Preservation/Storage/Return-to-Service of the APU (APS 3200)

TASK 49-20-00-600-002-A
Preservation/Storage/Return-to-Service of the APU (APS 3200)

WARNING: MAKE SURE THAT YOU HAVE THE CORRECT FIRE FIGHTING EQUIPMENT AVAILABLE.

WARNING: DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).

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

WARNING: WHILE THE APU OPERATES, DO NOT GO INTO THESE AREAS:

THE AREA BEHIND THE APU EXHAUST DUCT: 25m (82ft.) REARWARD OF THE DUCT, MORE THAN 3m (10ft.) ABOVE THE GROUND, AND THE WIDTH OF THE HORIZONTAL STABILIZER
THE AREA AROUND THE APU AIR-INTAKE: 2m (7ft) AROUND THE INTAKE
THE AREA OF THE OIL-COOLER OUTLET.

THERE IS A RISK OF INJURY IF YOU GO INTO THESE AREAS.

WARNING: PUT THE SAFETY DEVICES AND THE WARNING NOTICES IN POSITION BEFORE YOU START A TASK ON OR NEAR:

THE FLIGHT CONTROLS
THE FLIGHT CONTROL SURFACES
THE LANDING GEAR AND THE RELATED DOORS
COMPONENTS THAT MOVE.

MOVEMENT OF COMPONENTS CAN KILL OR CAUSE INJURY TO PERSONS AND/OR CAN CAUSE DAMAGE TO THE EQUIPMENT.

CAUTION: BEFORE YOU OPERATE THE APU, MAKE SURE THAT APPROVED PERSONNEL IS AVAILABLE AT MINIMUM ONE APU SHUTDOWN PANEL. THIS IS TO DO AN APU EMERGENCY SHUTDOWN IMMEDIATELY IF AN UNUSUAL MALFUNCTION OCCURS DURING APU OPERATION. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EQUIPMENT CAN OCCUR.

CAUTION: DO NOT DO AN UNCONTROLLED PRESERVATION IN A SALT AIR ENVIRONMENT. SALT AIR ENVIRONMENT CAN CAUSE CORROSION.

CAUTION: IF YOU DID NOT DO THE DEPRESERVATION OF THE APU: - ONLY CLOSE THE CIRCUIT BREAKERS TO DO THE NECESSARY OPERATIONAL TESTS, AND - OPEN THEM AGAIN AFTER YOU COMPLETE THE OPERATIONAL TESTS. IF YOU DO NOT OBEY THESE INSTRUCTIONS, AN ACCIDENTAL START OF THE APU CAN OCCUR, WHICH CAN CAUSE DAMAGE TO THE APU.

ZONE: 310
FIN: 4005KM ** ON A/C NOT FOR ALL

1. Reason for the Job
The preservation procedure of the APU prevents internal and external corrosion and deterioration when the APU is not in service.
For maximum protection, do the preservation procedure in clean and dry conditions.
The de-preservation procedure removes the preservation materials from the APU to make the APU serviceable again.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE
No specific	2	INDICATOR-HUMIDITY
No specific	1	LABEL - IDENTIFICATION
No specific	AR	PLUG - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	2	TAPE - ADHESIVE
No specific	AR	WARNING NOTICE(S)
98L12003001000	AR	HARNESS,SAFETY

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.08BBB1)	Non Aqueous Cleaner-- Petroleum Based -
(Material No.14SBA1)	Textile-Lint free Cotton -
No specific	Desiccant-Silica Gel
No specific	KRAFT - PAPER
No specific	Permeable polyethylene bag

