I have no idea why you are calculating MZFW plus required burn. All I can think is to check that this figure does not exceed your RTOW because then you just can't go at all.
In general, the way I do it is this.
The difference between max landing weight and max zero fuel weight is the absolute most fuel I can plan to land with while still providing the company with maximum payload. If I know the payload then I can increase the extra fuel to the difference between MLW and actual ZFW. If I have a rough idea of the payload but it may change a little, then I would use the difference between MLW and actual ZFW but with a bit of a buffer.
On my type, the vast majority of the time, the difference between MLW and MZFW is ample arrival fuel, so I can usually take the fuel I want and preserve max payload.
In your example, if you take 1.9T extra then yes, you are at your landing weight limit and can't take any extra payload.
Originally Posted by
carnival30
Thanks for the replies.
If we take 1.9 tons of extra in this case so basically we are limited to our 'planned' zfw which means we can not take any more extra load? 13.5+61.0+1.9= 76.4 (minus burn off gives us 66.4). We are absolutely limited by planned zfw. No additional LMC. Whereas if we took 1.7 tons extra that is (max zfw minus req) we could get 0.2 extra load? I am with the consideration of max ldg wt to be the limiting factor GIVEN we will not exceed planned zfw. My calculations,
(LDG wt + b/o) - planned zfw - req fuel = max fuel that can be uplifted
My another question is then why are we calculating Max ZFW plus Req fuel