Pitch Modes
. TO/GA – Takeoff
Engaged for takeoff by turning both F/D switches ON and pressing either
TO/GA switch. Both F/Ds must be ON to engage TO/GA prior to starting
takeoff.
The AFDS commands pitch attitude in the following order:
Copyright . The Boeing Company. See title page for details.
4.20.4 December 7, 2001
Automatic Flight -System Description 737 Operations Manual
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10 degrees nose down until 60 knots IAS
.
15 degrees nose up after 60 knots IAS
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15 degrees nose up after lift-off until a sufficient climb rate is acquired. Then, pitch is commanded to maintain MCP speed plus 20 knots.
TO/GA can also be engaged for takeoff with F/D switches OFF if a TO/GA switch is pushed after 80 knots IAS below 2,000 feet AGL and prior to 150 seconds after lift-off.
. TO/GA – Go-around
Engaged for go-around by pressing the TO/GA switch under the following conditions:
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in flight below 2,000 feet radio altitude
.
Not in takeoff mode
.
Either F/D ON or OFF The F/Ds command 15 degrees nose up pitch and roll to hold the approach ground track at time of go–around engagement. After reaching a programmed rate of climb, pitch commands the
maneuvering speed for each flap setting based on maximum weight calculations.
.VNAV – VNAV is engaged by pushing the VNAV switch. With a VNAV mode
engaged, the FMC commands AFDS pitch and A/T modes to fly the vertical profile selected on the FMC CDUs.
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VNAV SPD – The AFDS maintains the FMC speed displayed on the airspeed cursor and/or the CDU CLIMB or DESCENT pages
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VNAV PTH – The AFDS maintains FMC altitude or descent path with pitch commands.
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V/S (armed) – V/S mode can be engaged by moving Vertical Speed thumbwheel
.
V/S (engaged) – Pitch commands hold selected vertical speed
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ALT ACQ – Transition maneuver entered automatically from a V/S, LVL CHG, or VNAV climb or descent to selected MCP altitude. Engages but does not annunciate during VNAV transition
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ALT HOLD – Pitch commands hold MCP selected altitude or uncorrected barometric altitude at which ALT HOLD switch was pushed
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MCP SPD – Pitch commands maintain IAS/MACH window airspeed or Mach
.
G/S (armed) – The AFDS is armed for G/S capture
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G/S (engaged) – The AFDS follows the ILS glideslope.
Automatic Flight -System Description 737 Operations Manual
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FLARE (armed) – During a dual A/P ILS approach, FLARE is displayed
after LOC and G/S capture and below 1500 feet RA. The second A/P
couples with the flight controls, and A/P go–around mode arms.
.
FLARE (engaged) – During a dual A/P ILS approach, flare engages at 50
feet radio altitude. FLARE accomplishes the autoland flare maneuver.
Roll Modes
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LNAV – The AFDS intercepts and tracks the active FMC route. Either of
the following capture criteria must be met:
.
On any heading and within 3 NM of the active route segment
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If outside of 3 NM of active route segment, airplane must be on an intercept course of 90 degrees or less and intercept the route segment before the active waypoint.
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HDG SEL – The airplane is turning to or is on the heading selected in the
MCP heading display
.
VOR/LOC (armed) – AFDS is armed to capture selected VOR or LOC
COURSE
.
VOR/LOC (engaged) – AFDS tracks selected VOR course or tracks
selected localizer course along the inbound front course bearing.
Autopilot Control Wheel Steering
CWS Engage Switch Selected
Pressing a CWS engage switch engages the A/P pitch and roll axes in the CWS mode and displays CWS P and CWS R on the FMAs.
With CWS engaged, the A/P maneuvers the airplane in response to control pressures applied by either pilot. The control pressure is similar to that required for manual flight. When control pressure is released, the A/P holds existing attitude.
If aileron pressure is released with 6 degrees or less bank, the A/P rolls the wings level and holds existing heading. This heading hold feature with bank less than 6 degrees is inhibited when any of the following conditions exist:
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Below 1,500 feet RA with the landing gear down
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After F/D VOR capture with TAS 250 knots or less
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