Description (AMM 27-32-00)

 

A- Each stall management computer (SMC) uses information from the AOA sensor, the flap position transmitter, and other airplane systems to determine whether to activate the control column shaker. The SMC's are located on the E1-1 electronics shelf.

 

B- The airplane configuration changes the AOA angle at which the stall management system signals a stall condition. The airplane configuration is read by the stall management system from the program data bits which are on the Stall Management Computer. The program input bits can be displayed through the SMC BITE.

A comparision of the program data bits takes place every second between SMC's. When the SMC's disagree, a configuration message will appear on either or both SMC's. The inputs are numbered for identification for use by the SMC system and are listed in the table below.

 

(1) You can check the program word wiring using the SMC Bite. The BITE system configuration and the input discrete displays to compare the program data bits listed by the SMC against and the configuration for your airplane.

 

(2) The table below lists the program data bits. Grounding a program pin enables the function listed in the table. Leaving a program pin open disables that function for the stall management calculations.

 

C- SMC 1 activates the captain's control column shaker. SMC 1 is powered by 28 volts dc through a circuit breaker on the P18-2 panel from the standby bus. 

 

D- SMC 2 activates the first officer's control column shaker. SMC 2 is powered by 28 volts dc through a circuit breaker on the P6-1 panel from the electronics power bus No. 2.

 

E- Various flight conditions are monitored by the SMC to determine when to activate the control column shaker. The shaker will be activated by whichever condition gives the earliest warning of an approaching stall.

 

F- Stall Management Computer Output Bus.

 

G- BITE and SMC Input Monitoring

(1) The SMC has internal built-in test equipment (BITE) for maintenance and testing purposes. There is an SMC maintenance control panel on the front of the SMC. This panel has controls for selecting test and input monitoring functions and an alphanumeric display for showing the status of the functions selected.

(2) When the BITE ON OFF button is pushed, the SMC runs a BITE test. The display will read TEST IN PROGRESS during the test and then SYSTEM OK when the test passes. After the test passes, several test and monitoring functions can be selected with the MENU button. When the ON/OFF button is pushed again, the SMC returns to normal operation.