(b)
GUN 051; once the engage requests are received, each FCC energizes its appropriate arm solenoids if the FCC is not inhibited. The FCC is inhibited if:
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1) FCC program pin status invalid 2) conditions under single channel arm inhibit occur
(c)
GUN 001-050, 052-999; multichannel CMD engage requests are initiated when the APP mode is selected and one FCC is engaged in the CMD mode. Each unengaged FCC automatically energizes its appropriate arm solenoids if the FCC is not inhibited. The FCC is inhibited if: 1) FCC program pin status invalid 2) conditions under single channel arm inhibit occur
(d)
Once armed, each A/P channel transitions from ARM to OFF if: 1) aileron, elevator, or rudder servos fail or servo loops not verified 2) aileron or elevator servos not synchronized to surface position 3) yaw servo not synchronized to surface position within 3 seconds 4) any two identical aileron or elevator inner loop or autoland sensor parameters failed or invalid 5) any two identical rudder inner loop sensor parameters or
interfaces invalid 6) electrical power monitor detects a failure 7) conditions under single channel ARM to OFF transition occur
(e)
GUN 051; after the arm solenoids are energized, each engage switch is held in the CMD position.
(f)
GUN 001-050, 052-999; after the arm solenoids are energized, each CMD switch/light is lighted.
(g)
The appropriate engage solenoids are then energized if each FCC is not inhibited. The FCC remains in the arm state if: 1) aileron, elevator, or rudder inner loop data not valid 2) FCC program pin status not valid
(h)
Once engaged, each A/P channel will transition from CMD to OFF if: 1) FCC memory failed or self test monitors are not verified 2) aileron, elevator, or rudder servo or servo loop fails 3) any two identical inner loop sensors failed or invalid 4) electrical power monitor detects a failure 5) any two identical autoland sensors failed or invalid 6) FCC program pin status invalid 7) ALT HOLD or override function cannot be performed 8) autopilot disengage switch pressed
(i)
The cross-channel data buses allow each FCC to provide its engage status to the other two. If the first-in-command channel (first FCC engaged in CMD during multichannel operation) is disengaged, the first-in-command status is automatically transferred to the next channel as follows:. . . LEFT, RIGHT, CENTER, LEFT, etc..
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B. BITE
(1)
The FCC provides in-flight detection of AFDS and related component failures. Detection includes:
(a)
System fault detection and fault location.
(b)
Monitoring of servos, sensors, input interfaces, and output interfaces.
(c)
Self Test
(d)
Storage of internal fault identification.
(2)
Fault Detection and Location.
(a)
The FCC detects flight faults in the following AFDS System Components: 1) Autopilot Servos 2) Transducer Inputs and Outputs 3) MCP - FCC Interfaces 4) FCC
(b)
The FCC, in conjunction with the MCDP, can identify the location of the flight faults listed above. The MCDP ground tests verify the proper operation of the MCP front panel switch/lights, switches, and displays. The ground tests also verify proper operation of the A/P disengage and go-around switches.
(3)
FCC Interface Monitors
(a)
The A/P servo control functions are checked by command/response monitors which verify the function of the servo loop, and by current drive wraparounds, which check the circuitry to the servo drivers. The command/response monitors verify that the actuator moves when commanded. The current drive wraparounds verify that the servo is functioning correctly by comparing actual servo movement with the movement commanded by the FCC software.
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