use the alphanumeric keys to set the offsets of the APU hours and cycles to the required value.	The revised values of the AHRS and ACYC come into view.
On the MCDU front panel: Push the line key adjacent to the PRINT * indication.	On the center pedestal: The printer makes a printout of the revised values.
Push the line key adjacent to the * RETURN indication to memorize the new values.
On the MCDU front panel: Push the MCDU MENU mode key.	On the MCDU display: The MCDU MENU page comes into view.

5. Close-up
Subtask 31-36-00-860-053-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) On the overhead panel, on the APU section of panel 25VU, release the MASTER SW pushbutton switch (the blue-light of the ON legend goes off).
(2) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.01 08:31:09 UTC