Predictive Windshear Inputs

These are the inputs to the WXR R / T for predictive windshear (PWS):

Ground proximity warning system inhibit discrete

Auto throttle 1 switch pack throttle position discrete

Auto throttle 2 switch pack throttle position discrete

Radio altimeter 1 and 2.

The GPWS determines the priority for the aural warnings and cautions to the flight compartment. If the PWS CPU finds there is a windshear condition, the WXR R / T sends the warning or caution to the GPWS.

The auto throttle packs determine the position of the throttles. When the airplane is on the ground and either throttle is moved more than 53 degrees, the PWS comes on automatically.

The PWS CPU uses the radio altimeter input to turn the PWS on or off. When the airplane goes below 2300 feet radio altitude on approach, the PWS is turned on. When the altitude goes above 2300 feet during takeoff, the PWS is turned off.

Antenna Control

The WXR R / T gets attitude data for antenna stabilization from the ADIRUs. When the IRS select switch on the navigation / displays source select panel is in NORMAL or BOTH ON L, the R / T uses the left ADIRU for stabilization. You put the IRS select switch to BOTH ON R to change to the right ADIRU stabilization data. The IRS select switch sends a ground discrete to the WXR R / T.

Abbreviations and Acronyms | Antenna | WXR System Components | Air Data Inertial Reference System | WXR Output Data and Display | Physical Description | Antenna Pedestal | WXR System Messages | Sweep Patterns | WXR System Fail Messages and Display |

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