(b)  
Stop the display of the EICAS ANTISKID (status) and BRAKE LIMITER (status) messages for specified wheel locations

 (c)  
Stop the display of failure indications on the gear synoptic page for specified wheel locations

 (d)  
Will not change CMCS operation. CMCS operation related to the brake control system will stay the same for all wheel locations

 (e)  
Cause a CMCS fault message that shows the indication disable function is selected for specified wheel locations. The form of this CMCS fault message is FAULT INDICATION DEACTIVATED-WHEEL X (BSCU) (X is equal to 1 through 16 as applicable).

 (3)  
The BRAKE INDICATION DISABLE function can be selected for up to two wheel locations. The function is used in the procedure for brake deactivation. The function also permits continued use of the autobrake system when not all brakes are serviceable. The EICAS fault indication for a wheel location is stopped when the BRAKE INDICATION DISABLE switch is set to the related switch position. Normally, when the brakes at all wheel locations are serviceable, the switches are set to the NORM position.

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747-400
MAINTENANCE MANUAL

 J.  The brake system control unit can be tested using the central maintenance computer (CMC). A System BITE test on the brake control unit should be done after it has been installed. A malfunction of the brake-system-control unit is corrected by removing the unit and replacing it. Malfunctions are isolated by the BITE to individual circuit cards in the unit, and the data is stored in a nonvolatile memory. This data may be recalled during shop maintenance. No repairs or adjustments are done to the unit while it is installed in the airplane.
 3.  Transducer (Fig. 2)
__________
 A.  The wheel speed transducer measures the speed at which the wheel is turning. It contains only one moving part, a rotor which turns around a stator. The stator is attached to the axle and does not move. The rotor is attached to the hubcap of the wheel and turns at the same speed as the wheel.
 B.  The shaft of the transducer rotor has splines. A dog is installed on the shaft. The dog engages a flexible coupling that is attached to the hubcap. The transducer stator is attached to the transducer housing. The housing is installed in a transducer support which is attached to the inside of the axle with bolts. An electrical connector is installed in the back of the housing to connect the transducer through wire bundles to the brake control unit.
 C.  The stator contains 150 poles or lobes at an equal distance apart around the outside. It also has a permanent magnet and an induction coil. The rotor contains 150 poles at equal distances apart around the inside. The permanent magnet makes a magnetic field in the induction coil. When the rotor turns the poles on the rotor pass over the poles on the stator. This changes the magnetic field and causes an electrical pulse in the coil. The frequency of this pulse is in direct proportion to the speed at which the wheel turns.
 D.  Any malfunction of a transducer can be isolated to a wheel position using the CMC. Wheel speed transducers are removed and installed using procedures in this section. A test on these transducers is done as a part of the brake control system adjustment test. A shorter test may be done on one transducer after it is installed. No adjustments or repairs are done on transducers while they are installed in the airplane.
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A

747-400
MAINTENANCE MANUAL

SEE A
WHEEL
SEE B
TRANSDUCER DOG PADDED WASHER CUP COUPLING
BOLT
HUBCAP CLAMP
BOLT
A
Antiskid Transducer Location Figure 2 (Sheet 1)
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