Installation of the Microswitch

TASK 28-25-71-400-001-A
Installation of the Microswitch

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

WARNING: MAKE SURE THAT THE FLIGHT CONTROL SAFETY-LOCKS AND THE WARNING NOTICES ARE IN POSITION.

WARNING: MAKE SURE THAT THE GROUND SAFETY-LOCKS ARE IN POSITION ON THE LANDING GEAR. THIS WILL PREVENT UNWANTED MOVEMENT OF THE LANDING GEAR, AND THUS POSSIBLE INJURY TO PERSONS AND DAMAGE TO THE AIRCRAFT AND/OR EQUIPMENT.

FIN: 20QU

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	TIE WRAP
No specific	Torque wrench: range to between 0.82 and 0.63 m.daN (72.57 and 55.75 lbf.in )
98D27803500001	1	LOCKING TOOL ZERO POS

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.08BAA9)	Non Aqueous Cleaner-General - -
(Material No.12ACC1)	Corrosion Preventive Compound-Heavy Duty Soft Film -
(Material No.14QFB1)	Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -
(Material No.14SBA1)	Textile-Lint free Cotton -

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
622KB
192MB

D. 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 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
Micro-switch 20QU ** ON A/C NOT FOR ALL
Micro-switch 20QU ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 28-25-71-941-051-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) Make sure that the safety barriers are in position.

Subtask 28-25-71-860-051-A ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) Make sure that the access door 192MB is open.

NOTE: If operating in battery power, do not keep the door open longer than necessary because the battery can discharge.

Subtask 28-25-71-941-051-B ** ON A/C NOT FOR ALL

C. Safety Precautions
(1) Make sure that the safety barriers are in position.
(2) Make sure that the WARNING NOTICE(S) is in position to tell persons not to operate the slats.

Subtask 28-25-71-860-051-B ** ON A/C NOT FOR ALL

D. Aircraft Maintenance Configuration
(1) Make sure that the ACCESS PLATFORM 3M (10 FT) is below zone 622.
(2) Make sure that the access door 622KB is open.

NOTE: If operating in battery power, do not keep the door open longer than necessary because the battery can discharge.

(3) Make sure that the 98D27803500001 LOCKING TOOL ZERO POS is on the slat/flap control lever.

Subtask 28-25-71-865-051-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	FUEL/FQI/CHAN/1	1QT	A13
** ON A/C NOT FOR ALL
121VU	FUEL/FQI/CHANNEL/1 AND 2	8QT	L26
121VU	FUEL/RFL/DFL/SPLY	2QU	L24
** ON A/C ALL
121VU	FUEL/FQI/CHAN/2	2QT	M27
** ON A/C NOT FOR ALL
121VU	FUEL/FQI/CHANNEL/1 AND 2	8QT	L25
121VU	FUEL/RFL/DFL/SPLY	2QU	L23
** ON A/C ALL
122VU	ELEC/REFLNG/NORM	2PR	S27
122VU	ELEC/RFL/SPLY/LOGIC	4PR	U29
122VU	ELEC/REFLNG/ON/BAT	1PR	U28

4. Procedure
Subtask 28-25-71-420-050-A

A. Preparation for Installation
(1) Clean the component interface and/or the adjacent area with a Textile-Lint free Cotton - (Material No.14SBA1) made moist with Non Aqueous Cleaner-General - - (Material No.08BAA9) .
(2) Make sure that the parts retained from the removed component are clean and in the correct condition.
(3) Do an inspection of the component interfaces and the adjacent area.

Subtask 28-25-71-420-051-B ** ON A/C NOT FOR ALL

B. Installation of the Micro-switch 20QU

WARNING: USE PROTECTIVE GOGGLES AND GLOVES WHEN YOU REMOVE OR INSTALL LOCKWIRE. EACH TIME YOU CUT LOCKWIRE, REMOVE AND DISCARD IT IMMEDIATELY. LOOSE LOCKWIRE CAN CUT YOU OR MAKE YOU BLIND, AND/OR CAN CAUSE DAMAGE.

(1) Install the micro-switch (7) in the bracket (2).
(2) Install the position-washer (4), the lockwasher (5) and the locknut (6) on the microswitch (7).
(3) Tighten the locknut (6).
(4) Safety the locknut (6) to the lockwasher (5) with 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(5) Remove the CAP-BLANKING from each electrical connector and receptacle.
(6) Connect the electrical connector (1) to the micro-switch (7).
(7) Safety the support cable and the electrical connector (1) with a TIE WRAP.

Subtask 28-25-71-420-051-C ** ON A/C NOT FOR ALL

B. Installation of the Micro-switch 20QU

(1) Install the micro-switch (1) in the bracket (10).
(2) Install the position-washer (2), the lockwasher (3) and the locknut (4) on the microswitch (1).
(3) Tighten the locknut (4).
(4) Safety the locknut (4) to the lockwasher (3) with 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(5) Remove the CAP-BLANKING from each electrical connector and receptacle.
(6) Connect the electrical connector (11) to the micro-switch (1).

