Installation of the Battery of the Emergency Power Supply Unit (EPSU)

TASK 33-51-38-400-002-A
Installation of the Battery of the Emergency Power Supply Unit (EPSU)

FIN: 10WL
FIN: 11WL
FIN: 12WL
FIN: 13WL
FIN: 14WL ** ON A/C NOT FOR ALL
FIN: 15WL ** ON A/C NOT FOR ALL
FIN: 16WL ** ON A/C NOT FOR ALL
FIN: 17WL ** ON A/C NOT FOR ALL

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	1	STEPLADDER 1.5 M (5 FT)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [10WL] (POWER-EMERGENCY SUPPLY)
221BC
FOR [11WL] (EPSU)
251KC
241KW
FOR [12WL] (EPSU)
251KC
242KW
FOR [13WL] (EPSU)
261CC
FOR [14WL] (EPSU)
231JC
FOR [15WL] (EPSU)
231JC
FOR [16WL] (EPSU)
242KW
FOR [17WL] (EPSU)
241KW

C. 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)
TASK 33-51-00-710-001-A	Operational Check of Emergency Power Supply Units by BITE-Check
Battery of the EPSU ** ON A/C NOT FOR ALL
Battery of the EPSU ** ON A/C NOT FOR ALL
Battery of the EPSU ** ON A/C NOT FOR ALL
FOR [10WL] (POWER-EMERGENCY SUPPLY)
TASK 25-23-42-400-001-A	Installation of the Ceiling Panels - Forward Utility Area
FOR [11WL] (EPSU)
TASK 25-23-41-400-001-A	Installation of the Ceiling Panels
TASK 25-23-44-400-001-A	Installation of the Lower Sidewall Panels (Dado Panels)
FOR [12WL] (EPSU)
TASK 25-23-41-400-001-A	Installation of the Ceiling Panels
TASK 25-23-44-400-001-A	Installation of the Lower Sidewall Panels (Dado Panels)
FOR [13WL] (EPSU)
TASK 25-23-42-400-002-A	Installation of the Ceiling Panels - Aft Utility Area
TASK 35-21-41-400-001-A	Installation of the Emergency Oxygen Containers
FOR [14WL] (EPSU)
TASK 25-23-41-400-001-A	Installation of the Ceiling Panels
FOR [15WL] (EPSU)
TASK 25-23-41-400-001-A	Installation of the Ceiling Panels
FOR [16WL] (EPSU)
TASK 25-23-44-400-001-A	Installation of the Lower Sidewall Panels (Dado Panels)
FOR [17WL] (EPSU)
TASK 25-23-44-400-001-A	Installation of the Lower Sidewall Panels (Dado Panels)

3. Job Set-up
Subtask 33-51-38-865-059-A

A. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	LIGHTING/EMER LT/CABIN	2WL	H06
49VU	LIGHTING/EMER LT/CABIN	1WL	H05
** ON A/C NOT FOR ALL
49VU	LIGHTING/EMER LT/CABIN	2WL	H04
49VU	LIGHTING/EMER LT/CABIN	1WL	H03
** ON A/C ALL
122VU	LIGHTING/CABIN/EMER/LT	3WL	V07

Subtask 33-51-38-860-061-A ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) Make sure that the aircraft electrical circuits are energized.
(Ref. AMM TASK 24-41-00-861-002).
(2) Make sure that the STEPLADDER 1.5 M (5 FT) is in position below the related EPSU.
(3) On overhead panel 25VU, make sure that NO SMOKING switch 190RH is in the OFF position.
(4) On Forward Attendant Panel (FAP) 120RH, make sure that the LIGHT EMER pushbutton switch and its integral light are off.
(5) On overhead panel 25VU, set EMER EXIT LT switch 4WL to the ON position.
(6) Make sure that the loads connected to the emergency power supply unit operate.
(7) On overhead panel 25VU, set EMER EXIT LT switch 4WL to the OFF position.

