Removal of the Bypass Valve

TASK 21-58-52-000-001-A
Removal of the Bypass Valve

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.

WARNING: DO NOT TOUCH THE COMPONENT UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS.

FIN: 113HW ** 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	1	ACCESS PLATFORM 2M (6 FT)
No specific	AR	CAP - BLANKING
No specific	AR	PLUG - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	1	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
191KB

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
Bypass Valve (113HW)

3. Job Set-up
Subtask 21-58-52-861-050-A ** ON A/C NOT FOR ALL

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

Subtask 21-58-52-865-050-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	AIR BLEED/X FEED/VALVE/BAT	2HV	D13
49VU	AIR COND/TEMP CTL/SYS 1 CHAN B/28VDC	52HH	D08
** ON A/C NOT FOR ALL
49VU	AIR BLEED/ENG 1/CTL	3HA1	D12
49VU	AIR BLEED/ENG 1/MONG	2HA1	D11
** ON A/C NOT FOR ALL
49VU	AIR BLEED/ENG 2/MONG	3HA2	D12
49VU	AIR BLEED/ENG 1/CTL	2HA1	D11
** ON A/C NOT FOR ALL
121VU	IGGS/CTRL	7YA	N28
** ON A/C NOT FOR ALL
121VU	IGGS/CTRL	7YA	P28
** ON A/C NOT FOR ALL
122VU	CSAS / CTRL	1HW	U17
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
122VU	AIR BLEED/X FEED VALVE/NORM	1HV	Z20
** ON A/C NOT FOR ALL
122VU	AIR BLEED/ENG 2/CTL	3HA2	Z23
122VU	AIR BLEED/ENG 2/MONG	2HA2	Z22
** ON A/C NOT FOR ALL
122VU	AIR BLEED/ENG 1/MONG	3HA1	Z23
122VU	AIR BLEED/ENG 2/CTL	2HA2	Z22

Subtask 21-58-52-941-050-A ** ON A/C NOT FOR ALL

C. Safety Precautions
(1) On the panel 30VU, make sure that:

The APU BLEED pushbutton switch is in the off position (the ON legend is off).
The ENG 1 BLEED and the ENG 2 BLEED pushbutton switches are in the off position (the OFF legends are on).

(a) Put a WARNING NOTICE(S) in position to tell persons not to operate these pushbutton switches.
(2) On the HP ground connector put a warning notice in position to tell persons not to supply the ground air.

Subtask 21-58-52-010-050-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Put an ACCESS PLATFORM 2M (6 FT) in position at the zone 191.
(2) Remove the access panel 191KB (Ref. AMM TASK 53-35-13-000-002).

4. Procedure
Subtask 21-58-52-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the Bypass Valve

Bypass Valve (113HW) ** ON A/C NOT FOR ALL

(1) Disconnect the electrical connector (4).
(2) Put a CAP - BLANKING on the disconnected electrical connector (4).
(3) Disconnection of the Bonding Strap

CAUTION: MAKE SURE THAT THE ELECTRICAL CONNECTOR(S) IS(ARE) DISCONNECTED BEFORE YOU DISCONNECT THE BONDING STRAP(S).

(a) Remove the nut (7), the washer (6), the bonding strap (5) and the screw (8).
(4) Remove the clamps (1) and the bypass valve (3).
(5) Remove the seals (2) and discard them.
(6) Put PLUG - BLANKING on the disconnected line ends.

[Rev.10 from 2021] 2026.04.02 06:11:35 UTC