Fuel Required
Total fuel needed is the fuel-burn rate multiplied by flight time.
Formula
Variables
Example
10 gal/h for 2.5 h: F = 25 gal
How it works
This formula finds the total amount of fuel an aircraft will use by multiplying how quickly it burns fuel by how long it is operating. It works because fuel flow rate is measured as an amount per hour, so multiplying by hours cancels the time unit and leaves the total fuel consumed. In aviation planning, this gives a first estimate of how much fuel must be onboard to complete a flight segment.
When to use it
Use this when estimating fuel needed for a planned flight leg, taxi period, or other known-duration operation. It is especially useful for simple flight planning problems where the fuel burn rate is assumed constant.
Worked example, step by step
Given fuel flow rate \dot{f} = 18 gal/h and time t = 3 h F = \dot{f} \times t F = 18 \times 3 F = 54 gal Final answer: 54 gallons of fuel are required.
Common mistakes to avoid
- Using minutes instead of hours without converting the time first
- Confusing fuel flow rate with total fuel already onboard
- Forgetting that the units must match, such as gal/h times h giving gal
Did You Know?
Regulations require aircraft to carry reserve fuel beyond the trip — running the tanks dry is never an option.
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