*
The AUTOBRAKE and/or AUTOBRAKE SOL VALVE status
messages do not show
*
The ANTISKID advisory message does not show
*
Normal brake hydraulic system pressure is available (from
the normal brake hydraulic pressure switch)
*
ADIRU data is available.
If any of these conditions does not occur, the solenoid does not latch and the selector moves to the DISARM position. When the selector is in this position, the AUTOBRAKE advisory message shows.
If all these conditions occur, the selector stays in the selected position and one of these memo messages shows:
*
AUTOBRAKE 1
*
AUTOBRAKE 2
*
AUTOBRAKE 3
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ANTISKID/AUTOBRAKE SYSTEM -AUTOBRAKE FUNCTIONAL DESCRIPTION -LANDING ARMING LOGIC
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ANTISKID/AUTOBRAKE SYSTEM -AUTOBRAKE FUNCTIONAL DESCRIPTION -LANDING APPLICATION LOGIC
General
The autobrake function applies the brakes when these conditions occur:
*
Autobrake selector is in 1, 2, 3, 4, or MAX AUTO
*
Thrust levers are in the idle position
*
Ground mode (the two trucks are UNTILTED and the landing gear control lever is DOWN after a 0.1 second time delay)
*
Wheel spin-up (average wheel speed of the 4th, 5th, 6th, and 7th fastest wheels is more than 60 knots).
When all of the these conditions occur, the autobrake function energizes a relay in the BSCU. This supplies electrical power to the solenoid valve and connects the control valve command signal from the BSCU to the control valve.
The autobrake system then controls brake pressure to decrease the airplane speed at the specified deceleration rate.
The wheel spin-up signal latches when the average wheel speed is more than 60 knots for at least three seconds. This lets the autobrakes stay on after the speed decreases.
Training Information Point
During autobrake application, you can move the autobrake selector to change the rate of deceleration.
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ANTISKID/AUTOBRAKE SYSTEM -AUTOBRAKE FUNCTIONAL DESCRIPTION -LANDING APPLICATION LOGIC
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D633W101-BEJ Jan 05/2002
ANTISKID/AUTOBRAKE SYSTEM -AUTOBRAKE FUNCTIONAL DESCRIPTION -LANDING A/B DISARM LOGIC
General
Any of these conditions cause the autobrakes to disarm:
*
You turn the autobrake selector to the OFF or DISARM position
*
Left or right normal brake metered pressure is more than autobrake pressure
*
Left or right thrust lever is out of the idle position after the airplane is on the ground for more than 3 seconds (before 3 seconds causes brake release with no disarm)
*
Speedbrake lever moves to the DOWN position after ground speedbrake deployment (speedbrake lever more than the ARMED position)
*
Either AUTOBRAKE or AUTOBRAKE SOL VALVE status message shows
*
ANTISKID advisory message shows
*
ADIRU data is not available.
When disarmed, autobrake pressure stops and the autobrake selector latch solenoid releases the autobrake selector. The autobrake selector goes back to the DISARM position and the AUTOBRAKE advisory message shows.
The advisory message goes out of view when you move the autobrake selector to the OFF position.
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ANTISKID/AUTOBRAKE SYSTEM -AUTOBRAKE FUNCTIONAL DESCRIPTION -LANDING A/B DISARM LOGIC
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D633W101-BEJ Jan 05/2002
ANTISKID/AUTOBRAKE SYSTEM -AUTOBRAKE FUNCTIONAL DESCRIPTION -RTO ARM LOGIC
General
The autobrake selector latch solenoid holds the autobrake selector in the RTO position when the following arming conditions occur:
*
You move the autobrake selector to the RTO position
*
Ground mode (the two trucks are UNTILTED and the landing gear lever is DOWN)
*
No AUTOBRAKE and/or AUTOBRAKE SOL VALVE status message shows.
If any of these conditions do not occur, the solenoid does not latch and the autobrake selector moves to the OFF position.
The AUTOBRAKE RTO memo message shows when the autobrake selector is in the RTO position.
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