Installation of the Air Intake Diffuser and Elbow (131-9(A))

TASK 49-16-45-400-003-A
Installation of the Air Intake Diffuser and Elbow (131-9(A))

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.

ZONE: 315
ZONE: 316

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
315	TAIL CONE APU AND ACCESSORY COMPARTMENT
316	TAIL CONE APU AND ACCESSORY COMPARTMENT
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

E. Referenced Information

REFERENCE	DESIGNATION
TASK 20-28-00-912-802-A	Electrical Bonding - General Maintenance Procedure
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
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 49-16-45-860-057-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(2) On panel 25VU, make sure that the APU MASTER SW p/bsw 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 APU access doors 315AL and 316AR are open (Ref. AMM TASK 52-41-00-010-001).
(7) Make sure that LIGHT SW 11LJ is set to the ON position.

Subtask 49-16-45-865-057-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 49-16-45-220-052-B ** ON A/C NOT FOR ALL

A. Preparation for Installation
(1) Clean the component interfaces and the adjacent area.
(2) Do an inspection of the component interfaces and the adjacent area.
(3) Do an inspection for damage of the inner and outer surface of the diffuser (20) and elbow assembly (26). Examine the guide vanes in the elbow assembly (26) for damage and contamination. Replace or clean them as necessary.
(4) Do an inspection of the seal (3) for damage.
If necessary, replace the seal (3) as follows:
(a) Remove the screws (1).
(b) Remove the frame (2) and the seal (3) from the elbow assembly (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) and the nut plates (5).
(d) Align the seal (3) and the frame (2) on the elbow assembly (26).
(e) Install the screws (1) in the nut plates (5).
(5) Make sure that basic adjustments F and J of the eye-bolts (8 and 14) is 23.1 mm (0.9094 in.).
(6) Make sure that basic adjustment G is 18.0 mm (0.7087 in.).

NOTE: You can measure dimension G from the edge of the APU compartment door (view B) to the center of the eye-bolt and then add 3 mm (0.1181 in.) to the measured value. The AD line is the aircraft datum line (Y=0).

(7) Make sure 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 when you look forward from the 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 5 mm (0.1969 in.). The eye-bolt position is 2.5 mm (0.0984 in.) out of the center line of the elbow. The AD line is the aircraft datum line (Y=0).

NOTE: Steps 6 and 7 are only necessary if you must install a new eye-bolt or the air intake duct with elbow.

Subtask 49-16-45-420-055-A ** ON A/C NOT FOR ALL

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

.
(6) Safety the locknuts (7) and (13):

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.

(a) Safety the locknuts (7) and (13) with 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(7) 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.

Subtask 49-16-45-820-056-B ** ON A/C NOT FOR ALL

C. Adjustment
(1) When APU access door 316AR is closed, the seal (3) is fully compressed. Make sure that Dimension K is 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).
(2) If Dimension K is incorrect, adjust the diffuser (20) as follows:
(a) Open 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 the 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 is equal to 0.45 mm (0.0177 in.)). The adjustment range is between the marking grooves.
(g) Align the eye-bolt (8) and tighten the nut (7).
(h) Install the diffuser (20) and the elbow (26).
(i) Safety the nut (7) with the lockwasher (6).
(3) When APU access door 316AR is closed, the center of the elbow assembly (26) and of the APU plenum (33) must be aligned as 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 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 surfaces 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) .
(4) Close APU access door 316AR.
(5) 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.
(6) Examine the inner edges of the diffuser (20) to make sure that the maximum step between the diffuser (20) and the air inlet duct is as follows:
(a) Horizontally, 0.3 -0 mm or +0.4 mm (0.0118 +0.0000 in. or +0.0157 in.), and
(b) Laterally, 0.35 -0 mm or +0.55 mm (0.0138 +0.0000 in. or +0.0217 in.).
(7) If the dimensions are not satisfactory, adjust as follows:
(a) Open APU access door 316AR.
(b) Remove the castle nut (12), washer (10) and 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 is equal to 0.45 mm (0.0177 in.)). The adjustment range is between the marking grooves.

NOTE: If one half-turn is too much, adjust the eye-bolt (14) at the outside surface of the APU access door 316AR as an alternative to the inner surface.

