DOC AIRBUS | AMM A320FDetailed Inspection of APU Air Intake, Diffuser Elbow, Seals and Felt Metal
TASK 49-16-00-200-002-A
Detailed Inspection of APU Air Intake, Diffuser Elbow, Seals and Felt Metal
Refer to the MPD TASK: 491600-B1
DETAILED INSPECTION OF APU AIR INTAKE, DIFFUSER ELBOW, SEALS AND FELT METAL
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Work Zones and Access Panels
D. Referenced Information
3. Job Set-up
Subtask 49-16-00-860-064-A ** ON A/C NOT FOR ALL
Subtask 49-16-00-210-053-B ** ON A/C NOT FOR ALL
Subtask 49-16-00-410-068-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 04:06:47 UTC
Detailed Inspection of APU Air Intake, Diffuser Elbow, Seals and Felt Metal
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 JobRefer to the MPD TASK: 491600-B1
DETAILED INSPECTION OF APU AIR INTAKE, DIFFUSER ELBOW, SEALS AND FELT METAL
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 | AR | BRUSH - BRISTLED |
| No specific | 1 | CLEANING EQUIPMENT - STEAM |
| No specific | AR | SAFETY CLIP - CIRCUIT BREAKER |
| No specific | AR | WARNING NOTICE(S) |
| 98A57103013000 | 1 | TAP TEST-TOOL |
| 98L12003001000 | AR | HARNESS,SAFETY |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.08ABD1) | Aqueous Cleaner-Aircraft Exterior Gel Type - |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 313 | TAIL CONE APU AIR INTAKE AREA |
| 315 | TAIL CONE APU AND ACCESSORY COMPARTMENT |
| 314AR, 315AL, 316AR |
| REFERENCE | DESIGNATION |
|---|---|
| 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 49-00-00-100-003-A | Cleaning of the APU Compartment with installed APU (131-9(A)) |
| TASK 49-16-00-040-003-A | Deactivation of the APU Air Intake Flap (131-9(A)) |
| TASK 49-16-45-400-003-A | Installation of the Air Intake Diffuser and Elbow (131-9(A)) |
| 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 |
| TASK 52-41-23-010-801-A | Opening of Access Door 314AR |
| TASK 52-41-23-410-801-A | Closing of Access Door 314AR |
| NTM 511003 | |
Air Intake SystemSubtask 49-16-00-860-064-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 the APU section of overhead panel 25VU, make sure that the WARNING NOTICE(S) is in position to tell persons not to start the APU.
(3) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).
Subtask 49-16-00-010-066-A ** ON A/C NOT FOR ALL (1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(2) On the APU section of overhead panel 25VU, make sure that the WARNING NOTICE(S) is in position to tell persons not to start the APU.
(3) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).
B. Get Access
(2) If the air intake flap is not in the open position, open it.
(c) As an alternative, you can open the air intake flap manually (Ref. AMM TASK 49-16-00-040-003).
(3) Put the ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in position below the APU compartment and the air intake.
(4) Open APU access door 315AL (Ref. AMM TASK 52-41-00-010-001).
(5) Open access door 314AR and safety it in the open position.
(Ref. AMM TASK 52-41-23-010-801).
(6) Set the light switch to on.
(7) Remove the service panel (1).
Subtask 49-16-00-865-081-A ** ON A/C NOT FOR ALL 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) If the air intake flap is not in the open position, open it.
WARNING:
MAKE SURE THAT THE TRAVEL RANGE OF THE AIR-INTAKE SYSTEM COMPONENTS IS CLEAR. MOVEMENT OF AIR-INTAKE SYSTEM COMPONENTS CAN CAUSE INJURY AND/OR DAMAGE.
(a) On overhead panel 25VU, push the APU MASTER SW pushbutton switch (the ON legend comes on).NOTE: When you push the APU MASTER SW pushbutton switch, air intake flap-actuator 4015KM starts to operate immediately and it opens the air intake flap. It stops automatically in the flap open position.
