Cold Weather Maintenance - Auxiliary Power Unit

TASK 12-31-49-660-001-A
Cold Weather Maintenance - Auxiliary Power Unit

1. Reason for the Job
This procedure gives the cold weather maintenance practices for the Auxiliary Power Unit (APU) when the aircraft is in a cold soak condition.
2. Job Set-up Information
A. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
315AL

B. Referenced Information

REFERENCE	DESIGNATION
TASK 12-31-24-660-001-A	Cold Weather Maintenance - Electrical Power
TASK 12-33-21-618-001-A	Pre-conditioning through the LP Ground Connection (Aircraft Electrical Power Available)
TASK 12-33-21-618-001-A-01	Pre-conditioning through the HP Ground Connection
TASK 12-33-21-618-001-A-02	Pre-conditioning with the APU
TASK 12-33-21-618-001-A-03	Pre-conditioning through the LP Ground Connection (Aircraft Electrical Power Not Available)
TASK 49-00-00-860-005-A	APU Start by External Power
TASK 49-00-00-860-005-A-01	APU Start by Batteries
TASK 49-00-00-860-005-A	APU Start by External Power
TASK 49-00-00-860-005-A-01	APU Start by Batteries
TASK 49-00-00-860-006-A	APU Shutdown by External Power
TASK 49-00-00-860-006-A-01	APU Shutdown by Batteries
TASK 49-00-00-860-008-A	APU Start by External Power
TASK 49-00-00-860-008-A-01	APU Start by Batteries
TASK 49-00-00-860-008-A	APU Start by External Power
TASK 49-00-00-860-008-A-01	APU Start by Batteries
TASK 49-00-00-860-009-A	APU Shutdown by External Power (131-9(A))
TASK 49-00-00-860-009-A-01	APU Shutdown by Batteries (131-9(A))
TASK 49-61-34-000-002-A	Removal of the Electronic Control Box (ECB) (APS 3200)
TASK 49-61-34-000-003-A	Removal of the Electronic Control Box (ECB) (131-9(A))
TASK 49-61-34-400-002-A	Installation of the Electronic Control Box (ECB) (APS 3200)
TASK 49-61-34-400-003-A	Installation of the Electronic Control Box (ECB) (131-9(A))
TASK 49-90-00-600-005-A	Oil Change (Drain Procedure) (APS 3200)
TASK 49-90-00-600-005-A-01	Oil Change (Top-Off Procedure) (APS 3200)
TASK 49-90-00-600-005-A-02	Brand/Type Oil Change (Flush Procedure) (APS 3200)
TASK 49-90-00-600-008-A	Oil Change (Drain Procedure) (131-9(A))
TASK 49-90-00-600-008-A-01	Oil Change (Top-Off Procedure) (131-9(A))
TASK 49-90-00-600-008-A-02	Brand/Type Oil Change (Flush Procedure) (131-(A))

3. Job Set-up
Subtask 12-31-49-860-050-A

A. Not Applicable

4. Procedure
Subtask 12-31-49-660-057-A

A. APU Air Intake

NOTE: Ice and/or snow can form in the APU air intake and difficult the APU starting.

(1) If you can see snow or signs of ice on the APU air intake, do the de-icing of the aircraft before APU start.
(2) Wait 5 minutes before second start if first start carried out before removing snow & ice. snow & ice.

Subtask 12-31-49-660-055-A

B. Electronic Control Box 59KD (ECB 59KD)
(1) If the Outside Air Temperature (OAT) is/will be lower than -40 deg.C (-40.00 deg.F) and the aircraft is not pre-conditioned (heated) alternatively:

through the Low Pressure (LP) ground connection (Ref. AMM TASK 12-33-21-618-001),
the High Pressure (HP) ground connection (Ref. AMM TASK 12-33-21-618-001), or
with the APU (Ref. AMM TASK 12-33-21-618-001).

(a) Remove the Electronic Control Box (ECB) 59KD from the aircraft

If a GTCP 36-300 APU is installed
(Ref. AMM D/O 49-61-34-00)
If an APS 3200 APU is installed
(Ref. AMM TASK 49-61-34-000-002)
If a 131-9(A) APU is installed
(Ref. AMM TASK 49-61-34-000-003)

(b) Keep the ECB 59KD in a dry storage at a temperature of between 15 deg.C (59.00 deg.F) and 35 deg.C (95.00 deg.F).

Subtask 12-31-49-660-056-A

CAUTION: USE ONLY APPROVED TYPES/BRANDS OF LUBRICANTS.

C. Auxiliary Power Unit (APU)

NOTE: Do not mix oils of different brands or types.

NOTE: It is recommended to use type 1 for APU operation in cold weather conditions.

(1) Oil type.
(a) If necessary, do an oil change to type 1.

If a GTCP 36-300 APU is installed
(Ref. AMM D/O 49-90-00-60).
If an APS 3200 APU is installed
(Ref. AMM TASK 49-90-00-600-005).
If a 131-9(A) APU is installed
(Ref. AMM TASK 49-90-00-600-008).

(2) If no external power is available (Ref. AMM TASK 12-31-24-660-001).

