TURN AND BANK INDICATION - DESCRIPTION AND OPERATION

1.  General
A.  Bank indication is displayed on the pilot’s and copilot’s attitude director indicator (ADI) and is in the form of a ball-type inclinometer (Fig. 1).
B.  Fluid in the inclinometer tube damps out any vibration between ball and tube, thereby ensuring a smooth movement of the ball. With the airplane level, the ball should be centered between the two indices shown on Fig. 1. If the ball is not centered, the adjustment clamp may be loosened and the indicator rotated until the ball has centered.
C.  A rate-of-turn pointer is displayed on the pilot’s and copilot’s attitude direction indicator. The rate-of-turn pointer is biased out of view.

K78034
5C8  Attitude Director Indicator 
Oct 20/83  Figure 1  34-23-0 
Page 1 

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 - Unpublished Work - See title page for details.

TURN AND BANK INDICATION - MAINTENANCE PRACTICES
1. General
A.  During attitude director indicator installation it is extremely important that the ball in the turn and bank inclinometer is centered when the airplane is level laterally.
B.  To preclude improper (unlevel) installation, accomplish the following prior to indicator clamp screw tightening:
(1)  
Level the airplane laterally using a spirit level across the captain's and copilot's inboard seat tracks.

(2)  
Locate the indicator so that the ball is centered; then tighten the clamp adjustment screw.

NOTE:  The spirit level bubble and the turn and bank indicator ball move in opposite directions during airplane leveling.
C.  The following alternate procedure may be used when it is known that the indicator being changed is defective and there are no flight reports on the second indicator on the opposite panel:
(1)  Locate the replacement indicator so that the ball is positioned in the same position as the ball in the indicator on the opposite panel.
501 
Aug 1/74  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  34-23-0 Page 201 

MAGNETIC STANDBY COMPASS - DESCRIPTION AND OPERATION
1.  General
A.  The magnetic standby compass is installed forward of the forward overhead panel. The standby compass is a self-contained unit and indicates the magnetic heading of the airplane. It is used primarily in cases of emergency when all other compass systems fail. For a pictorial view of the magnetic standby compass, see figure 1.
2.  Magnetic Standby Compass
A.  The standby compass is a highly sensitive instrument of liquid-filled design. The card assembly, which indicates magnetic direction, is illuminated by a bulb located at the top of the compass.
B.  The standby compass for its operation depends upon the effect of the earth's magnetic field. The card assembly is so suspended that the magnets which are attached to the card assembly are free to align themselves with the horizontal component of the earth's magnetic field. The magnetic heading of the airplane is read from the card assembly against the lubber line.
C.  At the bottom of the standby compass under a cover plate are two compensators decaled N-S and E-W. The purpose of the compensators is to compensate for magnetic disturbances in the area of standby compass.
D.  The correction card holder mounted below the standby compass holds the correction card which is prepared during the compass swing. The compass card lists the heading for the pilot to steer to maintain a desired heading.
E.  The standby compass (figure 1) is shown in the swing-down position for normal operation. For better visibility, the pilot may place the standby compass in the stow position. To stow the standby compass, fold the card holder forward under the standby compass and then push the compass assembly aft and up against the airplane frame.
500 
Aug 15/68  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  34-24-0 Page 1 

H24443
Standby Compass Location Diagram  500 
34-24-0  Figure 1  Nov 15/72 
Page 2 
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

MAGNETIC STANDBY COMPASS - MAINTENANCE PRACTICES
1. General
A.  The maintenance practices included in this section are general maintenance instructions that do not definitely fall within a specific category. Any maintenance practices that fall within a specific category will be provided in the applicable page blocks.
B.  Standby compass maintenance practices consist of compass swinging procedures (Ref 34-24-11, Maintenance Practices or Ref 34-24-11, Magnetic Standby Compass -Maintenance Practices (Compass Swing)) and demagnetization. Demagnetization of certain parts of the airplane may be necessary after it has been exposed to heavy static or has been struck by lightning. Evidence of magnetization may show up in the magnetic standby compass, in the gyro compass system, or in both in the form of excessive errors in the compass readouts. When necessary, a handheld compass such as the standby compass may be used to detect the presence of any unduly large magnetic fields in the airplane structure.
　
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