(b) If you want to keep the air intake flap in the open position for the subsequent procedure, you must open the circuit breakers. Then you release the APU MASTER SW pushbutton switch.(c) As an alternative, you can open the air intake flap manually (Ref. AMM TASK 49-16-00-040-003).
(3) Put the ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in position below the APU compartment and the air intake.
(4) Open APU access door 315AL (Ref. AMM TASK 52-41-00-010-001).
(5) Open access door 314AR and safety it in the open position.
(Ref. AMM TASK 52-41-23-010-801).
(6) Set the light switch to on.
(7) Remove the service panel (1).
C. Open, safety and tag this(these) circuit breaker(s):
4. Procedure| PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 49VU | APU/FUEL/BLOW OFF/PUMP | 2QC | B14 |
| 49VU | AIR BLEED/X FEED/VALVE/BAT | 2HV | D13 |
| ** ON A/C NOT FOR ALL | |||
| 121VU | APU/FUEL/BLOW OFF/CTL | 1QC | K39 |
| ** 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 |
| ** ON A/C NOT FOR ALL | |||
| 121VU | APU/FUEL/BLOW OFF/CTL | 1QC | P38 |
Subtask 49-16-00-210-053-B ** ON A/C NOT FOR ALL
A. Detailed Inspection of the APU Air Intake, Diffuser Elbow, Seals and Felt Metal
(1) Clean the APU air-intake flap, the internal side of the air intake duct and the APU doors with Aqueous Cleaner-Aircraft Exterior Gel Type - (Material No.08ABD1) and the BRUSH - BRISTLED.
(2) Let the cleaning agent stay on the surfaces for 30 minutes.
(3) Flush the cleaning agent from the surfaces with the CLEANING EQUIPMENT - STEAM at the maximum temperature of 130 deg.C (266.00 deg.F) and the maximum pressure of 5 bar (72.5189 psi).
(4) Let the surfaces dry for 15 minutes.
(5) Open APU access door 316AR (Ref. AMM TASK 52-41-00-010-001).
(6) Examine the flexible seals (4), (7) and (9) for wear, tears and porosity.
(a) If they are not in the correct condition, replace them.
(7) Measure the height of the seal (7) in the expanded condition and make sure that it is a minimum of 20 +1.5 mm or -0 mm (0.79 +0.06 in. or +0.00 in.).
(a) If the height of the seal (7) is incorrect, replace it.
(8) Close APU access door 316AR (Ref. AMM TASK 52-41-00-410-001).
(9) Make sure that the distance between the APU plenum (11) and the flanges of the elbow assembly (6) is 18 +3 mm or -3 mm (0.709 +0.118 in. or -0.118 in.).
(a) If the clearance is incorrect, do the adjustment of the air intake diffuser and the elbow (Ref. AMM TASK 49-16-45-400-003).
(10) Measure and if necessary, adjust the vertical and horizontal clearances between the APU plenum and the air intake system (Ref. AMM TASK 49-16-45-400-003).
(11) Make sure that there are no signs of de-icing contamination.
(a) If you find contamination, clean the APU compartment (Ref. AMM TASK 49-00-00-100-003).
(12) Do the steps that follows on the air intake system:
(a) Examine the external and internal surfaces of the air intake system for delamination, distortion and cracks.
(b) Examine the diverter for damage.
(c) Examine the air intake system for damage from ice particles, corrosion, erosion or unwanted objects:
1 Do a check of the damping plate.
a Damage is permitted if:
(d) Do a tap test with the 98A57103013000 TAP TEST-TOOL NTM 511003:
1 Do a tap test for delamination on all the felt metal surfaces of the air intake system, the guide surfaces and the guide vanes (5). Tap at distances of 20 mm (0.79 in.) in rows with a distance of 20 mm (0.79 in.) between them.
2 Do a tap test for delamination on the external sandwich structure of the air inlet duct (2), air intake nose (8) and air intake flap (10) (composite flap). Tap at distances of 20 mm (0.79 in.) in rows with a distance of 20 mm (0.79 in.) between them.
a Make sure that there is no delamination, distortion or other damage.
