Installation of the Cabin-Pressure Detection Pressure-Switch

TASK 52-73-12-400-001-A
Installation of the Cabin-Pressure Detection Pressure-Switch

ZONE: 122
FIN: 14WN

1. Reason for the Job

NOTE: Two persons are necessary to do this procedure.

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE
No specific	AR	CAP - BLANKING
No specific	AR	PLUG - BLANKING
No specific	Torque wrench: range to between 2.5 and 2.1 m.N (22.12 and 18.58 lbf.in )
No specific	Torque wrench: range to between 4.0 and 3.6 m.N (35.40 and 31.86 lbf.in )
No specific	Torque wrench: range to between 13 and 12 m.N (115.04 and 106.19 lbf.in )

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
122	AVIONICS COMPARTMENT
811

C. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
6	O-RING	AIPC 52-73-01-02-030
6	O-RING	AIPC 52-73-81-02-030

D. Referenced Information

REFERENCE	DESIGNATION
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
TASK 34-21-00-790-001-A	Low-Range Leak Test of the Standby Pneumatic Circuits
TASK 34-22-25-790-001-A	Low range Leak Test of the Standby Pneumatic circuits
TASK 52-73-00-720-003-A	Operational Test of the Residual Cabin Pressure Warning System and In-Situ Functional Test of the Cabin Pressure Detection Pressure-Switch
Cabin Pressure Detection Pressure Switch - (14WN)

3. Job Set-up
Subtask 52-73-12-860-051-A

A. Aircraft Maintenance Configuration
(1) Make sure that avionics compartment access-door 811 is open.
(2) Make sure that the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE is in position at zone 122.
(3) Make sure that the ground service network is energized
(Ref. AMM TASK 24-42-00-861-001).

Subtask 52-73-12-865-051-A

B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	EIS/SLIDES/ARM AND WARN/FLT	15WN	P11
121VU	EIS/SLIDES/ARM AND WARN/GND	13WN	P10

4. Procedure
Subtask 52-73-12-420-050-A

CAUTION: USE A SECOND WRENCH TO APPLY COUNTERTORQUE TO THE RESTRICTOR WHEN YOU DISCONNECT/CONNECT THE STATIC LINE. IF YOU DO NOT USE A SECOND WRENCH, YOU CAN CAUSE DAMAGE TO THE PRESSURE SWITCH AND/OR THE STATIC LINE.

A. Installation of the Cabin-Pressure Detection Pressure-Switch

(1) Remove the PLUG - BLANKING from the connection of the line (8).
(2) Install the AIPC 52-73-01-02-030 O-RING (6) or the AIPC 52-73-81-02-030 O-RING (6) on the restrictor (7).
(3) Install the restrictor (7) on the cabin-pressure detection pressure-switch (5).
(4) TORQUE the restrictor (7) to between 4.0 and 3.6 m.N (35.40 and 31.86 lbf.in )

.
(5) Remove the PLUG - BLANKING from the hole of the calibrated plug (1).
(6) Install the calibrated plug (1) on the cabin-pressure detection pressure-switch (5).
(7) TORQUE the calibrated plug (1) to between 2.5 and 2.1 m.N (22.12 and 18.58 lbf.in )

.
(8) Put the cabin-pressure detection pressure-switch (5) in position and install the washers (2) and the bolts (3).
(9) Tighten the bolts (3).
(10) Install the line (8) on the restrictor (7).

CAUTION: USE A SECOND WRENCH TO HOLD THE MATING PARTS WHEN YOU LOOSEN OR TIGHTEN THE TUBE OR HOSE NUTS. IF YOU DO NOT OBEY THIS CAUTION, YOU CAN TWIST OR CAUSE DAMAGE TO THE TUBES OR HOSES.

(11) TORQUE the line (8) to between 13 and 12 m.N (115.04 and 106.19 lbf.in )

.
(12) Remove the CAP - BLANKING from the electrical connector (4).
(13) Connect the electrical connector (4) to the cabin-pressure detection pressure-switch (5).

Subtask 52-73-12-720-050-A ** ON A/C NOT FOR ALL

B. Functional Test
(1) Do the in-situ functional test of cabin-pressure detection pressure-switch 14WN (Ref. AMM TASK 52-73-00-720-003).
(2) Do the low-range leak test of the standby pneumatic circuits (Ref. AMM TASK 34-21-00-790-001).

Subtask 52-73-12-720-050-B ** ON A/C NOT FOR ALL

5. Close-up
Subtask 52-73-12-865-052-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 ALL
121VU	EIS/SLIDES/ARM AND WARN/FLT	15WN	P11
121VU	EIS/SLIDES/ARM AND WARN/GND	13WN	P10

Subtask 52-73-12-410-050-A

B. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close avionics compartment access-door 811.
(3) Remove the access platform(s).

Subtask 52-73-12-860-052-A

C. Aircraft Maintenance Configuration
(1) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).

[Rev.10 from 2021] 2026.04.02 06:28:36 UTC