(6)
GUN 051; the FCCs provide engage and mode status to the MCP. Mode status is indicated by the dot-bar matrix on the select switch/lights. Flight director and autopilot engage status is indicated by the dot-bar matrix on the CMD switches. Status is also indicated on the EADIs (Ref 22-14-00).
D. FCC Input Discretes From Remote Switches
(1) Two A/P disengage switches (one on each control wheel) provide discrete signals to the FCCs which disengage the autopilot. The go-around switches (one on each thrust lever) provide discretes to the FCCs to start the Go-Around (GA) mode.
E. AFDS Input Power
(1) The FCCs receive 28 vdc and 115 vac, 400 Hz power for internal use. The 115 vac is reduced to 26 vac in the FCC and supplied to the A/P servos Autopilot Lateral Control Servo (ALCS), Autopilot Rollout Guidance Servo (ARGS), and Autopilot Pitch Control Servo (APCS). The MCP power supply receives 28 vdc. Both the MCP and the FCC use 28 vdc for the actuator servo arm, engage, and disengage functions.
2. Component Details
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A. AFDS Mode Control Panel (Fig. 3)
(1)
The AFDS Mode Control Panel provides the primary interface between the flight crew and the autopilot/flight director and autothrottle (A/T) systems. It contains switches and logic circuits for mode selectors and control of all A/P, F/D, and A/T functions.
(2)
Autopilot Engage/Disengage Switches
(a)
AIRPLANES WITH CONTROL WHEEL STEERING; the MCP has 6 pushbutton switches for manual engagement of the L, C, and R autopilot channels in the CMD or CWS modes. Pushbutton legends are lighted whenever power is applied to the MCP. A dot-bar matrix on each pushbutton is lit by FCC logic when the request has been accepted by the FCC.
(b)
GUN 051; the MCP has 3 engage switches for manual engagement of the L, C, and R autopilot channels in the CMD mode. The switches are locked in the CMD position when the engage request has been accepted by the FCC.
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DOT/BAR MATRIX ON LOWER HALF OF SWITCH COVER IS ILLUMINATEDWHEN COMPUTER CONFIRMS VALID CONDITIONS AND SATISFIES REQUEST
AFDS Mode Control PanelFigure 3 (Sheet 1)
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(3)
(4)
(5)
(6)
757 MAINTENANCE MANUAL
(c)
GUN 001-050, 052-999; the A/P disengage bar is a rocker switch with contacts that interface with all three FCCs. It provides positive disengagement of all A/P servos. A dayglow-orange stripe on top of the bar gives a clear indication of the disengaged state.
Autothrottle Arm Switch
(a)
The Autothrottle (A/T) toggle switch allows arming and disarming of the autothrottle system for engagement in the EPR or speed mode.
Autothrottle Mode Engage Switches
(a)
Two pushbutton switches provide manual selection of the A/T modes. Contacts of these switches interface with the Thrust Management Computer (TMC) (AMM 22-31-00). The dot-bar matrix, controlled by TMC logic, lights when the mode is engaged.
Flight Director Switches
(a)
The flight director system is turned on/off with either of two F/D toggle switches on the MCP. The left F/D switch controls the captain's EADI command bars. The right F/D switch controls the first officer's EADI command bars.
Autopilot/Flight Director Mode Select Controls 中國航空網 m.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：757 AMM 飛機維護手冊 自動飛行 AUTOFLIGHT 1(93)
