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757 MAINTENANCE MANUAL
USUALLY SET TO INITIAL CLEARANCE-USUALLY SET TO SAFE
INACTIVE AT TAKEOFF
BLANK UNTIL V/S
EADI DISPLAY EADI DISPLAY EADI DISPLAY
A B C
Flight Director - Pitch Channel
Figure 9 (Sheet 1)
D01011
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757 MAINTENANCE MANUAL
USUALLY SET TO SAFE USUALLY SET TO
CLIMB SPEED (V2) AUTOPILOT CMD
BLANK UNTIL V/S INITIAL CLEARANCE-
ALSO INDICATED BY ENGAGE SWITCHES OFF
EADI DISPLAY EADI DISPLAY EADI DISPLAY
Flight Director - Pitch Channel
Figure 9 (Sheet 2)
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757
MAINTENANCE MANUAL
(5) Pitch Channel - Takeoff Mode
(a)
Takeoff mode is automatically engaged when either or both flight director switches are switched ON while the airplane is on the ground. Takeoff mode displays appropriate flight director bar commands for proper rotation and climbout. The flight director remains in takeoff mode until another valid mode is engaged.
(b)
Before takeoff, the crew must set a climbout speed on the MCP. The flight director will show a pitch-up command of 8.0 degrees. When the radio altimeter is more than 5.0 feet for
2.0 seconds, an INAIR signal adjusts the 8.0 degree command to the altitude command necessary to keep the takeoff speed.
(c)
The EADI flight mode annunciator displays TO when takeoff mode is engaged. It continues to display TO until takeoff mode is disengaged by selecting any other valid mode or by switching both flight directors OFF. The following are valid modes that disengage the takeoff mode: 1) Altitude mode active - select altitude hold or selected
altitude captured.
2) Flight level change - select FLCH mode.
3) Vertical navigation - VNAV captured
a) The VNAV ARM is a submode. When VNAV is pressed, the mode request is accepted and the dot-bar matrix is illuminated, VNAV is annunciated on the MCP and in the pitch mode armed section of the EADI. When the VNAV path is captured, VNAV mode is entered and VNAV is annunciated in the pitch mode engaged section of the EADIs. Pressing the VNAV switch/light a second time deactivates the VNAV modes.
4) If a valid mode is not selected and CMD is engaged, vertical speed mode automatically engages.
(6) Autopilot/Flight Director System Pitch Mode Logic and Control Signal Flow (Fig. 10)
(a) Takeoff Mode Control Logic
1) Takeoff mode logic causes Takeoff Attitude engage (TAKEOFF ATT ENG) to be a logic one when the airplane is not in the air, CMD switches are off, either or both F/D switches are ON, and TAKEOFF SPD ENG is logic zero. When TAKEOFF ATT ENG is logic one, the 8 degree pitch up bar command is enabled.
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MAINTENANCE MANUAL
FLIGHT CONTROL COMPUTER
Autopilot/Flight Director System Pitch Modes Logic SchematicFigure 10 (Sheet 1)
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本文链接地址：757 AMM 飞机维护手册 自动飞行 AUTOFLIGHT 1(124)
