Functional Test of the bulk-erase function and bulk-erase inhibition-logic of the CVR

TASK 23-71-00-720-002-A
Functional Test of the bulk-erase function and bulk-erase inhibition-logic of the CVR

WARNING: MAKE SURE THAT ALL THE CIRCUITS IN MAINTENANCE ARE ISOLATED BEFORE YOU SUPPLY ELECTRICAL POWER TO THE AIRCRAFT. UNWANTED ELECTRICAL POWER CAN BE DANGEROUS.

NOTE: This procedure is applicable to the CVR and the SSCVR.

ZONE: 210

1. Reason for the Job
To make sure that the CVR will erase only when the aircraft is on the ground with the parking brake set.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	HEADSET 600 OHMS

B. Work Zones and Access Panels

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

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 32-69-00-860-001-A	Simulation of Flight (With Aircraft on Ground)

3. Job Set-up
Subtask 23-71-00-860-057-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) Make sure that the engine shutdown occured not less than 5 minutes before you do the procedure.
(3) On the maintenance panel 50VU, connect a HEADSET 600 OHMS to the CVR/HEAD SET connector.

Subtask 23-71-00-865-052-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
49VU	COM/CVR/SPLY	2RK	E14
49VU	COM/CVR/CTL	4RK	E13
** ON A/C NOT FOR ALL
49VU	COM/CVR/SPLY	23RK	E14
49VU	COM/CVR/CTL	26RK	E13
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/PARK BRK/CTL/STBY	71GG	N37
121VU	HYDRAULIC/PARK BRK/CTL/NORM	70GG	N36

4. Procedure
Subtask 23-71-00-720-050-A ** ON A/C NOT FOR ALL

A. Do the functional test with the parking brake locked and the aircraft in the ground configuration:
(1) Aircraft Maintenance Configuration
(a) On the panel 110VU, make sure that the Parking Brake Control Switch (73GG) is in the ON position.
(b) Make sure that the aircraft is on the ground (landing gear compressed).
(2) Test:

ACTION	RESULT
1.On the overhead control and indicating panel 21VU:	On the panel 21VU:
Push the RCDR/GND CTL pushbutton switch.	On the pushbutton switch, the ON legend comes on.
	In the headset: you can hear the conversations from the CVR microphone.
Push the RCDR/CVR ERASE pushbutton switch for not less than 2 seconds and release it.	In the headset: you can hear the 400Hz tone signal.

Subtask 23-71-00-720-054-A ** ON A/C NOT FOR ALL

B. Do the functional test with the parking brake unlocked:
(1) Aircraft Maintenance Configuration
(a) On the panel 110VU, put the Parking Brake Control Switch (73GG) in the OFF position.
(b) Make sure that the aircraft is on the ground (landing gear compressed).
(2) Test:

ACTION	RESULT
1.On the overhead control and indicating panel 21VU: Push the RCDR/CVR ERASE pushbutton switch for not less than 2 seconds and release it.	In the headset: you cannot hear the 400Hz tone signal.

Subtask 23-71-00-720-055-A ** ON A/C NOT FOR ALL

C. Do the functional test with the aircraft in the flight configuration:
(1) Aircraft Maintenance Configuration
(a) On the panel 110VU, put the Parking Brake Control Switch (73GG) in the ON position.
(b) Put the aircraft in the flight configuration (Ref. AMM TASK 32-69-00-860-001).
(2) Test:

ACTION	RESULT
1.On the overhead control and indicating panel 21VU: Push the RCDR/CVR ERASE pushbutton switch for not less than 2 seconds and release it.	In the headset: you cannot hear the 400Hz tone signal.

5. Close-up
Subtask 23-71-00-860-056-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Disconnect the headset from the CVR/HEAD SET connector.
(2) Put the aircraft in the ground configuration (Ref. AMM TASK 32-69-00-860-001).
(3) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.03.31 23:16:06 UTC