Originally Posted by
riqsid
Thanx alot for your replies. I fully understand the reasons for double sectors fuelling. But I thought i should put forward an example to make things clearer for me.
MTOW - 73500 kgs
MLW - 64500kgs
MZFW - 60500 kgs
Max Fuel Capacity - 15000 kgs
DOM - 35000 kgs
Q1 - For a flight which requires 12000kgs of fuel, of which the burn-off is
5000kgs, what is the maximum payload that can be carried?
Answer - 22500 kgs
At TO: max payload = 73500 - 12000 - 35000 = 26500
At LDG : max payload = 64500 - (12000-5000) - 35000 = 22500
Respecting ZFW : max payload = 60500-35000 = 25500
Lowest value applies : max payload 22500
Q2 - If the payload is 15000kgs, what is the maximum fuel that can be
carried if the burn-off is 3000kgs?
Answer - 17500 kgs ( Pls indicate if ans correct or wrong)
At TO: max fuel = 73500 - 15000 - 35000 = 23500
At LDG : max fuel = 64500 - 15000 - 35000 = 14500 hence max +3000 = 17500 at TO
Respecting fuel volume : max fuel = 15000
Lowest value applies :
max fuel loaded at TO = 15000
Q3 - What is the maximum theoretical payload ?
Answer - 25500 kgs ( Pls indicate if ans correct or wrong)
Respecting ZFW : max payload = 60500-35000 = 25500
assuming no fuel constraints
Q4 - Double sector fuel is 14000kgs, Burn-off for the first sector is
8000kgs. Can a payload of 25000kgs be carried ? if not how much ?
(Pls answer for me with explanation. Thanks)
First sector, TO fuel 14000, LDG fuel 14000-8000=6000
Assuming 25000 payload:
TOM = 25000 + 14000 + 35000 = 74000 which is above MTOW so cannot go.
max payload to respect first sector MTOW is 73500-14000-35000 = 24500
max payload to respect first sector MLW is 64500-6000-35000 = 23500
So, based on first sector, max payload is 23500
Second sector has less fuel, so will be less restricted for payload, therefore double sector max payload is as determined by sector #1, i.e. 23500
Q5 - For a flight with a burn off of 8000kgs and total fuel requirements of 15000kgs, can the maximum theretical payload be carried? If not how much is the restricted ZFW?
Answer - No, restricted ZFW - 57500 ( Pls indicate if ans correct or wrong)]
TOfuel 15000, MTOW 73500 so max ZFW at TO = 73500-15000 = 58500
LDG fuel = (1500-8000)=7000, MLW = 64500 so max ZFW at LDG = 64500-7000 = 57500
MZFW 60500
Most restrictive applies i.e. 57500 as constrained on landing.