Ok so i have been runing  TOPCAT and it has been a wonderful tool    Please look at PIC  because being of by 10 + KG  is not an easy thing 

 

 

So which number is correct ?? I cant imagine that TOPCAT is off By 10,000 kg

 

Firas

Topcat is NOT a fuel-planning tool. The fuel figures are just rough estimates (not taking into account weather, route, traffic, holding, etc...). If you want a professional (fuel)planning tool get PFPX from the same developer.

So which number is correct ?? I cant imagine that TOPCAT is off By 10,000 kg

 

I can!

 

Why?

 

TOPCAT isn't a fuel planner.  It was never meant to be.  The only reason that field is there is so that you can get a notional weight value to see if you're within limits for takeoff, prior to getting actual numbers later on from a more exact fuel calculation (not from TOPCAT).

 

Note TOPCAT has no fields for cruise altitude, wind speed/direction (or even average wind component), type of cruise (cost index, LRC, constant Mach, etc), and other factors.  Those are all important to fuel planning, but they're not there.  Again, that's because TOPCAT isn't meant to plan fuel.  At all.  Ever.

 

If you're okay with notional values, they work most of the time, but in that case you simply have to accept the inexact nature of the value.

 

Always understand the program you're working with:

Thanks to both of you   But so far topcat has been doing very good with fuel  , I was Just very surprised  when i say 10,000 kg different  

 

many thanks   I would Like to get  PFPX  But this will make no sense for me since i already use EFB for my routing , so i am ok with EFB  and using the free Fuel Planer i found here on the Forum 

 

Firas