.  
annunciates VOR/LOC armed or engaged as roll mode and illuminates
VOR LOC switch light.

VOR LOC Mode
Pushing the VOR LOC switch selects VOR mode if a VOR frequency is tuned or selects LOC mode if a localizer frequency is tuned.
The VOR mode provides roll commands to track selected VOR course.
The LOC mode provides roll commands to track selected localizer course along inbound front course bearing.
The selected course can be intercepted while engaged in:
.
LNAV

.
HDG SEL

.
CWS R if an autopilot is engaged in CMD. The capture point is variable and depends on intercept angle and closure rate.

Localizer capture occurs not later than 1/2 dot deviation. Course capture is indicated when VOR/LOC annunciation changes from armed to engaged.
While engaged in VOR or LOC modes:
.  
A autopilot and Captain’s F/D use information from Captain’s course
selector and No. 1 VHF NAV receiver

. 
 B autopilot and First Officer’s F/D use information from First Officer’s
course selector and No. 2 VHF NAV receiver

.  
different courses and/or frequencies for two VHF NAV receivers can
cause disagreement between the Captain’s and First Officer’s F/D
displays and affect A/P operation.

Note:  When a localizer frequency is selected, VHF NAV radios automatically switch from tail antenna to nose antenna when VOR/LOC is annunciated (armed or engaged). If antenna switching does not occur, LOC mode is inhibited.
Note: Localizer backcourse tracking is not available.

Course Selector
Sets course in COURSE display for related VHF NAV receiver, AFDS and DU. Two course selectors and COURSE displays are located on the MCP.
Copyright . The Boeing Company. See title page for details.
Automatic Flight -Controls and Indicators 737 Flight Crew Operations Manual

Rotate Captain’s course selector – provides selected course information to:
.
A FCC

.
No. 1 VHF NAV receiver

.
Captain’s course pointer and course deviation bar.

Note:  In VOR LOC or APP mode, the A A/P and Captain’s F/D use selected course and navigation data from the No. 1 VHF NAV receiver.
Rotate First Officer’s course selector – provides selected course information to:
.
B FCC

.
No. 2 VHF NAV receiver

.
First Officer’s course pointer and course deviation bar.

Note:  In VOR LOC or APP mode, B A/P and First Officer’s F/D use selected course and navigation data from No. 2 VHF NAV receiver.

Bank Angle Selector
Rotate –
.  
sets maximum bank angle for AFDS operation in HDG SEL or VOR
modes

.
commanded bank angle can be selected at 10, 15, 20, 25, or 30 degrees.

Heading Select (HDG SEL) Switch
Push –
.
engages HDG SEL command mode

.
commands roll to follow selected heading

.  
annunciates HDG SEL as FMA roll mode and illuminates HDG SEL
switch light.

Heading Select Command Mode
The HDG SEL mode commands roll to turn to and maintain heading shown in MCP HEADING display:
.  
initial selection commands turn in shortest direction toward selected
heading bug

.  
after mode engagement, roll commands are given to turn in same
direction as rotation of heading selector

.
bank angle limit is established by bank angle selector

.  
HDG SEL mode automatically disengages upon capture of selected radio
course in VOR LOC and APP modes (VOR/LOC armed).

Copyright . The Boeing Company. See title page for details.
4.10.16   March 28, 2005

Automatic Flight -Controls and Indicators 737 Flight Crew Operations Manual

Approach (APP) Switch
Push –
.
illuminates APP switch light

.
arms the AFDS for localizer and glideslope capture

.
roll mode annunciates VOR/LOC armed

.
pitch mode annunciates G/S armed

.
enables engagement of both autopilots.

APP Mode
The approach mode arms AFDS to capture and track localizer and glideslope and can be engaged for dual or single autopilot operation.
One VHF NAV receiver must be tuned to an ILS frequency before approach mode can be engaged. With one VHF NAV receiver tuned, onside AFDS is enabled for guidance and operation.
For dual autopilot operation, both VHF NAV receivers must be tuned to the ILS frequency and both autopilots must be selected in CMD prior to 800 feet RA.
　
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