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## Fuel Calculation

• jukzizy
• Topic Author
• Away
• Posts: 154

### jukzizy created the topic: Fuel Calculation

if your charter flight time from departure to destination is 104 minutes and destination to alternate is 42 minutes, what is the minimum fuel requirement at start up if the fuel flow is 85 litres/hr and taxi is 15 litres?

Sir could you just confirm if my calculation is ok..

(104×85)÷60=147 litres
Flight fuel- 147 litres
variable 1.1
Fixed(45mins × 85)÷60= 64 litres
alternate- (42mins×85)÷60= 60 litres
Taxi- 15 litres

FOD@start up- 300.7 litres

please check if i'm doing it right or missing something..

Thank you

• John.Heddles
• Offline
• ATPL/consulting aero engineer
• Posts: 454

### John.Heddles replied the topic: Fuel Calculation

Looks fine.

As a suggestion, you might like to carry all your calculations to one decimal more than the final answer requires. So, for instance, should you want to obtain a final answer to the nearer litre, it would be appropriate to calculate (and carry forward) intermediate calculations to the first decimal point. In this way you minimise the effects of round off errors being carried through and muddying your final answer, somewhat.

There is little point in rounding off to the nearer litre for intermediate calculations and then providing the final answer to the first decimal (300.7). Were you to calculate to the first decimal throughout, you would end up with something closer to 300.3.

Engineering specialist in aircraft performance and weight control.

• jukzizy
• Topic Author
• Away
• Posts: 154