Subtask 28-25-71-865-052-A

C. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	FUEL/FQI/CHAN/1	1QT	A13
** ON A/C NOT FOR ALL
121VU	FUEL/FQI/CHANNEL/1 AND 2	8QT	L26
121VU	FUEL/RFL/DFL/SPLY	2QU	L24
** ON A/C ALL
121VU	FUEL/FQI/CHAN/2	2QT	M27
** ON A/C NOT FOR ALL
121VU	FUEL/FQI/CHANNEL/1 AND 2	8QT	L25
121VU	FUEL/RFL/DFL/SPLY	2QU	L23
** ON A/C ALL
122VU	ELEC/REFLNG/NORM	2PR	S27
122VU	ELEC/RFL/SPLY/LOGIC	4PR	U29
122VU	ELEC/REFLNG/ON/BAT	1PR	U28

Subtask 28-25-71-861-050-A

D. Energize the Electrical Circuits
(1) Energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-861-002)

Subtask 28-25-71-820-050-B ** ON A/C NOT FOR ALL

E. Adjustment of the Micro-switch 20QU

(1) Slowly close the door (8) and make sure that the refuel/defuel lighting goes off. If not, adjust the micro-switch (7).
(2) To adjust the micro-switch (7), do these steps:
(a) Loosen the fasteners (10) and remove the panel (9).
(b) Loosen the bolts (3).
(c) Adjust the micro-switch (7) so that the lighting of the refuel/defuel panel is off before the door (8) is closed.
(d) Start closing the door (8) and when almost closed, make sure that the refuel/defuel lighting is off.
(e) When the door (8) operates the light correctly, make sure that the bolts (3) are fully tightened.
(3) Apply a layer of Corrosion Preventive Compound-Heavy Duty Soft Film - (Material No.12ACC1) to the bolts (3).
(4) Install the panel (9) and tighten the fasteners (10).

Subtask 28-25-71-820-050-D ** ON A/C NOT FOR ALL

E. Adjustment of the Microswitch 20QU
(1) Slowly close the door (9) and make sure that the refuel/defuel lighting goes off. If not, adjust the microswitch (1).
(2) Do the adjustment of the microswitch (1) as follows:

(a) Remove and discard the lockwire from the nut (6) and the locknut (7).
(b) Loosen the nut (6) and the locknut (7) of the stop screw (5).
(c) Adjust the stop screw (5) and the contact of the microswitch (1) until it touches each other when the door (9) is closed.
(d) Slowly close the door (9) (not fully) and make sure that the microswicth (1) touches the stop screw (5):
1 REFUEL/DEFUEL light goes off.
(e) If the light is ON, loosen the stop screw (5) until the light goes off as follows:
1 Open the door (9).
2 Loosen the stop screw (5) by 2.5 +0.2 mm or -0.2 mm (0.0984 +0.0079 in. or -0.0079 in.).
3 Close the door (9) and make sure that the light goes off.
4 If the light is still ON, adjust the stop screw (5) until the light goes off.
5 If the light is ON after each adjustment of the stop screw (5), make sure that the microswitch (1) is serviceable.
6 If the microswitch (1) is not serviceable, replace it with a new serviceable microswitch (1).
7 Do the step (e) again for the new microswitch (1) until the light goes off.
(f) TORQUE the nut (6) and the locknut (7) to between 0.82 and 0.63 m.daN (72.57 and 55.75 lbf.in )

on the support fitting (8).

(g) Safety the nut (8) to the locknut (9) with the 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(3) Apply a layer of Corrosion Preventive Compound-Heavy Duty Soft Film - (Material No.12ACC1) to:

The nut (6)
The locknut (7)
The threads of the stop screw (5).

5. Close-up
Subtask 28-25-71-862-050-A

A. De-energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-862-002).

Subtask 28-25-71-410-050-A ** ON A/C NOT FOR ALL

B. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the access door 192MB.

Subtask 28-25-71-942-050-A ** ON A/C NOT FOR ALL

C. Removal of Equipment
(1) Remove the ground support and maintenance equipment, the special and standard tools and all other items.

Subtask 28-25-71-410-050-B ** ON A/C NOT FOR ALL

D. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the access door 622KB.

Subtask 28-25-71-942-050-B ** ON A/C NOT FOR ALL

E. Removal of Equipment
(1) Remove the 98D27803500001 LOCKING TOOL ZERO POS from the slat/flap control lever.
(2) Remove the WARNING NOTICE(S).
(3) Remove the access platform(s).
(4) Remove the ground support and maintenance equipment, the special and standard tools and all other items.

[Rev.10 from 2021] 2026.04.01 00:07:19 UTC