(b)  
Set the FMC switch on the P2-4 panel to the R position.

 CAUTION: THE SWITCHES ON THE MSU MUST FIRST BE PULLED AND THEN
_______ TURNED TO LEAVE THE NAV POSITION. IN THE NAV POSITION, IF YOU TRY TO TURN THESE SWITCHES BEFORE YOU PULL THEM, YOU CAN DAMAGE THE MSU.
 (c)  Set the switches on the IRS mode select unit (MSU) to the ALIGN position from the OFF position.
 NOTE: You can find the MSU on the P5 overhead panel.
____ A high latitude alignment takes 17 minutes.
 Note the present time for later use in this procedure.
 (d)  
Press the NEXT PAGE key to show the POS REF page.

 (e)  
Push the MENU key on the right CDU.
 1) Make sure that you can see the MENU page.

 (f)  
Push the line select key adjacent to the <FMC prompt.
 1) Make sure that you can see the IDENT page.

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MAINTENANCE MANUAL

 (g) (h) (i)  Push the line select key adjacent to the POS INIT> prompt. 1) Make sure that you can see the POS INIT page.Press the CLR key to erase the scratch pad.Record the latitude and the longitude data into the scratch pad line.
 NOTE:____ Do not put a space between the latitude and the longitude. (Example: N1234.5W01234.5)
 (j)  Push the line select key adjacent to the SET IRS POS> prompt.
 NOTE:____ The VERIFY IRS POSITION or ENTER IRS POSITION message may appear in the scratch pad. If this happens, check the position on the SET IRS POS line to be sure it is correct. If correct, reenter the same position.
 (k) (l)  Press the NEXT PAGE key to show the POS REF page. 1) Make sure that you can see the position you just entered on the IRS L, C and R lines.After 17 minutes, set the switches on the MSU to the NAV position from the ALIGN position. 1) Make sure that the IRS ALIGN MODE L, C and R messages are removed from the upper EICAS display.
 NOTE:____ The IRS is now aligned and in the navigation mode.

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 INERTIAL REFERENCE SYSTEM - ADJUSTMENT/TEST
___________________________________________
 1.  General_______
 A.  This procedure has two tasks. The first task is an operational test of the inertial reference system (IRS). The second task is a system test of the IRS.
 TASK 34-21-00-715-060
 2.  Operational Test - Inertial Reference System____________________________________________
 A.  General
 (1) This task contains the EIU Interface Test and the IRS Alignment.
 B.  References
 (1)  
AMM 24-22-00/201, Manual Control

 (2)  
AMM 34-21-00/201, Inertial Reference System

 C.  Access
 (1)  
Location Zones
 117 Electrical and Electronics Compartement
 221 Control Cabin, LH
 222 Control Cabin, RH

 (2)  
Access Panel
 117AL E/E Bay Access Door

 D.  Prepare for the Operational Test
 S 865-002
 (1)  
Supply electrical power (AMM 24-22-00/201).

 S 865-003

 (2)  
Open these circuit breakers:

 (a)  P6 Main Power Distribution Panel
 1) 6D7, IRS AC LEFT
 2) 6D8, IRS AC CENTER
 3) 6D9, IRS AC RIGHT
 4) 6E7, IRS DC LEFT

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