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MAINTENANCE MANUAL
3) Neither relay will allow the switch to the alternate ADC if the other is already in ALTN.
(5) The HYDIM card file, Primary Air/Gnd System, Alternate Air/Gnd System, Speed brake handle position RVDT, and FCU interfaces are shown in Figure 8. These sensors can not be switched between channels.
(a) Speed brake handle position
1) The Speed brake Handle Position sensor is a single RVDT with three separate output connectors to the three FCCs.
(6)
The LOC and G/S antenna switching interfaces are shown in Figure 9.
(7)
The CMC interfaces are shown in Figure 10.
5. Operation_________
A. Modes of Operation and Allowable Transitions (Figures 11 and 12)
(1) This section describes the various modes of operation; how each is selected, what the AFDS is controling, and what will cause a transition out of one mode and into another.
(a)
Control Inactive
1) Control Inactive is the configuration of the AFDS when no autopilot or flight director is engaged. During control inactive, the FCC processes roll angle commands from Runway Alignment, Heading/Track, and Localizer Processors to produce the Roll Attitude Command. This maintains a roll attitude reference when the A/P is not engaged and generates a roll to wings level command at CMDENG. The aileron servo command synchronizes to aileron position when the A/P is not engaged. This permits a smooth transition to A/P control at CMDENG. Processors not active in command computations synchronize to maintain a zero output.
(b)
Takeoff Mode (F/D only)
1) The takeoff mode has two submodes: on-ground and in-air. In the on-ground submode, the F/D provides a 8 degrees nose-up command for initial climbout. The F/D also provides a wings level roll command.
2) In the in-air submode, the F/D pitch command is referenced to the speed schedule with flap position and engine failure corrections. The F/D roll commands provide ground track hold after lift-off. There is no F/D yaw axis control.
(c)
Go-Around
1) The AFDS provides commands for a positive rate of climb using a speed reference schedule based on flap position. Roll channel commands initiate go-around (G/A) ground track hold. This mode is manually selected by pressing the go-around switch on the throttles.
(d)
Heading Hold
1) Heading hold is the basic roll axis mode. It is automatically selected when the F/D only mode is initially chosen or when any A/P channel is engaged in single-channel CMD (both F/D off). Heading hold can also be manually selected by pressing the HOLD switch/light on the MCP.
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MAINTENANCE MANUAL
SYNCHRONIZING SERVO COMMANDS ONLY TO UNPRESSURIZED CONTROL A/P SERVOS INACTIVE NO AUTOPILOT ENGAGED AND BOTH FLIGHT DIRECTORS OFF
MODE FCC SIGNAL PATHS SYNCHRONIZE TO REFERENCES CONDUCTS SYSTEM FAILURE DETECTION MONITORING TO DETERMINE PERMISSIBLE ACTIVE MODES FOR ENGAGEMENT
AUTOMATICALLY SELECTED
NO AUTOPILOT YAW AXIS CONTROL (TURN ON F/D ON GROUND) PITCH AXIS CONTROLS ROTATION ATTITUDE OR SPEED SCHEDULE ROLL AXIS COMMANDS WINGS LEVEL UNTIL LIFTOFF, THEN GROUND TRACK HOLD
PRESS GO AROUND SWITCH
YAW AXIS CONTROL MAINTAINED DURING MULTICHANNEL GO AROUND. YAW SYNCHRONIZING COMMANDS TO UNPRESSURIZED RUDDER SERVOS IN SINGLE CHANNEL GO AROUND PITCH AXIS COMMANDS FORWARD ACCELERATION & POSITIVE RATE OF CLIMB, USING SPEED SCHEDULE BASED ON FLAP POSITION ROLL AXIS COMMANDS INITIAL GA GROUND TRACK HOLD AT GO AROUND EXIT, G/A MODE IS MAINTAINED AS EITHER A CMD ROLL OR A CMD PITCH ENGAGED MODE
COMMANDS ROLL TO WINGS LEVEL AND AUTOMATIC TRANSITION INTO HDG HOLD
BASIC ROLL AXIS MODE COMMANDS TO HOLD HEADING REFERENCE
COMMANDS TO ACQUIRE AND HOLD MCP SELECTED HEADING
RESPONDS TO LATERAL STEERING COMMANDS FROM FLIGHT MANAGEMENT SYSTEM
COMMANDS TO ACQUIRE AND TRACK LOCALIZER CENTERLINE AFTER LOC CAPTURE MODE
SIMULTANEOUS PITCH AND ROLL MODES.
MCP Selectable Pitch & Roll Functions Figure 11 (Sheet 1)
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