Subtask 33-51-38-860-061-D ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) Make sure that the aircraft electrical circuits are energized.
(Ref. AMM TASK 24-41-00-861-002).
(2) Make sure that the STEPLADDER 1.5 M (5 FT) is in position below the related EPSU.
(3) On the overhead panel 25VU, make sure that the NO SMOKING switch 190RH is in the OFF position.
(4) On the Flight Attendant Panel (FAP) 120RH, make sure that the EMER pushbutton and its internal light are off.
(5) On the overhead panel 25VU, set the EMER EXIT LT switch 4WL to the ON position.
(6) Make sure that the loads connected to the emergency power supply unit operate.
(7) On the overhead panel 25VU, set the EMER EXIT LT switch 4WL to the OFF position.

Subtask 33-51-38-860-061-E ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) Make sure that the aircraft electrical circuits are energized.
(Ref. AMM TASK 24-41-00-861-002).
(2) Make sure that the STEPLADDER 1.5 M (5 FT) is in position below the related EPSU.
(3) On the overhead panel 25VU, make sure that the EXIT switch 190RH is in the OFF position.
(4) On the Flight Attendant Panel (FAP) 120RH, make sure that the EMER button and its light are off.
(5) On the overhead panel 25VU, set the EMER EXIT LT switch 4WL to the ON position.
(6) Make sure that the loads connected to the emergency power supply unit operate.
(7) On the overhead panel 25VU, set the EMER EXIT LT switch 4WL to the OFF position.

Subtask 33-51-38-860-061-F ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) Make sure that the aircraft electrical circuits are energized.
(Ref. AMM TASK 24-41-00-861-002).
(2) Make sure that the STEPLADDER 1.5 M (5 FT) is in position below the related EPSU.
(3) On the overhead panel 25VU, make sure that the No PED switch 190RH is in the OFF position.
(4) On the Flight Attendant Panel (FAP) 120RH, make sure that the LIGHT EMER pushbutton switch and its integral light are off.
(5) On the overhead panel 25VU, set the EMER EXIT LT switch 4WL to the ON position.
(6) Make sure that the loads connected to the emergency power supply unit operate.
(7) On the overhead panel 25VU, set the EMER EXIT LT switch 4WL to the OFF position.

Subtask 33-51-38-865-056-A

C. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	LIGHTING/EMER LT/CABIN	2WL	H06
49VU	LIGHTING/EMER LT/CABIN	1WL	H05
** ON A/C NOT FOR ALL
49VU	LIGHTING/EMER LT/CABIN	2WL	H04
49VU	LIGHTING/EMER LT/CABIN	1WL	H03
** ON A/C ALL
122VU	LIGHTING/CABIN/EMER/LT	3WL	V07

4. Procedure
Subtask 33-51-38-420-054-A ** ON A/C NOT FOR ALL

A. Installation of the Battery of the Emergency Power Supply Unit (EPSU)
(1) Make sure that the battery is serviceable.

NOTE: A serviceable battery will meet the requirements to supply the cabin emergency lights for at least 10 minutes. The battery will be fully charged after 30 minutes. This will start automatically after installation on the EPSU.

(2) Make sure that the contacts between the battery (2) and the EPSU (1) are clean and in good condition.

CAUTION: DO NOT USE THE TEACH-IN PROCEDURE TO CLEAR EPSU FAILURE MESSAGES. THE TEACH-IN PROCEDURE IS NOT A SYSTEM RESET. IT CAN CHANGE THE EMERGENCY LIGHT CONFIGURATION AND CAUSE HIDDEN FAILURES.

CAUTION: BEFORE YOU INSTALL THE BATTERY, MAKE SURE THAT THE SPACER PLATE IS REMOVED. IF YOU INSTALL THE BATTERY WITH THE SPACER PLATE, THE EMERGENCY LIGHT WILL NOT OPERATE IN EMERGENCY CONDITIONS.

(3) Carefully install the battery (2) on the EPSU (1) with the screws (3) and tighten the screws (3).

NOTE: To ensure EPSUs are correctly configured for CIDS PTP emergency lighting system test.

After installation of the battery pack and after connection to aircraft wiring, each EPSU checks the connected loads and store it in memory. If some lamps are faulty during this first check, the EPSU stores the wrong level of connected lamps and will lead to faulty test indications.
To prevent this, it is necessary to install all lamps, ensure they are operational and then remove the aircraft wiring connector from EPSU. Wait 15 seconds (approximately) and reconnect. This will ensure correct initialization of output loads.
As long as the battery is not charged or aircraft connector is not removed, the PTP will test correctly.

