bug FMS - F-PLN FUEL + FUEL&LOAD predictions - 1.08

[Der Michel]

FIRST:

Prior engine start, the FMS has to use the BLOCK FUEL of the FUEL&LOAD page for it's calculations!

With engine start it will switch to the measured fuel quantity inside the tanks.

Currently the FMS is always using the FUEL from tanks. That's just wrong. With this pilots can't do any preparation and prediction checks, while refueling is in progress.

Side note: Currently we don't get any predictions until BOCK is entered, but then it is not used.

SECOND:

ALTN fuel shouldn't be negative. The calculation is in this case just bogus.

I think you just mixed up the values of ALTN FUEL and ALTN EFOB.

In this example

ALTN FUEL should be 4T

ALTN EFOB should be -52.3T

This will also explain the error

            1.       for MIN FUEL AT DEST = ALTN + FINAL

                     That should be 6.2T and not -50.1T

           2.       for (PREFLIGHT) EXTRA = BLOCK (or FOB, after engine start) - TAXI - TRIP - MIN FUEL AT DEST - RTE RSV

                     That should be 10.7T and not 67T

 

THIRD:

TOW and LW are missing.

TOW
Indicates the Takeoff Weight (TOW).
Before engine start:
TOW = ZFW + block fuel - taxi fuel
After engine start:
TOW = GW - taxi fuel
 In flight:
TOW = GW

LW
Indicates the Landing Weight (LW).
Before engine start:
LW = TOW - trip fuel
After engine start:
LW = GW - trip fuel - taxi fuel
In flight:
LW = GW - trip fuel

FOURTH:

Behind the ALTN FUEL has to be an ALTN flight time indicated. That time will add to the DEST arrival time and result in the ALTN arrival time, which is in the lower example nonsense. If the calculated ALTN FUEL is overwritten by crew, the ALTN flight time and the ALTN arrival time will be dashed.

 

FIFTH:

The double dots ":" in time values are dark blue.

 

Edited 12 hours ago by Der Michel