Discard the Underwater Locator Beacon (ULB) Battery

TASK 31-33-55-920-001-A
Discard the Underwater Locator Beacon (ULB) Battery

ZONE: 312

1. Reason for the Job
Refer to the MPD TASK: 313300-01
DISCARD UNDERWATER LOCATOR BEACON BATTERY
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 5M (16 FT)- ADJUSTABLE
No specific	1	WARNING NOTICE(S)
No specific	Torque wrench: range to between 0.29 and 0.23 m.daN (25.66 and 20.35 lbf.in )

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
312	AFT FUSLG TAIL SECTION
312AR

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 31-33-00-710-015-A	Operational Check of ULB
Removal/Installation - Underwater Locator Beacon Battery ** ON A/C NOT FOR ALL
Removal/Installation - Underwater Locator Beacon Battery ** ON A/C NOT FOR ALL
Removal/Installation - Underwater Locator Beacon Battery ** ON A/C NOT FOR ALL

3. Job Set-up

NOTE: Make sure that a new ULB is available.

Subtask 31-33-55-861-050-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).

Subtask 31-33-55-010-052-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Put the WARNING NOTICE(S) in the cockpit in position to tell persons not operate the flight controls.
(2) Put the ACCESS PLATFORM 5M (16 FT)- ADJUSTABLE in the position at access door 312AR.
(3) Open access door 312AR.
(4) Set light switch 3LJ to the ON position.

4. Procedure
Subtask 31-33-55-020-051-A ** ON A/C NOT FOR ALL

A. Removal of the ULB from the DFDR

Removal/Installation - Underwater Locator Beacon Battery ** ON A/C NOT FOR ALL

(1) Remove the screws (1) and the cover plate (2).
(2) Remove the ULB (3) from the mounting cradle (4).

NOTE: If the ULB Type DK 100 is installed, send the ULB to the related vendor to replace the battery.

Subtask 31-33-55-020-051-C ** ON A/C NOT FOR ALL

A. Removal of the ULB from the DFDR

Removal/Installation - Underwater Locator Beacon Battery ** ON A/C NOT FOR ALL

(1) Remove the screws (1).
(2) Remove the ULB (2).

NOTE: If the ULB Type DK 100 is installed, send the ULB to the related vendor to replace the battery.

Subtask 31-33-55-960-050-A ** ON A/C NOT FOR ALL

B. In the Workshop
(1) Discard and replace the ULB battery.

NOTE: Send only the ULB type DK 100 to the related vendor to replace the battery.

NOTE: Send all other ULB types to the workshop to replace the battery.

Subtask 31-33-55-420-051-A ** ON A/C NOT FOR ALL

C. Installation of the ULB on the DFDR
(1) Put the ULB (3) in position on the mounting cradle (4).
(2) Install the ULB (3) together with the cover plate (2) and the screws (1).

NOTE: Install the ULB with the water sensitive switch in lower position and make sure that the switch is clean.

NOTE: Rotate the ULB until the battery replacement date is readable.

Subtask 31-33-55-420-051-C ** ON A/C NOT FOR ALL

C. Installation of the ULB on the DFDR
(1) Put the ULB (2) in position.
(2) Install the ULB (2) together with the screws (1).

NOTE: Install the ULB with the water sensitive switch in lower position and make sure that the switch is clean.

NOTE: Rotate the ULB until the battery replacement date is readable.

(3) TORQUE the screws (1) to between 0.29 and 0.23 m.daN (25.66 and 20.35 lbf.in )

Subtask 31-33-55-710-052-A ** ON A/C NOT FOR ALL

D. Operational Test
(1) Do the operational test of the ULB (Ref. AMM TASK 31-33-00-710-015).

5. Close-up
Subtask 31-33-55-410-052-A ** 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) Set light switch 3LJ to the OFF position.
(3) Close access door 312AR.
(4) Remove the access platform(s).
(5) Remove the WARNING NOTICE(S).

Subtask 31-33-55-862-050-A ** ON A/C NOT FOR ALL

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

[Rev.10 from 2021] 2026.04.01 00:35:09 UTC