VNAV not calculated when ARR Runway not entered

[63 Degrees Right]

Hello,

 

VNAV used to calculate TD/TC when entering Arrival STAR/Transition ONLY.

1.04 requires entering landing RUNWAY, otherwise it will not engage VNAV.

 

Is that suppose to be like this?

 

 

Many thanks

[cmbaviator]

13 hours ago, psitulskis said:

Hello,

 

VNAV used to calculate TD/TC when entering Arrival STAR/Transition ONLY.

1.04 requires entering landing RUNWAY, otherwise it will not engage VNAV.

 

Is that suppose to be like this?

 

 

Many thanks

 

i think so, you have to have no discontinuities between your departure and arrival runway,

[63 Degrees Right]

53 minutes ago, cmbaviator said:

 

i think so, you have to have no discontinuities between your departure and arrival runway,

There are no discontinuities.

Used to be- select arrival only because you don't know which runway will be in use for the landing.

[cmbaviator]

1 hour ago, psitulskis said:

There are no discontinuities.

Used to be- select arrival only because you don't know which runway will be in use for the landing.

but if you don't select a runway, there is a discontinuity then.... you can still enter the assumed arrival runway and if the wind has changed enroute, you can then change the arrival runway.

[capto]

Top Of Descent (T/D)
The point where the cruise phase changes to the descent phase is the top of
descent. The T/D point is shown on the map as a green open circle with the
label T/D. T/D is calculated from an end of descent (E/D) point.
Intermediate T/D points show on the map as green open circles with the label
T/D–XXXXX (altitude). Intermediate T/D points exist when path segments
between altitude restricted waypoints produce a level path segment. The
intermediate T/D point shows where the descent will resume.
FLT MGT NAV
Sec. 6.11 Page 20 737
Rev. 11/15/02 #41 Continental Flight Manual
End of Descent (E/D)
The FMC calculates a descent path based on airspeed restrictions, altitude
restrictions and the end of descent (E/D) point. The E/D point is shown on the
map as a green open circle with the label E/D. The E/D is the last of the
following, which is not preceded by a lateral discontinuity:
· The runway threshold for approaches with a runway waypoint on the RTE
LEGS page, or
· The missed approach point for approaches not showing a runway waypoint
on the RTE LEGS page, or
· The lowest “at” altitude restriction if no arrival procedure is entered.
Entering an instrument arrival procedure provides an E/D point.
If there is no E/D point, FMC predictions assume a computed profile to 1000
feet above the destination field elevation at a position, which varies according to
selection of arrival procedures. The FMC provides a slowdown profile for
approach. VNAV path descent is not available if there is no E/D point.

[63 Degrees Right]

Top Of Descent (T/D)

The point where the cruise phase changes to the descent phase is the top of

descent. The T/D point is shown on the map as a green open circle with the

label T/D. T/D is calculated from an end of descent (E/D) point.

Intermediate T/D points show on the map as green open circles with the label

T/D–XXXXX (altitude). Intermediate T/D points exist when path segments

between altitude restricted waypoints produce a level path segment. The

intermediate T/D point shows where the descent will resume.

FLT MGT NAV

Sec. 6.11 Page 20 737

Rev. 11/15/02 #41 Continental Flight Manual

End of Descent (E/D)

The FMC calculates a descent path based on airspeed restrictions, altitude

restrictions and the end of descent (E/D) point. The E/D point is shown on the

map as a green open circle with the label E/D. The E/D is the last of the

following, which is not preceded by a lateral discontinuity:

· The runway threshold for approaches with a runway waypoint on the RTE

LEGS page, or

· The missed approach point for approaches not showing a runway waypoint

on the RTE LEGS page, or

· The lowest “at” altitude restriction if no arrival procedure is entered.

Entering an instrument arrival procedure provides an E/D point.

If there is no E/D point, FMC predictions assume a computed profile to 1000

feet above the destination field elevation at a position, which varies according to

selection of arrival procedures. The FMC provides a slowdown profile for

approach. VNAV path descent is not available if there is no E/D point.

So entering Instrument arrival procedure will calculate/ set End of descent.

Does it mean that the runway selection is a must ?

Sent from my iPhone using Tapatalk

[mmerelles]

if i am correct this is a known shortcoming of the actual FMC development state, on the real thing you may select the STAR and/or arrival runway inflight. It is not a requirement to be set prior to departure.

[capto]

"The lowest “at” altitude restriction if no arrival procedure is entered. "

 I think you can determine the E/D by asigning an alt restriction to last waypoint.

[Litjan]

3 hours ago, capto said:

"The lowest “at” altitude restriction if no arrival procedure is entered. "

 I think you can determine the E/D by asigning an alt restriction to last waypoint.

Thats the way its coded. Sometimes a STAR may have an AT restriction, so in this case just having the STAR may work... in other cases it won´t.

Jan