Removal of the Differential Pressure Sensor

TASK 21-51-11-000-001-A
Removal of the Differential Pressure Sensor

WARNING: MAKE SURE THAT AIR IS NOT SUPPLIED TO THE AIR CONDITIONING SYSTEM FROM THE MAIN ENGINE, THE APU OR A GROUND SOURCE. HOT COMPRESSED AIR CAN CAUSE INJURY TO PERSONNEL.

NOTE: The procedure is the same for the pressure sensors pack 1 and pack 2.

FIN: 10HB ** ON A/C NOT FOR ALL
FIN: 23HB2 ** ON A/C NOT FOR ALL
FIN: 24HB2 ** ON A/C NOT FOR ALL
FIN: 9HB ** 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
FOR [10HB] (P1 FLOW SENSOR)
No specific	AR	CAP - BLANKING
No specific	AR	PLUG - BLANKING
FOR [9HB] (P2 FLOW SENSOR)
No specific	AR	CAP - BLANKING
No specific	AR	PLUG - BLANKING

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [10HB] (P1 FLOW SENSOR)
191KB
FOR [23HB2] (SENSOR-DELTA PRESS,PACK 1)
191KB
FOR [24HB2] (SENSOR-DELTA PRESS,PACK 2)
192KB
FOR [9HB] (P2 FLOW SENSOR)
192KB

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 53-35-13-000-002-A	Removal of the Quick-Release Access Panels from the Belly Fairing Structure
Pressure Sensor ** ON A/C NOT FOR ALL
Pressure Sensor - Component Location ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 21-51-11-861-050-A

A. Energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-861-002).

Subtask 21-51-11-865-050-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 10HB (P1 FLOW SENSOR)
122VU	AIR COND/PACK TEMP/CTL SYS1/1/115VAC	1HH	X22
122VU	AIR COND/PACK TEMP/CTL SYS1/1/28VDC	3HH	X21
122VU	AIR COND/PACK TEMP CTL SYS2/1/28VDC	4HH	Y19
122VU	AIR COND/PACK TEMP CTL SYS2/1/115VAC	2HH	Y18
FOR FIN: 9HB (P2 FLOW SENSOR)
122VU	AIR COND/PACK TEMP/CTL SYS1/2/115VAC	21HH	W22
122VU	AIR COND/PACK TEMP/CTL SYS1/2/28VDC	23HH	W21
122VU	AIR COND/PACK TEMP CTL SYS2/2/28VDC	24HH	Y21
122VU	AIR COND/PACK TEMP CTL SYS2/2/115VAC	22HH	Y20
** ON A/C NOT FOR ALL
FOR FIN: 23HB2 (SENSORDELTA PRESS,PACK 1)
49VU	AIR COND/TEMP CTL/SYS 1 CHAN B/28VDC	52HH	D08
122VU	AIR COND/TEMP CTL SYS 1/CHAN A/115VAC	49HH	X22
122VU	AIR COND/TEMP CTL SYS 1/CHAN A/28VDC	51HH	X21
122VU	AIR COND/TEMP CTL SYS 1/CHAN B/115VAC	50HH	Y18
FOR FIN: 24HB2 (SENSORDELTA PRESS,PACK 2)
122VU	AIR COND/TEMP CTL SYS 2/CHAN A/115VAC	53HH	W22
122VU	AIR COND/TEMP CTL SYS 2/CHAN A/28VDC	55HH	W21
122VU	AIR COND/TEMP CTL SYS 2/CHAN B/28VDC	56HH	Y21
122VU	AIR COND/TEMP CTL SYS 2/CHAN B/115VAC	54HH	Y20

Subtask 21-51-11-010-050-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Remove the access panel (Ref. AMM TASK 53-35-13-000-002):
(a) FOR [10HB] (P1 FLOW SENSOR)
191KB,
(b) FOR [9HB] (P2 FLOW SENSOR)
192KB.

Subtask 21-51-11-010-050-B ** ON A/C NOT FOR ALL

C. Get Access
(1) Remove the access panel (Ref. AMM TASK 53-35-13-000-002):
(a) FOR [23HB2] (SENSOR-DELTA PRESS,PACK 1)
191KB,
(b) FOR [24HB2] (SENSOR-DELTA PRESS,PACK 2)
192KB.

4. Procedure
Subtask 21-51-11-020-050-C ** ON A/C NOT FOR ALL

A. Removal of the Pressure Sensor

Pressure Sensor ** ON A/C NOT FOR ALL

(1) FOR [10HB] (P1 FLOW SENSOR)
(a) Disconnect the electrical connector (7).
(b) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(c) Disconnect the sense line connectors (1) and (5).
(d) Put the PLUG-BLANKING in each disconnected line end.
(e) Remove the nut (11), the washer (10), the screw (8) and disconnect the bonding strap (9).
(f) Remove the screws (4), the washers (3), the pressure sensor (12) and the clamps (2).
(g) Remove the clamps (2) from the pressure sensor (12).
(2) FOR [9HB] (P2 FLOW SENSOR)
(a) Disconnect the electrical connector (24).
(b) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(c) Disconnect the sense line connectors (21) and (32).
(d) Put the PLUG-BLANKING in each disconnected line end.
(e) Remove the nut (28), the washer (27), the screw (25) and disconnect the bonding strap (26).
(f) Remove the screws (31), the washers (30), the pressure sensor (29) and the clamps (22).
(g) Remove the clamps (22) from the pressure sensor (29).

Subtask 21-51-11-020-050-E ** ON A/C NOT FOR ALL

A. Removal of the Pressure Sensor

Pressure Sensor - Component Location ** ON A/C NOT FOR ALL

(1) Remove the screws (7), the washers (8) and the clamp (9).
(2) Discard the washers (8).
(3) Loosen and partially remove the screws (1).
(4) Push the screws (1) to disconnect the sensor (5) from the sensor mount (13).
(a) Use a soft-face mallet and apply moderate taps to the screws (1) to help to disconnect the sensor (5).

NOTE: Force may be necessary to disconnect the sensor. Do not use a hard metal tool to avoid damage to the sensor. It is recommended to use a tool with a soft grip.

(5) Remove the screws (1) and the washers (2).

NOTE: Make sure that the inserts (3) stay in the sensor mount (13).

(6) Disconnect the electrical connector (6) and remove the sensor (5).
(7) Remove and discard the O-rings (11) and (12).

[Rev.10 from 2021] 2026.04.05 10:34:31 UTC