VNAV Predictions

[Mariano]

Hardy,

On the Pegasus 767 FMC, we do not get any VNAV predictions until after we enter a ZFW. LEGS pages display no speed and altitude data, and neither do VNAV pages (all required data entered in PERF INIT except for ZFW (and ensuing GR WT)).

PSX calculates VNAV predictions without this (weight) data. Which weight does it use to perform these calculations?

Best regards,

Mariano

[Hardy Heinlin]

Gross weight.

Can't remember why it's still able to make predictions. Maybe it has been observed on a real 744, but I don't think it should do it.


Regards,

|-|ardy


I think it should blank these variables:
All ETAs
All profile points (S/C, T/C, T/D)
Fuel predictions
ECON speed values
Small font speeds/altitudes on LEGS pages

ETAs also require a running clock (left or right clock, or GPS clock).

[Mariano]

Hardy,

I agree with the blanked variables you listed.

I can't see how it is able to predict any of those without ZFW and GR WT.

Perhaps 744 guys could shed some light.

Best regards,

Mariano

[emerydc8]

I can confirm that the 767 Pegasus will not display the SPD RESTR feature until the weights are entered too.

[Hardy Heinlin]

When VNAV performance is unavailable, the VNAV pages are almost completely blank; only CRZ ALT, TRANS ALT, and STEP SIZE are enabled.

No worries, I just isolated the problem. I have several VNAV unavail flags in my code for certain page sections. But some of them excluded the gross weight and CI in their collections of conditions.

E.g. some parameters need a clock, and some others don't, etc. There's no global universal inhibit flag.


|-|ardy

[Mariano]

Trying to attach a picture but cant figure out how ;-)

Mariano

[emerydc8]

Go here http://resizeimage.net/ and upload the picture. Resize the image to 500 x whatever. You can crop here too. Then download the image to your computer. Take that image and go to http://www.hoppie.nl/forum/. Upload the image and copy the tag for the forum. Then just paste it in the message.

Jon

[Mariano]

Thanks, Jon!

Best regards,

Mariano

[Hardy Heinlin]

Predictions are now all blank in PSX 10.48:

http://aerowinx.com/board/index.php?topic=4191.0


|-|ardy

[Mariano]

Thanks, Hardy.

Best regards,

Mariano