TASK 49-61-10-002-021
 2.  Serial Number Identification Unit Removal (Fig. 201)_________________________________________
 A.  Access
 (1)  
Location Zones
 221 Control Cabin - Left
 222 Control Cabin - Right
 310 Fuselage - Station 2360 to Station 2792

 (2)  
Access Panels
 317AL APU Access Door - Left
 318AR APU Access Door - Right

 B.  
Prepare for the Removal

 S 862-022
 (1)  
Make sure the APU control switch on the P5 overhead panel is OFF and attach a DO-NOT-OPERATE tag.

 S 862-023

 (2)  
Open these circuit breakers and attach DO-NOT-CLOSE tags:

 (a)  
P6-2 Main Power Distribution Panel
 1) 6K18, APU ALTN CONT

 (b)  
P83 Aft APU Equipment Control and Circuit Breaker Panel 1) APU PRIME CONT

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 ALL  ú ú 02 Page 201 ú Jun 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 S 012-034
 (3)  
Open the left APU access door, 317AL, and right APU access door, 318AR:

 (a)  
While you hold the two APU access doors in the closed position, open the six latches on the right access door.

 NOTE: The left access door will open fully and the right
____ access door will drop approximately one inch (2.5 cm) from the fuselage frame when the last latch is opened.
 NOTE: A lanyard is attached to the aft end of the right access
____ door to hold the access door to the APU compartment bulkhead.
 CAUTION: BE CAREFUL NOT TO MOVE THE TWO APU ACCESS DOORS TO THE
_______ OUTBOARD SIDE FROM THE FULL OPEN POSITION. THE FULL OPEN POSITION IS WHERE THE APU ACCESS DOOR IS DOWN AND THE TWO HOLD-OPEN RODS ARE CONNECTED TO THE TWO BRACKETS ON THE APU COMPARTMENT BULKHEAD. DAMAGE TO THE ELEVATOR CONTROL SURFACES CAN OCCUR.
 (b)  
Open the left access door to the fully open position and remove the two hold-open rods from the two clips.

 (c)  
Remove the two quick-release pins from the two brackets on the left APU compartment bulkhead.

 (d)  
Connect the two hold-open rods from the left access door to the two brackets and install the two quick-release pins.

 (e)  
Push the right access door up and remove the lanyard from the pin on the aft APU compartment bulkhead.

 (f)  
Open the right access door to the fully open position and remove the two hold-open rods from the two clips.

 (g)  
Remove the two quick-release pins from the two brackets on the right APU compartment bulkhead.

 (h)  
Connect the two hold-open rods from the right access door to the two brackets and install the two quick-release pins.

 C.
Serial Number Identification Unit Removal

 S 022-025
 CAUTION: MAKE SURE YOU DO NOT HIT THE AIR INLET PLENUM WITH YOUR HANDS
_______ OR YOUR TOOLS. DAMAGE TO THE AIR INLET PLENUM CAN OCCUR.
 (1)  
Do these steps to remove the serial number identification unit (5):

 (a)  
Disconnect the electrical connector D95012 (P12) (3) from the serial number identification unit (5).

 (b)  
Remove the two bolts (2) and two washers (1) that attach the ground strap (4) and serial number identification unit (5) to the air inlet plenum.

 (c)  
Remove the serial number identification unit (5).

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 ALL  ú ú 02 Page 202 ú Jun 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A

747-400
MAINTENANCE MANUAL

SEE A
FWD
SEE B
APU COMPARTMENT
A  FWD
1.  
WASHER (2 LOCATIONS)

2.  
BOLT (2 LOCATIONS)

AIR INLET PLENUM 3. ELECTRICAL
CONNECTOR, D95012 (P12)
5.  SERIAL NUMBER
IDENTIFICATION
UNIT

SEE C
FWD