Subtask 49-16-00-210-053-D ** ON A/C NOT FOR ALL (1) Clean the APU air-intake flap, the internal side of the air intake duct and the APU doors with Aqueous Cleaner-Aircraft Exterior Gel Type - (Material No.08ABD1) and the BRUSH - BRISTLED.
(2) Let the cleaning agent stay on the surfaces for 30 minutes.
(3) Flush the cleaning agent from the surfaces with the CLEANING EQUIPMENT - STEAM at the maximum temperature of 130 deg.C (266.00 deg.F) and the maximum pressure of 5 bar (72.5189 psi).
(4) Let the surfaces dry for 15 minutes.
(5) Open APU access door 316AR (Ref. AMM TASK 52-41-00-010-001).
(6) Examine the flexible seals (4), (7) and (9) for wear, tears and porosity.
(a) If they are not in the correct condition, replace them.
(7) Measure the height of the seal (7) in the expanded condition and make sure that it is a minimum of 20 +1.5 mm or -0 mm (0.79 +0.06 in. or +0.00 in.).
(a) If the height of the seal (7) is incorrect, replace it.
(8) Close APU access door 316AR (Ref. AMM TASK 52-41-00-410-001).
(9) Make sure that the distance between the APU plenum (11) and the flanges of the elbow assembly (6) is 18 +3 mm or -3 mm (0.709 +0.118 in. or -0.118 in.).
(a) If the clearance is incorrect, do the adjustment of the air intake diffuser and the elbow (Ref. AMM TASK 49-16-45-400-003).
(10) Measure and if necessary, adjust the vertical and horizontal clearances between the APU plenum and the air intake system (Ref. AMM TASK 49-16-45-400-003).
(11) Make sure that there are no signs of de-icing contamination.
(a) If you find contamination, clean the APU compartment (Ref. AMM TASK 49-00-00-100-003).
(12) Do the steps that follows on the air intake system:
(a) Examine the external and internal surfaces of the air intake system for delamination, distortion and cracks.
(b) Examine the diverter for damage.
(c) Examine the air intake system for damage from ice particles, corrosion, erosion or unwanted objects:
1 Do a check of the damping plate.
a Damage is permitted if:
- The maximum dimensions of the damage area are:
* Width: 2 mm (0.0787 in.)
* Length: 5 mm (0.1969 in.)
* Depth: 1 mm (0.0394 in.). - Damage has no effect on the inner surface of the plate.
- The outer surface adjacent to the damage area has no cracks, delamination or other damage.
(d) Do a tap test with the 98A57103013000 TAP TEST-TOOL NTM 511003:
1 Do a tap test for delamination on all the felt metal surfaces of the air intake system, the guide surfaces and the guide vanes (5). Tap at distances of 20 mm (0.79 in.) in rows with a distance of 20 mm (0.79 in.) between them.
2 Do a tap test for delamination on the external sandwich structure of the air inlet duct (2), air intake nose (8) and air intake flap (10) (composite flap). Tap at distances of 20 mm (0.79 in.) in rows with a distance of 20 mm (0.79 in.) between them.
a Make sure that there is no delamination, distortion or other damage.
A. Detailed Inspection of the APU Air Intake, Diffuser Elbow, Seals and Felt Metal
(1) Use Aqueous Cleaner-Aircraft Exterior Gel Type - (Material No.08ABD1) and the BRUSH - BRISTLED to clean:
(3) Flush the cleaning agent from the surfaces with the CLEANING EQUIPMENT - STEAM at a maximum temperature of 130 deg.C (266.00 deg.F) and a maximum pressure of 5 bar (72.5189 psi).
(4) Let the surfaces dry for 15 minutes.
(5) Open APU access door 316AR (Ref. AMM TASK 52-41-00-010-001).
(6) Examine the flexible seals (4), (7) and (9) for wear, damage and defects (the seals must bond correctly).