NOTE: To measure and keep the load values, the load programming (TEACH IN) of the EPSU starts automatically when:

The AC and the DC power are available
On the Forward Attendant Panel 120RH the LIGHT EMER pushbutton switch is in the released position
On the overhead panel 25VU, EMER EXIT LT switch 4WL is in the OFF position
On the overhead panel 25VU, NO SMOKING switch 190RH is in the OFF position
The overwing emergency lights are off
The EPSU (1) is installed on the A/C for the first time, or The battery was removed for more than 5 s and then it is installed again.
The load values are used as reference values during the EPSU SYSTEM TEST. It is necessary to examine that all connected emergency lights of the related EPSU operate.

NOTE: The teach-in procedure of the EPSUs measures and keeps the load values that are related to each EPSU. The EPSU controller refers to these load values when the BITE test of the emergency lighting system operates. Thus, it is necessary that the emergency lights of the related EPSUs operate correctly during the teach-in procedure.

Subtask 33-51-38-420-054-B ** ON A/C NOT FOR ALL

A. Installation of the Battery of the Emergency Power Supply Unit (EPSU)
(1) Make sure that the battery is serviceable.

(2) Make sure that the contacts between the battery (2) and the EPSU (1) are clean and in good condition.

CAUTION: DO NOT USE THE TEACH-IN PROCEDURE TO CLEAR EPSU FAILURE MESSAGES. THE TEACH-IN PROCEDURE IS NOT A SYSTEM RESET. IT CAN CHANGE THE EMERGENCY LIGHT CONFIGURATION AND CAUSE HIDDEN FAILURES.

CAUTION: BEFORE YOU INSTALL THE BATTERY, MAKE SURE THAT THE SPACER PLATE IS REMOVED. IF YOU INSTALL THE BATTERY WITH THE SPACER PLATE, THE EMERGENCY LIGHT WILL NOT OPERATE IN EMERGENCY CONDITIONS.

(3) Carefully install the battery (2) on the EPSU (1) with the screws (3) and tighten the screws (3).

NOTE: To measure and keep the load values, the load programming (TEACH IN) of the EPSU starts automatically when:

The AC and the DC power are available
On the Forward Attendant Panel 120RH the LIGHT EMER pushbutton switch and its integral light are off
On the overhead panel 25VU, EMER EXIT LT switch 4WL is in the OFF position
On the overhead panel 25VU, EXIT switch 190RH is in the OFF position
The overwing emergency lights are off
The EPSU (1) is installed on the A/C for the first time, or The battery was removed for more than 5 s and then it is installed again.
The load values are used as reference values during the EPSU SYSTEM TEST. It is necessary to examine that all connected emergency lights of the related EPSU operate.

Subtask 33-51-38-420-054-C ** ON A/C NOT FOR ALL

A. Installation of the Battery of the Emergency Power Supply Unit (EPSU)
(1) Make sure that the battery is serviceable.

(2) Make sure that the contacts between the battery (2) and the EPSU (1) are clean and in good condition.

CAUTION: DO NOT USE THE TEACH-IN PROCEDURE TO CLEAR EPSU FAILURE MESSAGES. THE TEACH-IN PROCEDURE IS NOT A SYSTEM RESET. IT CAN CHANGE THE EMERGENCY LIGHT CONFIGURATION AND CAUSE HIDDEN FAILURES.

CAUTION: BEFORE YOU INSTALL THE BATTERY, MAKE SURE THAT THE SPACER PLATE IS REMOVED. IF YOU INSTALL THE BATTERY WITH THE SPACER PLATE, THE EMERGENCY LIGHT WILL NOT OPERATE IN EMERGENCY CONDITIONS.

(3) Carefully install the battery (2) on EPSU (1) with the screws (3) and tighten the screws (3).