(e) Align the eye-bolt (14) and tighten the nut (13).
(8) Make sure that the distance between the air inlet duct and the flange of the diffuser (20) is 3.0 -1.0 mm or +0 mm (0.1181 -0.0394 in. or +0.0000 in.) around the circumference. If it is not satisfactory, adjust as follows:
(a) Align the diffuser (20) and the 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 the 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 teeth of 0.75 mm (0.0295 in.).

(i) If necessary, adjust the length of the tie-rod (22) a maximum of 311.5 +10.0 mm or -10.0 mm (12.2638 +0.3937 in. or -0.3937 in.) .
(9) Tighten and safety all the nuts as follows:

WARNING: USE PROTECTIVE GOGGLES WHEN YOU REMOVE OR INSTALL A COTTER PIN. EACH TIME YOU REMOVE A COTTER PIN DURING THE TASK, DISCARD IT IMMEDIATELY. A LOOSE COTTER PIN CAN CUT YOU OR MAKE YOU BLIND.

(a) Safety the castle nuts (24) and (12) with the new AIPC 49-16-04-04-070 COTTER PIN (25) and AIPC 49-16-04-04-070 COTTER PIN (11).
(b) Connect the drain hoses (16) to the drain lines.
(c) Connect the bonding strap (17) with the screw (19) and the washer (18) (Ref. AMM TASK 20-28-00-912-802).
(d) Apply Corrosion Preventive Compound-Heavy Duty Hard Film - (Material No.12ACB1) around all the screw heads.

Subtask 49-16-45-820-056-C ** ON A/C NOT FOR ALL

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

(a) Open 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-High Temp. Area - Structure (Material No.06LDG2) to the mating surfaces 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) .
(4) Close APU access door 316AR.
(5) 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.
(6) Examine the inner edges of the diffuser (20) to make sure that the maximum step between the diffuser (20) and the air inlet duct is as follows:
(a) Horizontally, 0.3 -0 mm or +0.4 mm (0.0118 +0.0000 in. or +0.0157 in.), and
(b) Laterally, 0.35 -0 mm or +0.55 mm (0.0138 +0.0000 in. or +0.0217 in.).
(7) If the dimensions are not satisfactory, adjust as follows:
(a) Open APU access door 316AR.
(b) Remove the castle nut (12), washer (10) and 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 is equal to 0.45 mm (0.0177 in.)). The adjustment range is between the marking grooves.

NOTE: If one half-turn is too much, adjust the eye-bolt (14) at the outside surface of the APU access door 316AR as an alternative to the inner surface.

(e) Align the eye-bolt (14) and tighten the nut (13).
(8) Make sure that the distance between the air inlet duct and the flange of the diffuser (20) is 3.0 -1.0 mm or +0 mm (0.1181 -0.0394 in. or +0.0000 in.) around the circumference. If it is not satisfactory, adjust as follows:
(a) Align the diffuser (20) and the elbow assembly (26) longitudinally and laterally with the fittings (27) and (32).
(b) Apply 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 the elbow (26) laterally with the fitting (32) if necessary.
(g) Apply 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 teeth of 0.75 mm (0.0295 in.).

(i) If necessary, adjust the length of the tie-rod (22) a maximum of 311.5 +10.0 mm or -10.0 mm (12.2638 +0.3937 in. or -0.3937 in.).
(9) Tighten and safety all the nuts as follows:

WARNING: USE PROTECTIVE GOGGLES WHEN YOU REMOVE OR INSTALL A COTTER PIN. EACH TIME YOU REMOVE A COTTER PIN DURING THE TASK, DISCARD IT IMMEDIATELY. A LOOSE COTTER PIN CAN CUT YOU OR MAKE YOU BLIND.

5. Close-up
Subtask 49-16-45-410-055-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 LIGHT SW 11LJ to the OFF position.
(3) Close APU access doors 316AR 315AL (Ref. AMM TASK 52-41-00-410-001).
(4) Remove the access platform(s).

Subtask 49-16-45-865-058-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

Subtask 49-16-45-860-058-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration
(1) Put the related hydraulic system in the pressurized configuration (Ref. AMM TASK 29-00-00-864-001).
(2) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 01:28:09 UTC