Frustrating VNAV issues

[johnh]

I love the detail of this aircraft but I am having a problem with the Flight Plans. I have the latest AIRAC installed and my Route is NZCH DCT PORAM H110 NS H252 NP H384 KARRL DCT DAVEE DCT NZAA. I have set the Cruise Alt to FL310 but when I check the Legs page it doesn't climb over 9000?

Anyone got any ideas? Is anybody else having this issue?

[Taguilo]

Hi,

First of all, in LEGS page, do you have a VNAV Climb altitude constraint of 9000 ft.?

Did you reposition the Presel altitude (cyan value) above 9000 while climbing?

If both are true and aircraft leveled at 9000, did you select a climb pitch mode (VVS,VFLC,VPTCH) to start climbing?

Be aware for VNAV Climb phase the FMS won’t command a climb by itself, like happens with VPATH mode on descents. All what it can do is arm the mode and eventually make it active, but will need pilot’s input of speed, vs or pitch to initiate the climb.

Tomas

[Torkermax]

Right or wrong I have never used VNAV for climb with any Turboprop. FLCH mainly. Descent, yes.

[Taguilo]

I'm confused, sorry. If you are not using VNAV, then what is your specific problem? Can you give us more details?

Thanks!

Tomas

[Ephedrin]

I'm confused, sorry. If you are not using VNAV, then what is your specific problem? Can you give us more details?

Thanks!

Tomas

It's another person writing

[Taguilo]

Oops, yeah. Thanks for pointing out! Sounded like the same person to me.

Anyway, would be great that johnh could give more details.

Tomas

[johnh]

Thanks for the replies! This is all BEFORE I get off the ground. When I program the FMS I set the POS, enter the Flight Plan and Dep/Arr. I then enter the PERF info and finally check the LEGS.

The results are shown in the attached images

[Taguilo]

Johnh,

Thanks. That is a display bug already solved, won't be present in the SP.

Meanwhile, to avoid it just do not enter manual fuel in PERF INIT page. You can safely enter Cruize altitude, but until SP just leave the manual fuel entry field blank.

Tomas

[johnh]

Thanks for that Tomas,

I left out the MAN FUEL entry as you instructed but now I get no SPEED/ALT entries except for the SID/STAR/TRANS entries See attached image. Is this as designed?

Just a follow-up. Does the PERF INIT have no effect on the performance of the aircraft then?

[Taguilo]

I left out the MAN FUEL entry as you instructed but now I get no SPEED/ALT entries except for the SID/STAR/TRANS entries See attached image. Is this as designed?

Yes, that´s correct. VNAV fields (spped/alt/vpa,etc) must display only loaded procedure(s) info or data manually entered by the pilot, not predictions.

Just a follow-up. Does the PERF INIT have no effect on the performance of the aircraft then?

Data on PERF INIT helps the pilot take weights and fuel compsumption into account, but won't affect the performance of the aircraft. It is actually the inverse, will help the pilot predict how the aircraft will perform according to that info.

In fact, speed values are for reference only, as the KA does not include an autothrottle.

Tomas

[SAS443]

the CRZ ALT value on PERF-page is actually an optional value. All it does is to help the FMS to predict a descent point later in the flight.
Fuel calculations are unaffected by modifying CRZ ALT on PERF-page.

It's a simple FMS.