(a) If they are not in the correct condition, replace them.
(7) Measure the height of the seal (7) in the expanded condition, and make sure that it is in a minimum of 20 +1.5 mm or -0 mm (0.79 +0.06 in. or +0.00 in.).
(a) If the height of the seal (7) is incorrect, replace it.
(8) Close APU access door 316AR (Ref. AMM TASK 52-41-00-410-001).
(9) Make sure that the distance between the APU plenum (11) and the flanges of the elbow assembly (6) is 18 +3 mm or -3 mm (0.709 +0.118 in. or -0.118 in.).
(a) If the clearance is incorrect, do the adjustment of the air intake diffuser and the elbow (Ref. AMM TASK 49-16-45-400-003).
(10) Measure and if necessary, adjust the vertical and horizontal clearances between the APU plenum and the air intake system (Ref. AMM TASK 49-16-45-400-003).
(11) Make sure that there are no signs of de-icing contamination.
(a) If you find contamination, clean the APU compartment (Ref. AMM TASK 49-00-00-100-003).
(12) Do the steps that follows on the air intake system:
(a) Examine the external and internal surfaces of the air intake system for delamination, distortion and cracks.
(b) Examine the diverter for damage.
(c) Examine the air intake system for damage from ice particles, corrosion, erosion or unwanted objects:
1 Do a check of the damping plate.
a Damage is permitted if:
(d) Do a tap test with the 98A57103013000 TAP TEST-TOOL NTM 511003:
1 Do a tap test for delamination on all the felt metal surfaces of the air intake system, the guide surfaces and the guide vanes (5). Tap at distances of 20 mm (0.79 in.) in rows with a distance of 20 mm (0.79 in.) between them.
2 Do a tap test for delamination on the external sandwich structure of the air inlet duct (2). Do this tap test at distances of 20 mm (0.79 in.) and in rows that have a distance of 20 mm (0.79 in.) between them:
a Make sure that there is no delamination, distortion or other damage.
(13) Do a visual inspection of the air intake nose (8) and the air intake flap (aluminum flap) (10). This is to make sure that there are no signs of corrosion.
5. Close-up(1) Use Aqueous Cleaner-Aircraft Exterior Gel Type - (Material No.08ABD1) and the BRUSH - BRISTLED to clean:
- The APU air-intake flap.
- The internal surfaces of the air intake duct.
- The APU doors.
(3) Flush the cleaning agent from the surfaces with the CLEANING EQUIPMENT - STEAM at a maximum temperature of 130 deg.C (266.00 deg.F) and a maximum pressure of 5 bar (72.5189 psi).
(4) Let the surfaces dry for 15 minutes.
(5) Open APU access door 316AR (Ref. AMM TASK 52-41-00-010-001).
(6) Examine the flexible seals (4), (7) and (9) for wear, damage and defects (the seals must bond correctly).
(a) If they are not in the correct condition, replace them.
(7) Measure the height of the seal (7) in the expanded condition, and make sure that it is in a minimum of 20 +1.5 mm or -0 mm (0.79 +0.06 in. or +0.00 in.).
(a) If the height of the seal (7) is incorrect, replace it.
(8) Close APU access door 316AR (Ref. AMM TASK 52-41-00-410-001).
(9) Make sure that the distance between the APU plenum (11) and the flanges of the elbow assembly (6) is 18 +3 mm or -3 mm (0.709 +0.118 in. or -0.118 in.).
(a) If the clearance is incorrect, do the adjustment of the air intake diffuser and the elbow (Ref. AMM TASK 49-16-45-400-003).
(10) Measure and if necessary, adjust the vertical and horizontal clearances between the APU plenum and the air intake system (Ref. AMM TASK 49-16-45-400-003).
(11) Make sure that there are no signs of de-icing contamination.
(a) If you find contamination, clean the APU compartment (Ref. AMM TASK 49-00-00-100-003).
(12) Do the steps that follows on the air intake system:
(a) Examine the external and internal surfaces of the air intake system for delamination, distortion and cracks.
