Installation of the Air Intake Diffuser and Elbow (APS 3200)

TASK 49-16-45-400-002-A
Installation of the Air Intake Diffuser and Elbow (APS 3200)

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.

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	Torque wrench: range to between 4.64 and 3.87 m.daN (34.22 and 28.54 lbf.ft )

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.03QBA1)	Dry lubricant-General Assembly - -
(Material No.06AAB1)	Polysulfide Sealant-General Purpose Fillet -
(Material No.06LCG9)	Non Hardening Jointing Putty-Medium Temp. Area - -
(Material No.06LDG2)	Non Hardening Jointing Putty-High Temp. Area - Structure
(Material No.12ACB1)	Corrosion Preventive Compound-Heavy Duty Hard Film -
(Material No.12AGC2)	Corrosion Preventive Compound-- Soft Film System
(Material No.14QFB1)	Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
315AL, 316AR

D. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
11	COTTER PIN	AIPC 49-16-04-04-070
25	COTTER PIN	AIPC 49-16-04-04-070
6	LOCKWASHER	AIPC 49-16-45-05-150
11	COTTER PIN	AIPC 49-16-84-41-050
25	COTTER PIN	AIPC 49-16-84-41-050

E. Referenced Information

REFERENCE	DESIGNATION
TASK 20-28-00-912-802-A	Electrical Bonding - General Maintenance Procedure
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 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
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
Air Intake Diffuser and Elbow

3. Job Set-up
Subtask 49-16-45-860-050-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Make sure that the aircraft electrical circuits are energized (Ref. AMM TASK 24-41-00-861-002).
(2) On the panel 25VU, make sure that the APU MASTER SW pushbutton switch is set to the OFF position.
(3) Make sure that there is a warning notice in the cockpit 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).
(5) Make sure that the access platform is in position below the APU compartment.

WARNING: AFTER THE DIFFUSER IS REMOVED, CAREFULLY SUPPORT THE UNIT/ASSEMBLY BEFORE YOU CLOSE THE APU DOOR. IF YOU DO NOT SUPPORT THE UNIT/ASSEMBLY, IT CAN FALL AND BECOME DAMAGED, OR CAUSE INJURY TO PERSONNEL AND DAMAGE TO THE AIRCRAFT.

(6) Make sure that the APU access doors 315AL and 316AR are open (Ref. AMM TASK 52-41-00-010-001).
(7) Make sure that the LIGHT control switch 11LJ is set to the ON position.

Subtask 49-16-45-865-054-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

4. Procedure
Subtask 49-16-45-560-050-A ** ON A/C NOT FOR ALL

A. Preparation of the Replacement Component

Air Intake Diffuser and Elbow ** ON A/C NOT FOR ALL

(1) Clean the component interfaces and the adjacent area.
(2) Make an inspection for damage of the inner and outer surface of the diffuser (20) and the elbow (26). Examine the guide vanes in the elbow (26) for damage and unwanted matter. Replace or clean them as necessary.
(3) Make an inspection of the seal (3) for damage. If necessary, replace the seal as follows:
(a) Remove the nuts (5), the washers (4) and the screws (1).
(b) Remove the frame (2) and the seal (3) from the elbow (26).
(c) Apply Non Hardening Jointing Putty-Medium Temp. Area - - (Material No.06LCG9) or Non Hardening Jointing Putty-High Temp. Area - Structure (Material No.06LDG2) to the screws (1), the washers (4) and the nuts (5).
(d) Align the seal (3) and the frame (2) on the elbow (26).
(e) Install the screws (1), the washers (4) and the nuts (5).

Subtask 49-16-45-420-053-A ** ON A/C NOT FOR ALL

B. Installation of the Air Intake Diffuser and Elbow
(1) Make sure that the basic adjustment F and J of the eye-bolts (8 and 14) is 23.1 mm (0.9094 in.) (Ref. Detail B and D).
(2) Make sure, the basic adjustment G is 18.0 mm (0.7087 in.) .