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
310	FUSLG TAIL SECTION AFT OF AFT PRESS BHD
315AL, 316AR

D. Referenced Information

REFERENCE	DESIGNATION
TASK 10-11-00-555-013-A	Installation of the Aircraft Protection Equipment
TASK 10-11-00-555-014-A	Removal of the Aircraft Protection Equipment
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)
TASK 26-22-00-710-001-A	Operational Test of the APU Fire-Extinguishing Loop/Squib
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 49-00-00-100-002-A	Cleaning of the APU Compartment with installed APU (APS 3200)
TASK 49-00-00-710-008-A	Operational Test of the APU
TASK 49-16-00-100-006-A	Cleaning of the APU Air Intake (APS 3200)
TASK 49-16-00-210-805-A	General Visual Inspection of the APU Air Inlet Plenum and APU Air Intake (APS 3200)
TASK 49-20-00-290-001-A	Borescope Inspection of the APU Power Plant (APS 3200)
TASK 49-32-11-000-002-A	Removal of the Fuel Control Unit (APS 3200)
TASK 49-32-11-400-002-A	Installation of the Fuel Control Unit (APS 3200)
TASK 49-90-00-600-005-A	Oil Change (Drain Procedure) (APS 3200)
TASK 49-90-00-600-005-A-01	Oil Change (Top-Off Procedure) (APS 3200)
TASK 52-41-00-010-001-A	Open the APU Doors for Access
TASK 52-41-00-410-001-A	Close the APU Doors after Access

3. Job Set-up
Subtask 49-20-00-941-062-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) Make sure that the APU fire and overheat detection-system and the APU fire-extinguishing system are serviceable (Ref. AMM TASK 26-22-00-710-001).

Subtask 49-20-00-620-058-A ** ON A/C NOT FOR ALL

B. Table 301

Period Status	Requirement	Reference
Maximum 45 days without APU operation	Preservation	Refer to paragraph 4.A.
Maximum 180 days without APU operation	Preservation	Refer to paragraph 4.B.
More than 180 days without APU operation	Follow supplier instructions	-

Subtask 49-20-00-860-077-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(2) On overhead panel 25VU, make sure that the APU MASTER SW pushbutton switch is released (the ON legend is off).
(3) On the APU section of overhead panel 25VU, put the WARNING NOTICE(S) in position to tell persons not to start the APU.
(4) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).

Subtask 49-20-00-865-097-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41
121VU	APU/FUEL/LP VALVE/CTL	1QF	M40
121VU	APU/FUEL/LP VALVE/SPLY	2QF	M39
121VU	APU/FUEL/PUMP/CTL	3QC	M38

Subtask 49-20-00-010-067-A ** ON A/C NOT FOR ALL

E. Get Access

WARNING: BEFORE YOU START WORK, YOU MUST PUT ON A SAFETY HARNESS AND ATTACH IT TO THE ACCESS PLATFORM. WITHOUT A SAFETY HARNESS, YOU CAN FALL. THIS CAN KILL YOU OR CAUSE YOU INJURY.

(1) Put on and attach the HARNESS, SAFETY before you start work in the work area.
(2) Put the ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in position below APU access doors 315AL and 316AR.
(3) Open APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-010-001).
(4) Set the light switch 11LJ to the ON position.

4. Procedure
Subtask 49-20-00-620-057-A ** ON A/C NOT FOR ALL

A. APU Preservation for Storage during a Maximum of 45 days
(1) Do a general visual inspection of the APU and the APU compartment for oil leaks. No leaks are permitted:
(a) If you find oil leaks:
1 Repair all the oil leaks.
2 Clean the APU externally.
3 Clean the APU compartment (Ref. AMM TASK 49-00-00-100-002).
4 Clean the APU air intake (Ref. AMM TASK 49-16-00-100-006).
(2) Do a general visual inspection of the APU and the APU compartment for fuel leaks. No leaks are permitted:
(a) If you find fuel leaks:
1 Repair all the fuel leaks.
2 Clean the APU externally.
3 Clean the APU compartment (Ref. AMM TASK 49-00-00-100-002).
4 Clean the APU air intake (Ref. AMM TASK 49-16-00-100-006).
(3) Do a general visual inspection of the APU inlet plenum for Foreign Object Damage (FOD):
(a) If you find FOD:
1 Do a borescope inspection of the APU power plant (Ref. AMM TASK 49-20-00-290-001):
a If you find no damage:

Continue the APU preservation procedure.

b If you find damage:

Do the applicable repairs.

(4) If the relative humidity is 40 per cent or more put the Desiccant-Silica Gel on the inlet and exhaust ducts:

CAUTION: DO NOT PUT THE DESICCANT IN THE BLEED AIR DUCTS. IT CAN CAUSE SMELL IN THE CABIN.