NOTE: To measure and keep the load values, the load programming (TEACH IN) of the EPSU starts automatically when:

The AC and the DC power are available
On Forward Attendant Panel (FAP) 120RH the EMER button and its light are off
On overhead panel 25VU, EMER EXIT LT switch 4WL is in the OFF position
On overhead panel 25VU, No PED switch 190RH is in the OFF position
The EPSU (1) is installed on the A/C for the first time
The battery was removed for more than 5 second and then it is installed again.
The load values are used as reference values during the EPSU SYSTEM TEST. It is necessary to examine that all connected emergency lights of the related EPSU operate.

Subtask 33-51-38-865-058-A

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	LIGHTING/EMER LT/CABIN	2WL	H06
49VU	LIGHTING/EMER LT/CABIN	1WL	H05
** ON A/C NOT FOR ALL
49VU	LIGHTING/EMER LT/CABIN	2WL	H04
49VU	LIGHTING/EMER LT/CABIN	1WL	H03
** ON A/C ALL
122VU	LIGHTING/CABIN/EMER/LT	3WL	V07

Subtask 33-51-38-740-053-A

C. BITE Test
(1) Do the operational check of the EPSU thru BITE check (Ref. AMM TASK 33-51-00-710-001).

5. Close-up
Subtask 33-51-38-410-053-B ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the ceiling panel:
(a) FOR [10WL] (POWER-EMERGENCY SUPPLY)
install 221BC at the left forward passenger/crew door (Ref. AMM TASK 25-23-42-400-001).
(b) FOR [11WL] (EPSU)
install 251KC between the rear emergency exit doors (Ref. AMM TASK 25-23-41-400-001).
(c) FOR [12WL] (EPSU)
install 251KC between the rear emergency exit doors (Ref. AMM TASK 25-23-41-400-001).
(d) FOR [14WL] (EPSU)
install 231JC between the forward emergency exit doors (Ref. AMM TASK 25-23-41-400-001).
(e) FOR [15WL] (EPSU)
install 231JC between the forward emergency exit doors (Ref. AMM TASK 25-23-41-400-001).
(3) Engage the emergency oxygen container:
(a) FOR [13WL] (EPSU)

Lift and engage the emergency oxygen container 33WR between the aft passenger/crew doors (Ref. AMM TASK 35-21-41-400-001).

(4) Remove the stepladder(s).

Subtask 33-51-38-410-053-C ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the ceiling panel:
(a) FOR [10WL] (POWER-EMERGENCY SUPPLY)
install 221BC at the left forward passenger/crew door (Ref. AMM TASK 25-23-42-400-001).
(3) Install the lower sidewall panel:
(a) FOR [11WL] (EPSU)
install 241KW at the left emergency exit(s) (Ref. AMM TASK 25-23-44-400-001).
(b) FOR [12WL] (EPSU)
install 242KW at the right emergency exit(s) (Ref. AMM TASK 25-23-44-400-001).
(4) Engage the emergency oxygen container:
(a) FOR [13WL] (EPSU)

Lift and engage emergency oxygen container 33WR between the aft passenger/crew doors (Ref. AMM TASK 35-21-41-400-001).

(5) Remove the stepladder(s).

Subtask 33-51-38-410-053-D ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the ceiling panel(s):
(a) FOR [10WL] (POWER-EMERGENCY SUPPLY)
install 221BC at the left forward passenger/crew door (Ref. AMM TASK 25-23-42-400-001).
(b) FOR [11WL] (EPSU)
install 251KC between the aft emergency exit doors (Ref. AMM TASK 25-23-41-400-001).
(c) FOR [12WL] (EPSU)
install 251KC between the aft emergency exit doors (Ref. AMM TASK 25-23-41-400-001).
(3) Install the lower sidewall panel(s):
(a) FOR [16WL] (EPSU)
install 242KW at the emergency exits (Ref. AMM TASK 25-23-44-400-001).
(b) FOR [17WL] (EPSU)
install 241KW at the emergency exits (Ref. AMM TASK 25-23-44-400-001).
(4) Install the ceiling panel:
(a) FOR [13WL] (EPSU)
install the ceiling panel 261CC between the aft passenger/crew doors (Ref. AMM TASK 25-23-42-400-002).
(5) Remove the stepladder(s).

Subtask 33-51-38-862-052-A

B. De-energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.01 00:57:48 UTC