DOC AIRBUS | AMM A320FCold Weather Maintenance - Indicating/Recording systems and Navigation
TASK 12-31-31-660-001-A
Cold Weather Maintenance - Indicating/Recording systems and Navigation
This procedure gives the cold weather maintenance practices for the indicating/recording and navigation systems.
2. Job Set-up Information
A. Work Zones and Access Panels
B. Referenced Information
3. Job Set-up
Subtask 12-31-31-941-050-A
Subtask 12-31-31-660-050-A
[Rev.10 from 2021]
2026.04.01 04:22:16 UTC
Cold Weather Maintenance - Indicating/Recording systems and Navigation
ZONE: 120
1. Reason for the JobThis procedure gives the cold weather maintenance practices for the indicating/recording and navigation systems.
2. Job Set-up Information
A. Work Zones and Access Panels
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 120 | AVIONICS COMPARTMENT |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 12-31-21-660-001-A | Cold Weather Maintenance - Air Conditioning |
Subtask 12-31-31-941-050-A
A. Not Applicable
4. ProcedureSubtask 12-31-31-660-050-A
A. General.
(1) When the Outside Air Temperature (OAT) is very low, cold (temperature lower than -15 deg.C (5.00 deg.F)) in the avionics compartment can cause incorrect operation of the computers.
Subtask 12-31-31-660-051-A (1) When the Outside Air Temperature (OAT) is very low, cold (temperature lower than -15 deg.C (5.00 deg.F)) in the avionics compartment can cause incorrect operation of the computers.
NOTE: This is only due to the cold weather conditions and not to a technical malfunction.
B. Recommendations.
(1) Make sure that the computers are at a temperature equal to or higher than -15 deg.C (5.00 deg.F) for correct operation.
It is recommended to use the pre-conditioning procedure to increase the temperature in the avionics compartment (Ref. AMM TASK 12-31-21-660-001).
(b) Energization of the computers
If the temperature is higher than -40 deg.C (-40.00 deg.F), you can energize the computers to increase the temperature to -15 deg.C (5.00 deg.F). The time necessary to increase the temperature will change with the OAT, the humidity and the time since the avionics compartment ventilation stopped.
Subtask 12-31-31-660-052-A ** ON A/C NOT FOR ALL (1) Make sure that the computers are at a temperature equal to or higher than -15 deg.C (5.00 deg.F) for correct operation.
NOTE: If you energize the computers at very low temperatures the following can occur. If the temperature is :
(a) Preconditioning - equal to or lower than -40 deg.C (-40.00 deg.F), you can cause permanent damage to the computers.
- between -40 deg.C (-40.00 deg.F) and -15 deg.C (5.00 deg.F), the computers can operate but normal operation can stop momentarily.
- equal to or higher than -15 deg.C (5.00 deg.F), the computers operate normally.
It is recommended to use the pre-conditioning procedure to increase the temperature in the avionics compartment (Ref. AMM TASK 12-31-21-660-001).
(b) Energization of the computers
If the temperature is higher than -40 deg.C (-40.00 deg.F), you can energize the computers to increase the temperature to -15 deg.C (5.00 deg.F). The time necessary to increase the temperature will change with the OAT, the humidity and the time since the avionics compartment ventilation stopped.
C. Recommendations for the Flight Data Interface and Management Unit (FDIMU) (10TV) with SPC (10TV4) installed
(1) Make sure that the FDIMU is at a temperature equal to or higher than -15 deg.C (5.00 deg.F) for correct operation.
(a) If the temperature in the avionics compartment is less than -15 deg.C (5.00 deg.F):
It is recommended to use the pre-conditioning procedure to increase the temperature in the avionics compartment (Ref. AMM TASK 12-31-21-660-001).
(c) Restart the FDIMU
When the temperature in the avionic compartment is equal to or higher than -15 deg.C (5.00 deg.F), on panel 121VU, open and close the circuit breaker 5TV to restart the FDIMU.
(1) Make sure that the FDIMU is at a temperature equal to or higher than -15 deg.C (5.00 deg.F) for correct operation.
(a) If the temperature in the avionics compartment is less than -15 deg.C (5.00 deg.F):
- The Smart PCMCIA Card (SPC) installed on the FDIMU can become unserviceable.
- The DMU FAIL LED on the front face of the FDIMU can come on.
- It is impossible to write ACMS data on the SPC flash memory.
It is recommended to use the pre-conditioning procedure to increase the temperature in the avionics compartment (Ref. AMM TASK 12-31-21-660-001).
(c) Restart the FDIMU
When the temperature in the avionic compartment is equal to or higher than -15 deg.C (5.00 deg.F), on panel 121VU, open and close the circuit breaker 5TV to restart the FDIMU.