(4)
The SWC's continuously monitor for internal and interface faults. When a fault is detected, an EICAS message WARN ELEX status will be displayed to alert the flight crew, and an alphanumeric code will be displayed on the WEU BITE module.
(5)
Access to the Stall Warning Computers is through main equipment center access door.
C.
STALL Test Switches (Fig. 2)
(1)
The STALL L and R test switches are located on sidewall panel P61 in flight compartment. They are used to test the stall warning computer systems on the ground.
(2)
The STALL L test switch activates the left stick shaker. The STALL R switch activates the right shaker. When activated, either stall warning test switch will also test the auto slat function if the flaps and slats are in the takeoff position.
D.
WEU BITE Module (Fig. 4)
(1)
The WEU BITE module is located below the WEU P51 panel. It consists of a printed circuit board with faultballs for WEU power supplies A and B, a power reset switch, and two pairs of hex indicators to display stall warning computers configuration and fault codes.
(2)
The module displays alphanumeric codes for SWC's internal and interface faults, airplane configuration, airplane options, and software version.
3. Operation
_________
A. Functional Description (Fig. 4)
(1) The stall warning system is active in the air, and can be activated on ground by using the STALL test switches.
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SEE WARNING ELECTRONICS UNIT P51
A
Component Location Figure 3
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(2)
In the air, the SWC's monitor and compute data inputs from the interfacing systems and provide functional output signals to the stick shakers and windshear detection and guidance systems.
(3)
The SWC's will activate the stick shakers in the air when the airplane computed angle of attack exceeds the computed trip angle of attack of impending stall.
(4)
The two stick shakers operate independently of each other. The left stick shaker is controlled by the left SWC. The right stick shaker is controlled by the right SWC.
(5)
The SWC's compute a pitch limit value based on the difference between the computed trip angle of attack of impending stall and the airplane computed angle of attack. This value is transmitted to the EFIS, which displays the proper Pitch Limit Indicator (PLI) on the EADI to guide the pilots (Ref 34-22-00).
(6)
The SWC's also transmit the flap position to the GPWC to set the windshear sensitivity level (Ref 34-46-00).
(7)
On the ground, the SWC's can be set to a test mode. They monitor and detect internal and interface faults and display them on BITE and EICAS.
B.
BITE
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