APU Start by Batteries

TASK 49-00-00-860-008-A-01
APU Start by Batteries

WARNING: MAKE SURE THAT THE FWD AVIONICS ACCESS DOOR 811 IS OPEN WITH A WARNING PLACARD ATTACHED TO IT. THE WARNING NOTICE MUST TELL PERSONS NOT TO CLOSE THE DOOR. THIS PREVENTS ACCIDENTAL PRESSURIZATION OF THE AIRCRAFT.

WARNING: DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).

WARNING: WHILE THE APU OPERATES, DO NOT GO INTO THESE AREAS:

THE AREA BEHIND THE APU EXHAUST DUCT: 25m (82ft.) REARWARD OF THE DUCT, MORE THAN 3m (10ft.) ABOVE THE GROUND, AND THE WIDTH OF THE HORIZONTAL STABILIZER
THE AREA AROUND THE APU AIR-INTAKE: 2m (7ft) AROUND THE INTAKE
THE AREA OF THE OIL-COOLER OUTLET.

THERE IS A RISK OF INJURY IF YOU GO INTO THESE AREAS.

WARNING: DO NOT START THE APU WHEN THE AIRCRAFT IS IN THE HANGAR. WHEN THE APU OPERATES, THERE ARE RISKS OF INJURY FROM HIGH TEMPERATURES AND DANGEROUS FUMES (THAT CAN FILL THE HANGAR). MAKE SURE THAT PERSONS STAY AWAY FROM THE EXHAUST DUCT. THE EXHAUST DUCT IS DANGEROUS.

CAUTION: DO NOT START OR TRY TO START THE APU MORE THAN THREE TIMES, ONE AFTER THE OTHER. AFTER THE THIRD TIME, THERE MUST BE A MINIMUM OF ONE HOUR BEFORE YOU START OR TRY TO START THE APU AGAIN. THIS MAKES SURE THAT THE TEMPERATURE OF THE STARTER MOTOR DECREASES SUFFICIENTLY.

CAUTION: DO NOT START THE APU WITH ACCESS DOORS 315AL AND 316AR OPEN/REMOVED. THE APU FIRE EXTINGUISHER SYSTEM IS NOT SUFFICIENT TO EXTINGUISH A FIRE IF THE ACCESS DOORS 315AL AND 316AR ARE OPEN/REMOVED.

CAUTION: DO NOT TRY TO START THE APU AGAIN DURING A REFUEL/DEFUEL PROCEDURE AFTER AN AUTOMATIC SHUTDOWN OR FAILED APU START. IF YOU DO, THERE IS A RISK OF INJURY AND/OR DAMAGE.

CAUTION: OBEY THE SAFETY PRECAUTIONS.

ZONE: 210
ZONE: 310
FIN: 4005KM ** ON A/C NOT FOR ALL

1. Reason for the Job
Start and operate the APU to do maintenance tasks.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
210	CKPT,FWD COMPT BHD TO FLT COMPT BULKHEAD
310	FUSLG TAIL SECTION AFT OF AFT PRESS BHD
811

C. Referenced Information

REFERENCE	DESIGNATION
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 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 52-41-00-010-002-A	Open the Avionics Compartment Doors for Access
TASK 52-41-00-410-001-A	Close the APU Doors after Access

3. Job Set-up
Subtask 49-00-00-941-072-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) Make sure that the danger areas are clear of persons and/or equipment.

WARNING: WHILE THE APU OPERATES, DO NOT GO INTO THESE AREAS:

THE AREA BEHIND THE APU EXHAUST DUCT: 25m (82ft.) REARWARD OF THE DUCT, MORE THAN 3m (10ft.) ABOVE THE GROUND, AND THE WIDTH OF THE HORIZONTAL STABILIZER
THE AREA AROUND THE APU AIR-INTAKE: 2m (7ft) AROUND THE INTAKE
THE AREA OF THE OIL-COOLER OUTLET.