(b) Examine the diverter for damage.
(c) Examine the air intake system for damage from ice particles, corrosion, erosion or unwanted objects:
1 Do a check of the damping plate.
a Damage is permitted if:
- The maximum dimensions of the damage area are:
* Width: 2 mm (0.0787 in.).
* Length: 5 mm (0.1969 in.).
* Depth: 1 mm (0.0394 in.). - Damage has no effect on the inner surface of the plate.
- The outer surface adjacent to the damage area has no cracks, delamination or other damage.
(d) Do a tap test with the 98A57103013000 TAP TEST-TOOL NTM 511003:
1 Do a tap test for delamination on all the felt metal surfaces of the air intake system, the guide surfaces and the guide vanes (5). Tap at distances of 20 mm (0.79 in.) in rows with a distance of 20 mm (0.79 in.) between them.
2 Do a tap test for delamination on the external sandwich structure of the air inlet duct (2). Do this tap test at distances of 20 mm (0.79 in.) and in rows that have a distance of 20 mm (0.79 in.) between them:
a Make sure that there is no delamination, distortion or other damage.
(13) Do a visual inspection of the air intake nose (8) and the air intake flap (aluminum flap) (10). This is to make sure that there are no signs of corrosion.
Subtask 49-16-00-410-068-A ** ON A/C NOT FOR ALL
A. Close Access
(1) Install the service panel (1).
(2) Make sure that the work area is clean and clear of tools and other items.
(3) Remove the ground support and maintenance equipment, the special and standard tools and all other items.
(4) Set the light switch to off.
(5) Close access door 314AR (Ref. AMM TASK 52-41-23-410-801).
(6) Close access door 315AL (Ref. AMM TASK 52-41-00-410-001).
(7) Remove the access platform(s).
(8) Remove the 98L12003001000 HARNESS,SAFETY.
Subtask 49-16-00-865-127-A ** ON A/C NOT FOR ALL (1) Install the service panel (1).
(2) Make sure that the work area is clean and clear of tools and other items.
(3) Remove the ground support and maintenance equipment, the special and standard tools and all other items.
(4) Set the light switch to off.
(5) Close access door 314AR (Ref. AMM TASK 52-41-23-410-801).
(6) Close access door 315AL (Ref. AMM TASK 52-41-00-410-001).
(7) Remove the access platform(s).
(8) Remove the 98L12003001000 HARNESS,SAFETY.
B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
Subtask 49-16-00-860-065-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 49VU | APU/FUEL/BLOW OFF/PUMP | 2QC | B14 |
| 49VU | AIR BLEED/X FEED/VALVE/BAT | 2HV | D13 |
| ** ON A/C NOT FOR ALL | |||
| 121VU | APU/FUEL/BLOW OFF/CTL | 1QC | K39 |
| ** 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 |
| ** ON A/C NOT FOR ALL | |||
| 121VU | APU/FUEL/BLOW OFF/CTL | 1QC | P38 |
C. Put the aircraft back to its initial configuration.
(1) Close the air intake flap if it is not in closed position:
(3) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(4) Remove the WARNING NOTICE(S).
(1) Close the air intake flap if it is not in closed position:
WARNING:
MAKE SURE THAT THE TRAVEL RANGE OF THE AIR-INTAKE SYSTEM COMPONENTS IS CLEAR. MOVEMENT OF AIR-INTAKE SYSTEM COMPONENTS CAN CAUSE INJURY AND/OR DAMAGE.
(a) On overhead panel 25VU, release the APU MASTER SW pushbutton switch (the ON legend goes off).NOTE: When you release the APU MASTER SW pushbutton switch, air intake flap-actuator 4015KM starts to operate immediately and it closes the air intake-flap. It stops automatically in the flap close position.
(2) Put the related hydraulic system in the pressurized configuration (Ref. AMM TASK 29-00-00-864-001). (3) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(4) Remove the WARNING NOTICE(S).