NOTE: You can measure the dimension G from the edge of the APU compartment door (view B) to the center of the eye-bolt and then add to the measured value 3mm. The AD-line is the aircraft datum line (Y=0).

(3) Make sure, the basic adjustment H is 2.5 mm (0.0984 in.).

NOTE: You can measure the position of the eye-bolt (dimension A), from the sidewall of the Air-intake-duct elbow (view C) to the eye-bolt center with the measuring tape, aft looking forward direction left side. You can do the measurement again from the opposite side of the elbow (dimension B) to get a reference value. The difference of the two measured values must be 5mm. The eye-bolt position is 2.5mm out of the center line of the elbow. The AD-line is the aircraft datum line (Y=0).

NOTE: The worksteps 1,2 and 3 are only necessary if new eye-bolts or new air-intake duct should be installed.

(4) Put the diffuser (20) and elbow assembly (26) in position. Make sure that the eye bolt (8) and the fitting (9) are aligned.
(5) Install the bolt (15), the washer (10) and the castle nut (12). Do not fully tighten the nut at this time.
(6) Make sure that the specified length of the tie-rod (22) is 311.5 mm (12.2638 in.). Adjust if necessary.
(7) After adjustment put the eye-end fittings in line.
(a) TORQUE the nut (13) to between 4.64 and 3.87 m.daN (34.22 and 28.54 lbf.ft )

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.

(b) Safety the nut (13) with 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(8) Put the tie-rod (22) into the fitting and install the bolt (21), the washer (23) and the castle nut (24). Do not fully tighten the nut at this time.
(9) Close the APU access door 316AR (Ref. AMM TASK 52-41-00-410-001).

Subtask 49-16-45-820-055-B ** ON A/C NOT FOR ALL

C. Adjustment of the Air Intake Diffuser and Elbow
(1) When the APU access door 316AR is closed, the seal (3) is fully compressed. The K dimension must be 18.0 +3 mm or -3 mm (0.7087 +0.1181 in. or -0.1181 in.) between the APU plenum (33) and the flanges of the elbow assembly (26). If the clearance is incorrect, adjust the diffuser (20) as follows:
(a) Open the APU access door 316AR.
(b) Remove the diffuser (20) and the elbow (26).
(c) Open the lockwasher (6) and loosen the nut (7).
(d) Remove the eye-bolt (8) and discard the lockwasher (6).
(e) Install a new AIPC 49-16-45-05-150 LOCKWASHER (6) and install the eye-bolt (8).
(f) Adjust the eye-bolt (8) in half-turns until you get the correct length. (One half-turn equals 0.45 mm (0.0177 in.). The adjustment range is between the marking grooves.
(g) Align the eye-bolt (8).
(h) TORQUE the nut (7) to between 4.64 and 3.87 m.daN (34.22 and 28.54 lbf.ft )

.
(i) Install the diffuser (20) and the elbow (26).
(j) Safety the nut (7) with the lockwasher (6).
(2) When the APU access door 316AR is closed, the elbow assembly (26) and the APU plenum (33) must be centered as it is shown in drawing section A-A. If the clearance is incorrect, adjust the diffuser (20) as follows:

NOTE: The fittings (27) and (32) have adjustment serrations with a pitch of 0.75 mm (0.0295 in.)

(a) Open the APU access door 316AR.
(b) Align the diffuser (20) and the elbow (26) longitudinally with the fitting (27).
(c) Align the diffuser (20) and the elbow (26) laterally with the fitting (32).
(d) Apply the Non Hardening Jointing Putty-Medium Temp. Area - - (Material No.06LCG9) or Non Hardening Jointing Putty-High Temp. Area - Structure (Material No.06LDG2) to the mating surface of the tooth plates (29) and (30) and the screws (31).
(e) Seal the tooth plates with Polysulfide Sealant-General Purpose Fillet - (Material No.06AAB1) after installation.
(f) Apply Dry lubricant-General Assembly - - (Material No.03QBA1) to the screws (28) and paint the joints with Corrosion Preventive Compound-- Soft Film System (Material No.12AGC2) .
(3) Close the APU access door 316AR.
(4) Get access through the air inlet duct and make sure that the front flange of the diffuser (20) is in the center of the air inlet duct.
(5) Examine the inside edges of the diffuser (20) to make sure that the max. allowed step between the diffuser (20) and the air inlet duct is horizontally 0.3 -0 mm or +0.4 mm (0.0118 +0.0000 in. or +0.0157 in.) and laterally 0.35 -0 mm or +0.55 mm (0.0138 +0.0000 in. or +0.0217 in.). If not satisfactory, adjust as follows:
(a) Open the APU access door 316AR.
(b) Remove the castle nut (12), the washer (10) and the bolt (15).