(a) Put 8 units of Desiccant-Silica Gel in one Permeable polyethylene bag and 16 units of Desiccant-Silica Gel in a different Permeable polyethylene bag.
(b) Keep each Permeable polyethylene bag open.
(c) Put the INDICATOR-HUMIDITY in each Permeable polyethylene bag.
(d) Make sure that you can see the INDICATOR-HUMIDITY when the APU is in the storage condition.
(e) Put the Permeable polyethylene bag with 8 units of Desiccant-Silica Gel in a KRAFT - PAPER, on the APU exhaust duct.
(f) Use the TAPE - ADHESIVE to attach the Permeable polyethylene bag with 16 units of Desiccant-Silica Gel to the inner side of the air inlet.
(g) Tag and record the number of Desiccant-Silica Gel units in the APU logbook.
(h) Examine the INDICATOR-HUMIDITY during the scheduled checks:
1 If the INDICATOR-HUMIDITY shows a blue indication, you can continue to use Desiccant-Silica Gel.
2 If the INDICATOR-HUMIDITY shows a pink indication, replace the Desiccant-Silica Gel.
(5) Install the APU protections:

CAUTION: PUT PLASTIC CAPS OR PLUGS ON ALL FUEL AND/OR LUBRICATION SYSTEM COMPONENTS AND LINES. IF YOU USE TAPE, CLOTH, OR METAL CAPS ON THEM, YOU CAN DAMAGE THE APU.

(a) Attach the protection covers to the air inlets and outlets (Ref. AMM TASK 10-11-00-555-013).
(6) Attach a LABEL - IDENTIFICATION to the APU with the indication "THIS PRESERVATION IS VALID UNTIL MM/DD/YY".

NOTE: The maximum permitted date is 45 days after the preservation of the APU.

Subtask 49-20-00-620-066-A ** ON A/C NOT FOR ALL

B. APU Preservation for a Maximum Storage Time of 180 Days
(1) Do a General Visual Inspection (GVI) of the APU and the APU compartment and make sure that there are no oil leaks:
(a) If you find oil leaks:
1 Repair all the oil leaks.
2 Clean the APU externally.
3 Clean the APU compartment (Ref. AMM TASK 49-00-00-100-002).
4 Clean the APU air intake (Ref. AMM TASK 49-16-00-100-006).
(2) Do a GVI of the APU and the APU compartment and make sure that there are no fuel leaks:
(a) If you find fuel leaks:
1 Repair all the fuel leaks.
2 Clean the APU externally.
3 Clean the APU compartment (Ref. AMM TASK 49-00-00-100-002).
4 Clean the APU air intake (Ref. AMM TASK 49-16-00-100-006).
(3) Do a GVI of the APU inlet plenum for FOD:
(a) If you find FOD:
1 Do a borescope inspection of the APU power plant (Ref. AMM TASK 49-20-00-290-001).
a If there is no damage:

Continue the APU preservation procedure.

b If you find damage:

Do the applicable repairs.

(4) Drain the oil (Ref. AMM TASK 49-90-00-600-005) but then, make sure that you do not fill the reservoir and you do not operate the APU at this time.
(5) Put the WARNING NOTICE(S) in position on the APU to tell persons that there is no oil in the gearbox.
(6) Disconnect the fuel supply:

CAUTION: DO NOT PUT HYDROCARBON FUEL(S)/OIL(S) INTO THE ENGINE COMPRESSOR. THEY CAN BURN SUDDENLY AND DAMAGE THE APU.

(a) Disconnect the fuel-pump inlet tube from the Fuel Control Unit (FCU) (Ref. AMM TASK 49-32-11-000-002).
(b) Put the PLUG-BLANKING in each disconnected line end.
(c) Drain the fuel from the filter of the FCU.
(7) Put the Desiccant-Silica Gel on the inlet and exhaust ducts:

CAUTION: DO NOT PUT THE DESICCANT IN THE BLEED AIR DUCTS. IT CAN CAUSE SMELL IN THE CABIN.

Put eight units of Desiccant-Silica Gel in one Permeable polyethylene bag.
Put 16 units of Desiccant-Silica Gel in a different Permeable polyethylene bag.