NOTE: These values are only applicable if all the access doors are closed.

(a) It is recommended to start the APU every three hours and operate it for one hour if the Outside Air Temperature (OAT) is lower than -30 deg.C (-22.00 deg.F).

If a GTCP 36-300 APU is installed
(Ref. AMM TASK 49-00-00-860-003)
If an APS 3200 APU is installed
(Ref. AMM TASK 49-00-00-860-005) (Ref. AMM TASK 49-00-00-860-006)
If a 131-9(A) APU is installed
(Ref. AMM TASK 49-00-00-860-008) (Ref. AMM TASK 49-00-00-860-009)

Subtask 12-31-49-660-054-A

D. APU Starting after a Cold Soak Condition
(1) ECB 59KD.

NOTE: Do not operate the ECB 59KD for more than 30 minutes at -40 deg.C (-40.00 deg.F) or lower.

(a) If the ECB was on the aircraft during the cold soak, make sure that the temperature of the ECB is higher than -40 deg.C (-40.00 deg.F).
If the temperature of the ECB is lower than -40 deg.C (-40.00 deg.F), use a pre-conditioning procedure to increase the temperature of the ECB to a minimum of -40 deg.C (-40.00 deg.F) (Ref. AMM TASK 12-33-21-618-001) or (Ref. AMM TASK 12-33-21-618-001):

through the Low Pressure (LP) ground connection (Ref. AMM TASK 12-33-21-618-001),
the High Pressure (HP) ground connection (Ref. AMM TASK 12-33-21-618-001).

(b) If the ECB was removed from the aircraft and kept at a temperature of between 15 deg.C (59.00 deg.F) and 35 deg.C (95.00 deg.F), install the ECB

If a GTCP 36-300 APU is installed
(Ref. AMM D/O 49-61-34-40)
If an APS 3200 APU is installed
(Ref. AMM TASK 49-61-34-400-002)
If a 131-9(A) APU is installed
(Ref. AMM TASK 49-61-34-400-003)

(2) Electrical Power.
(a) For the cold weather maintenance - electrical power (Ref. AMM TASK 12-31-24-660-001).
(3) Start and operate the APU If a GTCP 36-300 APU is installed.
(a) Open the APU access door 315AL.
(b) If oil heater operates:

NOTE: If oil type I is used, it is not necessary to increase the temperature of the APU, but it is recommended.

Blow hot air with a HOT AIR BLOWER MAX OPERATING 55 deg.C (131 deg.F) on the APU to increase the temperature of the APU oil to a minimum of -40 deg.C (-40.00 deg.F).
Remove the HOT AIR BLOWER MAX OPERATING 55 deg.C (131 deg F).
Close the APU access door 315AL.

If oil type I is used, blow hot air with a HOT AIR BLOWER MAX OPERATING 55 deg. C (131 deg.F) on the APU to increase the temperature of the APU oil to a minimum of -40 deg.C (-40.00 deg.F).
If oil type II is used, blow hot air with a HOT AIR BLOWER MAX OPERATING 55 deg.C (131 deg.F) on the APU to increase the temperature of the APU oil to a minimum of -29 deg.C (-20.2 deg.F).
Remove the HOT AIR BLOWER MAX OPERATING 55 deg.C (131 deg.F).
Close the APU access door 315AL.

(d) Start and operate the APU (Ref. AMM TASK 49-00-00-860-003)
(4) Start and operate the APU If APS 3200 APU is installed.
(a) Open the APU access door 315AL.
(b) Blow hot air with a HOT AIR BLOWER MAX OPERATING 55 deg.C (131 deg.F) on the APU to increase the temperature of the APU oil to a minimum of -40 deg.C (-40.00 deg.F).
(c) Remove the HOT AIR BLOWER MAX OPERATING 55 deg.C (131 deg.F).
(d) Close the APU access door 315AL.
(e) Start and operate the APU (Ref. AMM TASK 49-00-00-860-005) (Ref. AMM TASK 49-00-00-860-005)
(5) Start and operate the APU If 131-9(A) APU is installed.
(a) Open the APU access door 315AL.

NOTE: If oil type I is used, it is not necessary to increase the temperature of the APU but it is recommended.

(b) Blow hot air with a HOT AIR BLOWER MAX OPERATING 55 deg.C (131 deg.F) on the APU to increase the temperature of the APU oil to a minimum of -40 deg.C (-40.00 deg.F).
(c) Remove the HOT AIR BLOWER MAX OPERATING 55 deg.C (131 deg.F).
(d) Close the APU access door 315AL.
(e) Start and operate the APU (Ref. AMM TASK 49-00-00-860-008) (Ref. AMM TASK 49-00-00-860-008)

Subtask 12-31-49-660-053-A

E. Turn-Around Time
For turn-around in cold weather conditions, when it is not pratical to remove equipment, it is recommended to keep the APU in operation. In this configuration :

the temperature in the cabin will not decrease,
no specific cold weather maintenance practices are necessary for the APU system.

[Rev.10 from 2021] 2026.04.01 04:22:21 UTC