B777 Climb/ FMC inputs 2 questions.

[novicef]

Two questions on the LEGS page. Unlike descent where you can insert an altitude to be at a particular waypoint and the FMC calculates a T/D to meet that restriction. If a climb is required with a similar requirement, i.e. to be at a waypoint at a particular altitude, the FMC does not seem to have the capability to calculate the point where the climb can commence. Apart form doing this maually through V/S or FLCH is there a way of making the FMC calculate the climb. I know about the Step Climb feature on the VNAV page, but if the climb requirement is before the VNAV calculated climb which can be several miles past the waypoint is there a way of forcing the FMC to give a point of where to commence the climb.

Secondly it appears difficult at times to place a speed and Flight level at a particular waypoint in the cruise portion of the LEGS page. Yet placing a requirement on the descent portion of the LEGS page is relatively straight forward. Could somebody please explain the rationale.

[hotcurry]

On the legs page insert ,for example a climb from FL330 to FL350 and speed .83 , .83/FL350S.

That will help the fuel and time predictions.

[suninmyeyes]

You are correct in that the FMS will not tell you when to commence the climb. However once you have commenced a climb if you go to the legs page it will give you estimates of crossing altitudes/flight levels at each waypoint provided you have not put any height restraints in. These are sometimes slightly optimistic otherwise accurate.

It is a common error that people have difficulty putting en route speeds and heights in to the FMS legs page, ie .84 FL350. As mentioned above you have to put it in in the format .84/350S.

[Bpalmer]

One approach would be to put in the step climb at the waypoint of interest (so that the weight is about right), and see how many miles the FMS predicts that climb to take.
Then build a waypoint (WYPNT/-30) at least that many miles prior to the reference waypoint and insert your step climb there.
Don't do this if you are using ADS-C as the extra waypoint will be reported to ATC and it won't agree with their flight plan routing.

[Tonic Please]

suninmyeyes,

You wrote .84/350S. What is S?

Just curious :)

TP

[flyhardmo]

suninmyeyes,

You wrote .84/350S. What is S?

Just curious

TP


S stands for step