DOC AIRBUS | TSM A320FAir Conditioning Noise
TASK 21-00-00-810-804-A
Air Conditioning Noise
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 21-00-00-210-050-A
Subtask 21-00-00-810-057-A
[Rev.8 from Aug 2018]
2026.04.04 04:24:35 UTC
Air Conditioning Noise
1. Possible Causes
- panels
- RECIRC FILTER CARTRIDGE 1 [4012HM]
- RECIRC FILTER CARTRIDGE 2 [4013HM]
- ducts between the trim air valves and the mixer unit
- air outlet grids and filter mats
- downstream supply ducts
- RECIRC FAN 2 [14HG]
- RECIRC FAN 1 [15HG]
- RECIRC CHECK VALVE 1 [4020HM]
- RECIRC CHECK VALVE 2 [4021HM]
- FAN-BLOWER, AVNCS VENT [20HQ]
- FAN-EXTRACT, AVNCS VENT [18HQ]
- TRIM VALVE CKPT [11HK]
- TRIM VALVE FWD CAB [12HK]
- TRIM VALVE AFT CAB [13HK]
- TRIM AIR PRESS VALVE [14HK]
- P1 CHECK VALVE DOWNSTREAM [15HM]
- P2 CHECK VALVE DOWNSTREAM [16HM]
- Individual Air Distribution
- Individual Air Outlets
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| AMM 21-21-41-000-001 | Removal of the Recirculation Filter |
| AMM 21-21-41-400-001 | Installation of the Recirculation Filter |
| AMM 21-21-42-000-001 | Removal of the Recirculation Check Valve |
| AMM 21-21-42-400-001 | Installation of the Recirculation Check Valve |
| AMM 21-21-51-000-001 | Removal of the Cabin Recirculation Fans |
| AMM 21-21-51-400-001 | Installation of the Cabin Recirculation Fans |
| AMM 21-26-51-000-001 | Removal of the Extract and Blower Fans |
| AMM 21-26-51-400-001 | Installation of the Extract and Blower Fans |
| AMM 21-52-43-000-001 | Removal of the Pack Downstream Check-Valves |
| AMM 21-52-43-400-001 | Installation of the Pack Downstream Check-Valves |
| AMM 21-63-51-000-001 | Removal of the Trim Air Valve |
| AMM 21-63-51-400-001 | Installation of the Trim Air Valve |
| AMM 21-63-52-000-001 | Removal of the Pressure Regulating Valve |
| AMM 21-63-52-400-001 | Installation of the Pressure Regulating Valve |
| AMM 25-54-12-000-001 | Removal of the Forward Cargo-Compartment Partition FR34 or FR35.5 |
Subtask 21-00-00-210-050-A
A. Do an acoustical check to find if the noise comes from:
4. Fault Isolation- The cabin and cockpit at the same time
- The cockpit or
- The cabin.
Subtask 21-00-00-810-057-A
A. If you hear the noise in the cabin and in the cockpit at the same time:
(1) Do a check with RECIRC FANS ON.
(a) Do an acoustical and a vibration check in the cabin.
(c) Use ear protection to prevent damage to your ears.
(d) Remove the access panels AMM 25-54-12-000-001 in the FWD Cargo Compartment.
Subtask 21-00-00-810-055-A (1) Do a check with RECIRC FANS ON.
(a) Do an acoustical and a vibration check in the cabin.
- Open one of the fan circuit breakers and then the other.
(c) Use ear protection to prevent damage to your ears.
(d) Remove the access panels AMM 25-54-12-000-001 in the FWD Cargo Compartment.
- Make sure that the RECIRC FILTER CARTRIDGE 1 [4012HM] and RECIRC FILTER CARTRIDGE 2 [4013HM] are in a good condition.
- Put your hands at each fan and make sure that the fans operate constantly.
B. If the noise comes from the cockpit:
(1) Make sure, with CAB FANS ON, that air blows out of the air outlets.
(c) Make sure that the air outlet grids and filter mats are in good condition. Repair or replace damaged parts.
(d) Remove the lining and the equipment to make sure that the downstream supply ducts are not damaged.
(3) If the noise continues, do a check of RECIRC FILTER CARTRIDGE 1 [4012HM] and RECIRC FILTER CARTRIDGE 2 [4013HM] , and replace if necessary AMM 21-21-41-000-001 and AMM 21-21-41-400-001.
(4) If the noise continues, make sure that RECIRC CHECK VALVE 1 [4020HM] and RECIRC CHECK VALVE 2 [4021HM] are in a good condition and replace if necessary AMM 21-21-42-000-001 and AMM 21-21-42-400-001.
