Removal of the Mixer Flap Actuator

TASK 21-51-52-000-001-A
Removal of the Mixer Flap Actuator

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.

FIN: 20HB

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	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
131NW, 131PW, 825

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 25-54-12-000-001-A	Removal of the Forward Cargo-Compartment Partition
TASK 52-30-00-860-001-A	Open the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump
Mixer Unit-Flap Actuator

3. Job Set-up
Subtask 21-51-52-861-051-A

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

Subtask 21-51-52-865-050-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	AIR COND/TEMP CTL/SYS 1 CHAN B/28VDC	52HH	D08
** ON A/C NOT FOR ALL
122VU	AIR COND/FLOW/MIXER/FLAP	3HB	V22
122VU	AIR COND/ZONE TEMP CTL/28VDC/SYS2	4HK	V20
122VU	AIR COND/ZONE TEMP CTL/28VDC/SYS1	3HK	V19
122VU	AIR COND/ZONE TEMP CTL/115VAC/SYS2	2HK	V18
122VU	AIR COND/ZONE TEMP CTL/115VAC/SYS1	1HK	V17
** ON A/C ALL
122VU	AIR COND/RECIRC FAN/R/CTL	11HG	W20
122VU	AIR COND/RECIRC FAN/R/SPLY	3HG	W18
122VU	AIR COND/RECIRC FAN/L/CTL	2HG	X20
122VU	AIR COND/RECIRC FAN/L/SPLY	1HG	X18
** ON A/C NOT FOR ALL
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 1/CHAN A/115VAC	49HH	X22
122VU	AIR COND/TEMP CTL SYS 1/CHAN A/28VDC	51HH	X21
122VU	AIR COND/TEMP CTL SYS 2/CHAN B/28VDC	56HH	Y21
122VU	AIR COND/TEMP CTL SYS 2/CHAN B/115VAC	54HH	Y20
122VU	AIR COND/TEMP CTL SYS 1/CHAN B/115VAC	50HH	Y18

Subtask 21-51-52-941-051-A

C. Safety Precautions
(1) On the overhead panel, on AIR COND panel 30VU:
(a) Make sure that:

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

(b) Put a WARNING NOTICE(S) in position to tell persons not to operate these pushbutton switches.
(2) On the HP and the LP ground connectors, put a WARNING NOTICE(S) in position to tell persons not to supply the ground air.

Subtask 21-51-52-010-050-A

D. Get Access
(1) Put an ACCESS PLATFORM 2M (6 FT) in position at the forward cargo-compartment door 825.

WARNING: DO NOT OPEN OR GO NEAR PRESSURE-SEALED DOORS WHEN THE AIRCRAFT IS PRESSURIZED. A PRESSURE-SEALED DOOR THAT OPENS WHEN THE AIRCRAFT IS PRESSURIZED:

WILL CAUSE EXPLOSIVE DECOMPRESSION.
CAN KILL OR CAUSE INJURY TO PERSONS AND/OR CAUSE DAMAGE TO THE AIRCRAFT OR EQUIPMENT.

(2) Open the FWD cargo-compartment door 825 (Ref. AMM TASK 52-30-00-860-001).
(3) Remove access panels 131PW and 131NW (Ref. AMM TASK 25-54-12-000-001).

4. Procedure
Subtask 21-51-52-020-050-A

A. Removal of the Mixer Flap Actuator
(1) Disconnect the electrical connector (3).
(2) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(3) Loosen the clamp (8) and disconnect the sleeve (7).
(4) Remove the nuts (13), the washers (12) and the bolts (10).
(5) Carefully remove the mixer-flap actuator housing (9) and the seal (11).
(6) Remove the bolts (4), the washers (5) and the mixer flap actuator (6).
(7) Put protective covers on the open ends of the sleeve (7), the mixer unit (14) and the mixer-flap actuator housing (9).

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