Boeing 737-800 - MCP Speed Intervention

737 Flight Crew Operations Manual
Flight Management, Navigation -
Flight Management System
Operation
Boeing Proprietary. Copyright © Boeing. May be subject to export restrictions under EAR. See title page for details.
11.31.24 D6-27370-866-EGP
Step Climb
If a step climb altitude is entered in the CRZ page STEP altitude, the FMC
calculates the point where the step climb should begin.
The distance and ETA to the next step point are shown on the CRZ and
PROGRESS pages. The next step point is shown on the map as a green open circle
with the label S/C.
MCP Speed Intervention
The above illustration shows VNAV mode for each phase of flight during speed
intervention.
With VNAV engaged, pushing the speed intervention switch enables speed
intervention. Speed intervention allows the flight crew to change airplane speed
with the IAS/MACH selector.
In a path descent using speed intervention, VNAV PTH changes to VNAV SPD
when the active descent segment is an idle or non-idle thrust segment. In VNAV
PTH, thrust controls speed; in VNAV SPD, pitch controls speed.
Note: Aircraft equipped with geometric descent path will transition to VNAV
PTH after the first altitude restriction.
YW273, YW274
(SB Changes YK981 - YQ456)
FMCS speed targets constrain the aircraft within its operating limits except when
in the speed intervention mode. These operating limits include stall protection,
maximum operating speed, flap placards, thrust limits, and maneuver margins.
When a navigation data base vertical angle leg is flown (GP x.xx on RTE LEGS
page), VNAV switches to VNAV PTH if not already in VNAV PTH.
In approach phase during speed intervention, the pitch mode remains in VNAV
PTH after speed intervention is exited. The FMC will remain in the current
vertical mode regardless of IAS MACH selector changes.
When speed intervention is exited the descent mode will switch back to path
mode.
V
N
A
V
S
P
D
CRZ
D
E
S
A
p
p
r
o
a
c
h
C
L
B
VNAV PTH
V
N
A
V
S
P
D
ALTITUDE
VNAV PTH
RESTRICTION
V
N
A
V
P
T
H
V
N
A
V
S
P
D
C
L
B
ALTITUDE
VNAV PTH
RESTRICTION
D
E
S
V
N
A
V
P
T
H
SPEED INTERVENTION PITCH MODES
September 15, 2016