(b) Keep each Permeable polyethylene bag open.
(c) Put the INDICATOR-HUMIDITY in each Permeable polyethylene bag.
(d) Make sure that you can see the INDICATOR-HUMIDITY when the APU is in the stored position.
(e) Put the Permeable polyethylene bag with eight units of Desiccant-Silica Gel in the KRAFT - PAPER and put this on the APU exhaust duct.
(f) Use the TAPE - ADHESIVE to attach the Permeable polyethylene bag with 16 units of Desiccant-Silica Gel to the inner side of the air inlet.
(g) Record the number of the Desiccant-Silica Gel in the APU logbook and tag it.
(h) Examine the INDICATOR-HUMIDITY after 45 days:
1 If the INDICATOR-HUMIDITY shows a blue indication:

The humidity level is less than 40 per cent.
Keep the Desiccant-Silica Gel in position.

2 If the INDICATOR-HUMIDITY shows a pink (or not fully pink) indication:

Replace the Desiccant-Silica Gel.
Examine the Desiccant-Silica Gel each month.

3 If the INDICATOR-HUMIDITY shows a pink (or not fully pink) indication for two subsequent months:

Do the depreservation of the APU.
Do the preservation procedure again.

(8) Install the APU protections:

CAUTION: PUT PLASTIC CAPS OR PLUGS ON ALL FUEL AND/OR LUBRICATION SYSTEM COMPONENTS AND LINES. IF YOU USE TAPE, CLOTH, OR METAL CAPS ON THEM, YOU CAN DAMAGE THE APU.

(a) Put the protection covers on the air inlets and on the air outlets (Ref. AMM TASK 10-11-00-555-013).
(9) Attach the LABEL - IDENTIFICATION to the APU with the indication "THIS PRESERVATION IS VALID UNTIL MM/DD/YY".

NOTE: The maximum permitted date is 180 days after the preservation of the APU.

Subtask 49-20-00-630-050-A ** ON A/C NOT FOR ALL

C. De-preservation of the APU
(1) Remove the caps, covers or seals from all the external pressure ports, fittings and all other openings of the APU (Ref. AMM TASK 10-11-00-555-014).
(2) Remove the Permeable polyethylene bag with eight units of Desiccant-Silica Gel from the APU exhaust duct.
(3) Remove the Permeable polyethylene bag with 16 units of Desiccant-Silica Gel from the air inlet.
(4) Do the GVI of the APU exhaust duct and the air inlet for contamination and unwanted objects (Ref. AMM TASK 49-16-00-210-805).
(5) If the tag is installed on the oil filler cap to identify that the oil system is empty, remove the tag.
(6) Do the oil servicing as follows:
(a) If you did the preservation of the APU for a maximum storage time of 45 days, do the oil servicing procedure (Ref. AMM TASK 49-90-00-600-005) but do not start the APU.
(b) If you did the preservation of the APU for a maximum storage time of 180 days, do the oil servicing procedure (Ref. AMM TASK 49-90-00-600-005) but do not start the APU.
(7) Clean the external surfaces of the APU with the Non Aqueous Cleaner-- Petroleum Based - (Material No.08BBB1) and a Textile-Lint free Cotton - (Material No.14SBA1) .
(8) Do a visual inspection of the harness to make sure that there are no disconnected connectors or missing hardware.
(9) If the fuel-pump inlet tube is disconnected from the FCU, connect it (Ref. AMM TASK 49-32-11-400-002).
(10) Remove the tag that identifies the preservation for the fuel system.
(11) If the WARNING NOTICE(S) is (are) installed in the cockpit and on the APU during the APU preservation, remove them.
(12) Remove the preservation LABEL - IDENTIFICATION.
(13) Do the operational test of the APU (Ref. AMM TASK 49-00-00-710-008).
(a) During the test, select APU BLEED to operate the inlet guide-vane actuator and the bleed control valve.
(b) Make sure that there are no fuel, oil or air leaks on the engine.

5. Close-up
Subtask 49-20-00-410-069-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Set the light switch 11LJ to the OFF position.
(3) Close APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-410-001).
(4) Remove the access platform(s).
(5) Remove the safety harness.

Subtask 49-20-00-865-087-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41
121VU	APU/FUEL/LP VALVE/CTL	1QF	M40
121VU	APU/FUEL/LP VALVE/SPLY	2QF	M39
121VU	APU/FUEL/PUMP/CTL	3QC	M38

Subtask 49-20-00-860-078-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration
(1) Pressurize the aircraft hydraulic systems
(Ref. AMM TASK 29-00-00-864-001).
(2) Remove the WARNING NOTICE(S).
(3) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.01 01:28:35 UTC