THERE IS A RISK OF INJURY IF YOU GO INTO THESE AREAS.

(2) Close the APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-410-001).
(3) If an emergency or a malfunction occurs during operation of the APU, do the emergency shutdown procedure immediately. You can start the emergency shutdown from:

The APU FIRE PUSH pushbutton switch on the panel 20VU.
The APU SHUT OFF pushbutton switch on the panel 108VU.

NOTE: Do the emergency shutdown immediately if fire, smoke, unusual noise, fuel or oil leakage occurs.

Subtask 49-00-00-860-120-A ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) Open the access door 811 (Ref. AMM TASK 52-41-00-010-002).
(2) Put the WARNING NOTICE(S) in position on the opened access door 811 which tells persons not to close the door.
(3) Remove the APU air intake and exhaust blanking plugs.
(4) On the ELEC section on the panel 35VU:

Push the BAT 1 and BAT 2 pushbutton switches in the auto position.
Make sure that both batteries are serviceable (the OFF and FAULT legends are off).

(5) Make sure that there is sufficient fuel in the A/C fuel system.
(6) On the AIR COND section of the panel 30VU:

Make sure that the APU BLEED pushbutton switch is in the off position (the ON and FAULT legends are off).
Make sure that the X BLEED selector switch is in the AUTO position.

Subtask 49-00-00-865-129-A ** ON A/C NOT FOR ALL

C. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	APU/FUEL/BLOW OFF/PUMP	2QC	B14
** ON A/C NOT FOR ALL
121VU	APU/FUEL/BLOW OFF/CTL	1QC	K39
** ON A/C NOT FOR ALL
121VU	APU/FIRE AND OVHT/DET/LOOP B	2WG	L44
121VU	APU/FIRE AND OVHT/DET/LOOP A	1WG	L43
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41
121VU	APU/FIRE/EXTIG/SQUIB/B	2WF	L39
121VU	APU/FIRE/EXTIG/SQUIB/A	1WF	L38
121VU	APU/FIRE/LP VALVE/NORM	4WF	M42
121VU	APU/FIRE/LP VALVE/STBY	3WF	M41
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

4. Procedure
Subtask 49-00-00-875-052-A ** ON A/C NOT FOR ALL

A. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/AUTO/EXTIG/GND/TEST	30WF	L40

Subtask 49-00-00-860-121-A ** ON A/C NOT FOR ALL

CAUTION: OBEY THE SAFETY PRECAUTIONS.

B. Start and Operate the APU

NOTE: When the aircraft supply is from the batteries, the test of the APU fire pushbutton-switch shows only the status of fire loop A but not the status of fire loop B.

NOTE: If you must start the APU with the batteries and the Outside Air Temperature (OAT) is 0 deg. C or less, we recommend that you:

Select the APU generator to supply aircraft electrical power
Start the L1 or L2 main fuel boost-pump.
You must do this immediately after the APU starts and the AVAIL light comes on. Thus, you will prevent APU AUTO S/D because of air in the APU fuel delivery-line.

NOTE: If the battery voltage is less than 25.5 V, a battery charging-cycle of approximately 20 minutes is necessary.

(1) Make sure that there is a minimum interval of three seconds between the time you set the APU MASTER SW pushbutton switch to ON and the time you set the APU START pushbutton switch to ON.
(2) On rear circuit-breaker panel 121VU, make sure that circuit breaker APU AUTO EXTIG GND TEST 30WF (L40) is open.

NOTE: This is necessary to prevent an unwanted automatic fire-extinguisher discharge during the test.