Remove and discard the lockwire and loosen the nut (13).

(d) Adjust the eye-bolt (14) in half-turns until you get the correct length. (One half-turn equals 0.45 mm (0.0177 in.)). The adjustment range is between the marking grooves.

NOTE: If a half-turn is too much, screw the eye-bolt (14) out rather than into the door.

(e) Align the eye-bolt (14).
(f) TORQUE the nut (13) to between 4.64 and 3.87 m.daN (34.22 and 28.54 lbf.ft )

(g) Safety the nut (13) with 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(6) Make sure that the distance between the air inlet duct and the flange of the diffuser (20) measures 3.0 -1.0 mm or +0 mm (0.1181 -0.0394 in. or +0.0000 in.) around the circumference. If not satisfactory, adjust as follows:
(a) Align the diffuser (20) and elbow assembly (26) longitudinally and laterally with the fittings (27) and (32).
(b) Apply Non Hardening Jointing Putty-Medium Temp. Area - - (Material No.06LCG9) or Non Hardening Jointing Putty-High Temp. Area - Structure (Material No.06LDG2) to the mating surfaces of the tooth plates (29).
(c) Seal the tooth plates with Polysulfide Sealant-General Purpose Fillet - (Material No.06AAB1) after installation.
(d) Apply Dry lubricant-General Assembly - - (Material No.03QBA1) to the screws (28).
(e) Paint the connection with Corrosion Preventive Compound-- Soft Film System (Material No.12AGC2) .
(f) Align the diffuser (20) and elbow (26) laterally with the fitting (32) if necessary.
(g) Apply Non Hardening Jointing Putty-Medium Temp. Area - - (Material No.06LCG9) or Non Hardening Jointing Putty-High Temp. Area - Structure (Material No.06LDG2) to the mating surface of the tooth plate (30) and to the screws (31).
(h) Seal the tooth plate with Polysulfide Sealant-General Purpose Fillet - (Material No.06AAB1) after the installation.

NOTE: The fittings (27 and 32) have a pitch of parallel toothing of 0.75 mm (0.0295 in.).

(i) Adjust the length of the tie-rod (22) by max 311.5 +10.0 mm or -10.0 mm (12.2638 +0.3937 in. or -0.3937 in.) if necessary.

Subtask 49-16-45-420-054-A ** ON A/C NOT FOR ALL

D. Final Installation of the Air Intake Diffuser and Elbow
(1) Tighten and safety all the nuts.
(2) Safety the castle nut (24) with a new AIPC 49-16-04-04-070 COTTER PIN (25) or AIPC 49-16-84-41-050 COTTER PIN (25).
(3) Safety the castle nut (12) with a new AIPC 49-16-04-04-070 COTTER PIN (11) or AIPC 49-16-84-41-050 COTTER PIN (11).
(4) Connect the drain hoses (16) to the drain lines.
(5) Connect the bonding strap (17) with the screw (19) and the washer (18) (Ref. AMM TASK 20-28-00-912-802).
(6) Apply Corrosion Preventive Compound-Heavy Duty Hard Film - (Material No.12ACB1) around all the screw heads.

Subtask 49-16-45-410-053-A ** ON A/C NOT FOR ALL

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

Subtask 49-16-45-865-055-A ** ON A/C NOT FOR ALL

F. 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

Subtask 49-16-45-860-054-A ** ON A/C NOT FOR ALL

G. Aircraft Maintenance Configuration
(1) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.01 01:28:07 UTC