(5) If the noise continues and apparently comes from below the cockpit floor:
again do the checks steps (1) thru (5) with PACKS ON and APU ON.
(8) If the noise continues: make sure that the TRIM VALVE FWD CAB [12HK] is in good condition and replace if necessary AMM 21-63-51-000-001 and AMM 21-63-51-400-001.
(9) If the noise continues: make sure that the TRIM VALVE AFT CAB [13HK] is in good condition and replace if necessary AMM 21-63-51-000-001 and AMM 21-63-51-400-001.
(10) If the noise continues: make sure that the TRIM AIR PRESS VALVE [14HK] is in good condition and replace if necessary AMM 21-63-52-000-001 and AMM 21-63-52-400-001.
(11) If the noise continues:
Subtask 21-00-00-810-056-A (1) Make sure, with CAB FANS ON, that air blows out of the air outlets.
NOTE: Do not operate the packs for this step.
(a) Put your hand at the air outlets and make sure that you feel a continuous airflow from the opened - Ceiling outlets,
- Lateral outlets,
- Individual air outlets.
(c) Make sure that the air outlet grids and filter mats are in good condition. Repair or replace damaged parts.
(d) Remove the lining and the equipment to make sure that the downstream supply ducts are not damaged.
NOTE: Compressed or broken ducts can cause noise.
(2) If the noise continues, do a check of RECIRC FAN 2 [14HG] and RECIRC FAN 1 [15HG] , and replace if necessary , AMM 21-21-51-000-001 and AMM 21-21-51-400-001. (3) If the noise continues, do a check of RECIRC FILTER CARTRIDGE 1 [4012HM] and RECIRC FILTER CARTRIDGE 2 [4013HM] , and replace if necessary AMM 21-21-41-000-001 and AMM 21-21-41-400-001.
(4) If the noise continues, make sure that RECIRC CHECK VALVE 1 [4020HM] and RECIRC CHECK VALVE 2 [4021HM] are in a good condition and replace if necessary AMM 21-21-42-000-001 and AMM 21-21-42-400-001.
(5) If the noise continues and apparently comes from below the cockpit floor:
- Do a visual inspection of the avionics ventilation ducting to make sure that there is no damaged duct.
- Do a check of the FAN-BLOWER, AVNCS VENT [20HQ] , and replace if necessary AMM 21-26-51-000-001 and AMM 21-26-51-400-001.
- Do a check of the FAN-EXTRACT, AVNCS VENT [18HQ] , and replace if necessary AMM 21-26-51-000-001 and AMM 21-26-51-400-001.
again do the checks steps (1) thru (5) with PACKS ON and APU ON.
NOTE: On the ground, in climates where the atmosphere is cold and humid (mist/fog), small ice particles can occur in the ventilation ducting. This can cause noise. The noise stops in flight or when the packs are set to OFF on ground.
NOTE: With PACKS ON an BLEED AIR ON, it is possible that the trim air valve is in operation. This can cause unstable noise.
(7) If the noise continues: make sure that the TRIM VALVE CKPT [11HK] is in good condition and replace if necessary AMM 21-63-51-000-001 and AMM 21-63-51-400-001. (8) If the noise continues: make sure that the TRIM VALVE FWD CAB [12HK] is in good condition and replace if necessary AMM 21-63-51-000-001 and AMM 21-63-51-400-001.
(9) If the noise continues: make sure that the TRIM VALVE AFT CAB [13HK] is in good condition and replace if necessary AMM 21-63-51-000-001 and AMM 21-63-51-400-001.
(10) If the noise continues: make sure that the TRIM AIR PRESS VALVE [14HK] is in good condition and replace if necessary AMM 21-63-52-000-001 and AMM 21-63-52-400-001.
(11) If the noise continues:
- Make sure that the Pack Outlet Duct is in good condition.
- Do a visual inspection of the flappers of P1 CHECK VALVE DOWNSTREAM [15HM] and P2 CHECK VALVE DOWNSTREAM [16HM] , and replace the check valves if necessary AMM 21-52-43-000-001 and AMM 21-52-43-400-001.
C. If the noise comes from the cabin:
(1) Do a check of the Air Distribution Ducting:
(a) Do a check of the Individual Air Distribution . When the check valves are in the closed position, a leak can cause noise.
(b) Do a check of the Individual Air Outlets .
(1) Do a check of the Air Distribution Ducting:
(a) Do a check of the Individual Air Distribution . When the check valves are in the closed position, a leak can cause noise.
(b) Do a check of the Individual Air Outlets .
- Make sure that the lining parts are in the correct position in relation to the Cabin Air Outlets.
- Make sure that the ducts are not disconnected and that there is no leakage. Insulation blankets that move because of leakage of ducts, or open duct ends, can also cause noise.