Copyright . The Boeing Company. See title page for details.
September 29, 2005 11.31.29
Flight Management, Navigation -Flight Management System Operation 737 Flight Crew Operations Manual
YD652 - YD655
Copyright . The Boeing Company. See title page for details.
11.31.30 September 29, 2005
Flight Management, Navigation -Flight Management System Operation
737 Flight Crew Operations Manual
Cruise
Before the top of descent, FMC is in cruise mode and uses VNAV PTH and ECON cruise speed.
Descent
After top of descent, FMC is in descent mode and VNAV changes to economy descent speed and descends in VNAV PTH.
Speed Restriction Deceleration
Before the speed restriction altitude, VNAV decelerates to commanded speed using VNAV PTH.
When at restricted speed, VNAV commands decreased pitch and descends in VNAV PTH.
Altitude Restrictions
YA613 - YD651, YK101 - YK104 The VNAV path conforms to altitude restrictions at MNO, EPG, and the FAF. If required, VNAV uses a level path until intercepting the idle thrust descent path to the next altitude constrained waypoint.
YD652 - YD655 The VNAV path conforms to altitude restrictions at MNO, EPG, and the FAF. The thrust mode changes to FMC SPD as required to maintain the target speed.
Approach
VNAV descends and starts approach in VNAV PTH at the commanded speed.
Missed Approach
When TOGA is pushed during approach, or when crossing the missed approach point, VNAV disengages.
When selected during missed approach, VNAV engages in VNAV SPD.
Missed Approach Level Off
At missed approach altitude VNAV changes to VNAV PTH.
VNAV Speed Descent
A speed descent may be selected manually by selecting the SPEED prompt on the PATH DES page. With no E/D specified, the speed descent is the only descent mode available.
Copyright . The Boeing Company. See title page for details.
Flight Management, Navigation -Flight Management System Operation 737 Flight Crew Operations Manual
The speed descent maintains the target speed. Normally, the target speed is economy above the airspeed restriction altitude and 240 knots below that altitude, until deceleration is necessary for the approach. VNAV will not permit descent below the altitude restriction until the airspeed is at or below the restricted value.
The speed descent normally begins automatically at the calculated T/D, provided the MCP altitude is reset for the descent. At the T/D, the FMC commands pitch to maintain target descent speed. LNAV does not have to be engaged in order to fly a VNAV speed descent.
The descent attempts to comply with waypoint altitude restrictions, and will not violate these restrictions. The VNAV speed descent will not, however, guarantee the airplane reaches an altitude restriction at the required point.
A speed descent cannot automatically revert to a path descent, except during STAR, approach transition, or approach leg with a vertical angle. However, if all required parameters for a path descent are available, a path descent may be manually selected at any time by selecting the PATH prompt on the speed descent page.
Copyright . The Boeing Company. See title page for details.
11.31.32 March 28, 2005
Flight Management, Navigation -Flight Management System Operation
737 Flight Crew Operations Manual
VNAV Cruise and Speed Descent Profile (Instrument Approach using VNAV)
YA613 - YD651, YK101 - YK104
T/D
VNAV SPD
VNAV PTH VNAV SPD
VNAV SPD
10,000'
MNO EPG FAF
E/D50'
Copyright . The Boeing Company. See title page for details.
Flight Management, Navigation -Flight Management System Operation 737 Flight Crew Operations Manual
YD652 - YD655
T/D
VNAV SPD
EPG
MNO
FAF
E/D50'
Copyright . The Boeing Company. See title page for details.
11.31.34 September 29, 2005
Flight Management, Navigation -Flight Management System Operation
737 Flight Crew Operations Manual
Cruise
Before the top of descent, FMC is in cruise mode and uses VNAV PTH and ECON cruise speed.
Descent
After top of descent, FMC is in descent mode and VNAV changes to economy descent speed and descends in VNAV SPD.
Speed Restriction Deceleration
Before the speed restriction altitude, VNAV decelerates to commanded speed using VNAV SPD.
When at restricted speed, VNAV commands decreased pitch and descends in VNAV SPD.
VNAV Path
During a speed descent, VNAV may not maintain the FMC computed VNAV path. However, if E/D shows, a VNAV path is available.
Altitude Restrictions
VNAV conforms to altitude restrictions at MNO and EPG. After MNO VNAV
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