ACTION	RESULT
1.On overhead control and indicator panel 25VU, on the APU section: Push the APU MASTER SW pushbutton switch (14KD).	On overhead control and indicator panel 25VU, on the APU section: The ON legend of the APU MASTER SW pushbutton switch (14KD) comes on.
2.On overhead panel 20VU, on engine APU FIRE panel 1WD:	On overhead panel 20VU, on engine APU FIRE panel 1WD:
Push and hold the APU FIRE TEST pushbutton switch.	The APU FIRE light of the APU FIRE pushbutton switch comes on (half-light). The SQUIP/DISCH legend of the AGENT pushbutton switch comes on.
Release the APU FIRE TEST pushbutton switch.	The APU FIRE light and the SQUIP/DISCH legend go off.
3.On rear circuit-breaker panel 121VU: Close circuit breaker APU AUTO EXTIG GND TEST 30WF (L40).
4.On overhead control and indicator panel 25VU, on the APU section: Push the APU START pushbutton switch (2KA).	On overhead control and indicator panel 25VU, on the APU section: The ON legend of the APU START pushbutton switch (2KA) comes on. NOTE: The Electronic Control Box (ECB) (59KD) controls and monitors the APU start.
At the end of the APU start sequence:
	On overhead control and indicator panel 25VU, on the APU section: The ON legend of the APU START pushbutton switch (2KA) goes off. The AVAIL legend of the APU START pushbutton switch (2KA) comes on.

NOTE: If necessary, the APU generator can energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-861-002).

NOTE: If necessary, the APU can supply bleed air for the pre-conditioning (Ref. AMM TASK 12-33-21-618-001).

Subtask 49-00-00-860-121-B ** ON A/C NOT FOR ALL

CAUTION: OBEY THE SAFETY PRECAUTIONS.

B. Start and Operate the APU

NOTE: When the aircraft supply is from the batteries, the test of the APU fire pushbutton-switch shows only the status of fire loop A but not the status of fire loop B.

NOTE: If you must start the APU with the batteries and the Outside Air Temperature (OAT) is 0 deg. C or less, we recommend that you:

Select the APU generator to supply aircraft electrical power
Start the L1 or L2 main fuel boost-pump.
You must do this immediately after the APU starts and the AVAIL light comes on. Thus, you will prevent APU AUTO S/D because of air in the APU fuel delivery-line.

NOTE: If the battery voltage is less than 25.5 V, a battery charging-cycle of approximately 20 minutes is necessary.

(1) Make sure that there is a minimum interval of three seconds between the time you set the APU MASTER SW pushbutton switch to ON and the time you set the APU START pushbutton switch to ON.

ACTION	RESULT
1.On overhead control and indicator panel 25VU, on the APU section: Push the APU MASTER SW pushbutton switch (14KD).	On overhead control and indicator panel 25VU, on the APU section: The ON legend of the APU MASTER SW pushbutton switch (14KD) comes on.
2.On overhead panel 20VU, on engine APU FIRE panel 1WD:	On overhead panel 20VU, on engine APU FIRE panel 1WD:
Push and hold the APU FIRE TEST pushbutton switch.	The APU FIRE light of the APU FIRE pushbutton switch comes on (half-light). The SQUIP/DISCH legend of the AGENT pushbutton switch comes on.
Release the APU FIRE TEST pushbutton switch.	The APU FIRE light and the SQUIP/DISCH legend go off.
3.On overhead control and indicator panel 25VU, on the APU section: Push the APU START pushbutton switch (2KA).	On overhead control and indicator panel 25VU, on the APU section: The ON legend of the APU START pushbutton switch (2KA) comes on. NOTE: The Electronic Control Box (ECB) (59KD) controls and monitors the APU start.
At the end of the APU start sequence:
	On overhead control and indicator panel 25VU, on the APU section: The ON legend of the APU START pushbutton switch (2KA) goes off. The AVAIL legend of the APU START pushbutton switch (2KA) comes on.

NOTE: If necessary, the APU generator can energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-861-002).

NOTE: If necessary, the APU can supply bleed air for the pre-conditioning (Ref. AMM TASK 12-33-21-618-001).

[Rev.10 from 2021] 2026.04.01 01:25:42 UTC