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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL

 NOTE: Ferromagnetic parts installed near the standby compass can cause
____ compass heading errors. Make sure no ferromagnetic parts are near the captain's and the first officer's window frames. If found, replace the parts with non-magnetic, corrosion-resistant steel (CRES) parts.
 S 582-003
 (1)  Tow the airplane to the compass swing area (AMM 9-11-00/201).
 NOTE: The compass swing area must be a level area with a smooth
____ surface. It must be sufficiently strong to hold the weight of the airplane. The area must be large enough to tow or taxi the airplane. Make sure all vehicles other than the tow vehicle are not less than 250 feet from the airplane.
 The horizontal component of the earth's magnetic field must be constant (|1 degree) in the test area. Measure the horizontal component if magnetic material (such as a new building) is less than 600 feet from the compass rose. Do not use the compass rose if the horizontal component is not constant (|1 degree).
 S 862-004
 (2)  
Supply the electrical power (AMM 24-22-00/201).

 S 862-005

 (3)  
Energize all of the electronic equipment, radios, and control cabin lighting for the usual conditions that occur in flight.

 S 862-006

 (4)  
Set the mode selector on the EFIS control panels to VOR (AMM 31-61-00/501) .

 S 862-038

 (5)  
Set the HDG switch above the upper EICAS display to MAG.

 (6)  
Align the IRS to the NAV mode (AMM 34-21-00/201).

 S 862-007
 S 862-008
 CAUTION:_______USE TOOLS THAT ARE NOT MAGNETIC. MAGNETIC TOOLS CAN CAUSE COMPASS DIFFERENCES.
 (7)  Make sure that the N-S and E-W adjustment screws on the standby compass are at neutral.
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 S 862-009
 (8)  
Make sure that one navigation display (ND) shows a magnetic heading that is less than one degree from the other ND.

 S 752-010

 (9)  
Make sure all vehicles but the tow truck are not less than 250 feet from the airplane .

 E. Standby Compass Adjustment
 NOTE: The steps that follow are for the four point calibration swing:
____ S 582-011
 (1)  
Turn the airplane to a direction where the captain's ND shows a magnetic heading (MH)n that is less than 2 degrees from magnetic north.

 S 972-012

 (2)  
Make a record of the magnetic heading (MH)n and the standby compass heading (CH)n.

 S 972-013

 (3)
Calculate and make a record of the north heading deviation (Dn) as

 follows:
 Dn = (MH)n - (CH)n

 S 582-014
 (4)  
Turn the airplane to a direction that is less than 2 degrees of an east magnetic heading (MH)e.

 S 972-015

 (5)  
Make a record of the magnetic heading (MH)e and the compass heading (CH)e.

 S 972-016

 (6)  
Calculate and make a record of the east heading deviation (De) as follows:

 De = (MH)e - (CH)e
 S 582-017
 (7)  
Turn the airplane to a direction that is less than 2 degrees of a south magnetic heading (MH)s.

 S 972-018

 (8)  
Make a record of the magnetic heading (MH)s and the compass heading (CH)s.

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
　
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