After planning all my routes, wind and fuel in the EFB in accordance with Simbrief OFP, the EFOB figure in the F-Pln page is in magenta indicating insufficient fuel on board. But when I tried to increase the fuel through the EFB the magenta fugure EFOB on the F-Pln page increases correspondingly. Shouldn't it decrease instead with the added amount of fuel?

A few things to check.

Are the weight units für your flightplan and aircraft the same lbs/lbs kg/kg . Something like kg/lbs can result in to little fuel.

If you want to load your simbrief fuel and weights go to Settings/Accounts in the EFP.

Select Set Payload + Fuel to Simbrief

Go into you mcdu INIT Page and request your flp init, only the the fuel and weights will be set automaticly .

16 hours ago, MarsVenus said:

After planning all my routes, wind and fuel in the EFB in accordance with Simbrief OFP, the EFOB figure in the F-Pln page is in magenta indicating insufficient fuel on board.

I'm not sure what a magenta EFOB number indicates versus a white number, but magenta certainly doesn't indicate insufficient fuel -- that is indicated by amber (source).

16 hours ago, MarsVenus said:

But when I tried to increase the fuel through the EFB the magenta fugure EFOB on the F-Pln page increases correspondingly. Shouldn't it decrease instead with the added amount of fuel?

The EFOB figure is the expected fuel on board at destination. If you load more fuel, you'll end up with more fuel left at your destination, so it's expected that the EFOB figure will increase.

8 hours ago, edhl said:

I'm not sure what a magenta EFOB number indicates versus a white number, but magenta certainly doesn't indicate insufficient fuel -- that is indicated by amber (source).

The EFOB figure is the expected fuel on board at destination. If you load more fuel, you'll end up with more fuel left at your destination, so it's expected that the EFOB figure will increase.

I think you are correct. The magenta EFOB in the A340-600 does not mean insufficient fuel. This is normally indicated by a -ve number instead. Thanks for the correction.

Also, make sure you import winds in your FCDU Initialization page. Having the correct winds does alter EFOB.