.
ALT HOLD engages

.
V/S engages

.
G/S capture occurs.

A/T does not set thrust above displayed N1 limit, however, A/T can exceed N1 value manually set by N1 Manual Set Knob.
Automatic Flight -Controls and Indicators 737 Operations Manual

IAS/MACH Selector
Rotate –
.
sets speed in IAS/MACH display and positions airspeed cursor

.
selected speed is reference speed for AFDS and A/T

.
not operative when IAS/MACH display is blank.

Vertical Navigation

VNAV Switch
Push –
.
VNAV switch light illuminates

.
pitch mode annunciates VNAV SPD, VNAV PTH

.
A/T mode annunciates FMC SPD, N1, RETARD, or ARM

.  
IAS/MACH display blanks and airspeed cursors positioned to FMC
commanded airspeed.

VNAV Mode
The FMC commands AFDS pitch and autothrottle to fly vertical profile selected on FMC CDUs. Profile includes climb, cruise, descent, speeds, and can also include waypoint altitude constraints.
Note:  If the airplane is between the FMC target altitude (depicted on the RTE LEGS page for the active waypoint) and the manually entered MCP target altitude, VNAV will not engage. To enable VNAV, adjust the FMC or MCP target altitude as appropriate.
Climb –
.
autothrottle holds FMC thrust limit

.
AFDS holds FMC target speed

.  
automatic level off occurs at MCP altitude or VNAV altitude, whichever
is reached first.

Copyright . The Boeing Company. See title page for details.
4.10.4   June 7, 2002

Automatic Flight -Controls and Indicators 737 Operations Manual
Cruise –
.
autothrottle holds FMC target speed

.
AFDS holds FMC altitude

.  
selecting a lower MCP altitude arms FMC to automatically begin descent upon arrival at FMC top of descent point.

Descent –
.
VNAV SPD descent

.
autothrottle holds idle

.
AFDS holds FMC target speed

.
VNAV PTH descent

.  
autothrottle holds idle but can command FMC SPD mode if ground speed becomes too slow to maintain FMC vertical path

.
AFDS tracks FMC descent path

.  
automatic level-off occurs at MCP altitude or VNAV altitude, whichever is reached first

.
VNAV constrained level-off annunciates VNAV PTH.

Inhibited below 400 ft. RA or if performance initialization not complete.
VNAV mode is terminated by any one of the following:
.
Selecting another pitch mode

.
Glideslope capture

.
Transition of glideslope intercept waypoint

.
flaps extended beyond 15

.
flaps extended beyond 15 (prior to FMC U7.1)

.  
Crosstrack greater than RNP while active leg has a nav data base vertical angle (FMC U7.1 or later, but prior to U10.3)

Altitude Selector (SEL)
Rotate –
.  
with unmodified selector pushed in, sets altitude in ALTITUDE display in 100 foot increments

.  
with unmodified selector pulled out, sets altitude in ALTITUDE display in 1,000 foot increments

.  
with modified selector, sets altitude in ALTITUDE display in 100 foot
increments

.
arms V/S mode if rotated while in ALT HOLD at selected altitude

Automatic Flight -Controls and Indicators 737 Operations Manual

ALTITUDE Display
Displays selected altitude
.  
displayed altitude is reference for altitude alerting and automatic
level–offs

.
altitude range is 0 to 50,000 feet in 100 foot increments

Vertical Speed (VERT SPEED) Display
Displays:
.
blank when V/S mode not active

.
present V/S when V/S mode is engaged with V/S switch

.
selected V/S when V/S set with thumbwheel

.
range is –7900 to +6000 fpm.

Displays in increments of:
.
 50 fpm if V/S is less than 1000 fpm

.
100 fpm if V/S is 1000 fpm or greater.

Vertical Speed Thumbwheel
Rotate –
.
DN –

.
sets vertical speed in VERT SPEED display

.
increases rate of descent or reduces rate of ascent

.
UP –

.
sets vertical speed in VERT SPEED display.

.
increases rate of ascent or reduces rate of descent

Level Change (LVL CHG) Switch
Push –
.
LVL CHG switch light illuminates
　
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本文鏈接地址：737-300機組操作手冊Flight Crew Operations Manual FCOM 2(22)