Check of the Pressure Rate Sensor of the Back Up Control Panel

TASK 52-51-00-040-012-A
Check of the Pressure Rate Sensor of the Back Up Control Panel

Task Summary

Access	Test	Specific Tools	Mhr	E/T	Nb Men
NO	NO	NO	0.3	0.3	1

1. Reason for the Job
MMEL 52-01-02-03A
PRESSURE RATE SENSOR ON THE CKPT DOOR CONT BK UP OVERHEAD PANEL
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	PUMP - VACUUM

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 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power

3. Job Set-up
Subtask 52-51-00-860-099-A

A. 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 access to the cockpit is available.

Subtask 52-51-00-865-084-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
122VU	DOORS/PAX/MONG	1MQ	T13
122VU	CKPT/OVRD SYS/SPLY	4MQ	S10

4. Procedure
Subtask 52-51-00-780-052-A

A. Verification of the remaining Pressure Rate Sensor
(1) Do the test to make sure that the remaining pressure sensor in the back up control unit 28MQ operates correctly.
(2) Simulate a rapid decompression of the cabin pressure with a PUMP - VACUUM.
(3) Set the guarded toggle switch 21MQ on the back up control panel 271VU to the "BKUP" position.

NOTE: If LED CHAN 1 is on, examine RH pressure sensor hole.
If LED CHAN 2 is on, examine LH pressure sensor hole.

ACTION	RESULT
1.On the Back Up Control Unit 295VU:	On the Cockpit Door:
put the vacuum pump in the applicable pressure sensor hole and operate it.	you can hear a clacking noise from the solenoids of the electrical release strikes.
	as soon as an equal pressure occurs the electrical release strikes operate automatically to lock the cockpit door.

(4) Remove the vacuum pump from the pressure sensor.

5. Close-up
Subtask 52-51-00-860-100-A

A. Put the aircraft back to the serviceable condition.
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Put an applicable placard in position in the cockpit (refer to your standard practices and local regulations).
(3) Make an entry in the logbook.
(4) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).

[Rev.10 from 2021] 2026.04.02 06:28:22 UTC